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利用X-射线衍射、金像显微镜和洛氏硬度计,对不同淬火温度、保温时间以及回火后组织进行了分析,研究了不同的热处理工艺对高铬铸铁组织和性能的影响。结果表明:在970℃淬火,保温4h,200℃回火,使硬度值达到62.8HRC。随着淬火温度升高和保温时间的延长,能使奥氏体中的碳含量增加,转变成的马氏体中的含碳量也增加,提高基体硬度;当淬火温度过高或保温时间过长,奥氏体中的碳含量过高,降低MS点,增加残余奥氏体,降低基体硬度。随着回火温度的升高,加速了马氏体的分解和碳化物的析出,马氏体硬度下降,使高铬铸铁的硬度下降。
The effects of different heat treatment processes on microstructure and properties of high chromium cast iron were studied by X-ray diffraction, metallography microscope and Rockwell hardness tester. The effects of different quenching temperature, holding time and microstructure after tempering were analyzed. The results showed that quenching at 970 ℃, holding for 4h and tempering at 200 ℃ made the hardness reach 62.8HRC. With the increase of quenching temperature and holding time, can increase the carbon content in austenite, the carbon content of the transformed martensite also increases, increasing the matrix hardness; when the quenching temperature is too high or holding time Long, austenitic carbon content is too high, lower MS point, increase the residual austenite, reduce the hardness of the matrix. With the tempering temperature increases, accelerating the decomposition of martensite and carbide precipitation, martensitic hardness decreased, so that the hardness of high-chromium cast iron decreased.