Tempering heat
Tempering heat the steel which was quenched at the tempreature below AC1,than cool down after holding for period of time.
Tempering may divide into the low-temperature tempering,the mid-temperature tempering and the high-temperature tempering.
1.low-temperature tempering(250℃below), mainly used by carbon tool steel,the production of low alloy steel as mould,tool,carburization and hardening parts.
2.mid-temperature tempering(350~500℃),always work for all kinds of elastic element.
3.high-temperature tempering(500~650℃),mainly used for producting constitutional detail,such as connecting rod,bolt,wheel gear and bearing.
Tempering purpose:
First,to reduce residual stress and brittleness caused by quenching.
Second,to get technical requirements of mechanical properties.
Third,to stabilize the size of the workpiece.
Forth,for high hadenability steel,tempering can reduce the hardness and shorten the softening cycle of the steel.
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