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18Cr2Ni4WA 钢是一种合金元素含量较高的结构钢,经淬、回火后具有良好的综合机械性能。因此,被广泛应用于发动机重要结构件上。按照传统观念,这种钢属于马氏体钢,空冷后即可得到马氏体组织,有较好的疲劳性能。但实际情况并非如此,某厂用该钢制的曲轴,淬火(空冷)回火后的疲劳性能(σ_(-1))常达不到技术要求。当然,原因是多方面的,但显微组织是一个重要的影响因素。为此,研究18Ct2Ni4WA钢不同冷速和零件实际冷速下的显微组织及其对性能的影响,并找到提高疲劳性能的热处理途径是一个重要的研究课题。本文根据实际使用的18Cr2Ni4WA 钢的碳量波动范围,制备了两种不同含碳量的试样,测
18Cr2Ni4WA steel is a high content of alloying elements of steel, after quenching, tempering has a good overall mechanical properties. Therefore, it is widely used in the important structural parts of the engine. According to the traditional concept, this kind of steel belongs to the martensitic steel, after air cooling, the martensite structure can be obtained, which has good fatigue performance. However, the actual situation is not the case, a plant with the steel crankshaft, quenched (air cooled) after the fatigue properties (σ _ (- 1)) often fail to meet the technical requirements. Of course, the reasons are manifold, but the microstructure is an important factor. Therefore, it is an important research topic to study the microstructure of 18Ct2Ni4WA steel at different cooling rates and the actual cooling rate of the part and its effect on the properties, and to find the heat treatment way to improve the fatigue performance. In this paper, according to the actual use of 18Cr2Ni4WA steel carbon fluctuation range, prepared two different carbon content of the sample, measured