What is a disadvantage of high heat input during welding?

High heat input during welding can lead to distortion and warping of the base metal due to the excessive thermal energy applied to the material. When the temperature of the metal increases significantly, it expands; upon cooling, the metal contracts. This expansion and contraction cycle can create stresses within the metal, potentially leading to unwanted deformations, such as warping or buckling.

In the context of welding, maintaining optimal heat input is crucial for controlling not only the quality of the weld but also the integrity of the base materials. A lower heat input is typically advantageous for reducing the risk of such distortions, allowing for more precise control of the weld area and minimizing adverse effects on surrounding material.

While the other options might appear beneficial in some contexts, they do not address the key drawbacks associated with excessive heat input in welding processes.