What is considered the main hazard when welding cold worked parts?

The main hazard when welding cold worked parts is cracking. Cold working processes alter the material structure, increasing its hardness and lowering its ductility. This transformation can create residual stresses within the metal. When heat is applied during welding, these residual stresses can become problematic.

As the welded area cools, the differential cooling rates and thermal expansion can lead to the formation of cracks. These cracks often occur in places where there is a high concentration of stresses, such as at weld ends or in heat-affected zones. Understanding this hazard is crucial for welders and inspectors, as it informs not only the welding technique used but also the need for preheating or post-weld heat treatment to alleviate stress concentrations and reduce the likelihood of cracking.

In contrast, while corrosion, burn through, and electrode contamination are important considerations in welding, they do not directly pertain to the inherent material properties introduced by cold working.