The document discusses welding processes and their importance, types of welds and weld defects, including causes and methods of detection. It examines the microstructure of welds and defines features like the fusion zone, heat affected zone, and unaffected base metal zone. Various weld defects are described such as cracks, cavities, inclusions, lack of fusion/penetration, imperfect shape, and miscellaneous faults.
What is laser beam hardening (LBH)? Advantages, Disadvantages
Applications, What is laser peening? Difference between laser beam hardening (LBH) and electron beam hardening (EBH)
What is laser beam hardening (LBH)? Advantages, Disadvantages
Applications, What is laser peening? Difference between laser beam hardening (LBH) and electron beam hardening (EBH)
PPT Includes physical Metallurgy for Titanium and its alloys, Weld ability of them and two welding processes : GTAW and EBW. PPT also describes the Problems with the Welding of Titanium and alloys.
Introduction Hot Working and Cold Working of Metals Forging Processes- Open, impression die forging, Closed die forging-forging operation Rolling of metals-types of rolling- Flat strip rolling-shape rolling operation -Defects in rolled parts- Principle of rod and wire drawing-tube drawing -Principle of extrusion Types-hot and cold extrusion.
this ppt pdf beneficial for 1st year engineering student who studying workshop technology. in this pdf types of joining, gas welding, arc welding, spot welding, tig welding, mig welding, soldering brazing and different welding defect has been discussed.
Heat treatment 2 by
P.SENTHAMARAI KANNAN,
ASSISTANT PROFESSOR ,
DEPARTMENT OF MECHANICAL ENGINEERING,
KAMARAJ COLLEGE OF ENGINEERING AND TECHNOLOGY,
VIRUDHUNAGAR, TAMILNADU.
INDIA.
Welding process
Arc Welding
Resistance Welding
Oxy fuel Gas Welding
Other Fusion Welding Processes
Solid State Welding
Weld Quality
Weld ability
Design Considerations in Welding
PPT Includes physical Metallurgy for Titanium and its alloys, Weld ability of them and two welding processes : GTAW and EBW. PPT also describes the Problems with the Welding of Titanium and alloys.
Introduction Hot Working and Cold Working of Metals Forging Processes- Open, impression die forging, Closed die forging-forging operation Rolling of metals-types of rolling- Flat strip rolling-shape rolling operation -Defects in rolled parts- Principle of rod and wire drawing-tube drawing -Principle of extrusion Types-hot and cold extrusion.
this ppt pdf beneficial for 1st year engineering student who studying workshop technology. in this pdf types of joining, gas welding, arc welding, spot welding, tig welding, mig welding, soldering brazing and different welding defect has been discussed.
Heat treatment 2 by
P.SENTHAMARAI KANNAN,
ASSISTANT PROFESSOR ,
DEPARTMENT OF MECHANICAL ENGINEERING,
KAMARAJ COLLEGE OF ENGINEERING AND TECHNOLOGY,
VIRUDHUNAGAR, TAMILNADU.
INDIA.
Welding process
Arc Welding
Resistance Welding
Oxy fuel Gas Welding
Other Fusion Welding Processes
Solid State Welding
Weld Quality
Weld ability
Design Considerations in Welding
Basic metallurgy for welding & fabricaton professionalsPuneet Sharma
Eurotech Organizing 2 days "Metallurgy" Course is very beneficial for Welding and Fabrication professionals as it would results in increasing your efficiency. The course objectives are: metals and their properties, to check material test certificate, heat treatment process, Destructive testing, Stainless steel and types, and many more.
It will definitely increase your learning and your work efficiency and boost your career in welding
Please do not hesitate to contact me if you require further information Metallurgy" Course
Best Regards,
Puneet Sharma
Email: (aws.cwi.training@gmail.com)
Mobile no. 08196980555
Welding Defects
Eurotech Now inteducing Welding Defects. Welding Defect is any type of flaw in the object which requires welding. Seven type of Welding Defect
Seven type of Common weld defects include:
1. Lack of fusion
2. Lack of penetration or excess penetration
3. Porosity
4. Inclusions
5. Cracking
6. Undercut
7. Lamellar tearing
Any of these defects are potentially disastrous as they can all give rise to high stress intensities which may result in sudden unexpected failure below the design load or in the case of cyclic loading, failure after fewer load cycles than predicted.
A simple slideshow of common welding process, welding terminology, welding symbols / joint configurations, welder related operations, and welding safety.
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In the dimly lit conference room, the hum of anticipation fills the air as the audience settles into their seats, eager to delve into the intricate world of welding defects. The projector flickers to life, casting a brilliant glow onto the screen, where a meticulously crafted slide presentation awaits. Each slide is a gateway into the complex realm of welding imperfections, a journey through the pitfalls and challenges faced by welders every day.
