A large forging is repaired by welding. What does an irregular indication parallel with the weld passes suggest?

An irregular indication parallel with the weld passes suggests the presence of weld shrinkage cracks. These cracks typically occur as a result of the contraction of the weld metal as it cools after the welding process. When welding, the heat generated can cause the metal to expand; upon cooling, it contracts and may lead to stresses that manifest as cracks.

In the case of irregular indications that run parallel to the weld passes, it indicates that the cracking is a direct consequence of the welding process itself, which aligns with the described characteristics of shrinkage cracks. Recognizing this pattern is crucial for identifying potential defects and ensuring the integrity of the weld and the overall structure of the forging.

Other options, such as inclusions or surface checking, may exhibit different characteristics and don't typically appear in the same manner as shrinkage cracks, which specifically relate to the cooling and solidification of the weld metal in relation to the applied heat. Crater cracks, on the other hand, would usually be found at the end of a weld bead rather than running parallel to the weld. Thus, identifying the pattern as a sign of shrinkage cracking is essential for effective assessment and remediation of welding defects.