摘要
Cold metal transfer(CMT) welding is a brand-new arc welding technique which shows adequate results for welding of thin sheets and dissimilar materials. Corrosion behavior of dissimilar aluminum joints should be determined in terms of predicting the effect of welding process on the possible failures in their constructions caused by corrosive agents. The present study investigates the effect of heat input on mechanical properties and corrosion rate of AA5754-AA7075 joints welded by CMT using ER5356 filler wire. Pore formation was observed not only in the weld metal but also in the partially melted zone of AA7075 base metal due to the vaporization of zinc. Increased heat input caused over aging and zinc vaporization in AA7075 base metal, and grain coarsening in AA5754 base metal consequently decreased the tensile strength. The average tensile strength of AA7075-AA5754 joints varies between 235 and 240 MPa. The ductile fracture occurred at the AA5754 base metal side in all samples. Pitting was observed as the dominant corrosion mechanism. Corrosion resistance tended to increase with increasing heat input. Heat input values between 95 and 110 J/mm are recommended for the optimization of corrosion resistance and strength.
冷金属转移(CMT)焊接是一种全新的电弧焊技术,在薄板及异种材料的焊接中取得了良好的效果。不同类型铝接头的腐蚀行为应根据腐蚀介质对其结构可能造成的失效的影响来进行预测。研究了热输入对ER5356焊丝CMT焊接的AA5754-AA7075接头力学性能和腐蚀速率的影响。在焊缝金属和AA7075基体金属的部分熔化区都可观察到气孔的形成,这是由于锌的蒸发作用造成的。随着热输入的增加,AA7075基体金属发生过时效和锌汽化,AA5754基体金属晶粒粗化,从而降低了抗拉强度。AA7075-AA5754接头的平均抗拉强度在235~240MPa。所有样品中,塑性断裂均发生在AA5754母材一侧。腐蚀机理以点蚀为主。随着热输入的增加,耐蚀性逐渐增强。为优化耐腐蚀性和强度,建议热输入值在95至110 J/mm之间。
基金
Project(215M623)supported by the Scientific and Technological Research Council of Turkey
Project(CBU-BAP 2015-130)supported by the Scientific Research Project Office of Manisa Celal Bayar University,Turkey
