夹杂物尺寸与S135钻杆钢疲劳强度的相关性

摘要

Rotary bending fatigue tests were conducted on S135 drill pipe steel, and then the fatigue performance was studied and the effect of inclusion on the fatigue property was analyzed.The diameters of maximum inclusions in different field-of-views were measured by optical microscope.The fatigue strength of samples was predicted by Murakami model and compared with the tested result.The results show that fatigue cracks originated at the complex aluminum oxide inclusions in the surface or subsurface of samples.The fatigue strength measured by the staircase method was 541.87 MPa.The maximum relative error between the fatigue strength calculated by the Murakami model and the tested value was 5.62%,indicating a relatively high accuracy of the calculation by the Murakami model.%对S135钻杆钢进行了旋转弯曲疲劳试验,研究了其疲劳性能,分析了夹杂物对疲劳性能的影响;利用光学显微镜测得不同视场下钢中最大夹杂物的直径,利用Murakami模型预测得到试样的疲劳强度,并与试验结果进行了对比.结果表明:疲劳裂纹源位于试样表面或次表面的复杂氧化铝夹杂物处,由升降法测得的疲劳强度为541.87 MPa;利用Murakami模型计算得到的疲劳强度与试验值的相对误差最大为5.62%,Murakami模型计算的准确性较高.