about the welding types

1. Repair and MaintenanceRepair and Maintenance
Lab ReportLab Report
Submitted to:
Mam Sana
Submitted by:
Mudassar Hussain
2015-IM-03
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2. Welding ProcessWelding Process
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3. WELDINGWELDING
Welding is a materials joining process which
produces coalescence of materials by heating
them to suitable temperatures with or without
the application of pressure or by the
application of pressure alone, and with or
without the use of filler material.
◦ Welding is used for making permanent joints.
◦ It is used in the manufacture of automobile bodies,
aircraft frames, railway wagons, machine frames,
structural works, tanks, furniture, boilers, general repair
work and ship building.
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4. TYPESTYPES
Plastic Welding or Pressure Welding
The piece of metal to be joined are heated to a
plastic state
and forced together by external pressure
(Ex) Resistance welding
Fusion Welding or Non-Pressure
Welding
The material at the joint is heated to a molten state
and allowed to solidify
(Ex) Gas welding, Arc welding
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5. Classification Of Welding Processes:Classification Of Welding Processes:
(i) Arc Welding
 Carbon arc
 Metal arc
 Metal inert gas
 Tungsten inert gas
 Plasma arc
 Submerged arc
 Electro-slag
(ii) Gas Welding
 Oxy-acetylene
 Air-acetylene
 Oxy-hydrogen
(iii) Resistance Welding
 Butt
 Spot
 Seam
 Projection
 Percussion
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(v) Solid State Welding
• Friction
• Ultrasonic
• Diffusion
• Explosive
(vi) Newer Welding
• Electron-beam
• Laser
(vii) Related Process
• Oxy-acetylene cutting
• Arc cutting
• Hard facing
• Brazing
• Soldering

6. Arc WeldingArc Welding
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 Uses an electric arc to coalesce metals
 Arc welding is the most common method of welding metals
 Electricity travels from electrode to base metal to ground

7.  Arc Welding Equipment :Arc Welding Equipment :
1) A welding generator (D.C.) or Transformer (A.C.)
2) Two cables- one for work and one for electrode
3) Electrode holder
4) Electrode
5) Protective shield
6) Gloves
7) Wire brush
8) Chipping hammer
9) Goggles
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8. Arc Welding EquipmentArc Welding Equipment
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9. Metal Arc WeldingMetal Arc Welding
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10. Carbon Arc WeldingCarbon Arc Welding
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11. Arc WeldingArc Welding
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Advantages Disadvantages
 Most efficient way to join
metals
 Manually applied, therefore
high labor cost.
 Lowest-cost joining method  Need high energy causing
danger
 Affords lighter weight
through better utilization of
materials
 Not convenient for
disassembly
 Joins all commercial metals  Defects are hard to detect at
joints.
 Provides design flexibility

12. GAS WELDINGGAS WELDING
 Sound weld is obtained by selecting proper size of flame,
filler material and method of moving torch
 The temperature generated during the process is 33000
c
 When the metal is fused, oxygen from the atmosphere and
the torch combines with molten metal and forms oxides,
results defective weld
 Fluxes are added to the welded metal to remove oxides
 Common fluxes used are made of sodium, potassium.
Lithium and borax.
 Flux can be applied as paste, powder,liquid.solid coating or
gas.
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13. GAS WELDING EQUIPMENTGAS WELDING EQUIPMENT
1. Gas Cylinders
Oxygen – 125 kg/cm2
Acetylene – 16 kg/cm2
2. Regulators
Working pressure of oxygen 1 kg/cm2
Working pressure of acetylene 0.15 kg/cm2
Working pressure varies depends upon the thickness
of the work pieces welded.
3. Pressure Gauges
4. Hoses
5. Welding torch
6. Check valve
7. Non return valve
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14. Oxy-Acetylene WeldingOxy-Acetylene Welding
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15. TYPES OF FLAMESTYPES OF FLAMES
 Oxygen is turned on, flame immediately changes into a
long white inner area (Feather) surrounded by a
transparent blue envelope is called Carburizing flame
(30000
c)
 Addition of little more oxygen give a bright whitish cone
surrounded by the transparent blue envelope is called
Neutral flame (It has a balance of fuel gas and oxygen)
(32000
c)
 Used for welding steels, aluminium, copper and cast iron
 If more oxygen is added, the cone becomes darker and
more pointed, while the envelope becomes shorter and
more fierce is called Oxidizing flame
 Has the highest temperature about 34000
c
 Used for welding brass and brazing operation
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16. Three basic types of oxyacetylene flames used in oxyfuel-gasThree basic types of oxyacetylene flames used in oxyfuel-gas
welding and cutting operations: (a) neutral flame; (b)welding and cutting operations: (a) neutral flame; (b)
oxidizing flame; (c) carburizing, or reducing flame.oxidizing flame; (c) carburizing, or reducing flame.
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17. GAS CUTTINGGAS CUTTING
 Ferrous metal is heated in to red hot condition and a jet
of pure oxygen is projected onto the surface, which
rapidly oxidizes
 Oxides having lower melting point than the metal, melt
and are blown away by the force of the jet, to make a
cut
 Fast and efficient method of cutting steel to a high
degree of accuracy
 Torch is different from welding
 Cutting torch has preheat orifice and one central orifice
for oxygen jet
 PIERCING and GOUGING are two important operations
 Piercing, used to cut a hole at the centre of the plate or
away from the edge of the plate
 Gouging, to cut a groove into the steel surface
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18. GAS CUTTINGGAS CUTTING
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Automatic Gas Cutting Manual Gas Cutting

19. WeldWeld JJointointss
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20. TIG WeldingTIG Welding
Development Of Tig Welding:
After the discovery of the electric arc in 1800 by Humphry Davy, arc
welding developed slowly.
C. L. Coffin had the idea of welding in an inert gas atmosphere in
1890, but even in the early 1900s, welding non-ferrous materials like
aluminum and magnesium remained difficult, because these metals
reacted rapidly with the air, resulting in porous and dross-filled welds.
To solve the problem, bottled inert gases were used in the beginning
of the 1930s.

