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对S38C中碳钢进行表面感应淬火+低温回火处理,对处理后的试样显微组织、截面硬度分布和抗拉强度进行表征,通过疲劳试验和断口形貌分析评价压痕对先压痕后淬火和先淬火后压痕两类试样疲劳性能的影响。结果表明,试样有效淬硬层厚度为700μm,淬硬层有未转变的铁素体存在,最大硬度480 HV0.2在亚表面200μm处。淬火试样抗拉强度比基体材料高140MPa,断裂伸长率只有基体的一半。当压痕较小时,两类试样的疲劳强度没有差异,当试样压痕较大时,淬火后压痕疲劳断面有微裂纹,造成这类试样疲劳强度迅速下降,表面强化材料表面冲击损伤不能简单的当作一般缺陷处理。
S38C medium carbon steel surface induction quenching + low temperature tempering treatment of the sample after the microstructure, cross-section hardness distribution and tensile strength were characterized by fatigue test and fracture surface evaluation of indentation on the first impression After quenching and after quenching the first two types of specimen indentation fatigue properties. The results show that the effective hardened layer thickness of the sample is 700μm, the non-transformed ferrite exists in the hardened layer, and the maximum hardness of 480 HV0.2 is at the sub-surface of 200μm. Quenched specimen tensile strength higher than the base material 140MPa, elongation at break is only half of the matrix. When the indentation is small, there is no difference in the fatigue strength of the two types of specimens. When the indentation of the specimen is large, there are micro-cracks in the indentation fatigue fracture surface after quenching, resulting in the rapid decrease of the fatigue strength of such specimens, Damage can not simply be treated as a general defect.