Cr含量对低合金耐蚀管线钢焊接接头组织和性能的影响

采用钨极氩孤弧焊(TIG)对Cr含量为1wt%～5wt%的低合金耐蚀管线钢进行焊接,研究Cr含量对焊接接头组织和力学性能的影响。结果表明,随着低合金耐蚀管线钢中Cr含量提高,粗晶热影响区晶粒尺寸变大,熔合区组织不均匀,易出现淬硬组织。随Cr含量提高,焊接接头的硬度呈上升趋势,冲击韧性呈下降趋势,尤其当Cr含量达5wt%时,硬度的提高和冲击韧性的下降尤为明显。低合金耐蚀管线钢的Cr含量不超过3wt%时,可得到硬度适中、韧性较高的焊接接头。

Effects of Cr content on microstructure and properties of low alloy corrosion resistant pipeline steel weld joints

Low alloy corroaion resistant pipeline steels containing 1wt% ～ 5wt% Cr were welded by tungsten inert gas welding (TIG) , and the effect of Cr content on microstructure and mechanical properties of the weld joints were investigated.The results show that, with Cr content increasing.grain size of heat-affected zone with coarse grain increases, inhomogeneous microstructure is observed in fusion zone,and hardened phases tend to be present in the weld joint.With Cr content increasing hardness of the weld joint increases and its impact toughness decreases, especially when Cr content is up to 5 wt% .The weld joints with proper hardness and higher toughnesa can be obtained when the Cr content of low alloy corrosion resistant pipeline steel is no more than 3 wt% .