The first slide materializes, its title bold and commanding: "Understanding Welding Defects." As the presenter begins to unravel the intricacies of the topic, images of porosity dance across the screen, their irregular patterns a stark reminder of the importance of proper gas shielding. The audience leans in, captivated by the visual representation of gas pockets trapped within the weld, a flaw that compromises structural integrity.
Transitioning to the next slide, the focus shifts to another common defect: lack of fusion. Here, the audience is confronted with images of incomplete weld penetration, a consequence of inadequate heat input or improper technique. As the presenter elaborates on the causes and consequences of this flaw, murmurs of realization ripple through the room, punctuated by nods of understanding.
With each successive slide, the presentation delves deeper into the myriad challenges encountered in the world of welding. Cracks, undercutting, and spatter are dissected with precision, their origins and implications laid bare for all to see. Through meticulously curated visuals and insightful commentary, the audience gains a newfound appreciation for the complexities of the craft.
Yet, amidst the exploration of defects, a thread of optimism weaves its way through the presentation. Each flaw serves not only as a cautionary tale but also as an opportunity for growth and improvement. As the presenter concludes the presentation, the final slide emblazoned with the words "Continuous Improvement," a sense of determination fills the room.
Armed with newfound knowledge and insight, the audience disperses, their minds buzzing with possibilities. For in the world of welding, as in life, it is not the presence of defects that defines us, but rather our ability to acknowledge them, learn from them, and emerge stronger as a result. And as the lights dim and the projector fades to black, the echoes of the presentation linger, a reminder of the power of knowledge and the promise of progress.
As the lights in the conference room slowly brightened, the audience departed with a renewed sense of purpose, their minds buzzing with newfound insights and their resolve strengthened to confront the complexities of welding defects head-on. And as they stepped out into the world beyond, they carried with them not only the lessons learned from the presentation but also the indomitable spirit of innovation and perseverance that defines the welding profession.
The presentation reached its climax and had to be finish
There are numerous welding processes including arc welding, electron beam welding,
friction welding, laser welding, and resistance welding. This article will concentrate on arc
welding, which is the most common technique used to join most steels. Factors affecting
weld quality will be discussed and how to avoid common weld defects will be presented.
Arc welding requires striking a low-voltage, high-current arc between an electrode and the
base metal. The intense heat generated with this arc melts the base metal and allows the
joining of two components. The characteristic of the metal that is being welded and the joint
type (i.e. groove, fillet, etc.) dictates the welding parameters and the procedure that needs to
be followed to obtain a sound weld joint.
The Certified Welding Inspector (CWI) plays an important role during any welded construction activities ensuring the required specifications and standards are followed. Due to the numerous materials and processes associated with metal joining (welding) THIS PRESENTATION SHALL SHOW ONLY THE BASIC WELDING PROCESSES AND EXAMINATION METHODS (NDE). National and International Codes and Specifications along with measuring devices are the Inspector’s tools. Hopefully the following presentation shall give an insight into basic welding inspection.
This Presentation covers the basic concepts of Hot cracks and cold cracks in welding. For more information, please refer the books mentioned in the references slide.... Thank you
Era industrialisasi
Perkembangan K3 mengikuti penggunaan teknologi (APD, safety device dan alat-alat pengaman)
Era Manajemen
Heinrich (1931), teori domino
Bird and German, teori Loss Causation Model
ISO, SMK3 dll
2. Tujuan:
• Lebih mengenal proses pengelasan dan efeknya
pada material
• Untuk melihat strukturmikro dan hardness pada
Heat Affected Zone (HAZ)
• Mengetahu cacat-cacat las, penyebab dan
usaha penanggulanganya.
• Industrial radiography techniques
3. Definitions:
• Welding is the joining of multiple pieces of metal
by the use of heat and or pressure. A union of
the parts is created by fusion or recrystallization
across the metal interface. Welding can involve
the use of filler material, or it can involve no
filler.
4. What commercial and technological
importance does welding have?
