Quenching is performed after heating a metal to its hardening temperature.
For most steels, the heating temperature is typically between 800°C and 900°C before quenching.
The heated metal is then rapidly cooled in water, oil, air, or brine.
What is the temperature of quenching?
The quenching temperature depends on the type of steel being heat-treated.
For Carbon Steels
- Hypoeutectoid steels (< 0.8% C): 30–50°C above the upper critical temperature (A₃), typically 800–900°C.
- Eutectoid steel (~0.8% C): about 760–800°C.
- Hypereutectoid steels (> 0.8% C): 30–50°C above the lower critical temperature (A₁), typically 750–850°C.
Conclusion
For most engineering workshop and manufacturing-process questions:
Quenching temperature = 800–900°C (approximately 850°C for plain carbon steel).
After heating to this temperature, the steel is rapidly cooled in water, oil, or another quenching medium to form hard martensite.
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