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用电阻法研究了含1.43%Cr,1.02%C的滚珠钢在室温到马氏体点(159℃)温度范围内奥氏体等温转变过程。结果指出在这一温度范围内的等温转变是以马氏体转变的形式进行的,而不产生中温转变形式的等温转变。当样品由1100℃淬火至室温后再“上淬”至低于马氏体点的温度进行等温保持时,部分的残留奥氏体即等温转变为马氏体。根据动力学的考虑,这一转变很可能不是通过形成新的晶核,而是已有马氏体晶体的长大过程。同时,这种转变主要受已有马氏体回火过程的控制。在100℃左右长期等温保持时可以得到最大的残留奥氏体转变量。更高或更低的温度,在同一时间内转变量都较100℃左右为小,这可作为精密量具刃具实际热处理的参考。
The isothermal transformation of austenite in ball steel containing 1.43% Cr and 1.02% C at room temperature to martensite point (159 ℃) was studied by means of electrical resistance method. The results indicate that the isothermal transformation in this temperature range is in the form of a martensitic transformation without the formation of an isothermal transformation of the mesothermal transformation. When the sample is quenched from 1100 ° C to room temperature and then “quenched” to a temperature below the martensitic point for isothermal holding, part of the retained austenite is isothermally transformed into martensite. According to kinetic considerations, this transformation is likely not through the formation of new nuclei, but the growth of martensite crystals have been. At the same time, this shift is largely controlled by the existing martensite tempering process. In the long-term isothermal holding at about 100 ℃ can get the maximum amount of retained austenite transformation. Higher or lower temperature, at the same time the amount of change is smaller than about 100 ℃, which can be used as a precision measuring tool heat treatment reference.