descon internship report

1
INTERNSHIP REPORT
ACKNOWLEDGEMENT
My internship was started by the refrence of Adnan Nawaz who was my senior in college
and now he is employee of Descon Engineering limited.He help me to start my internship
in QC Department of Descon engineering limited.
Other who helped me to completed my intrship in descon engineering limited is below
mentioned
1. Engr. Muhammad Sajid(Hod)
2. Engr. Sajid Manzoor
3. Engr. Almas Baig
4. Abrar Hussain(Cordinator of QA)
5. Engr. Hamd
6. Engr. Syed Sadit Ali
7. Engr. Bilal Mehmood
8. Engr. Binya Amin
9. Engr. Adnan Nawaz
10.Engr. M.Shahid
11.Engr. Muhammad Irfan
12.Engr. Sheraz
13.Engr. Rafaqat Ali

DESCON ENGINEERING LIMITED UOG Gujrat
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Abstract
My internship at LMW was a great motivating and educational experience. My supervisor
guided me about the working procedure of the organization and helped me understand the
team working of various departments of LMW. I was given various reading material on the
documentation and quality assurance & quality control procedures associated with a
project.
I was also assisted on types of material standards i.e. ASTM, ASME, TRD, EN etc. and
how they are of materials, management of material scrap or procured, generation of MTRs
of all the material used in manufacturing of a particular job and procedure of inspection
carried out by QA&QC engineers, third party inspectors, Authorized Inspector (ASME) and
clients.
I made myself familiar with all the welding procedures used in LMW, how they are used for
different kinds of materials, their differentiating involved in quality checking of a project. I
was told about the procurement of material, stamping from each other, consumables used
in welding procedures i.e. filler wires and electrodes etc., types of welding joints and
different welding position and how all this knowledge can be put together to yield a good
quality weld and consequently a good quality joint. I was also guided about the parameters
of acceptance or rejection of a welded joint through use of NDT and measures adopted to
overcome the defects of a joint.
My supervisor also assisted me in getting initial knowledge about the generation of non-
conformance report and how corresponding revision is done to the drawing.
We were made familiar with surface preparation techniques of sand/bead blasting,
passivation and painting/galvanizing processes, attachment of name plate and dispatch of
the manufactured product with its as-built drawing documents to the client.

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Chapters
1. Introduction
1.1DESCON
1.2Lahore Manufacturing Works (LMW)
1.3 Departments of LMW
1.4 QA & QC
2. Documentation
2.1 Preliminary Drawing
2.2 Quality Inspection Plan (QIP)
2.3 Weld book
2.4 Inspection Data Manual (IDM)
3. Role of QA/QC
3.1 Incoming Material Inspection
3.2 Material Standards
3.3 Material Store
4. Fabrication
4.1 Marking
4.2 Cutting
4.3 Rolling
4.4 Machining
5. Fitup & Welding
5.1 Welding Processes
5.2 Welding Procedure Specifications (WPS)
5.3 Procedure Qualification Report (PQR)
5.4 Weld Matrix
5.5 Welding Inspection

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6. Non-destructive Testing (NDT)
6.1 Dye Penetrant Testing (DPT)
6.2 Magnetic Particle Testing (MPT)
6.3 Radiographic Testing (RT)
6.4 Ultrasonic Testing (UT)
7. Finishing and Dispatch
7.1 Final inspection
7.2 surface preparation
7.3 Name Plate
7.4 Dispatch
7.5 Non-Conformance Report
8. Daily Activity Reportes
9. S-W-O-T Analysis
10. Conclusion and Recommendations
11. References

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Chapter # 1
Introduction
1.1 DESCON
It all started in a small one room office in Lahore. The pioneers of the company came from
a fertilizer plant. It was the entrepreneurial spirit of four people who had a vision of building
a lasting institution prominent for its professionalism and distinguished by the desire of
creating a world-class engineering powerhouse. Today that vision has come true and the
journey has been replete with significant strides forward in its history.
Descon's Headquarters is located in Lahore, Pakistan. The company is well-established in
United Arab Emirates, Saudi Arabia, Qatar and Kuwait with projects executed in Iraq,
Oman and Egypt as well. Joint ventures include Olayan Descon in Saudi Arabia, and
Presson Descon International Limited (PDIL).
General contracting is the core activity with large projects executed for owners/operators,
major EPC companies and International Oil Companies. This strength is vested in our
experienced project team and a large inventory of equipment. All operations have requisite
ISO, OHSAS and ASME certifications in addition to Descon's own QA/QC and HSE
standards.
Descon Engineering is part of DESCON group which has three major businesses viz.
Engineering, Chemicals & Power. Descon Engineering is a multi-dimensional engineering,
construction and manufacturing company operating in Pakistan and the Middle East. With
over 450 million man-hours of construction work executed in industrial and infrastructure
projects, Descon employs over 34000 professionals and other personnel.

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1.2 Lahore Manufacturing Works (LMW)
This is Descon Lahore Manufacturing Works (LMW), the largest private owned
manufacturing facility in Pakistan.
Some products of LMW are:
 Pressure Vessels.
 Columns
 Separators
 Dehydration Plants
 DEW Point Control Units
 Slug Catchers
 Skids
 Piping (Process & Power)
 Heat Exchangers including Air Cooler
 Heat Recovery Steam Generators (HRSG’s)
 Industrial & Package Type Boilers
 Storage Tanks
 Water& Waste Water Treatment Plant
 Stainless Steel Equipment
 Boozers

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 Steel Structure
 Towers
1.3 Departments Of LMW
LMW has various departments which are:
 Marketing
 Finance
 Procurement
 PMT (Process Management)
 PMT (Boiler Management)
 Operations Boiler Design
 Process Equipment Design
 QA/QC (Quality Assurance & Quality Control)
 Production
 E & C (Erection & Commissioning)
 E & I (Erection & Installation)
 Store
1.4 QA&QC
QA&QC is the department of Quality Assurance and Quality control. It crosschecks all the
activities being carried out at various steps in the Production Department to ensure that
the job is produced in its best quality standards.
Quality assurance is based on process approach. Quality monitoring and its assurance
ensure that the processes and systems are developed and adhered in such a way that the
deliverables are of good quality. This process is meant to produce defect-free goods or
services which means being right the first time with no or minimum rework. Quality control
is product-based approach.
It has sub departments.
1. QC Material
2. QC Fabrication

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Chapter # 2
Documentation
It is basically all the paperwork associated with a product which is to be manufactured.
Documentation is a very important step in the construction as it can be kept on record by
the construction company to refer for assistance and problems in working of the product
faced by the client.
2.1 Drawings
Preliminary Drawings
Preliminary drawings are the initial plans for projects prepared by the designer or
architects and engineers firm during the early planning or promotional stage of the
building development. They provide a means of communication between the designer
and the user (customer). These drawings are not intended to be used for construction, but
they are used for exploring design concepts, material selection, preliminary cost estimates,
and approval by the client, and a basis for the preparation of finished working drawings.
As the project is received by a company, the design section of the company issues a
preliminary drawing for study by the client, production & QA&QC department. If the
drawing is approved by the client, it is sent to production department with issue for
construction (IFC).
Final Drawings
Final drawings are 100 percent complete, signed by the contracting officer, and
used forbidding purposes. This set of plans becomes official contract drawings once the
contract is awarded. Final drawings are often revised to show changes made by a scope
change or by a change order with the concurrence of both the engineer and client. At this
stage of completion, no further functional input may be introduced into the final drawings
because of time constraints. In general, final drawings, together with project
specifications, cost estimates, and all of the calculations, comprise the final stages of
design requirements.
As-Built Drawings

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These are the original contract drawings that you will change to show the as-built
conditions from the red-lined drawings. Upon completion of facilities, the
manufacturing engineer is required to provide the client with as-built drawings
indicating manufacturing deviations from the contract drawings. Allot the as-built
marked-up prints must reflect exactas-built conditions and show all features of the projects
constructed. The original contract drawings, corrected according to the marked prints,
provide a permanent record of as-built conditions upon completion of the instruction
work on a project.
2.2 Quality Inspection Plan (QIP)
The Quality Control Inspection Plan (QCIP) is the master document that controls the
quality of the project requirements. It can either control all sub contractors on site or
control each subcontractor individually. The QCIP must be in place and agreed by all
concerned parties prior to the commencement of any construction activities.
The requirements of the QCIP must identify the following:
 The quality targets to be achieved in relation to the customers projects technical
and contractual requirements.
 The specific assignments and responsibilities of the involved inspection parties.
 The specific procedures, methods and work instructions to be applied
 Methods for dealing with revisions and changes of the QCIP during the progress of
the project
 Reference to inspection check sheets for each manufacturing discipline
The purpose of an Inspection and Test Plan is to put together in a single document that
records all inspection and testing requirements relevant to a specific process. On a
manufacturing contract the process is likely to be a manufacturing activity, element of
work, trade work or providing a product section.
Hold Point
A 'hold' point defines a point beyond which work may not proceed without the authorization
of the customer of customer’s representative.
Third Part Testing Authority Surveillance
The customer of customer’s representative might be an agency's or other or a regulatory
authority (such as a council, Third Part Testing Authority Surveillance which is intermittent
monitoring of any stage of the work in progress (whether by the service provider or
customer).

