What is the typical interpass temperature range for carbon steels, acknowledging code variations?

What is the typical interpass temperature range for carbon steels, acknowledging code variations?

• A. 100-200°C
• B. 150-250°C
• C. 350-450°C
• D. 250-350°C

Answer: (B)

Interpass temperature management is about keeping the weld area at a controlled temperature between passes to influence the metal's microstructure and cracking risk. For carbon steels, the typical range to target is around 150–250°C. This window strikes a balance: it’s high enough to allow good fusion on subsequent passes and prevent overly brittle, hard microstructures, yet low enough to minimize grain growth and residual stresses and to let hydrogen diffuse away during cooldown, reducing the chance of hydrogen-induced cracking. Codes vary, and some allow different windows depending on the filler metal, process, or service requirements, but 150–250°C is the range most commonly cited for carbon steels. The other ranges are less representative of standard practice: too high a range can encourage coarse grains and higher cracking risk, while the lower end can lead to limitations in fusion or processing constraints in some welding setups.

Interpass temperature management is about keeping the weld area at a controlled temperature between passes to influence the metal's microstructure and cracking risk. For carbon steels, the typical range to target is around 150–250°C. This window strikes a balance: it’s high enough to allow good fusion on subsequent passes and prevent overly brittle, hard microstructures, yet low enough to minimize grain growth and residual stresses and to let hydrogen diffuse away during cooldown, reducing the chance of hydrogen-induced cracking. Codes vary, and some allow different windows depending on the filler metal, process, or service requirements, but 150–250°C is the range most commonly cited for carbon steels. The other ranges are less representative of standard practice: too high a range can encourage coarse grains and higher cracking risk, while the lower end can lead to limitations in fusion or processing constraints in some welding setups.