Stress relief temperatures for thick sections occur __________ the material transformation temperature.

Stress relief temperatures for thick sections are typically set below the material transformation temperature. This relationship is important because the transformation temperature indicates a phase change in the material, such as from one crystalline structure to another, often associated with changes in properties like strength or hardness. By performing stress relief below this threshold, it allows for the reduction of residual stresses induced during welding or fabrication without causing detrimental effects to the material's microstructure.

Implementing stress relief at a lower temperature helps to distribute stress more evenly and allows for the relaxation of internal stresses without promoting significant changes that could weaken the material. This practice is crucial in ensuring the integrity and durability of welded structures, particularly in thicker sections where residual stresses can be pronounced.