Primary processing discontinuities (part 2)

Question 1

Arc strikes

Answer 1

Welding. Localized surface damage spots on base metal caused when a welding arc is accidentally struck outside the intended weld area.

Question 2

Heat affected zone cracking

Answer 2

Welding. Cracking in the base metal next to a weld caused by metallurgical changes and residual stresses from welding heat.

Question 3

Inclusions (welding) (MT)

Answer 3

Welding. Non-metallic materials trapped inside the weld metal or at the fusion boundary during welding.

Question 4

Lack of penetration

Answer 4

Welding. Weld metal does not extend through the joint thickness to fully fuse the base metals, leaving unbonded areas at the root or along the joint.

Question 5

Porosity (gas) (PT)

Answer 5

Welding. The formation of small gas-filled cavities in a weld due to entrapped gases during solidification

Question 6

Surface shrinkage cracks

Answer 6

Welding. Cracks that occur on the weld surface when solidifying weld metal shrinks and tensile stresses exceed the metal’s strength.

Question 7

Undercut (PT)

Answer 7

Welding. Base metal along the edges of a weld is eroded or gouged, creating a groove that reduces the effective thickness of the base metal.