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探讨了淬火和回火温度对喷射成形M42高速工具钢显微组织及硬度的影响。结果显示:淬火温度低于1180℃时,钢的淬火态硬度随温度升高而增大;高于1180℃之后,钢的淬火态硬度随温度升高而减小。淬火温度升高过程中,钢中碳化物的数量呈减少趋势,马氏体不断粗化,同时残留奥氏体数量逐渐增加。钢的硬度随回火温度的升高逐渐增大,并在550℃时达到极大值,随后逐渐减小。回火温度升高过程中,马氏体中不断析出碳化物并聚集长大,同时马氏体和部分残留奥氏体会向回火马氏体转变。
The effect of quenching and tempering temperature on the microstructure and hardness of spray forming M42 high speed tool steel was discussed. The results show that when the quenching temperature is lower than 1180 ℃, the hardness of quenched steel increases with the increase of temperature. When the temperature is higher than 1180 ℃, the hardness of quenched steel decreases with increasing temperature. During the quenching temperature, the amount of carbides in the steel tends to decrease, the martensite continuously coarsens, and the amount of retained austenite gradually increases. The hardness of steel gradually increases with the increase of tempering temperature and reaches the maximum at 550 ℃, then decreases gradually. Tempering temperature, the continuous precipitation of martensite carbide and growth, while the martensite and some retained austenite will be transformed into tempered martensite.