• Provides a permanent joint
• Weld joint can be stronger than parent material
– If the filler material has superior strength characteristics and proper
techniques are used
• Usually the most economical way to join components
• Can be done in the field away from a factory
5. Limitations?
• Expensive in terms of labour cost
• Most welding processes involve the use high energy, are
inherently dangerous
• Welds are permanent bonds, not allowing for convenient
disassembly
• The welded joint can suffer from certain quality defects
that are difficult to detect, these defects can reduce the
quality of the joint
6. Types:
• Arc Welding
– A fusion welding process in which the coalescence of the metals is
achieved by the heat from an electric arc between an electrode
and the work
7. • Shielded Metal Arc Welding (SMAW)
– An arc welding process that uses a consumable electrode
consisting of a filler metal rod coated with chemicals that
provide flux and shielding
8. • Gas Metal Arc Welding (GMAW)
– Arc welding process in which the electrode is a consumable bare
metal wire and shielding is accomplished by flooding the area
with gas
9. • Submerged Arc Welding
– Arc welding process that uses a continuous, consumable bare
wire electrode, arc shielding is provided by a cover of granular
flux
10. • Resistance Welding
– A fusion welding process that utilizes a combination of heat and
pressure to accomplish coalescence, the heat being generated
by electrical resistance to current flow at the junction to be
welded
11. • Oxyacetylene Welding
– A fusion welding process performed by a high-temperature flame
from a combustion of acetylene and oxygen
C2 H 2 + O2 → 2CO + H 2 + HEAT
2CO + H 2 + 1.5O2 → 2CO2 + H 2O + HEAT
12. Fusion Weld Joint
• Fusion Zone
– A mixture of filler metal and base metal that has completely
melted
– High degree of homogeneity among the component metals that
have been melted during welding
– The mixing of these components is motivated largely by
convection in the molten weld pool
13. • Weld Interface
– The narrow boundary that separates the fusion zone and the
heat affected zone
– This interface consists of a thin band of base metal that was
melted or partially melted (localized melting within the grains)
during the welding process, but immediately solidified before any
mixing could take place
• Heat Affected Zone (HAZ)
– The metal in this region has experienced temperature below its
melting point, but high enough to change the microstructure
– This metal consists of the base metal which has undergone a
heat treatment due to the welding temperatures, so that its
properties have been altered.
– The amount of metallurgical damage in the HAZ depends on the
amount of heat input, peak temp reached, distance from fusion
zone, time at elevated temp, cooling rate, and the metal’s
thermal properties
14. • Heat Affected Zone (HAZ) cont’d
– The effect on the mechanical properties is usually negative, and
it is most often the region of the weld joint where failure occurs
• Unaffected Base Metal Zone
– Where no metallurgical change has occurred
– The base metal surrounding the HAZ is likely to be in a state of
high residual stress, due to the shrinkage in the fusion zone
16. Solidification Cracking
• Causes:
– Large depth/width ratio of weld
bead
– High arc energy and/or preheat
– Sulphur, phosphorus or niobium
pick-up from parent metal
17. Hydrogen Induced HAZ Cracking
• Causes:
– Hardened HAZ coupled with the
presence of hydrogen diffused from
weld metal
– Susceptibility increases with the
increasing thickness of section
especially in steels with high carbon
equivalent composition
– Can also occur in weld metal
– Increase welding heat beneficial
– Preheating sometimes necessary
– Control of moisture in consumables
and cleanliness of weld prep
desirable
18. Lamellar Tearing
• Causes:
– Poor ductility in through-thickness
direction in rolled plate due to non-
metallic inclusions
– Occurs mainly in joints having weld
metal deposited on plate surfaces
– Prior buttering of surface beneficial
for susceptible plate
19. Reheat Cracking
• Occurs in creep resisting and some
thick section structural low alloy steels
during post weld heat treatment
• Causes:
– Poor creep ductility in HAZ
coupled with thermal stress
– Accentuated by severe notches X 35
such as preexisting cracks, or
tears at weld toes, or unfused root
of partial penetration weld
– Heat treatment may need to
include low temperature soaking
– Grinding or peening weld toes
after welding can be beneficial
X 200
21. Worm Holes
• Resulting from the entrapment of gas
between the solidifying dendrites of
weld metal, often showing ‘herringbone’
array ( B )
• Causes:
– The gas may arise from
contamination of surfaces to be
welded, or be prevented from
escaping from beneath the weld by
joint crevices
22. Uniformly Distributed Porosity
• Resulting from the entrapment of gas
in solidified weld metal
• Causes:
– Gas may originate from dampness
or grease on consumables or
workpiece, or by nitrogen
contamination from the
atmosphere
– If the weld wire used contains
