熔渣成分和微观结构对自保护药芯焊丝脱渣性的影响

Effect of slag composition and microstructure on slag detachability of self shielded flux cored wire

采用SEM,XRD对X80管线钢用碱性自保护药芯焊丝的焊后熔渣进行了分析,研究了熔渣化学成分、熔渣微观组织结构对脱渣性的影响.结果表明,BaO,TiO_2的复合相在熔渣中占有较大比重,在造渣及脱渣中起着重要作用;随着熔渣中TiO_2含量的增加,CaO,SiO_2含量的减少,熔渣的微观组织结构由小颗粒状逐渐转变为非等轴的针状、棒束状、小块儿状,熔渣的方向性变强,内部结合力增大,同时,能形成尖晶石的自由氧化物减少,熔渣与焊缝金属之间的结合力降低,粘渣变少,脱渣性变好;当熔渣中TiO_2/CaO比值达到4~6,同时将SiO_2/CaO比值控制在1~2时,能获得较好的脱渣性.

The slag of alkaline self-shielded flux cored wire for X80 pipeline steel were analyzed by means of scanning electron microscopy(SEM)and X-ray diffraction(XRD).The effects of chemical compositions and microstructure of slag on its slag detachability were studied.The results show that the composite phase of BaO and TiO 2,which plays an important role in slaggability and detachability and occupies a large proportion in slag.With the increase of TiO 2 content in slag and the decrease of CaO and SiO 2 content,the microstructures of slag transforms gradually from fine particles to anisometric grains such as acicular,rod-like,small block particles.The orientation of the slag becomes stronger and the internal bonding force increases.Meanwhile the free oxide that can form spinel decreases,the bonding force between the slag and the weld metal decreases,the amount of the slag decreases,and the detachability becomes better.When the TiO 2/CaO ratio in slag reaches 4~6 and the SiO 2/CaO ratio is controlled in 1~2,the better slag detachability can be obtained.