汽车齿轮的锻造余热等温退火工艺

Forging residual heat isothermal annealing for automobile gear products

以国产低碳合金钢8620H汽车齿轮产品为研究对象,进行锻造余热等温退火工艺试验。针对锻造加热温度、锻后恒温温度、恒温后的冷却方法、等温转变温度及等温时间等5个工艺要素,分别进行工艺试验。试验结果分析表明,锻造余热等温退火工艺的关键要素是对晶粒度的控制,合适的工艺为:锻造加热温度1200±50℃,锻后高温恒温温度920±10℃,空冷或以合适的方式冷却至稍高于等温温度(630~650℃),然后进入600±10℃等温炉等温70 min后空冷。

Isothermal annealing tests by use of forge residual heat were carried out on automobile gear products made of low carbon alloy steel 8620 H with change of forging temperature , constant temperature after forging and the subsequently cooling method , isothermal transformation temperature and time .The results show that the key factor of isothermal annealing by use of forge residual heat is to control the grain size , the appropriate process is that the forging temperature is 1200 ±50 ℃, the constant temperature after forging is 920 ±10 ℃, and air cooling to 630-650 ℃, then isothermally holding at 600 ±10 ℃for 70 min and air cooling .