大口径高钢级螺旋埋弧焊管强度测试影响因素分析

Analysis for Factors Affecting Strength Testing of SAWH Pipe with Large Diameter

针对西气东输二线用大口径高钢级螺旋埋弧焊管,采用两种试样进行拉伸试验。综合分析影响螺旋焊管强度测试的因素,如试样形式、试验方法等。研究结果表明:不同形式试样测定的螺旋焊管管体横向屈服强度值是包辛格效应、形变强化效应及组织等因素综合作用的结果;包辛格效应是影响其屈服强度测试结果的主要因素;测定屈服强度时采用的总伸长量应根据胀环试验测定的管体实际屈服强度值确定。

The several issues such as the type of specimen and the test procedure which affects the strength testing of SAWH pipe are analyzed.It is presented that the yield strength value of base metal in transverse direction of SAWH pipe from different kinds of specimen may be affected by many factors,such as Bauschinger effect,strain hardening effect,bending angle of the specimens and microstructure etc.The yield strength values were measured by two kinds of tensile specimen cut from SAWH pipe for the 2nd West-East Pipeline Project,the results show that Bauschinger effect is the main factor affected the yield strength measurement for the SAWH pipe used in the 2nd West-East Pipeline Project.It is suggested that the total elongation in total extension under load method for high grade SAWH pipe should be verified by ring expansion test.