药芯焊丝焊缝中的夹杂物对针状铁素体形成的影响规律

系统研究了药芯焊丝焊缝金属中非金属夹杂物尺寸大小和分布规律，用透射电镜和能谱仪分析了焊缝金属中非金属夹杂物的非状和化学成分。结果表明：药芯焊丝焊缝金属中促进针状铁素体形核长大的非金属夹杂物是Ｔｉ、Ｍｎ、Ｓｉ、Ａｌ、Ｃｕ形成的氧硫复合物。焊缝金属中Ｎｉ、Ｍｎ、Ｍｏ的含量和焊接线能量对非金属夹杂物的尺寸大小及化学成分影响很小。药芯焊丝焊缝金属中针状素体的形核长大是由于非金属夹杂物有高能惰性界面，以及非

The Effect of the Inclusions in Weld Metals for Flux Cored Wires on the Forming of Acicular Ferrite

The sizes of non-metallic inclusions in weld metals for flux cored wires and the rule of their distribution are systematically studied. The chemical composition and the figures of nonmetallic inclusions in weld metals are analyzed with transmission electron microscopy and X ray microanalysis. The results show that the non-metallic inclusions beneficial to nucleation and growth of acicular ferrite in weld metals are oxidation products of Ti, Mn, Si, Al and the sulphides of Mn and Cu. The percentage of Ni,Mn and Mo in the weld metals and welding energy input have little effect on the chemical composition,sizes and figures of non-metallic inclusions in the weld metals. As nucleation sites, the non-metallic inclusions can reduce the nucleation energy remarkably. Besides they have different thermal expansion coefficients from that of the substrate metals, which will introduce a high stress-stain field around the inclusions during the cooling process. These two factors are the main driving forces to the nucleation and growth of acicular ferrite.