材料期刊网

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 =100时的 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。

High strain low cycle fatigue properties of the hot-rolling H beam steel were investigated. By using an axle strain controlled method, the low cycle fatigue properties were tested on a type of Instron 1342 fatigue testing machine. Cycle strain response character of the tow kinds of hot-rolling H beam steel and the relationship between cycle stress and strain were researched. Conffin-Manson formula was used to induce fatigue life formula of the materials, and the values of ?were gained when =100. The SEM micrographs revealed that the microcracks nucleation occurred not only at the surface but also in the interior of the specimen. And with the propagation of the microcracks , they joined together and formed the macrocracks , at last, when the stress was over the ultimate strength of the material ,then fractured.