X60管线钢在-20℃低温焊接的接头组织性能

Welded joint properties of X60 pipeline steel at -20 ℃

结合X60管线钢在-20℃低温条件下的焊接施工实际情况进行了试验、测定及分析,研究了711 mm×15.9 mm管道环焊接头的力学性能、接头的金相组织、硬度、冲击吸收功以及冲击断口形貌等.结果表明,在-20℃低温条件下,焊接完成的X60管线钢环焊接头力学性能测试;其HAZ的最大硬度值为210 HV10,符合相关技术标准.该工艺方案经过国内北部地区长输管道的工程使用,质量合格;经过金相显微组织分析,在X60钢-20℃条件下焊接的接头中,未发现淬硬组织;对冲击试件断口形貌的扫描电镜分析表明,该环焊接头的韧性满足相关技术标准的要求.

In accordance with the site construction of X60 pipeline steel at-20 ℃,the mechanical properties,metallograpic structure,hardness,Charpy impact absorbing energy and the fracture structure of the girth welded joints of 711 × 15.9 mm pipeline are analyzed.The results show that the highest HAZ hardness value of the X60 pipe steel joints girth-welding at -20 ℃ cryo-welding is 210 HV10 which meets related standards.The welding procedure specification has been used on the long-distance pipeline projects in China＇s northern area,which obtains satisfactory results： no hardened structures in the joints through metallurgical microscopic observation and the toughness of the joints meeting the requirement of related technical standards through microscopic observation of the cross section of the Charpy test sample.