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Self-inspection
It is where the service provider performing the work verifies the quality progressively often
with the aid of checklists.
Work area
IT is a discrete section of the whole work, usually defined by location, where any trade
work or activity would be completed before it moves onto another area.
2.3 Welding
The weld book contains all the documents for working procedures and specifications for a
job to be constructed. It contains various documents, which are:
 Weld Map
 Weld Matrix
 Working Procedure Specifications
 Procedure Qualifications Record
 Welder’s Qualification Test
 Continuity Lists
2.4 Inspection Data Manual
The IDM contain all the necessary documents that are to be provided to the client for its
safe use and operation. The documents included in IDM are given below:
I. Drawing as Built
II. Design Calculation
III. QIP
IV. Weld Map and Matrix
V. Welder Continuity
VI. MTR Summary Sheet (with MTC record)
VII. Dimension Inspection Report
VIII. NDT Personals
IX. NDT Reports
X. Hydro/Pneumatic Test
XI. Sandblasting/painting
XII. Name Plate
XIII. MDR
XIV. DCR’s
XV. NCR’s

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Chapter # 3
ROLE OF Incoming QA/QC
It involves all the materials being used in the manufacturing of a job, the material’s
specifications and certifications and it also involves the 3rd party concern.
Material control includes materials as received and also as processed. If necessary, a
complete supply chain assessment is possible. One area of particular importance in many
industries is in-process cleanliness validation.
3.1 Incoming Material Inspection:
Once the Design and Development phase is complete, the transfer of the design to
manufacturing can occur. Raw materials will be ordered and manufacturing can begin to
produce good quality product. But what if the materials that manufacturing receives are
substandard? Incoming Material Control is a vital because if substandard material enters
the manufacturing process, the burden of inspecting quality into the product becomes
greater
Development, installation and maintenance of inspection and procedures including sample
plans for determining acceptable levels of quality prior to use:
 Plans, procedures and facilities for handling discrepant material
 Efficient operation of incoming material quality assurance that does not cause
undue downtime
 Sufficient information concerning inspection and test results so corrective action
can be initiated, vendor rating programs and future purchasing decision should be
based on vendor performance history
 Economical statistical sampling procedures to appraise inventory quality, determine
deterioration rates, and provide feedback to design, purchasing, and production
which will aid in maximizing inventory serviceable life
To measure performance and efficiency of incoming material quality assurance,
measurements should be made. Performance measurements can include, % of incoming
lots rejected, lots reworked, lots sorted, lots returned to vendor, lots scrapped, time to
complete inspection, lots inspected per day, backlog of logs awaiting inspection, and
backlog of lots awaiting disposition. It is not always necessary to provide incoming
inspection on every item, but every item must be thoughtfully reviewed to determine if
such assurance is required or can be omitted. Omit incoming inspection by plan, not by
accident.

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Material inspection and assurance involves generation of MTRs. MTR refers to material
testing report. The MTR shows the percentage of alloy used in manufacture, the tensile
strength, the yield strength, reduction of area, elongation, and hardness of a sample piece
to represent the whole batch of a run of material. These reports are provided to the users
of a metal as verification that the material is of a certain grade. Of course, the material
must bear a heat number or some other kind of cross-reference-able marking to positively
identify that the paper refers to that pour or melt of material. To verify a test report, you
would need to do a PMI or positive material identification.
The MTR proves that the material we receive meets the grade we require. The
mechanical tests involve the following tests:
 Tensile test
 Bend Test
 Impact Test
 Hardness Test
Tensile Test
Tensile testing, also known as tension testing, is a fundamental materials science test in
which a sample is subjected to uniaxial tension until failure. The results from the test are
commonly used to select a material for an application, for quality control, and to predict
how a material will react under other types of forces. Properties that are directly measured
via a tensile test are ultimate tensile strength, maximum elongation and reduction in area.
From these measurements the following properties can also be determined: Young's
modulus, Poisson's ratio, yield strength, and strain-hardening characteristics.
Bend Test
The three point bending flexural test provides values for the modulus of elasticity in
bending Ef, flexural stress σf, flexural strain εf and the flexural stress-strain response of the
material. The main advantage of a three point flexural test is the ease of the specimen
preparation and testing. However, this method has also some disadvantages: the results
of the testing method are sensitive to specimen and loading geometry and strain rate.
Impact Test
An arm held at a specific height is released. The arm hits the sample and breaks it. From
the energy absorbed by the sample, its impact strength is determined.
Impact tests are used in studying 'toughness' of material , that is the ability of material to
absorb energy during plastic deformation because of high toughness the material have
strength and at the same time large durability . Brittle materials have low toughness

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means they have low plastic deformation. The impact value of material used also change.
The temperature of the material is directly proportional to impact value and size of
specimen is inversely proportional to the impact nature, so at lower temperature durability
of the material is decreased. It is of two types:
1. Charpy
2. Izod
Charpy impact test, also known as the Charpy v-notch test, is a standardized high strain-
rate test which determines the amount of energy absorbed by a material during fracture.
This absorbed energy is a measure of a given material's toughness and acts as a tool to
study temperature-dependent brittle-ductile transition. It is widely applied in industry, since
it is easy to prepare and conduct and results can be obtained quickly and cheaply. But a
major disadvantage is that all results are only comparative.
Izod impact strength testing is an ASTM standard method of determining impact
strength. A notched sample is generally used to determine impact strength. Impact is a
very important phenomenon in governing the life of a structure. In the case of aircraft,
impact can take place by the bird hitting the plane while it is cruising, during takeoff and
landing there is impact by the debris present on the runway
Hardness Test
It is used to measure hardness of outer surface and inner surface of a material. It can be
measured by various methods but the most commonly used methods are:
 Rockwell hardness test
 Brinell hardness test
 Vicker hardness test
Maintaining the traceability between the material and this paperwork is an important
quality assurance issue. QA often requires the heat number to be written on the pipe.
Precautions must also be taken to prevent the introduction of counterfeit materials. As a
backup to etching/labeling of the material identification on the pipe, Positive Material
Identification (PMI) is performed using a handheld device; the device scans the pipe
material using an emitted electromagnetic wave (x-ray fluorescence/XRF) and receives a
reply that is spectrographically analyzed.

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3.2 Material Standards:
The manufacturer performs these tests and reports the composition in a traceability
report and the mechanical tests in a material test report, both of which are referred to by
the acronym MTR. Material with these associated test reports is called traceable. For
critical applications, third party verification of these tests may be required; in this case an
independent lab will produce a certified material test report(CMTR), and the material will
be called certified.
DEL is already on its way to become a world class engineering company in the
international market as DEL has worked hard to maintain a well-known position in the
competitive regional market.
Some widely used standards are:
 ASTM
 ASME
 TRD
 CEN
ASTM International(ASTM), known as the American Society for Testing and Materials,
is an international standards organization that develops and publishes voluntary
consensus technical standards for a wide range of materials, products, systems, and
services.
The American Society of Mechanical Engineers (ASME) is a professional body,
specifically an engineering society, focused on mechanical engineering. The
organization is known for setting codes and standards for mechanical devices. The
ASME conducts one of the world's largest technical publishing operations through
its ASME Press, holds numerous technical conferences and hundreds of
professional development courses each year, and sponsors numerous outreach
and educational programs.
 SEC I (BOILERS)
 SEC II (MATERIALS)
 SEC IV (HEATING BOILERS)
 SEC V (NON DESTRUCTION TESTING)
 SEC VI (MAINTENANCE CARE & OPERATION OF HEATING BOILERS)
 SEC VII (CARE OF POWER BOILERS)

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 SEC VIII (BOILERS & PRESSURE VESSEL CODE)
 SEC IX (WELDING)
 SEC X (FIBER REINFORCED PLASTIC PRESSURE VESSELS)
 SEC XI (RULES FOR INSERNCE INSPECTION OF NUCLEAR POWER
PLANT COMPONENTS)
CEN is European Standard. It stands for Committee for European Standardization.
TRD is German standard. TRD stands for Technical Rules Directive.
3.3 Material Store:
Material store contains all the materials used for fabrication. The procured materials such
as smaller parts of boilers, heat exchangers, pressure vessels etc. are kept in store until
use. These parts are:
 Flanges
 Tees
 Elbow
 Gasket
 Weldolet
 Valves
 Beam
 Reducer
Flanges:
A flange is an external or internal ridge, or rim (lip), for strength, as the flange of an iron
beam such as an I-beam or a T-beam; or for attachment to another object, as the flange
on the end of a pipe, steam cylinder, etc. These are of following types:
 Long neck Flange
 Blind Flange
 Threaded Flange
 Slip-on Flange

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Reducer:
A reducer is the component in a pipeline that reduces the pipe size from a larger to a
smaller bore (inner diameter). It is of two types:
 Concentric
 Eccentric
Figure 3.3.1a Concentric Figure 3.3.1b Eccentric
Valves:
A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids,
fluidized solids, or slurries) by opening, closing, or partially obstructing various
passageways. These are of following types:
 Gate valve
 Globe valve
 Swing-check valves
 Butterfly valve
 Needle valve
Figure 3.3.2a Gate valve Figure 3.3.2b Globe valve

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Tees:
These are used for a connection of three directions in pipe
.
Figure 3.3.3 Tee
Elbow:
It is used for turns in a piping system.
Figure 3.3.4 Elbow

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Weldolet:
It is used for branching of small pipe on a large diameter pipe.
Figure 3.3.5 Weldolet
Gasket:
A gasket is a mechanical seal which fills the space between two or more mating surfaces,
generally to prevent leakage from or into the joined objects while under compression.
Figure 3.3.6 Gasket
Beam:
A beam is a horizontal structural element that is capable of withstanding load primarily by
resisting bending. It is of two types:
 I-beam
 H-beam

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Figure 3.3.7 Beam

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Chapter # 4
Production
Fabrication involves all the basic steps of cutting, rolling, drilling and machining required in
manufacturing of a job. It is done in layout section and workshop section of LMW. The
layout section is divided into four sections further which are:
 Bay 1 outside
 Bay 2 outside
 Bay 3 outside
 Bay 4 outside
The workshop section is also divided into four sections which are:
 Bay 1 inside
 Bay 2 inside
 Bay 3 inside
 Bay 4 inside
Fabrication is mainly concerned with the production department of LMW. The layout &
workshop contains many fabrication machines used for various purposes. The machines
include:
Shaper, Lathe, Planar, Drilling machine, Milling, Rolling machine and cold-cutting
machine.
4.1 Marking:
Marking is simply the process of marking the dimensions on the plates according to the
dimensions given in the drawing for corrective machining, cutting and drilling of plates or
sheets used in manufacturing of a job.
It is done by markers and measuring tools. The worker is then told to cut the pieces
according to the marked lengths and diameters of plates and grooves respectively.
It is the fundamental step in fabrication and we can’t skip this step at any cost.

