Why is it considered good practice to normalize a part after welding?

Normalizing a part after welding is considered good practice primarily because it effectively relieves internal stresses that may have developed during the welding process. When materials are welded, they undergo rapid heating and cooling, leading to thermal gradients that can produce stresses within the metal. These internal stresses can cause issues such as warping, cracking, or unpredictable changes in mechanical properties.

Normalizing involves heating the welded part to a temperature above its critical range—typically until it becomes austenitic—followed by controlled cooling, usually in air. This thermal treatment allows for the reorganization of the metal's grain structure, resulting in a more uniform microstructure. The process reduces residual stresses generated during welding, thereby enhancing the dimensional stability and overall mechanical performance of the component.

While options regarding surface finish, weight reduction, or corrosion resistance are important considerations in material treatment, the primary reason for normalizing in the context of welding is the effective management of internal stresses. This process ultimately leads to improved performance and reliability of the welded structure, which is crucial in various applications.