When is hardness testing indicated in welding practice?

When is hardness testing indicated in welding practice?

• A. For decorative welds.
• B. For high-strength steels and PWHT requirements; to verify local properties.
• C. For all welds regardless of material.
• D. Only for cosmetic joints.

Answer: (B)

Hardness testing is used to verify local properties in the weld and heat-affected zone, especially when the material or service requirements call for careful control of hardness after welding. This is most important for high-strength steels, where the balance between strength and toughness can be sensitive to heat input and possible phase changes during welding. If a post-weld heat treatment (PWHT) is required, hardness checks help confirm that the local regions haven’t hardened or softened beyond what the design or code allows, which could affect toughness and crack resistance. This kind of testing isn’t needed for decorative or cosmetic welds, where there are no critical property requirements, and it isn’t performed on every weld regardless of material. It’s specified by the welding procedure, material standards, or service conditions, and performed to ensure that the weld and surrounding heat-affected zone meet the required local property limits.

Hardness testing is used to verify local properties in the weld and heat-affected zone, especially when the material or service requirements call for careful control of hardness after welding. This is most important for high-strength steels, where the balance between strength and toughness can be sensitive to heat input and possible phase changes during welding. If a post-weld heat treatment (PWHT) is required, hardness checks help confirm that the local regions haven’t hardened or softened beyond what the design or code allows, which could affect toughness and crack resistance.

This kind of testing isn’t needed for decorative or cosmetic welds, where there are no critical property requirements, and it isn’t performed on every weld regardless of material. It’s specified by the welding procedure, material standards, or service conditions, and performed to ensure that the weld and surrounding heat-affected zone meet the required local property limits.