The tempering temperature is generally 350-500 degrees Celsius, and the tempering tissue is a large number of fine-grained carburizing bodies distributed on the ferrite matrix, that is, tempered daltensite tissue. The ferrite in the tempered quellsonite tissue still retains the form of martensitic.
The internal stress of the workpiece is basically eliminated after medium temperature and fire, and it has high elastic limit and yield strength, high strength and hardness (35-45HRC), good plasticity and toughness. Medium temperature tempering is mainly used for various spring parts and hot forging molds.