研究了焊剂碱度对管线钢埋弧焊熔敷金属显微组织和韧性的影响。结果表明 :随焊剂碱度的提高 ,焊缝中锰、钛含量增加 ,而氧、硅含量降低 ,同时具有有利于针状铁素体形核的夹杂物尺寸和分布 ,促进了奥氏体晶粒内针状铁素体的形成 ,提高了熔敷金属的低温冲击韧性 The effect of flux alkalinity on microstructure and toughness of submerged arc welded metal in pipeline steel was studied. The results show that with the increase of flux alkalinity, the content of manganese and titanium in the weld increases, while the content of oxygen and silicon decreases, and the size and distribution of inclusions are favorable for the acicular ferrite nucleation and the austenite grains The formation of acicular ferrite increases the low temperature impact toughness of the deposited metal