Peening in welding is sometimes used to relieve residual stresses and reduce distortion. What is a common code-related restriction when peening is used?

Peening in welding is sometimes used to relieve residual stresses and reduce distortion. What is a common code-related restriction when peening is used?

• A. It is required on all root passes.
• B. It is prohibited on root passes or final passes due to masking flaws.
• C. It must follow post-weld heat treatment.
• D. It is only allowed for stainless steel welds.

Answer: (B)

Peening can relieve surface stresses, but codes restrict where it can be used because the plastic deformation it produces can mask surface defects and complicate nondestructive inspection. The most common rule is that peening is not allowed on root passes or final passes, since those areas must be verifiable for cracks or other flaws through inspection. If peening were performed there, tiny cracks or indications could be concealed or distorted, making NDE results unreliable. Other options don’t fit because peening is not required on every root pass, it isn’t universally tied to a post-weld heat treatment step, and it isn’t limited only to stainless steel welds.

Peening can relieve surface stresses, but codes restrict where it can be used because the plastic deformation it produces can mask surface defects and complicate nondestructive inspection. The most common rule is that peening is not allowed on root passes or final passes, since those areas must be verifiable for cracks or other flaws through inspection. If peening were performed there, tiny cracks or indications could be concealed or distorted, making NDE results unreliable.

Other options don’t fit because peening is not required on every root pass, it isn’t universally tied to a post-weld heat treatment step, and it isn’t limited only to stainless steel welds.