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4.2 Cutting:
The common methods used in cutting metal are oxygas flame cutting and plasma-arc
cutting. The method used depends on the type of metal to be cut and the availability of
equipment.
Following cutting processes are being used in Descon Production Unit:
1. Plasma Arc Cutting
2. Gas Cutting
3. Cutting through Disk Cutter
Plasma Arc cutting
Plasma cutting is a process that is used to cut steel and other metals of different
thicknesses using a plasma torch. In this process, an inert gas (in some units,
compressed air) is blown at high speed out of a nozzle; at the same time an electrical arc
is formed through that gas from the nozzle to the surface being cut, turning some of that
gas to plasma. The plasma is sufficiently hot to melt the metal being cut and moves
sufficiently fast to blow molten metal away from the cut.
Figure 4.2.1 Plasma Arc Cutting
It works fast, do not require a preheat cycle, minimize the heat-affected zone and yields a
cut with a small kerf.
Process:
The HF Contact type uses a high-frequency, high-voltage spark to ionize the air through
the torch head and initiate an arc. These require the torch to be in contact with the job
material when starting, and so are not suitable for applications involving computer
numerical controlled (CNC) cutting.

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The Pilot Arc type uses a two cycle approach to producing plasma, avoiding the need for
initial contact. First, a high-voltage, low current circuit is used to initialize a very small high-
intensity spark within the torch body, thereby generating a small pocket of plasma gas.
This is referred to as the pilot arc. The pilot arc has a return electrical path built into the
torch head. The pilot arc will maintain itself until it is brought into proximity of the work
piece where it ignites the main plasma cutting arc. Plasma arcs are extremely hot and are
in the range of 25,000 °C (45,000 °F).
Plasma is an effective means of cutting thin and thick materials alike. Hand-held torches
can usually cut up to 2 inches (51 mm) thick steel plate, and stronger computer-controlled
torches can cut steel up to 6 inches (150 mm) thick. Since plasma cutters produce a very
hot and very localized "cone" to cut with, they are extremely useful for cutting sheet metal
in curved or angled shapes.
Gas Cutting
Flame cutting consists of a number of cutting processes used to cut metals by means of
the chemical reaction of oxygen with the base metal at elevated temperatures. The
required temperature is maintained by a flame obtained from the combustion of a specified
fuel gas mixed with pure oxygen.
A jet of pure oxygen is directed into the preheated area instigating a chemical reaction
between the oxygen and the metal to form iron oxide or slag, which the oxygen jet blows
away.
Flame cutting technology is still the principal process for cutting metal plate for most metal
processors. This process uses gases, propane, and oxygen to produce a controlled flame.
Applications are limited to carbon and low alloys steel. These materials can be cut
economically, and set up is simple and quick.
Figure 4.2.2 Gas Cutting

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Principle:
The initial combustion of the acetylene gas heats the steel to a molten state, then, by
adding a pressurized stream of oxygen, the steel is ignited and burned away through the
kerf of your cut. This is why this process is called burning steel and steel and carbon steel
are the only materials it is used to cut. Aluminum, stainless steel, and other metals and
alloys cannot be cut with a cutting torch.
Procedure:
 Ensure that the piece to be cut is positioned so that no part of the support is under
the cut line.
 Hold the torch close to the work; the bright-blue portion of the flame should touch
the edge of the area to be cut.
 Heat the work until the edge starts to glow. Small sparks may start to come off the
metal.
 Press down on the cutting lever and open it fully. Move the torch along the line you
want to cut. The speed of your movement will depend on the thickness of the metal
and the size tip on the torch. The proper speed will result in a continual stream of
sparks as the metal is cut. You should go as fast as you can to control the torch and
get continual cutting.
 Close the acetylene valve first, then the cutting tip oxygen.
 Close the tank valves.
 Open the acetylene valve on the torch to purge the gas from the hose, then press
the cutting lever to purge the oxygen hose. Close the oxygen valve on the torch
handle.
CNC cutting methods:
Plasma cutters have also been used in CNC machinery. Manufacturers build CNC cutting
tables, some with the cutter built in to the table. The idea behind CNC tables is to allow a
computer to control the torch head making clean sharp cuts. Modern CNC plasma
equipment is capable of multi-axis cutting of thick material, allowing opportunities for
complex welding seams on CNC welding equipment that is not possible otherwise. For
thinner material cutting, plasma cutting is being progressively replaced by laser cutting,
due mainly to the laser cutter's superior hole-cutting abilities.
Cutting through Disk Cutter:

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Cutting discs are often mounted to a variety of metal cutting machines, including handheld
rotary tools, grinders and cutoff saws. Metal cutting discs are made from abrasive
materials, such as diamond and tungsten carbide.
Figure 4.2.4 Cutting Discs
4.3 Rolling
To perform rolling process on a lead bar in order to observe the change in both the cross-
sectional area and the general shape.
Figure 4.3.1 Rolling Machine
The basic rolling mill consists of two opposite rotating rolls and is referred to as a two-high
rolling mill. In the three-high configuration, there are three rolls in a vertical column, and
the direction of rotation of each roll remains unchanged.
Rolling involves high complexity of metal flow during the process. From this point of view,
rolling can be divided into the following categories:

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1. Uniform reduction in thickness with no change in width: Here, the deformation is in
plane strain, that is, in the directions of rolling and sheet thickness. This type
occurs in rolling of strip, sheet, or foil.
2. Uniform reduction in thickness with an increase in width: Here, the material is
elongated in the rolling direction, is spread in the width direction, and is compressed
uniformly in the thickness direction. This type occurs in the rolling of blooms, slabs,
and thick plates.
3. Moderately non-uniform reduction in cross section: Here, the metal is elongated in
the rolling direction, is spread in the width direction, and is reduced non-uniformly in
the thickness direction.
4. Highly non-uniform reduction in cross section: Here, the reduction in the thickness
direction is highly non-uniform. A portion of the rolled section is reduced in
thickness while other portions may be extruded or increased in thickness. As a
result, in the width direction metal flow may be toward the center.
4.4 Machining
Conventional machining is a collection of material-working processes in which power-
driven machine tools, such as milling machines, lathes, and drill presses, are used with a
sharp cutting tool to mechanically cut the material to achieve the desired geometry.
Machining is a part of the manufacture of almost all metal products, and it is common for
other materials, such as wood and plastic, to be machined.
Milling:
It is the complex shaping of metal or other materials by removing material to form the final
shape. It is generally done on a milling machine, a power-driven machine that in its basic
form consists of a milling cutter that rotates about the spindle axis (like a drill), and a
worktable that can move in multiple directions (usually two dimensions [x and y axis]
relative to the work piece).
Lathe:
A lathe is a machine tool which spins a block or cylinder of material so that when abrasive,
cutting, or deformation tools are applied to the work piece, it can be shaped to produce an
object which has rotational symmetry about an axis of rotation.

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Turning:
Turning is a metal cutting process for producing a cylindrical surface with a single point
tool. The work piece is rotated on a spindle and the cutting tool is fed into it radially, axially
or both. Producing surfaces perpendicular to the work piece axis is called facing.
Producing surfaces using both radial and axial feeds is called profiling.
The turning tool material must be harder than the material being turned in order for the
process to work. Production rates for this process depend on the object being turned and
the speed at which it can be done. More complex materials, therefore, will take more time.
Threading:
There are many threading processes including: cutting threads with a tap or die, thread
milling, single-point thread cutting, thread rolling and forming, and thread grinding. A tap is
used to cut a female thread on the inside surface of a pre-drilled hole, while a die cuts a
male thread on a preformed cylindrical rod.
Grinding:
Grinding uses an abrasive process to remove material from the work piece. A grinding
machine is a machine tool used for producing very fine finishes, making very light cuts, or
high precision forms using an abrasive wheel as the cutting device. This wheel can be
made up of various sizes and types of stones, diamonds or inorganic materials.
Filing :
A file is an abrasive surface like this one that allows machinists to remove small, imprecise
amounts of metal.
Filing is combination of grinding and saw tooth cutting using a file. Prior to the
development of modern machining equipment it provided a relatively accurate means for
the production of small parts, especially those with flat surfaces.
Drilling:
Drilling is a cutting process that uses a drill bit to cut or enlarge a hole in solid materials.
The drill bit is a multipoint, end cutting tool. It cuts by applying pressure and rotation to the
work piece, which forms chips at the cutting edge. Drilled holes are characterized by their
sharp edge on the entrance side and the presence of burrs on the exit side (unless they
have been removed). Also, the inside of the hole usually has helical feed marks.

