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从热轧双相钢的实际应用需求出发,研究了高强度热轧双相钢DP600的低周疲劳性能。采用轴向应变控制方法对DP600钢进行了低周疲劳试验,并对试验数据进行拟合计算,得到DP600钢的循环应力-应变曲线、应变-寿命曲线和过渡疲劳寿命。通过扫描电镜观察疲劳断口,结果显示低周疲劳条件下,DP600钢断裂裂纹起源于试样表面,裂纹扩展前期呈现部分脆性断裂特征,后期则以明显的韧性断裂为主。
Based on the practical application requirements of hot-rolled dual-phase steel, the low-cycle fatigue properties of high-strength hot-rolled dual-phase steel DP600 were studied. The low-cycle fatigue test of DP600 steel was carried out with axial strain control method. The test data were fitted and calculated to obtain cyclic stress-strain curve, strain-life curve and transition fatigue life of DP600 steel. The fatigue fracture was observed by scanning electron microscopy. The results show that the fractures of DP600 steel originate from the surface of the specimen under low cycle fatigue condition, and show some brittle fracture characteristics at the early stage of crack propagation and the obvious ductile fracture at the later stage.