What can happen if interpass temperature is too low in a multi-pass weld?

• A. Interpass temperature only affects color.
• B. Welding with interpass temperatures that are too low can lead to poor bonding between passes and potential cracking.
• C. Interpass temperature affects deposition rate.
• D. Interpass temperature has no effect.

Answer: (B)

In multi-pass welding, how hot the area between passes is matters for how well each new bead fuses to the one before it and how the metal relaxes and changes its microstructure. If the interpass temperature is too low, the previous pass has cooled too much, and the next bead doesn’t wet and fuse reliably with it. That weak bonding between passes creates geometric and metallurgical discontinuities that can become crack initiation sites as the weld cools and stresses develop. So, keeping the interpass temperature within the recommended range helps ensure proper fusion between passes and reduces the risk of cracking.

The other ideas aren’t the main effect: interpass temperature isn’t primarily about color or deposition rate, and it does have a real effect on the weld between passes, so saying it has no effect isn’t accurate.