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本文测定了18Cr2Ni4WA钢奥氏体连续冷却转变曲线,分析了不同冷速下的显微组织,研究了冲击疲劳、旋转弯曲疲劳、断裂韧性和常规机械性能,讨论了组织和性能的关系。结果表明:该钢的显微组织依冷速不同可分别获得板条马氏体、板条马氏体和贝氏体、贝氏体、以至全部为粒状贝氏体。冷却时间约一小时得到以粒状贝氏体为主的组织,其综合机械性能优于其他组织。不同冷速的组织中均存在一定数量和尺寸的(M/A)岛,对疲劳裂纹扩展有阻碍作用,可提高疲劳寿命。
In this paper, the continuous cooling transformation curves of 18Cr2Ni4WA steel were measured. The microstructures of the 18Cr2Ni4WA steel were analyzed under different cooling rates. The impact fatigue, spin-bending fatigue, fracture toughness and mechanical properties were studied. The relationship between microstructure and properties was also discussed. The results show that the microstructure of the steel can be obtained according to different cooling rates lath martensite, lath martensite and bainite, bainite, and even all of the granular bainite. Cooling time of about one hour to get granular bainite-based organizations, its overall mechanical properties superior to other organizations. There are a certain number and size of (M / A) islands in different cooling rates, which hinders the fatigue crack growth and improves the fatigue life.