感应淬火对半轴用非调质钢高周疲劳性能的影响

利用旋转弯曲疲劳试验方法对比研究了一种半轴用铁素体+珠光体型非调质钢感应淬火前后高周疲劳性能的变化。结果表明,试验钢试样感应淬火后表层形成了厚度约1.2 mm、平均显微硬度约650 HV0.3的马氏体组织淬硬层。该淬硬层具有较高的残余压应力和十分细小的原奥氏体晶粒。感应淬火处理后,试验钢的疲劳耐久极限从420 MPa提高到716 MPa。疲劳断口的SEM观察表明,未经感应淬火试样的疲劳裂纹均起源于试样的表面基体,而经表面感应淬火后的疲劳裂纹则起裂于淬硬层边界附近的内部基体。

Effect of induction hardening on high-cycle fatigue property of medium-carbon microalloyed steel for semi-axle

High-cycle fatigue property for semi-axle made of a medium-carbon microalloyed steel before and after induction hardening was investigated by using rotating bending fatigue test.The results show that a martensitic hardened layer with a thickness of about 1.2 mm and an average microhardness of about 650 HV0.3 is formed after induction hardening.This harden layer has relatively higher compressive residual stress and much finer prior austenite grain.The fatigue endurance limit stress of the tested steel increases from 420 MPa to 716 MPa after induction hardening.Further SEM observations of fatigue fracture surface reveals that all the fatigue cracks of the specimen without induction hardening initiate from specimen shallow subsurface,whereas all the fatigue cracks of the specimen with induction hardening initiate under the depth of about 1.2 mm.