Interpass temperature is the temperature maintained between weld passes to control hydrogen diffusion, microstructure, and residual stresses; excessive temperatures can cause cracking. Which statement best describes interpass temperature?

Interpass temperature is the temperature maintained between weld passes to control hydrogen diffusion, microstructure, and residual stresses; excessive temperatures can cause cracking. Which statement best describes interpass temperature?

• A. The temperature of the base metal during the welding pass
• B. Temperature maintained between weld passes to control hydrogen diffusion, microstructure, and residual stresses; excessive temperatures can cause cracking
• C. The temperature of the shielding gas supply
• D. Ambient temperature during welding

Answer: (B)

Interpass temperature is the temperature kept between weld passes to influence how hydrogen diffuses, how the microstructure develops in the heat-affected zone and weld metal, and how residual stresses are retained or relieved. Keeping this temperature within a controlled range helps prevent problems like cracking as the weld cools after each pass. If the interpass temperature gets too high, the repeated heating can coarsen the microstructure, raise residual stresses, and alter hydrogen behavior in a way that makes cracking more likely when the weld eventually solidifies. This is why welding procedures specify a maximum interpass temperature and require cooling between passes. The other described temperatures—during the actual weld pass, in the shielding gas supply, or ambient conditions—do not define interpass temperature.

Interpass temperature is the temperature kept between weld passes to influence how hydrogen diffuses, how the microstructure develops in the heat-affected zone and weld metal, and how residual stresses are retained or relieved. Keeping this temperature within a controlled range helps prevent problems like cracking as the weld cools after each pass. If the interpass temperature gets too high, the repeated heating can coarsen the microstructure, raise residual stresses, and alter hydrogen behavior in a way that makes cracking more likely when the weld eventually solidifies. This is why welding procedures specify a maximum interpass temperature and require cooling between passes. The other described temperatures—during the actual weld pass, in the shielding gas supply, or ambient conditions—do not define interpass temperature.