60Si2Mn弹簧钢碳化物快速球化工艺研究

Study on the Technique of Carbide Fast Spheroidizing for 60Si2Mn Spring Steel

从离异共析转变的原理出发,开发60Si2Mn弹簧钢的快速球化退火工艺。讨论加热温度对残留碳化物粒子数量和分布的影响规律以及残留碳化物粒子对碳化物快速球化的作用,研究冷却速度对相变模式的影响。结果表明快速球化退火中,加热温度过高,碳化物完全溶解,没有残留的碳化物作为后续形核核心,加热温度过低,片层状碳化物溶解、断裂不完全;60Si2Mn弹簧钢快速球化退火的加热温度应控制在760℃附近;随着冷却速度的降低,球状碳化物颗粒增大、组织硬度下降,60℃/h为最佳冷却速度。

Based on the principle of divorced eutectoid transformation,fast spheroidizing annealing process of 60Si2Mn spring steel is developed.Discussed the effect of heating temperature on the residual amount and distribution of carbide particles and effect of residual carbide particles on fast spheroidizing.Results show that the carbide is dissolved fully when heating temperature is too high,and there is not cores for subsequent nucleation;the lamellar carbide is dissolved and broken inadequately if the heating temperature is too low.The appropriate heating temperature for 60Si2Mn steel fast spheroidizing is about 760℃.With the cooling rate decrease,the spherical carbide particle size increase and hardness decrease.The optimal cooling rate is 60℃/h.