手工自蔓延焊接Al_2O_3-SiO_2-CaO渣系研究

Study on Al_2O_3-SiO-2-CaO Slags of Manual SHS Welding

以SiO2、CaO作为造渣剂,研究其对焊渣、焊条燃烧及焊接质量的影响。结果表明,造渣剂的添加明显改善了渣液分离和焊接效果,随添加量增多,燃烧型焊条燃烧速度降低,焊渣密度发生改变但无明显变化规律,综合考虑焊接质量及操作性,SiO2和CaO的添加量分别以0.6~0.9g和0.3~0.6g为宜。手工自蔓延焊接熔渣为玻璃态和晶体共存的多元渣系,焊渣具有Al2O3、2CaO·3SiO2、CaO·Al2O3、FeO·Al2O3和金属Cu。接头断口中仍存在少量未分离的焊渣,抗拉强度达350MPa以上,满足应急抢修的力学性能需求。

SiO2 and CaO were added as slagging elements and the effect of their addition were studied. Results show that slagging addition accelerates the separation for slag from the weld pool. As the addition amount of SiO2 and CaO increases, the combustion velocity of the rod becomes lower and the density of the slag also changes, but without obvious changing rule. In view of the quality and the controlling of welding, the appropriate addition amount of SiO2 and CaO are 0.6-0.9 g and 0.3-0.6 g respectively. SEM results indicate that the microstructure of the manual SHS welding slag includes glass and crystalloid. XRD analysis show that the slag has 5 phases. A few of slagging inclusion appear in the fractured surface of welded joint, indicating some slag has not separated from the weld metal. The tensile strength of the joint reaches 350 MPa, meeting the requirement of mechanical properties for emergency welding.