insufficient deoxidant it is also
possible for carbon monoxide to
cause porosity
23. Restart Porosity
• Causes:
– Unstable arc conditions at weld
start, where weld pool protection
may be incomplete and temperature
gradients have not had time to
equilibrate, coupled with inadequate
manipulative technique to allow for
this instability
24. Surface Porosity
• Causes:
– Excessive contamination from
grease, dampness, or atmosphere
entrainment
– Occasionally caused by excessive
sulphur in consumables or parent
metal
25. Crater Pipes
• Resulting from shrinkage at the end
crater of a weld run
• Causes:
– Incorrect manipulative technique or
current decay to allow for crater
shrinkage
26. 3. Solid Inclusions
Detection
- normally revealed by radiography
Linear Slag Inclusions
• Cause:
– Incomplete removal of slag
in multi-pass welds often
associated with the
presence of undercut or
irregular surfaces in
underlying passes
27. Isolated Slag Inclusions
• Causes:
– Normally by the presence of mill
scale and/or rust on prepared
surfaces, or electrodes with
cracked or damaged coverings
– Can also arise from isolated
undercut in underlying passes of
multi-pass welds
28. 4. Lack of Fusion and Penetration
Detection
– This type of defect tends to be sub surface and is therefore
detectable only by ultrasonics or X-ray methods
– Lack of side wall fusion which penetrates the surface may be
detected using magnetic particle, dye or fluorescent
penetrant inspection
Cause
– Incorrect weld conditions (eg. low current) and/or incorrect
weld preparation (eg. root face too large)
– Both cause the weld pool to freeze too rapidly
29. Lack of side-wall fusion Lack of root fusion Lack of inter-run fusion
Lack of penetration
30. 5. Imperfect Shape
Detection
- all shape defects can be determined by visual inspections
Linear Misalignment
• Cause:
– Incorrect assembly or
distortion during fabrication
31. Excessive Reinforcement
• Causes:
– Deposition of too much weld metal,
often associated with in adequate
weld preparation
– Incorrect welding parameters
– Too large of an electrode for the
joint in question
32. Overlap
• Causes:
– Poor manipulative technique
– Too cold a welding conditions
(current and voltage too low)
33. Undercut
• Results from the washing away of edge
preparation when molten
• Causes:
– Poor welding technique
– Imbalance in welding conditions
34. Excessive Penetration
• Causes:
– Incorrect edge preparation
providing insufficient support
at the weld root
– Incorrect welding conditions
(too high of current)
– The provision of a backing bar
can alleviate this problem in
difficult circumstances
35. Root Concavity
• Causes:
– Shrinkage of molten pool at
weld root, due to incorrect root
preparation or too cold of
conditions
– May also be caused by
incorrect welding technique
36. 5. Miscellaneous Faults
Arc Strikes
• Cause:
– Accidental contact of an
electrode or welding torch
with a plate surface remote
from the weld
– Usually result in small hard
spots just beneath the
surface which may contain
cracks, and are thus to be
avoided
37. Spatter
• Causes:
– Incorrect welding conditions
and/or contaminated
consumables or preparations,
giving rise to explosions within
the arc and weld pool
– Globules of molten metal are
thrown out, and adhere to the
parent metal remote from the
weld
38. Copper Pick-Up
• Causes:
– Melting of copper contact tube in
MIG welding due to incorrect
welding conditions
X 275
39. PROCEDURE
1. Students are provided with weldments of approximately 0.4% C
steel. The first weldment was prepared without preheat treatment.
The electrode used produces a large amount of hydrogen which
diffuses into the weld metal. The second was preheated to 150˚C.
An electrode with relatively low hydrogen content was used. For
each of these samples:
a) Examine the microstructure of the weldments in a traverse from weld
metal to parent metal, sketching about five different areas. Using the
Fe-C diagram and your knowledge of the phase transformations in
steel, comment on the microstructures describing the time-temperature
history and how this history resulted in the observed structure.
b) Conduct a microhardness traverse across the HAZ and correlate the
hardness with the microstructure observed in (a).
2. Some radiographs of weld defects are provided. Examine these
radiographs and describe the defects responsible, citing ways of
avoiding the problem.
40. Radiographs
ID # Position Comments Results Page
1
Q13 1gf Shallow undercut by cap pass Acceptable
Q18 4gf Incompletefusion at the root Fail
Q10 1gf Incompletefusion at the root Fail
2
H2 4gf Incompletefusion at the root & slag throughout Fail
H1 1gf Porosity throughout Fail
J3 4gf Slag inclusions Acceptable
3
F10 1gf Slag inclusions Fail
F2 2g Incompletefusion at the root Fail
F7 3gf Minor slag Acceptable
4
983 2g Slag inclusions Acceptable
983 3gf Slag inclusions at the root & inner passes Fail
982 3gf Slag inclusions Fail
5
852 2g No defects Acceptable
852 3gf Slag inclusion at the root & porosity Fail
850 4gf Minor slag & film scratch Acceptable