铝对自保护药芯焊丝焊缝组织及力学性能的影响

Effect of Al on Microstructure and Mechanical Properties ofWeld Metal of Self-Shielded Flux Cored Wire

通过光谱分析、Luzex.F图像分析、扫描电镜、能谱分析、力学性能试验等手段,研究了高铝BaF2渣系自保护药芯焊丝焊缝中的Al含量对焊缝中夹杂物、微观组织和力学性能的影响.研究结果表明:随焊缝中的Al含量增高,焊缝夹杂物平均尺寸增大;焊缝中的夹杂物以AlN和Al2O3为主,在低Al焊缝中以Al2O3为主的夹杂物较多,而在高Al焊缝中AlN夹杂较多;Al含量的不同会引起焊缝微观组织的改变,以Al2O3为主的夹杂物能够诱导焊缝中针状铁素体形核,而AlN夹杂会引起焊缝组织粗大;焊缝中Al含量增加使焊缝的强度增高而韧性下降.

The effect of Al on inclusions, microstructure and mechanical properties of weld metal of self-shielded flux cored wire with high Al content BaF2 slag was investigated. The experimental results reveal that the average size of the inclusions grows with the increase of Al component in the weld metal, and the inclusions in weld metal mainly consist of AlN and Al2O3; the inclusions in the weld with low Al concentration are predominantly Al2O3, and the inclusions in the weld with high Al concentration are mostly AlN. Welds exhibit different microstructures owing to different Al contents in weld metal. Al2O3-predominated inclusions can induce acicular ferrite by acting as nucleating center. And AlN inclusions can lead a coarse microstructure of weld metal. The weld strength is enhanced and the weld toughness is weakened with the increase of Al in the weld metal.