X80高强度高韧性厚壁管线钢及高速埋弧焊接头性能

Properties of welded joint of X80 thick-walled pipeline steel for high-speed submerged arc welding

研究分析了西气东输二线用X80管线钢的组织和性能,通过TEM观察了晶体结构特征,表明X80管线钢晶粒细小、晶界纯净,金相组织均匀,力学性能稳定,是一种高强度、高韧性管线钢。针对这种X80管线钢高速埋弧焊,通过焊丝焊剂的成分设计和焊缝组织设计,以及高纯净度炼钢技术,研制出高性能焊丝焊剂,采用优化的焊接工艺,使焊接接头不但具有较好的力学性能,而且焊接工艺性能良好,实现了高强度厚壁管线钢的高速焊接,焊速可达1.70 m/m in左右。

The structure and performance of X80 pipeline steel which used in the 2nd West-east Gas Pipeline project were analyzed.The TEM analyses on crystal structure shows that X80 pipeline steel is a high strength and toughness pipeline steel with small grains,pure crystal boundary,uniform microstructure and stable mechanical properties.For submerged arc welding of X80 pipeline steel,welding wire and flux with high performance were developed by optimizing the compositions of welding wire and flux and designing the structure of weld.By using of the optimized welding parameters and the welding wire and flux with good performance,the welded joint not only has good mechanical properties,but also get the excellent technical properties,which realizes the high-speed welding(the welding speed can be up to 1.70 m/min) of the high strength and high toughness pipeline steel.