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采用升降法对CSP工艺生产的2mm厚Ti微合金化高强钢的疲劳性能进行研究.结果发现:高强钢的抗拉强度为830 MPa;疲劳强度为685 MPa,约为抗拉强度的0.83倍;伸长率为18.8%.绘制了高强钢的S--N曲线,并拟合出疲劳寿命与最大应力的关系.通过扫描电镜对疲劳断裂机理进行了分析.宏观疲劳断口可见明显的裂纹源区、扩展区和瞬断区形貌.疲劳裂纹起始于带钢表面微裂纹;疲劳扩展区存在微观疲劳辉纹、二次裂纹和宏观疲劳贝纹线;瞬断区出现撕裂棱,兼有韧窝存在.
The fatigue behavior of 2mm thick Ti microalloyed high strength steel produced by CSP process was studied by lifting method.The results show that the tensile strength of high strength steel is 830 MPa, the fatigue strength is 685 MPa, which is about 0.83 times of the tensile strength, Elongation of 18.8% .The S - N curve of high strength steel was drawn and the relationship between fatigue life and maximum stress was fitted.The fatigue fracture mechanism was analyzed by scanning electron microscope.The obvious source of crack , Extended zone and instantaneous zone.Fatigue cracks originated in the micro-cracks on the surface of the steel strip.The micro fatigue fatigue, secondary cracks and macroscopic fatigue crack lines existed in the fatigue extension zone, and the tear edges appeared in the instantaneous zone, Dimples exist.