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通过中频真空感应炉冶炼了试验钢,采用箱式电阻炉进行了热处理试验,并分析了预处理、淬火、回火等不同热处理下的组织、硬度变化规律,探讨了淬火温度对试验钢最终组织和力学性能的影响。结果表明,试验钢预处理后的组织为高温回火马氏体+弥散的第二相,组织均匀细化,晶界连续的网状组织完全消除。淬火组织为板条马氏体+残余奥氏体,硬度较高;回火组织主要为回火马氏体+少量残余奥氏体,马氏体板条较为明显,硬度下降。随淬火温度提高,回火组织中回火马氏体板条更为细小化,残余奥氏体含量略有增加;试验钢淬火态、回火态硬度均提高;冲击功先略有降低,当淬火温度超过1040℃时又提高。
The test steel was smelted by the intermediate frequency vacuum induction furnace and the heat treatment test was carried out by using the box type resistance furnace. The changes of microstructure and hardness under different heat treatments such as pretreatment, quenching and tempering were analyzed. The effects of quenching temperature on the final structure of the test steel And mechanical properties. The results show that the microstructure of the pretreated steel is tempered martensite + dispersed second phase, the microstructure is refined and the continuous network structure of the grain boundary is completely eliminated. Quenched tissue lath martensite + retained austenite, higher hardness; tempered martensite mainly a small amount of retained austenite, martensite lath is more obvious, the hardness decreased. With the increase of quenching temperature, the tempered martensite slab in tempering microstructure is more fine and the content of retained austenite slightly increases. The quenched and tempered hardness of the test steels are both improved; Quenching temperature is higher than 1040 ℃ again.