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Chapter#5
Fitup & Welding
Fitup:
Fitup is also carried out in layout. By fitup we actually mean the setting of parts and
holding them together for various processes. It is most commonly done for welding
process.
Often used to refer to the manner in which two members are brought together to be
welded, such as the actual space or any clearance or alignment between two members to
be welded.
Proper fit-up is important if a good weld is to be made. Tacking, clamping or fixturing is
often done to ensure proper fit-up.
Where it applies, base metal must be beveled correctly and consistently. Also, any root
openings or joint angles must be consistent for the entire length of a joint.
An example of poor fit-up can be too large of a root opening in a V-groove butt weld which
can result in poor welding of the part.
Tack Welding
Tack welding is a vital part of a pressure vessel fabricated by welding. This is why the
ASME Boiler and Pressure Vessel Code requires qualification of the welding procedure
used for tack welding. The code requires the tack welding procedure to be qualified in
accordance with the referencing book section and Section IX the same as for other
weldments.
Procedure
A high heat input process may be selected for the welding, but the tack is applied by the
shielded metal arc welding process. The tack is a very rapid quench application and a
brittle, crack sensitive micro structure results usually at the root of the weld. The tack may
be subsequently pulled and stressed during the fitup operation with a resultant underbead
crack in the pressure retaining material at the root of the weld. Subsequent weld passes
with the high heat input process do not, generally, remove the cracks. In fact, the cracks
may propagate further into the base metal and/or weld metal during the subsequent
welding operations.
Tack welds are important! If the vessel is to be Post Weld Heat Treated (PWHT) the
Welding Procedure Specification (WPS) for the tack welding shall be qualified with PWHT.

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If the welding process is qualified with preheat, the tack weld shall be applied within the
preheat range qualified. This is why the code requires the tack weld to be applied following
a WPS that has been qualified in accordance with the requirements of Section IX of the
code.
Tack welds made at the root of a groove weld must be qualified by a groove weld test in
accordance with the requirements of Section IX. Tack welds of the fillet type may be
qualified by a groove weld test or fillet weld test in full compliance with the requirements of
Section IX.
The code requires the tack welding to be applied following a qualified WPS whether it is
removed, left in place or incorporated into the weld. Tack welding to a qualified WPS is
required for any code tack weld including attachments such as backing strips, legs,
saddles, lifting lugs, reinforcing rings, thermometer wells, etc. There is at least one
exception to this. Section VIII, UW-28 and Section I, PW-28 state in part that procedure
qualification testing is not required for any machine welding process used for attaching no
pressure bearing attachments to pressure parts which have essentially no load carrying
function. Section IV has exceptions for stud welding.
Poorly applied tack welds are frequently the cause of entrapped slag, porosity, lack of full
penetration, leaks and cracks. This is why the ASME code requires tack welds to be
procedure and performance qualified and incorporated into the controlled manufacturing
system of the manufacturer for any code fabrication.
Qualify the tack weld procedure, qualify the tack welders performance and control the
application of the tack in accordance with your quality control program. A respected tack
weld may pay you back with dividends of which you may never have been aware. The
dividends may be no x-ray repairs, no leaks and no product failure.
Clamping & Fixturing
Clamping & fixturing is simply the act of setting up of parts for welding or other operations
or process.
In the case that the clamp is being tightened, this is when the objects being secured are
satisfactorily secured. If the clamp is being loosened, this is when a sufficient amount of
force is released to allow the secured objects to be moved.
It is done for sake of better hold of the metal work piece and to provide a stable platform
for the welding process to be performed to achieve good results.

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Welding:
Welding is a fabrication or sculptural process that joins materials, usually metals, by
causing coalescence. This is often done by melting the work pieces and adding a filler
material to form a pool of molten material (the weld pool) that cools to become a strong
joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the
weld.
Welding Processes:
There are five kinds of welding processes that currently being used in LMW. These are as
follows:
1. Submerged Arc Welding (SAW)
2. Flux Cored Arc Welding (FCAW)
3. Gas Metal Arc Welding (GMAW)
4. Shielded Metal Arc Welding (SMAW)
5. Gas Tungsten Arc Welding (GTAW)
Welding Positions:
1. Flat Welding Position
The flat welding position when welding like this is called the 1G or 1F. It is the most basic
and easiest welding position there is.
2.Horizontal Welding Position
The horizontal welding position is also referred to as the 2G or 2F. It is slightly harder to do
than the flat weld as gravity is trying to pull the molten metal down towards the ground. But
it is still easy to do.
3.Vertical Welding Position
This is called the 3G or 3F, and you can go up or down. Going up in this position is called
the vertical up weld and going down is the vertical down weld.
The vertical down weld is way easier than going up, but it only has limited penetration.
4. Overhead Welding Position
The overhead welding position is just that, overhead. The welding position here is also
referred to as the 4G or 4F

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.
5. Welding Position at 90 Degree
This welding is done at 90 degrees angle. It is commonly referred as 5G.
6. Inclined Welding Position of 45 Degree
This welding is done at 45 degrees angle and referred as 6G.
5G and 6G pipe are applicable in the fabrication and installation of piping and pipelines for
industrial plants, oil and gas industry, chemical plants and other industry which uses piping
and pipelines.
7. Inclined Welding Position with Restricted Ring
In this welding position the job is inclined at any angle other than 90 degree and 45
degrees. It is refereed as 6GR. 6GR is applicable mainly in the fabrication and installation
of offshore structure and other structure
Types of joints:
 Butt weld
 Socket weld
 Fillet weld
 Plug weld
 Edge weld
 Compound weld
5.1 Welding Processes
a. Submerged Arc Welding (SAW)

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Submerged arc welding (SAW) is a common arc welding process. It requires a
continuously fed consumable solid or tubular (flux cored) electrode. The molten weld and
the arc zone are protected from atmospheric contamination by being “submerged” under a
blanket of granular fusible flux consisting of lime, silica, manganese oxide, calcium
fluoride, and other compounds. When molten, the flux becomes conductive, and provides
a current path between the electrode and the work. This thick layer of flux completely
covers the molten metal thus preventing spatter and sparks as well as suppressing the
intense ultraviolet radiation and fumes that are a part of the shielded metal arc welding
(SMAW) process.
Figure 5.1.1 SMAW
SAW is characterized by its blackish gray color and very fine sharp angular ripples.
Features
Electrode
SAW filler material usually is a standard wire as well as other special forms. This wire
normally has a thickness of 1/16 in. to 1/4 in. (1.6 mm to 6 mm). In certain circumstances,
twisted wire can be used to give the arc an oscillating movement. This helps fuse the toe
of the weld to the base metal.
Key SAW process variables
 Wire feed speed (main factor in welding current control)

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 Arc voltage
 Travel speed
 Electrode stick-out (ESO) or contact tip to work (CTTW)
 Polarity and current type (AC or DC) & variable balance AC current
Material applications
 Carbon steels (structural and vessel construction)
 Low alloy steels
 Stainless steels
 Nickel-based alloys
 Surfacing applications (wear-facing, build-up, and corrosion resistant overlay of steels)
Advantages
 High deposition rates (over 100 lb/h (45 kg/h) have been reported).
 High operating factors in mechanized applications.
 Deep weld penetration.
 Sound welds are readily made (with good process design and control).
 High speed welding of thin sheet steels up to 5 m/min (16 ft/min) is possible.
 Minimal welding fume or arc light is emitted.
 Practically no edge preparation is necessary.
 The process is suitable for both indoor and outdoor works.
 Distortion is much less.
 Welds produced are sound, uniform, ductile, corrosion resistant and have good impact
value.
 Single pass welds can be made in thick plates with normal equipment.
 The arc is always covered under a blanket of flux, thus there is no chance of spatter of
weld.
 50% to 90% of the flux is recoverable.
Limitations
 Limited to ferrous (steel or stainless steels) and some nickel based alloys.
 Normally limited to the 1F, 1G, and 2F positions.
 Normally limited to long straight seams or rotated pipes or vessels.
 Requires relatively troublesome flux handling systems.
 Flux and slag residue can present a health & safety concern.
 Requires inter-pass and post weld slag removal.
b. Flux Cored Arc Welding (FCAW)
Flux-cored arc welding (FCAW or FCA) is a semi-automatic or automatic arc welding
process. FCAW requires a continuously-fed consumable tubular electrode containing a
flux and a constant-voltage or, less commonly, a constant-current welding. An externally

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supplied shielding gas is sometimes used, but often the flux itself is relied upon to
generate the necessary protection from the atmosphere. The process is widely used in
manufacturing because of its high welding speed and portability.
The advantage of FCAW over SMAW is that the use of the stick electrodes used in SMAW
is unnecessary. This helped FCAW to overcome many of the restrictions associated with
SMAW.
Figure 5.1.2 FCAW
FCAW is characterized by its blackish color and shiny surface with little or no
ripples seen.
Process variables
 Wire feed speed (and current)
 Arc voltage
 Electrode extension
 Travel speed and angle
 Electrode angles
 Electrode wire type
 Shielding gas composition (if required) Note: FCAW wires that don't require a shielding
gas commonly emit fumes that are extremely toxic; these require adequate ventilation
or the use of a sealed mask that will provide the welder with fresh air.
Advantages

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 FCAW may be an "all-position" process with the right filler metals (the consumable
electrode)
 No shielding gas needed making it suitable for outdoor welding and/or windy conditions
 A high-deposition rate process (speed at which the filler metal is applied) in the
1G/1F/2F
 Some "high-speed" (e.g., automotive applications)
 Less precleaning of metal required
 Metallurgical benefits from the flux such as the weld metal being protected initially from
external factors until the flux is chipped away
Application
Used on the following alloys:
 Mild and low alloy steels
 Stainless steels
 Some high nickel alloys
 Some wear facing/surfacing alloys
Disadvantages
Of course, all of the usual issues that occur in welding can occur in FCAW such as
incomplete fusion between base metals, slag inclusion (non-metallic inclusions), and
cracks in the welds. But there are a few concerns that come up with FCAW that are worth
taking special note of:
 Melted Contact Tip – happens when the electrode actually contacts the base metal,
thereby fusing the two
 Irregular wire feed – typically a mechanical problem
 Porosity – the gases (specifically those from the flux-core) don’t escape the welded
area before the metal hardens, leaving holes in the welded metal
 More costly filler material/wire as compared to GMAW.

