What is a typical interpass temperature limit for TIG welding stainless steel according to common practice?

• A. 0°C
• B. 150°C
• C. 300°C
• D. 500°C

Answer: (B)

Interpass temperature is the maximum temperature allowed at the weld area between passes. For TIG welding stainless steel, keeping this limit around 150°C is typical because it helps prevent carbide precipitation and sensitization along grain boundaries, which can reduce corrosion resistance and increase the risk of cracking in the heat-affected zone. Higher interpass temperatures, like 300°C or 500°C, can lead to unintended microstructural changes and more demanding heat input control, while 0°C isn’t practical to maintain during welding. Therefore, 150°C best aligns with common practice.