What characterizes a "cold" weld in GMAW?

A "cold" weld in GMAW is characterized by little or no fusion between the base metal and the weld metal, which often results in a buildup of material on the surface. This occurs when insufficient heat is applied during the welding process, preventing adequate melting of the base materials. The lack of proper fusion leads to weak joints that may not hold up under stress, as the weld does not penetrate into the base material sufficiently.

In the context of GMAW, achieving the right heat input is crucial for proper metal transfer and ensuring that the weld pool reaches the necessary temperatures for effective bonding. Insufficient heat can also lead to defects, as it does not allow for a thorough integration of the materials being joined, resulting in poor mechanical properties and compromising the integrity of the weld.

Other options describe different welding issues or characteristics that do not correspond to a cold weld situation. For instance, high penetration and strong fusion indicate a well-executed weld, while excessive spatter or poor bead appearance relates more to improper technique or settings rather than fusion adequacy. Minimal heat input and rapid cooling, while they can contribute to undesirable effects, do not explicitly describe the condition of a cold weld as effectively as insufficient fusion with surface buildup.