c. Gas Metal Arc Welding (GMAW)
Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas
(MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc
welding process in which a continuous and consumable wire electrode and a shielding gas
are fed through a welding gun. A constant voltage, direct current power source is most
commonly used with GMAW, but constant current systems, as well as alternating current,
can be used. There are four primary methods of metal transfer in GMAW, called globular,

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short-circuiting, spray, and pulsed-spray, each of which has distinct properties and
corresponding advantages and limitations.
Figure 5.1.3 GMAW
GMAW is characterized by its grayish color appearance. and U-shaped ripples
Process Fundamentals
 Automatic feeding of continuous, consumable electrode shielded by externally
supplied gas.
 Automatic self-regulation of arc characteristics.
 Manual control
1. Travel speed
2. Direction
3. Gun positioning
 Welding gun
 Cable assembly
 Electrode feed unit
 Power supply
Equipment

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To perform gas metal arc welding, the basic necessary equipment is a welding gun, a wire
feed unit, a welding power supply, an electrode wire, and a shielding gas supply.
Welding gun and wire feed unit
The typical GMAW welding gun has a number of key parts—a control switch, a contact tip,
a power cable, a gas nozzle, an electrode conduit and liner, and a gas hose. The control
switch, or trigger, when pressed by the operator, initiates the wire feed, electric power, and
the shielding gas flow, causing an electric arc to be struck. The contact tip, normally made
of copper and sometimes chemically treated to reduce spatter, is connected to the welding
power source through the power cable and transmits the electrical energy to the electrode
while directing it to the weld area. It must be firmly secured and properly sized, since it
must allow the passage of the electrode while maintaining an electrical contact. Before
arriving at the contact tip, the wire is protected and guided by the electrode conduit and
liner, which help prevent buckling and maintain an uninterrupted wire feed. The gas nozzle
is used to evenly direct the shielding gas into the welding zone and if the flow is
inconsistent, it may not provide adequate protection of the weld area. Larger nozzles
provide greater shielding gas flow, which is useful for high current welding operations, in
which the size of the molten weld pool is increased. The gas is supplied to the nozzle
through a gas hose, which is connected to the tanks of shielding gas. Sometimes, a water
hose is also built into the welding gun, cooling the gun in high heat operations. The wire
feed unit supplies the electrode to the work, driving it through the conduit and on to the
contact tip.
Limitations
 Equipment is more complex, costly and less portable than SMAW.
 GMAW is more difficult to use in hard to reach areas. Welding gun must be close
to joint for proper shielding of weld metal.
 Air drafts disperse shielding gas and hence it is not suited for outdoor applications.
 Comparatively higher radiated heat and arc intensity and so operator at risk
d. Shielded Metal Arc Welding (SMAW)
Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding, flux
shielded arc welding or informally as stick welding, is a manual arc welding process that
uses a consumable electrode coated in flux to lay the weld. An electric current, in the form
of either alternating current or direct current from a welding power supply, is used to form
an electric arc between the electrode and the metals to be joined. As the weld is laid, the
flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas
and providing a layer of slag, both of which protect the weld area from atmospheric
contamination.

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Because of the versatility of the process and the simplicity of its equipment and operation,
shielded metal arc welding is one of the world's most popular welding processes. It
dominates other welding processes in the maintenance and repair industry, and though
flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in
the manufacturing of steel structures and in industrial fabrication. The process is used
primarily to weld iron and steels (including stainless steel) but aluminum, nickel and
copper alloys can also be welded with this method.
Figure 5.1.4 SMAW
SMAW is characterized by its blackish gray color with sharp U-shaped ripples with a
very fine overall appearance.
Application and materials
Shielded metal arc welding is one of the world's most popular welding processes,
accounting for over half of all welding in some countries. Because of its versatility and
simplicity, it is particularly dominant in the maintenance and repair industry, and is heavily
used in the manufacturing of steel structures and in industrial fabrication. In recent years
its use has declined as flux-cored arc welding has expanded in the manufacturing industry
and gas metal arc welding has become more popular in industrial environments. However,
because of the low equipment cost and wide applicability, the process will likely remain
popular, especially among amateurs and small businesses where specialized welding
processes are uneconomical and unnecessary.
SMAW is often used to weld carbon steel, low and high alloy steel, stainless steel, cast
iron, and ductile iron. While less popular for nonferrous materials, it can be used on nickel
and copper and their alloys and, in rare cases, on aluminum.

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e. Gas Tungsten Arc Welding (GTAW)
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an
arc welding process that uses a no consumable tungsten electrode to produce the weld.
The weld area is protected from atmospheric contamination by a shielding gas (usually an
inert gas such as argon), and a filler metal is normally used, though some welds, known as
autogenously welds, do not require it.
A current welding produces energy which is conducted across the arc through a column of
highly ionized gas and metal vapors known as a plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous
metals such as aluminum, magnesium, and copper alloys. The process grants the
operator greater control over the weld than competing processes such as shielded metal
arc welding and gas metal arc welding, allowing for stronger, higher quality welds.
However, GTAW is comparatively more complex and difficult to master, and furthermore, it
is significantly slower than most other welding techniques. A related process, plasma arc
welding, uses a slightly different welding torch to create a more focused welding arc and
as a result is often automated.
Figure 5.1.5 GTAW
GTAW is characterized by its fish-like welding appearance of grayish color.

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Operation
Manual gas tungsten arc welding is often considered the most difficult of all the welding
processes commonly used in industry. Because the welder must maintain a short arc
length, great care and skill are required to prevent contact between the electrode and the
work piece. Similar to torch welding, GTAW normally requires two hands, since most
applications require that the welder manually feed a filler metal into the weld area with one
hand while manipulating the welding torch in the other. However, some welds combining
thin materials (known as autogenously or fusion welds) can be accomplished without filler
metal; most notably edge, corner, and butt joints.
Welders often develop a technique of rapidly alternating between moving the torch forward
(to advance the weld pool) and adding filler metal. The filler rod is withdrawn from the weld
pool each time the electrode advances, but it is never removed from the gas shield to
prevent oxidation of its surface and contamination of the weld. Filler rods composed of
metals with low melting temperature, such as aluminum, require that the operator maintain
some distance from the arc while staying inside the gas shield. If held too close to the arc,
the filler rod can melt before it makes contact with the weld puddle. As the weld nears
completion, the arc current is often gradually reduced to allow the weld crater to solidify
and prevent the formation of crater cracks at the end of the weld.
Advantages
 Superior quality welds.
 Spatter minimization.
 Excellent control of root pass weld penetration
 High speed.
 Very versatile joining technique.
 Independent control of heat source & filler metal additions.
Disadvantages
 Lower deposition rates in comparison to consumable arc welding processes.
 More dexterity required on part of operator
 Not suitable in drafty environments.
 Tungsten inclusions can occur if electrode contacts weld pool.
 Improper gas shielding of filler metal can cause contamination of weld metal.
 Possible contamination due to coolant leakage from water cooled torches.

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 Arc blow/deflection as with other processes.

5.2 Welding Procedure Specifications
A Welding Procedure Specification (WPS) is a formal document describing welding
procedures. The purpose of the document is to guide welders to the accepted procedures
so that repeatable and trusted welding techniques are used. A WPS is developed for each
material alloy and for each welding type used. Specific codes and/or engineering societies
are often the driving force behind the development of a company's WPS. A WPS is
supported by a Procedure Qualification Record (PQR or WPQR).
According to the American Welding Society (AWS), a WPS provides in detail the required
welding variables for specific application to assure repeatability by properly trained
welders. The AWS defines welding PQR as a record of welding variables used to produce
an acceptable test weldment and the results of tests conducted on the weldment to qualify
a Welding Procedure Specification.
The American Society of Mechanical Engineers (ASME) similarly defines a WPS as a
written document that provides direction to the welder or welding operator for making
production welds in accordance with Code requirements. ASME also defines welding PQR
as a record of variables recorded during the welding of the test coupon. The record also
contains the test results of the tested specimens.

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Figure 5.2.1 WPS
5.3 Procedure Qualification Record
A PQR is a record of a test weld performed and tested (more rigorously) to ensure that the
procedure will produce a good weld. Individual welders are certified with a qualification test
documented in a Welder Qualification Test Record (WQTR) that shows they have the
understand.

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Figure 5.3.1 PQR

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FIGURE 5.3.2 PQR

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5.4 Weld Matrix
To support the welding QA/QC process, weld matrix is a comprehensive weld procedure
management document, which catalogues and controls all associated weld procedure
documents (PQR, WPP & WPS) and assists in the working procedure of welding.
Figure 5.4.1 Weld Matrix

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Figure 5.4.2 Weld Matrix

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5.5 Welding Inspection
Welding inspection involves observing the defects of welding visually or through NDT. A
welding defect is any flaw that compromises the usefulness of the finished weldment. A
good weld will have least defects.
Types of Defects
1. External Defects
They can be identified by a visual inspection method.
2. Internal Defects
These require a Non-Destructive testing (NDT) method e.g.: RT or Ultrasonic testing.
Main Causes:
 Welding operators carelessness or lack of skill
 Adverse working conditions
 Poor Design or lack of preparation
Main Defects:
 Undercut
 Lack of fusion.
 Slag inclusions
 Incomplete penetration
 Porosity
 Weld cracking
 Overlap or over-roll
 Joint Misalignment
 Cracks

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Undercut
I groove at the toe or root of a weld either on the weld face or in previously deposited weld
metal.
Causes
 Excessive amperage.
 Too long an arc length.
 Excessive weaving of the electrode.
 Too fast a rate of travel.
 Angle of electrode too inclined to the joint face.
Result
A stress concentration site and a potential site for fatigue
Over-lap or Over-roll
An imperfection at the toe or root of a weld caused by metal flowing onto the surface of the
parent metal without fusing to it.
Causes
 Incorrect rate of travel.
 Incorrect “angle of approach”.
 Too large an electrode size.
 Too low an amperage.
Result
Has a similar effect as undercut and produces a stress concentration site due to the
unfused weld metal.

