What is the maximum temperature that steel can be heated to while heat shaping?

• A. 700 C
• B. 500 C
• C. 590 C (1100 F) for quenched and tempered steel; 650 C (1200 F) for all others
• D. 650 C (1200 F) for quenched and tempered; 590 C (1100 F) for all others

Answer: (C)

When heating steel for shaping, you want to stay in a temperature range that doesn’t undo the work already done to the metal’s structure. For steel that has been quenched and tempered, heating above about 590 C (1100 F) can reverse the tempering—softening the steel and lowering its hardness and strength. That’s why the safe maximum for heat shaping quenched and tempered steel is 590 C. Other steels that haven’t been quenched and tempered have a slightly broader safe window and can tolerate up to about 650 C (1200 F) for hot forming without the same risk of losing their temper. Heating to 700 C would push quenched and tempered steel beyond its limit and degrade its properties, while 500 C is typically too low to achieve effective shaping.