合金元素对高强管线钢埋弧焊缝组织性能的影响

Effect of Alloy Elements on Microstructure and Mechanical Properties of Submerged Arc Weld Metal for High Strength Pipeline Steel

通过对X80管线钢进行埋弧焊接试验,分析了合金元素Mn、Ni对高强度管线钢埋弧焊缝的显微组织和力学性能的影响。试验结果表明,当Mn元素含量过高时,焊缝金属的冷裂纹敏感指数提高,细化原奥氏体晶粒尺寸,对针状铁素体形核不利;相比较而言,Ni元素对焊缝的冷裂纹敏感指数影响较小,且使焊缝金属易于产生交滑移,更易保证焊缝针状铁素体含量,从而提高焊缝金属的韧性;另外,随着Mn、Ni元素含量的增加,焊缝金属中先共析铁素体受到抑制。

Taking submerged arc weld metal of X80 pipeline steel as an example,the effect of Mn and Ni elements on the microstructure and mechanical properties of submerged arc weld metal for high strength pipeline steel were analyzed.The results show that excessive Mn content can enhance the sensitivity exponent of weld crack and refine the original austenite grain,which is adversed to the acicular ferrite in the weld.Comparatively,Ni has little effect on the sensitivity exponent of weld crack and activated cross slip of weld metal,which can effectively obtain more high-strength and toughness for promoting the nucleation of acicular ferrite,moreover,with Mn and Ni content increasing,the eutectoid ferrite in the weld metal reduces.