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Slag Inclusions
Refers to any non-metallic material in a completed weld joint. These inclusions can create
a weak point in the weld deposit.
Causes
 Failure to remove slag from previous runs.
 Insufficient amperage.
 Incorrect electrode angle or size.
 Faulty preparation.
Result
Slag inclusions reduce the cross sectional area strength of the weld and serve as a
potential site for cracking.
Porosity
A hole or cavity found internally or externally in the weld. Porosity can originate from wet
electrodes, electrode flux breaking down or from impurities on the surface of the parent
metal. Also known as “Blow or Worm Holes”
Other Causes
 Unclean parent metal surface i.e. oil, dust, dirt or rust contamination.
 Incorrect electrode for parent metal.
 Inadequate gas shielding of the arc.
 Parent metals with a high percentage of sulphur and phosphorus.
Result
Severely reduces the strength of the welded joint. Surface porosity can allow a corrosive
atmosphere to attack the weld metal which may cause failure.
Lack of Fusion
A lack of bonding between the weld metal and the parent metal or between weld metal
passes.

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Causes
 Small electrodes used on cold and thick steel.
 Insufficient amperage.
 Incorrect electrode angle and manipulation.
 Rate of travel too fast, not allowing proper fusion.
 Unclean surface (mill scale, dirt, grease etc.).
Result
Weakens the welded joint and becomes a potential fatigue initiation site.
Incomplete Penetration
A failure of the weld metal to penetrate into the root of the join.
Causes
 Current too low.
 Insufficient root gap.
 Too large an electrode size.
Result
Weakens the welded joint and becomes a potential fatigue initiation site.
Weld Cracking
Planar (Two Dimensional) discontinuities produced by the tearing of parent or weld metal.
Weld metal cracking can occur in either the plastic condition (hot shortness) or by
fracturing when cold (cold shortness). There are many types of cracks that can occur in
the base.
Some common types of cracking include:
1. Crater Cracking
Hot cracking is mainly caused by a failure to fill up the crater depression at the end of a
weld pass. Shrinkage stresses and inadequate weld metal in the crater causes crater
cracking.

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2. Underbead Cracks
Cold cracking that is usually in the heat-affected zone (HAZ) of the parent metal.
3. Longitudinal Crack
It is usually a hot cracking phenomenon. Cracking runs along the length of the weld.
Misalignment
Normally defined as an unnecessary or unintentional variation in the alignment of the parts
being welded. Misalignment is a common fault in prepared butt welds, and is produced
when the root faces of the parent plate (or joint) are not placed in their correct position for
welding.
Causes
 Poor assembly of the parts to be welded.
 Inadequate tack welds that break or insufficient clamping that results in movement.
Result
Misalignment is a serious defect since failure to melt both edges of the root will result in
stress concentration sites which in service may lead to premature fatigue failure of the
joint.

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Chapter#6
Non-destructive Testing
Nondestructive testing or Non-destructive testing (NDT) is a wide group of analysis
techniques used in science and industry to evaluate the properties of a material,
component or system without causing damage. The terms Nondestructive examination
(NDE), Nondestructive inspection (NDI), and Nondestructive evaluation (NDE) are also
commonly used to describe this technology. Because NDT does not permanently alter the
article being inspected, it is a highly-valuable technique that can save both money and
time in product evaluation, troubleshooting, and research. Common NDT methods include
ultrasonic, magnetic-particle, liquid penetrant, radiographic testing.
6.1 Dye-Penetrant Testing (DPT)
Dye penetrant testing (DPT), also called liquid penetrant inspection (LPI) or penetrant
testing (PT), is a widely applied and low-cost inspection method used to locate surface-
breaking defects in all non-porous materials (metals, plastics, or ceramics). The penetrant
may be applied to all non-ferrous materials and ferrous materials; although for ferrous
components magnetic-particle inspection is often used instead for its subsurface detection
capability. DPT is used to detect casting, forging and welding surface defects such as
hairline cracks, surface porosity, leaks in new products, and fatigue cracks on in-service
components.
Figure 6.1 DPT

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Principles
DPT is based upon capillary action, where low surface tension fluid penetrates into clean
and dry surface-breaking discontinuities. Penetrant may be applied to the test component
by dipping, spraying, or brushing. After adequate penetration time has been allowed, the
excess penetrant is removed, a developer is applied. The developer helps to draw
penetrant out of the flaw where a visible indication becomes visible to the inspector.
Inspection is performed under ultraviolet or white light, depending upon the type of dye
used - fluorescent or no fluorescent (visible). LMW uses non-fluorescent technique only.
DPT depends on
 Contact angle (angle should be <90 degree otherwise the dye wont wet the surface)
 Wettability
 Surface Tension
Inspection steps
Below are the main steps of Liquid Penetrant Inspection:
1. Pre-cleaning:
The test surface is cleaned to remove any dirt, paint, oil, grease or any loose scale that
could either keep penetrant out of a defect, or cause irrelevant or false indications... The
end goal of this step is a clean surface where any defects present are open to the surface,
dry, and free of contamination.
2. Application of Penetrant:
The penetrant is then applied to the surface of the item being tested. The penetrant is
allowed "dwell time" to soak into any flaws (generally 5 to 30 minutes). The dwell time
mainly depends upon the penetrant being used, material being testing and the size of
flaws sought. As expected, smaller flaws require a longer penetration time.
3. Excess Penetrant Removal:

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The excess penetrant is then removed from the surface. The removal method is controlled
by the type of penetrant used. Emulsifiers represent the highest sensitivity level, and
chemically interact with the oily penetrant to make it removable with a water spray. If
excess penetrant is not properly removed, once the developer is applied, it may leave a
background in the developed area that can mask indications or defects. In addition, this
may also produce false indications severely hindering your ability to do a proper
inspection.
4. Application of Developer:
After excess penetrant has been removed a white developer is applied to the sample.
Choice of developer is governed by penetrant compatibility and by inspection conditions.
Developer should form a semi-transparent, even coating on the surface.
The developer draws penetrant from defects out onto the surface to form a visible
indication, commonly known as bleed-out. Any areas that bleed-out can indicate the
location, orientation and possible types of defects on the surface. Interpreting the results
and characterizing defects from the indications found may require some training and/or
experience.
5. Inspection:
The inspector will use visible light with adequate intensity for visible dye penetrant.
Inspection of the test surface should take place after a 10 minute development time. This
time delay allows the blotting action to occur. The inspector may observe the sample for
indication formation when using visible dye. It is also good practice to observe indications
as they form because the characteristics of the bleed out are a significant part of
interpretation characterization of flaws.
6. Post Cleaning:
The test surface is often cleaned after inspection and recording of defects, especially if
post-inspection coating processes are scheduled.
Outcome
The dye penetrates into the crack making the crack surface and interior clearly visible to
the naked eye.

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6.2 Magnetic Particle Testing
Magnetic particle inspection (MPI) is a non-destructive testing (NDT) process for detecting
surface and subsurface discontinuities in ferroelectric materials such as iron, nickel,
cobalt, and some of their alloys. The process puts a magnetic field into the part. The piece
can be magnetized by direct or indirect magnetization. Direct magnetization occurs when
the electric current is passed through the test object and a magnetic field is formed in the
material. Indirect magnetization occurs when no electric current is passed through the test
object, but a magnetic field is applied from an outside source. The magnetic lines of force
are perpendicular to the direction of the electric current which may be either alternating
current (AC) or some form of direct current (DC) (rectified AC).
Figure 6.2.1 MPT
Types of electrical currents used
There are several types of electrical currents used in MPI. For a proper current to be
selected one needs to consider the part geometry, material, the type of discontinuity you're
looking for, and how far the magnetic field needs to penetrate into the part.
Alternating current (AC)
It is commonly used to detect surface discontinuities. Using AC to detect subsurface
discontinuities is limited due to what is known as the skin effect, where the current runs
along the surface of the part. Because the current alternates in polarity at 50 to 60 cycles
per second it does not penetrate much past the surface of the test object. This means the
magnetic domains will only be aligned equal to the distance AC current penetration into
the part. The Frequency of the Alternating Current decides how deep the penetration.
Direct current (DC, full wave DC)

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It is used to detect sub surface discontinuities where AC cannot penetrate deep enough to
magnetize the part at the depth needed. The amount of magnetic penetration depends on
the amount of current passed through the part. DC is also limited on very large cross
sectional parts how effective it will magnetize the part.
Half wave DC (HWDC or pulsating DC)
It works similar to full wave DC with slightly more magnetic penetration into the part.
HWDC is known to have the most penetrating ability in magnetic particle testing. HWDC is
advantageous for inspection process because it actually helps move the magnetic
particles over the test object so that they have the opportunity to come in contact with
areas of magnetic flux leakage. The increase in particle mobility is caused by the pulsating
current which vibrates the test piece and particles.
Each method of magnetizing has its pros and cons. AC is generally always best for
discontinuities open to the surface and some form of DC for subsurface.
Equipment
MPI uses a magnetic yoke which is a hand held devices that induces a magnetic field
between two poles. Common applications are for outdoor use, remote locations, and weld
inspection... For proper inspection the yoke needs to be rotated 90 degrees for every
inspection area to detect horizontal and vertical discontinuities. Yokes subsurface
detection is limited. These systems used dry magnetic powders and wet powders.
Magnetic particle powder
A common particle used to detect cracks is iron oxide, for both dry and wet systems.
Dry particle powders range in size from 5 to 170 micrometers, designed to be seen in
white light conditions. The particles are not designed to be used in wet environments. Dry
powders are normally applied using hand operated air powder applicators
Inspection
The following are general steps for inspecting on a wet horizontal machine:
 Part is cleaned of oil and other contaminants.
 Necessary calculations done to know the amount of current required to magnetize
the part.
 The magnetized yoke is placed on the job to be tested and is applied for 5 seconds
during which the operator washes the part with the particle, stopping before the
magnetic pulse is completed. Defects only appear that are 45 to 90 degrees the
magnetic field. So inspection can be time consuming to carefully look for indications
that are only 45 to 90 degrees from the magnetic field.

