Which low-temperature heat treatment is used to relieve residual stresses after welding?

• A. Preheat
• B. Tempering
• C. Stress relieving
• D. Normalizing

Answer: (C)

Residual stresses from welding can leave a component distorted or prone to cracking if not relieved. A low-temperature post-weld heat treatment called stress relieving is designed to do just that: relax internal tensile stresses without significantly altering the metal’s microstructure or properties. By heating to a temperature below the transformation range and holding for a suitable time, atoms rearrange enough to ease stresses, which improves dimensional stability and reduces cracking risk during service. Other options either act before welding (preheat), or aim to change hardness or grain structure at higher temperatures (tempering or normalizing), so they don’t specifically target relieving residual welding stresses in the same way.