合金元素Mo、Ni对X70管线钢管性能和焊接性影响研究

Effect of Mo and Ni on Properties and Weldability of X70 Line Pipe

运用光学显微镜、力学性能测试、硬度云图等分析方法,对比分析了两种不同成分合金元素对X70管线钢管和环焊缝的组织和性能的影响。结果表明:Mo、Ni不仅有利于提高钢管管体的拉伸性能、管体和制管焊缝的冲击性能,而且有利于提高钢管对接环焊的组织性能。同时,在相同的环焊工艺条件下,即使在较高的热输入下,含Mo、Ni钢管的对接环焊熔合线及热影响区不同位置的冲击韧性高于不含Mo、Ni的钢管。综合结果表明,适当增加Mo、Ni有利于提高管体母材、制管焊缝和环焊热影响区的综合性能,保证高钢级管道建设的安全施工和运营。

Effects of different alloy elements composition on micro-structures and properties of X70 line pipe and girth weld were analyzed using optical microscope,mechanical properties test and hardness mapping.It is concluded that alloy elements Mo and Ni is beneficial not only to improve the tensile properties and impact performance of the pipe body and heat affected zone(HAZ)of the seam weld,but also to improve the welding performance of the girth weld.It shows that under the same girth welding process conditions,even under slightly higher heat input,the mechanical performance of girth weld HAZ containing Mo and Ni elements is obviously better than that without Mo and Ni elements.The comprehensive results show that appropriate addition of Mo and Ni alloy elements is beneficial to improve the comprehensive performance of pipe base metal,seam weld and girth weld HAZ,and ensures the safe construction and operation of high steel grade pipeline.