21. In TIG welding an arc is formed between
a non-consumable tungsten electrode
and the metal being welded.
Gas is fed through the torch to shield
the electrode and molten weld pool. If
filler wire is used, it is added to the weld
pool separately.
In TIG Tungsten is used as electrode

22. Contineous WeldingContineous Welding
•A weld that is continuous along the entire
length of the joint.
•Smooth Surface
•Fine Surface
•Use for light metal
•In this the roller are used to smoth the surface
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23. Spot Welding
Lesson Objectives
When you finish this lesson you will understand:
• Basics of Resistance Welding Processes
• Heat Generation & Control
• Spot Welding Process and Applications
Learning Activities
1. View Slides;
2. Read Notes,
3. Listen to lecture
4. View Demo
5. Do on-line workbook
Keywords: Resistance Spot Welding, Heat Generation, Equipment Control,
Contact Resistance, Upslope, Downslope, Hold Time, Temper, Squeeze Time,
Electrode

24. Definition of ResistanceDefinition of Resistance
WeldingWelding
 Resistance welding is a fusion welding
process in which coalescence of metals is
produced at the faying surfaces by the heat
generated at the joint by the resistance of
the work to the flow of electricity.
 Force is applied before, during, and after the
application of current to prevent arcing at
the work piece.
 Melting occurs at the faying surfaces during
welding.

25. Principal Types of ResistancePrincipal Types of Resistance WeldsWelds
Electrodes
or Welding
Tips
Electrodes
or Welding
Wheels
Electrodes
or Dies
Projection
Welds
Electrodes or Dies
Spot Weld Seam Weld Projection Weld
Upset Weld Flash Weld
After Welding After Welding
[Reference: Resistance Welding Manual, RWMA, p.1-3]

26. Typical Equipment of Resistance SpotTypical Equipment of Resistance Spot
WeldingWelding
(a) (b)
[Reference: Welding Process Slides, The Welding Institute]

27. Advantages of Resistance SpotAdvantages of Resistance Spot
WeldingWelding
Adaptability for Automation in High-Rate Production of
Sheet Metal Assemblies
High Speed
Economical
Dimensional Accuracy

28. Limitations of Resistance SpotLimitations of Resistance Spot
WeldingWelding
Difficulty for maintenance or repair
Adds weight and material cost to the product, compared with
a butt joint
Generally have higher cost than most arc welding equipment
Produces unfavorable line power demands
Low tensile and fatigue strength
The full strength of the sheet cannot prevail across a spot
welded joint
Eccentric loading condition

29. MigMig
weldingwelding
Introduction to practicalIntroduction to practical
application of wire feed weldingapplication of wire feed welding

30. MIG – Metal Inert Gas WeldingMIG – Metal Inert Gas Welding
May be called GMAW (Gas Metal Arc
Welding)
Avoid cutting in drafty or windy conditions
Molten pool is shielded by the inert gas
envelope
Joints are stronger, more ductile, and
more corrosion resistant
Flux center wire has slag; Solid wire has
no slag, thus eliminating slag inclusion
Welded metal does not readily distort

31. ToolsTools
Power
Supply
Gas Supply
Wire feeder
Gun and
Whip
Process

32. MIG Machine OperationMIG Machine Operation
Wire is fed at a pre-set rate
Gas flows at about 35 cubic feet per hour
and is directed around the welding wire
for shielding

33. Advantages
 Welding can be done in
all positions
 High rates of metal
deposition
 Excellent filling ability
for poor-fit joints
 High weld Quality
 No electrode stub loss
 Less distortion due to
narrow, deep weld
profile
 Easier process to learn
and use
 Disadvantages
 Welding power source
expensive
 Shielding gas expensive
 Higher electrode wire
cost
 Most machines require
three-phase input power
 Not as versatile as
SMAW for maintenance
Welding cast iron
Cutting
Carbon arc torch
applications

34. Power supplyPower supply
Stationary
Portable
◦ Integrated
◦ Nonintegrated
Advantages and
Disadvantages
Adjustments

35. Gas SuplyGas Suply
Containers
Regulators
◦ Ball and Dial indicators
Gases Materials
◦ Carbon dioxide Steel
◦ Argon Stainless Steel
◦ Helium Aluminum
◦ Oxygen

36. Wire FederWire Feder
Types
◦ Integrated
◦ Component
Advantages
Disadvantages
Parts
Feed motor
Drive Assembly
Spool Assembly
Wire speed control
Computer controller

37. Gun And WhipGun And Whip
 Gun Types
Inline
Handle
 Gun
Characteristics
Wire Guide
Tips
Shielding Gas
Nozzle
Insulator
Internal Gun wire
driver
 Whip Characteristics
Shielding Gas
Sheath
Liner
Power feed

38. Mig welding ProcessMig welding Process
Wire Types
Hard Wire (Solid)
Dual Shield
Flux Core
Polarity
DCRP
DCSP
Advantages
Disadvantages
Advantages
Disadvantages