weld defects and discontinuities
TRANSCRIPT
Discontinuity• An interruption of the typical structure of a
material, such as a lack of homogeneity in its mechanical, metallurgical, or physical characteristics. A discontinuity is not necessarily a defect.
Weld Joint Discontinuities• Misalignment (hi-lo)• Undercut• Underfill• Concavity or Convexity• Excessive reinforcement• Improper reinforcement• Overlap• Burn-through• Incomplete or Insufficient
Penetration• Incomplete Fusion• Surface irregularity
– Overlap• Arc Strikes
• Inclusions– Slag– Wagontracks– Tungsten
• Spatter• Arc Craters• Cracks
– Longitudinal– Transverse– Crater– Throat– Toe– Root– Underbead and
Heat-affected zone– Hot– Cold or delayed
• Base Metal Discontinuities– Lamellar tearing– Laminations and
Delaminations– Laps and Seams
• Porosity– Uniformly Scattered– Cluster– Linear– Piping
• Heat-affected zone microstructure alteration
• Base Plate laminations• Size or dimensions
Defect• A flaw or flaws that by nature or accumulated
effect render a part or product unable to meet minimum applicable acceptance standards or specifications. The term designates rejectability.
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Types of Defect:The following figures give a rough survey about the
classification of welding defects to DIN 8524. This standard does
not classify existing welding defects according to their origin but
only to their appearance.
Welding defect
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1- Defect Class: Shape Defects
Welding defect
6
Welding defect
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2- Defect Class: Cracks and Cavities
Welding defect
8
Welding defect
9
Welding defect
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3- Defect Class: Lack of Fusion, Insufficient Through-Weld
Welding defect
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Welding defect
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4- Defect Class: Solid Inclusions
Welding defect
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Welding defect