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 The part is either accepted or rejected based on pre-defined accept and reject
criteria
 The part is demagnetized.
 Depending on requirements the orientation of the magnetic field may need to be
changed 90 degrees to inspect for defects that cannot be detected.
6.3 Ultrasonic Testing (UT)
In ultrasonic testing (UT), very short ultrasonic pulse-waves with center frequencies
ranging from 0.1-15 MHz and occasionally up to 50 MHz are launched into materials to
detect internal flaws or to characterize materials. The technique is also commonly used to
determine the thickness of the test object, for example, to monitor pipework corrosion.
Figure 6.3.1 UT
Ultrasonic testing is often performed on steel and other metals and alloys, though it can
also be used on concrete, wood and composites, albeit with less resolution. It is a form of
non-destructive testing used in many industries including aerospace, automotive and other
transportation sectors.
In ultrasonic testing, an ultrasound transducer connected to a diagnostic machine is
passed over the object being inspected. The transducer is typically separated from the test
object by a couplant (such as oil) or by water, as in immersion testing.
Two types of probes are used:

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TR probe generate longitudinal waves
Angle beam probe generate shear waves
There are two methods of receiving the ultrasound waveform, reflection and attenuation. In
reflection (or pulse-echo) mode, the transducer performs both the sending and the
receiving of the pulsed waves as the "sound" is reflected back to the device. Reflected
ultrasound comes from an interface, such as the back wall of the object or from an
imperfection within the object. The diagnostic machine displays these results in the form of
a signal with an amplitude representing the intensity of the reflection and the distance,
representing the arrival time of the reflection. In attenuation (or through-transmission)
mode, a transmitter sends ultrasound through one surface, and a separate receiver
detects the amount that has reached it on another surface after traveling through the
medium. Imperfections or other conditions in the space between the transmitter and
receiver reduce the amount of sound transmitted, thus revealing their presence. Using the
couplant increases the efficiency of the process by reducing the losses in the ultrasonic
wave energy due to separation between the surfaces.
Types of waves are used by UT:
Longitudinal waves- for finding thickness
Shear waves- defect orientation
Features
 High penetrating power, which allows the detection of flaws deep in the part.
 High sensitivity, permitting the detection of extremely small flaws.
 Only one surface need be accessible.
 Greater accuracy than other nondestructive methods in determining the depth of
internal flaws and the thickness of parts with parallel surfaces.
 Some capability of estimating the size, orientation, shape and nature of defects.
 Non-hazardous to operations or to nearby personnel and has no effect on
equipment and materials in the vicinity.
 Capable of portable or highly automated operation.
Outcome
UT is performed usually for finding subsurface defects. It can also measure the thickness
of job and defect orientation.
6.4 Radiographic Testing

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Radiography is the use of ionizing radiation to see slag, porosity and undercuts in a
material job. Radiography has grown out of engineering, and is a major element of
nondestructive testing. It is a method of inspecting materials for hidden flaws by using the
ability of short X-rays and Gamma rays to penetrate various materials.
Gamma radiation sources, most commonly Iridium-192 and Cobalt-60, are used to inspect
a variety of materials. The radioactive source used in LMW is Iridium 192. Cobalt-60 is
used for very thick jobs but it is not generally used because of its toxicity. The vast majority
of radiography concerns the testing and grading of welds on pressurized piping, pressure
vessels, high-capacity storage containers, pipelines, and some structural welds. Other
tested materials include concrete (locating rebar or conduit), welder's test coupons,
machined parts, plate metal, or pipe wall (locating anomalies due to corrosion or
mechanical damage).
First of all we place the container containing radioactive element in front of the job to be
tested.. On the opposite side of the job, we place a photographic film. This exposure
arrangement is ideal - when properly arranged and exposed, all portions of all exposed
film will be of the same approximate density. It also has the advantage of taking less time
than other arrangements since the source must only penetrate the total wall thickness
once and must only travel the radius of the inspection item, not its full diameter.
The source does not come in direct contact with the item, but is placed a distance away,
depending on client requirements. In each case, the radiographic film is located on the
opposite side of the inspection item from the source. Only one wall is exposed, and only
one wall is viewed on the radiograph. The material is exposed for some time and then
photograph film is retrieved.
Before commencing a radiographic examination, it is always advisable to examine the
component with one's own eyes, to eliminate any possible external defects. If the surface
of a weld is too irregular, it may be desirable to grind it to obtain a smooth finish, but this is
likely to be limited to those cases in which the surface irregularities (which will be visible
on the radiograph) may make detecting internal defects difficult.
After this visual examination, the operator will have a clear idea of the possibilities of
access to the two faces of the weld, which is important both for the setting up of the
equipment and for the choice of the most appropriate technique.

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.Chapter#7
Final Inspection and Dispatch
7.1 Final Inspection
Visual & Dimensional Inspection
This involves analyzing the visual defects and carrying out dimensional check.
Visual test
It is basically performed to analyze that the built job needs further finishing or not.
Often the surface has slight defects like spatter of welds or small projections that can be
examined by eye. These kind of defects can be grinded to give a good surface finish.
Similarly, sometimes the surface has deep cuts which can be visually examined also.
These cuts are then buildup in which the surface is welded and then grinded to achieve a
defect free surface.
Dimensional Test
It is carried out to ensure proper designing of job and to check whether the dimensions of
the finished job are within dimensional tolerances. It involves the check using rulers and
metallic tapes and by various gauges for checking welding throat thickness and leg
thickness.
Hydro Testing
A hydrostatic test is a way in which leaks can be found in pressure vessels such as
pipelines and plumbing. The test involves placing water, which is often dyed for visibility, in
the pipe or vessel at the required pressure to ensure that it will not leak or be damaged. It
is the most common method employed for testing pipes and vessels. Using this test helps
maintain safety standards and durability of a vessel over time. Newly manufactured pieces
are initially qualified using the hydrostatic test. They are then continually re-qualified at

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regular intervals using the proof pressure test which is also called the modified hydrostatic
test. Hydrostatic testing is also a way in which a
gas pressure vessel, such as a gas cylinder or a boiler, is checked for leaks or flaws.
Testing is very important because such containers can explode if they fail when containing
compressed gas.
Testing procedures
Hydrostatic tests are conducted under the constraints of either the industry's or the
customer's specifications. The vessel is filled with a nearly incompressible liquid - usually
water or oil - and examined for leaks or permanent changes in shape. The test pressure is
always considerably higher than the operating pressure to give a margin for safety. This
margin of safety is typically 150% or 130% of the design pressure, depending on the
regulations that apply. Water is commonly used because it is almost incompressible
(compressible only by weight, not air pressure), so will only expand by a very small
amount should the vessel split. If pressure gas were used, then the gas would expand to
perhaps several hundred times its compressed volume in an explosion, with the attendant
risk of damage or injury. This is the risk which the testing is intended to mitigate.
Small pressure vessels are normally tested using a water jacket test. The vessel is visually
examined for defects and then placed in a container filled with water, and in which the
change in volume of the vessel can be measured by monitoring the water level. For best
accuracy, a digital scale is used to measure the smallest amounts of change. The vessel
is then pressurized for a specified period, usually 30 or more seconds, and then
depressurized again. The water level in the jacket is then examined. The level will be
greater if the vessel being tested has been distorted by the pressure change and did not
return to its original volume, or some of the pressurized water inside has leaked out. In
both cases, this will normally signify that the vessel has failed the test. If the Rejection
Elastic Expansion is more than 10%, or not up to customer standards, the cylinder fails,
and then goes through a condemning process marking the cylinder as unsafe. This
measures the overall leakage of a system instead of locating the leaks and additives can
be added to the water to reduce resistivity and increase the sensitivity of the test. The
hydrostatic test fluid can also clog small holes as a result of the increase in pressure. This
is another reason why water is commonly used.
All the information the tester needs is stamped onto the cylinder. This includes the
information, serial number, manufacturer, and manufacture date. Other information is
stamped as needed such as how much the manufacturer specifies the cylinder should
expand before it is considered unsafe. All this information is usually taken down and
stored on a computer prior to the testing process. All this information is necessary for
keeping track of when the cylinder has been or needs to be hydro tested.

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Pneumatic Testing
Pressure testing of a process vessel by the use of air pressure is called pneumatic testing.
It is a test for leaks in drainage systems, in soil, waste, and ventilating pipe systems, or in
ductwork; all openings are sealed, and compressed air is introduced into the system; air
leakage is indicated by means of a U-gauge or other suitable pressure gauge.
It is concerned with ASTM A1047 / A1047M - 05(2009) which is Standard Test Method for
Pneumatic Leak Testing of Tubing.
If pneumatic testing is to be undertaken, the quality management system manual must
describe the procedures to be followed to conduct the test in a safe manner. Provision
for pneumatic testing of piping systems up 1677 kJ of stored energy (equivalent to 500
liters internal volume and 2172 kPa internal pressure) may be included as a standard
testing procedure in the quality system.
Test Medium
The gas used as test medium shall use the nonflammable and nontoxic gas
such as N2 or inert gas, if not compressed air.
Test Pressure
The test pressure shall be 110% of design pressure. Equipment for testing
should be as following:
 Air Compressor
 Flexible hose
 Calibrated Pressure gauge
 Oil filter
 Temporary piping set
 N2 cylinder, if required
 Safety valve
Safety valve required for pneumatic testing, rapid opening or pop action
of over pressure, should be installed and connected with an adequate
system of piping not containing valve which can isolate tested system.

