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对热轧H型钢的高应变低周疲劳性能进行了研究。采用轴向应变控制的方法,在Instron-1342型电液伺服疲劳试验机上测定了热轧H型钢的低周疲劳性能数据,研究了在循环载荷下材料的循环应力响应特征、循环应力与应变关系,并用Coffin-Manson公式拟合得到热轧H型钢的疲劳寿命计算公式,据此计算了Nf=100时的aσ.Δtε值。通过断口扫描发现,裂纹不仅在试样表面处形核,同时也在试样内部杂质处形核,然后通过不断的扩展形成微裂纹,许多微裂纹通过扩展连接形成宏观裂纹,最终导致材料断裂。
The high strain and low cycle fatigue properties of hot rolled H-section steels were studied. The axial strain control method was used to measure the low cycle fatigue properties of hot rolled H-section steel on an Instron-1342 electro-hydraulic servo fatigue tester. The cyclic stress response characteristics, cyclic stress and strain of the material under cyclic loading were investigated. , And the fatigue life of hot-rolled H-section steel was fitted by the Coffin-Manson formula to calculate the value of aσ.Δtε for Nf = 100. Through the fracture scanning, it is found that the crack not only forms nuclei on the surface of the sample, but also forms nuclei in the impurities inside the sample and then forms microcracks through continuous expansion. Many microcracks form macroscopic cracks by expanding the connection, which eventually leads to material fracture.