2Cr12Ni4Mo3VNbN新型叶片钢高频淬火后的显微组织与疲劳性能

为提高2Cr12Ni4Mo3VNbN马氏体不锈钢叶片的疲劳性能,对调质处理后的叶片刃口区进行了高频淬火处理,研究了高频淬火前后2Cr12Ni4Mo3VNbN钢的显微组织、残余应力分布和疲劳性能。结果表明:2Cr12Ni4Mo3VNbN钢高频淬火后显微组织中的原奥氏体晶粒和马氏体板条束都得到细化,没有明显的析出物,而未高频淬火的马氏体有较多窄条状M3C析出。2Cr12Ni4Mo3VNbN叶片高频淬火区表层层深0.1 mm以内主要为压应力,应力值约在-450 MPa^-20 MPa之间,且随层深增加而减小。高频淬火态2Cr12Ni4Mo3VNbN钢的疲劳裂纹扩展门槛值为6.75 MPa·m^1/2,高于未高频淬火态下的4.73 MPa·m^1/2,并且高频淬火态2Cr12Ni4Mo3VNbN钢中的疲劳裂纹扩展速率低于未高频淬火态。这表明,高频淬火处理提高了2Cr12Ni4Mo3VNbN马氏体不锈钢的疲劳裂纹扩展抗力和疲劳裂纹扩展寿命。

Microstructure and fatigue properties of 2Cr12Ni4Mo3VNbN new blade steel after high-frequency quenching

In order to improve the fatigue properties of 2Cr12Ni4Mo3 VNbN martensite stainless steel blade, the blade edge area after quenching and tempering was treated by high frequency quenching. Microstructure, residual stress distribution and fatigue properties of the 2Cr12Ni4Mo3 VNbN steel before and after high frequency quenching were studied. The results show that the primary austenite grains and martensite lath bundles in the microstructure of the 2Cr12Ni4Mo3 VNbN steel are refined after high frequency quenching, and there are no obvious precipitates, but there are many narrow strip M3C precipitates in the martensite of the steel before high frequency quenching. The compressive stress is mainly within 0.1 mm layer depth of the high frequency quenching zone of the 2Cr12Ni4Mo3 VNbN blade, and the stress value is about-450 MPa--20 MPa, and decreases with the increase of layer depth. The threshold of fatigue crack propagation of the 2Cr12Ni4Mo3 VNbN steel before and after high frequency quenching is 4.73 MPa·m^1/2, and 6.75 MPa·m^1/2, respectively, and the fatigue crack growth rate in the high frequency quenched 2Cr12Ni4Mo3 VNbN steel is lower than that in the non high frequency quenched steel. The results show that the fatigue crack propagation resistance and fatigue crack growth life of the 2Cr12Ni4Mo3 VNbN martensite stainless steel are improved by high frequency quenching.