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本文通过金相、电镜、电阻、X 光、机械性能及切削试验,系统地研究了分级淬火冷却规范对高速钢组织和性能的影响。结果表明,随分级温度的提高,钢的晶界加宽,固溶体浓度下降,残留奥氏体量减少,表明沿晶界有碳化物析出。这种析出首先影响钢的韧性,即使650℃分级淬火,钢的韧性也有明显下降。硬度、红硬性、抗弯强度等要在较高温度下才有明显下降。试样尺寸越大这种影响越明显。在带有较强烈冲击条件下进行的切削试验,得到了与苏联近期某些资料相反的结果,例如 W18Cr4V 钢车刀,分级淬火温度由600℃提高到675℃,将使刀具的切削性能降低15～20%,对加工高硬度材料及大尺寸的刀具影响可能更大。综合上述结果认为,普通高速钢的分级淬火温度以600℃左右为宜。本文最后对试验中的一些现象和与分级淬火有关问题进行了讨论。
In this paper, the effects of grading quenching and cooling regulation on the microstructure and properties of high-speed steel have been studied systematically through metallographic, electron microscope, electrical resistance, X-ray, mechanical properties and cutting tests. The results show that with the increase of the grading temperature, the grain boundary of steel widens, the concentration of solid solution decreases, and the amount of retained austenite decreases, which indicates the precipitation of carbides along the grain boundaries. This precipitation first of all affect the toughness of steel, even if 650 ℃ classification quenching, the toughness of steel also decreased significantly. Hardness, red hardness, bending strength, etc., to be significantly lower at higher temperatures. The bigger the sample size, the more obvious this effect is. The cutting test carried out under more intense impact conditions resulted in the opposite result to some recent Soviet data such as the W18Cr4V steel turning tool and the gradual quenching temperature was raised from 600 ° C to 675 ° C and the cutting performance of the tool was reduced by 15 ~ 20%, the impact of processing high hardness materials and large size tool may be greater. Based on the above results, the classification of ordinary high-speed steel quenching temperature of about 600 ℃ is appropriate. At the end of this paper, some phenomena in the experiment and the problems related to the classification and quenching are discussed.