Which statement about PWHT is correct?

Which statement about PWHT is correct?

• A. PWHT is never required
• B. PWHT is for cosmetic appearance
• C. PWHT is typically required for certain materials or thicker welds
• D. PWHT replaces preheating

Answer: (C)

Post-weld heat treatment is used to relieve residual stresses and reduce weld hardness, which helps improve toughness and minimize the risk of cracking in service. This is especially important for thicker welds and for certain materials that are prone to hardening or brittle behavior after welding. That’s why the statement that PWHT is typically required for specific materials or thicker welds is the correct one. PWHT isn’t about cosmetics, and it isn’t something that never happens. It also doesn’t replace preheating, which is done before welding to slow cooling; PWHT is performed after welding to adjust the welded area’s microstructure and stress state.

Post-weld heat treatment is used to relieve residual stresses and reduce weld hardness, which helps improve toughness and minimize the risk of cracking in service. This is especially important for thicker welds and for certain materials that are prone to hardening or brittle behavior after welding. That’s why the statement that PWHT is typically required for specific materials or thicker welds is the correct one. PWHT isn’t about cosmetics, and it isn’t something that never happens. It also doesn’t replace preheating, which is done before welding to slow cooling; PWHT is performed after welding to adjust the welded area’s microstructure and stress state.