模拟点蚀油气管线钢的拉伸性能

根据发生点腐蚀的油气管线基体有许多点蚀坑的特点,通过计算机产生随机数确定点蚀坑的位置,用小钻头打孔的方法模拟X60管线钢基体的多孔特征进行拉伸试验,测得其弹性模量、屈服强度和抗拉强度,并将理论计算值与前二者进行比较和修正,给出了多孔钢材的抗拉强度与孔隙率的函数关系.结果表明,多孔钢材弹性模量的实测值随孔隙率的变化与理论预测结果较为吻合;钢材实测屈服强度也随着孔隙率的增加而减少,但在较高孔隙率时其减少趋势变缓;衰减速率的实测值略大于理论预测值;实测抗拉强度随孔隙率的变化曲线与屈服强度相似,但对孔隙率更敏感.

Tensile Characteristics of Steel for Oil and Gas Pipeline with Simulative Pitting Corrosion

According to the characteristics of pitting corrosion of pipe with concavities distributed randomly on the surface in different depth, the location of simulated concavities of pitting corrosion on pipe surface of X60 steel were detetermined by computer and the simulative specimens were prepered to measure elastic modulus, yield strength and tensile strength of porous material by tensle test, and the testing results were compared with calculated value to modify theoretical formulae and suitable expression was obtained for tensile strength. The results showed that the elastic modulus and yield strength of porous material are decreased with the increase of porosity, and the change is slowed down gradually. The measured elastic modulus agree with calculated, but measured yield strength is less than calculated. The measured average tensile strength is decreased also evidently with porosity, but more sensible to porosity.