添加剂对手工自蔓延焊接高Al_2O_3熔渣性能的影响

Influence of Additive Agents on the Performance of Manual SHS Welding Slag with High Content of Al_2O_3

向手工自蔓延焊接燃烧体系中添加Fe O、CaF2、CaCO3作为造渣剂,系统研究添加剂对焊渣性质和焊接性能的影响。结果表明,添加剂导致焊条的燃烧速度和反应的绝热燃烧温度降低,其中CaCO3的作用最为明显。添加剂降低了焊渣的密度和凝固温度,扩大了焊渣的凝固温度范围,促进了焊渣和金属熔池的分离及熔池中气体的排出。每根燃烧型焊条中Fe O、CaF2、CaCO3的适宜添加量分别为（0.60.8）g、（0.20.4）g、（0.40.6）g。获得了微观结构为玻璃基体上分布少量富Cu和Fe晶体颗粒的玻璃态焊接熔渣,脱渣性能良好。焊缝合金为以α-Cu固溶体为基体、弥散分布富Fe第二相的纯净金属组织,基本无非金属夹杂,抗拉强度达410 MPa,具有良好的力学性能。

FeO, CaF_2 and CaCO_3 were added into the combustion system of manual SHS welding as slagging elements and the effects of their additivity were studied. Results show that the combustion velocity and the adiabatic combustion temperature both become lower as the amount of the additives increases, especially CaCO_3. The additives decrease the density and the solidification temperature of the slag, which accelerates the separation of the slag and the gas from the weld pool. The appropriate addition amounts of FeO, Ca F_2 and CaCO_3 for each combustion weld rod are(0.6~0.8)g,(0.2~0.4)g and(0.4~0.6)g, respectively. Glassy weld slag has been obtained, which is brittle and has excellent detachability. Analysis of the microstructure and the composition shows that the matrix of the slag is glass and a few of crystalloid grains with high content of Cu and Fe distributed on it. The matrix of the weld metal is α-Cu solid solution, on which a second phase with high content of Fe precipitates. There are no non-metallic inclusions in the weld metal ultimately. The weld joint has favorable mechanical performance, whose tensile strength reaches 410 MPa, meeting the requirement of emergency welding.