用插销力衰减法研究管线钢焊接接头应力腐蚀的动态过程

Study on Dynamic State of SCC or Pipe Line Steels and Their Weld Metals by Implant-force-decreasing Method

本文首次用插销试验法进行了力、位移跟踪测试，成功地获得了高频输送焊管应力腐蚀破裂（ＳＣＣ）的动态参数．结果表明：在ＳＣＣ研究中，用跟踪力松驰曲线来估算裂纹扩展速率是可行的，这种方法具有简单、可靠、易自动化等优点；不仅增加了新的测试途径，而且扩充了插销法在ＳＣＣ研究中的应用范围．实验中结合四种管线钢及其对应的高频焊缝等八种试样，分别在０．９σｂ的初始应力下进行了裂纹扩展的动态观测，得到的变化规律与其ＳＣＣ监界值σｉｍｐＳＣＣ的变化规律基本一致；四种焊缝的值均高于相应母材的值；随着初始应力σｉｍｐ的增加，增加，裂纹稳定扩展时间下降．

The dynamic parameters of SCC of pipe line steels and their weld metals were firstly obtainted by implant SCC test method through the changes of the force and displacement of the specimens in SCC. The result showed: It was feasible that the force-decreasing curve was used to estimate the propagation speed of SC-crack( )of pipe line steels and their weld metals. This method possesses simple, reliable and easly automatical advantages. It not only added the new method to messure the in SCC, but also expanded the range applied by Implant SCC test method.The force-decreasing curves of four kinds of pipe line steel and their weld metals were messured when intial stress σimp was equal to 0. 9σb. The change tendency of the coincided with that of the critical value of SCC. The of four kinds of weld metal was higher than that of four kinds of pipe line steels. The of test materials increased and the time of stable propagation of SC-crack decreased with initial stress increased.