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Testing Preparations
 All joints, including welds, shall be accessible and left uninstalled, unpainted and
exposed for examination during the test joints previously tested in accordance with
this specification may be insulated or covered.
 Before testing piping systems shall have been completely checked for correctness.
 All lines, vessels and equipment shall be checked to insure the entire system can
be completely drained after testing.
 Temporary gaskets may be used, which are not the same as permanent gaskets
provided.
o Such use will not lead to damage of the flange faces.
o Temporary gaskets are removed immediately after completion of tests.
 Short pieces of piping, which must be removed to permit installation of a blind or
blank, shall be tested separately.
 Lines containing check valves shall have the source of pressure located in the
piping upstream of the check valve so that the pressure is applied under the seat.
 If this is possible, remove or jack open the check valve closure mechanism or
remove check valve completely and provide necessary spool piece or blinds.
 Test equipment to be used during testing shall have suitable capacity for the range
of test pressure required. The range of pressure gauges to be used shall be with a
minimum span of 1.5 times pressure and maximum span of 2 times of test
pressure.
 All pressure gauges are to be calibrated prior to use. If gauges have been used
previously on other projects or for other purposes, they shall be recalibrated.
Recalibration shall be required if the calibrated gauge/recorder is damaged or
strained.
 If the specified test duration exceeds 8 hours, then a chart recorder shall be used to
record test pressure.
Prior approval must be obtained from the CONTRACTOR and PTT/Consultant
Pneumatic Test Procedure
 Prior testing start, Supervisor/Tester is to set up the exclusion zone, complete with
signs, three languages, prior to pressure being raised on the system.
 During pneumatic testing care must be exercised not to exceed the specified design
pressure by more than ten (10) percent.
 A double block and vent valve arrangement shall be included in the pressurizing
line to the system being tested. A test pressure gauge shall be downstream of the
double block. After each pressure step has been reached, close the block valves
and open vent valve to atmosphere. If after a 10 minutes period the “Step Pressure”
has held, proceed to the next “Step Pressure”. If not, examine the entire system for
leakage.

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 The pressure shall be held at design pressure for 10 minutes prior to raising the
pressure to the test pressure. At test pressure shall be held for 30 minutes during
which time to access within the exclusion zone will be allowed.
 After 30 minutes the test pressure shall be reduced to design pressure at which
point access within the exclusion zone will be allowed to the testing team only and
the inspection of the joints shall be undertaken. All flange, threaded, welded joints
and attachment shall be inspected with a proprietary testing solution. The design
pressure shall be maintained until inspections of all joints are completed.
 Any leak identified shall be marked with marker pen and the system shall be
depressurized prior to any repair or rectification work being undertaken.
 Depressurization of the system on completion of the inspection shall be by
nominated vent valves taking into consideration any none return valves included
within system.
 All instrument shall be disconnected from the test system prior to the test
commencing.
7.2 Surface Preparation
Blasting
Abrasive blasting is the operation of forcibly propelling a stream of abrasive material
against a surface under high pressure to smooth a rough surface, roughen a smooth
surface, shape a surface, or remove surface contaminants. A pressurized fluid, typically
air, or a centrifugal wheel is used to propel the media.
There are several variants of the process, such as bead blasting and sandblasting
Types
 Sand Blasting
 Bead Blasting
Sand Blasting
It is a procedure for cleaning of metal surfaces, for which fine silica sand is blasted through
a nozzle onto the surface by means of compressed air to remove scale as well as other
coverings.
Sand blasting is a common element of concrete manufacturing and routine building
maintenance. Sand blasting can be used to etch decorative patterns into freshly poured
concrete and is the most efficient way of removing graffiti and other unwanted paint. Sand

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blasting is also great for removing rust from any metallic surface. As diverse as the uses of
sand blasting are, you are essentially spraying sand at high velocity. That means there is
the potential to damage surfaces if certain precautions and procedures are not followed.
Bead blasting
Bead blasting is the process of removing surface deposits by applying fine glass beads at
a high pressure without damaging the surface.
It is used to clean calcium deposits from pool tiles or any other surfaces, and removes
embedded fungus and brighten grout color. It is also used in auto body work to remove
paint.
Glass bead blasting is a metal cleaning process that creates a clean, bright, uniform
matte texture. The glass beads are applied to a surface using low air pressure. This
process removes paint, rust and corrosion from all types of metals, from autos, trucks,
equipment, machinery engine blocks, heads and intakes. Using the bead blasting
process a surface can be cleaned without any damage. The beads come in a variety of
sizes. The smaller the glass beads, the smoother the surface, larger beads produce a
more textured finish.
Bead blasting creates a uniform matte texture by shooting small glass beads at a surface
using air pressure. The blasting process:
 Removes surface deposits
 Removes many cosmetic imperfections
 Improves the appearance of metal surfaces
 Prepares surfaces for painting
 Removes paint and rust from existing surfaces.
Bead blasting is a low cost process often used for decorative parts including:
 Custom jewelry
 Custom shift knobs
 Custom golf putters
 Custom Front Panels
 Custom Motorcycle Parts
 Custom Auto Parts
 Custom Knobs

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Bead blasting is often applied to:
 Aluminum
 Stainless Steel
 Copper
 Steel
 Brass
 Titanium
 Sterling Silver
Safety
Bead blasting is chemically inert and environmentally friendly. This method of metal
cleaning is an acceptable method when properly controlled. The glass beads used in
this process are made from lead-free, soda like type glass, containing no free silica that
is made into preformed ball shapes. The glass beads can be recycled approximately 30
times.
Benefits
Glass bead blasting is an effective process used in automotive restoration. Bead
blasting produces a much smoother and brighter finish than angular abrasives. There is
no dimensional change to the metal surface. Glass bead blasting leaves no embedded
contaminates or residue. This process smoothest away any surface defects. You will be
able to see every dent, stretch mark, file stroke, and every stroke of the sand paper.
Glass bead blasting can also improve corrosion resistance.
Application
Glass Bead blasting can be used on a wide range of materials including aluminum,
stainless steel, copper, steel, brass, titanium, sterling silver, bronze, metal, glass,
plastic and rubber. It can be used in the restoration processes of cars and trucks. Glass
bead blasting is also an effective cleaning process on equipment, machinery engine
blocks, heads and intakes. Bead blasting is a low cost process and can be used on
decorative parts including: custom auto parts and custom motorcycle parts.

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Painting/Galvanization
Painting
Painting is done in order to give a good surface finish and to protect the surface of a
constructed job.
Anticorrosive painting
Paints are barrier coatings that, when applied and used properly, give sufficient corrosion
protection to steel for many common applications. They are, however, not impervious to
moisture, and rust can occur under even a perfectly applied paint if exposure time to
moisture is long enough. Nevertheless, surface cleanliness and surface preparation are
essential for good protection by anticorrosive paints. Surface preparation and corrosion
protection of steel by protective paint systems are addressed in many standards.
Pretreatment
The surface to be painted must be completely clean before painting. The standards for
inspection of steel surface cleanliness should be followed. The standards covers the
preparation of steel substrates before application of paints and related products and the
tests for the assessment of surface cleanliness. The roughness of the steel surface
influences the adhesion of the paint and the corrosion protection. Surface roughness can
be estimated
which describes the preparation of steel substrates before application of paints and related
products and the surface roughness characteristics of blast-cleaned steel substrates.
The pre-treatment methods for steel surfaces are given in standard which covers the
preparation of steel substrates before application of paints and related products -- Surface
preparation methods.
Information of the blast-cleaning abrasives used in surface preparation is given in the
standards for covering the preparation of steel substrates before application of paints and
related products -- Specifications for metallic blast-cleaning abrasives; and the preparation
of steel substrates before application of paints and related products -- Specifications for
non-metallic blast-cleaning abrasives.

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Protective paint systems
Protective paint systems are addressed in the standards. Paints and varnishes classifies
protective paint systems by durability. The durability class does not imply any guarantee
period but the expected serviceable life before repainting for maintenance.
Paints and varnishes which specifies the corrosivity categories according to the type of
atmosphere and stress caused by immersion. Design considerations are also present. The
standard specifies the most common types of anti-corrosive paint and gives instructions
for the selection of these for different environmental classes.
The standard guide us about laboratory performance test methods, execution and
supervision of paint work and development of specifications for new work and
maintenance.
Galvanization
Galvanization is the process of applying a protective zinc coating to metal, in order to
prevent rusting and galvanic corrosion.
Although galvanization can be done with electrochemical and electro deposition
processes, the most common method in current use is hot-dip galvanization, in which steel
parts are submerged in a bath of molten zinc.
Metal protection
In current use, the term refers to the coating of steel or iron with zinc. This is done to
prevent galvanic corrosion (specifically, rusting) of the ferrous item. The value of
galvanizing stems from the relative corrosion resistance of zinc, which, under most service
conditions, is considerably less than those of iron and steel. The zinc therefore serves as a
sacrificial anode, so that it cathodically protects exposed steel. This means that even if the
coating is scratched or abraded, the exposed steel will still be protected from corrosion by
the remaining zinc - an advantage absent from paint, enamel, powder coating and other
methods. Galvanizing is also favored as a means of protective coating because of its low
cost, ease of application and comparatively long maintenance-free service life.
The term galvanizing, while technically referring specifically to the application of zinc
coating by the use of a galvanic cell (also known as electroplating), is also generally
understood to include hot-dip zinc coating. The practical difference is that hot-dip
galvanization produces a thick, durable and matte gray coating - electroplated coatings
tend to be thin and brightly reflective. Due to its thinness, the zinc of electroplated coatings
is quickly depleted, making them unsuitable for outdoor applications (except in very dry

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