摘要
采用TIG熔-钎焊方法并添加AlSi_5焊丝,对1.5 mm厚的5A06铝合金和3 mm厚的镀锌Q235钢进行焊接。分析了焊后退火热处理对接头微观组织和力学性能的影响规律,热处理条件为280℃保温30 min。研究结果表明,采用TIG熔-钎焊的方法可以实现铝/钢异种金属的焊接,铝/钢界面处会产生金属间化合物层,焊态接头中金属间化合物层的厚度为4～5μm,化合物层主要由Al_8Fe_2Si相和少量的[Al,Fe,Si],Al13Fe4相组成,接头的抗拉强度值为163 MPa,断裂发生在焊缝处。对接头进行退火热处理后,接头中金属间化合物层的厚度增加到9～10μm,化合物层的组织无明显变化,主要由Al_8Fe_2Si相和少量的[Al,Fe,Si],Al_(13)Fe_4相组成,接头的抗拉强度值达到185 MPa,断裂发生在铝母材侧。
1. 5 mm thick 5 A06 aluminum alloy and 3 mm thick galvanized Q235 steel were lap joined by TIG welding-brazing with Al Si5 filler metal. Dissimilar metals joints were annealed at 280 ℃ for 30 min and the effect of post-weld annealing heat treatment on microstructure and mechanical properties of joints was investigated. The results show that the welding of dissimilar metals between aluminum and steel can be realized by TIG welding-brazing and the intermetallic compounds layer is inevitably formed at the interface between aluminum and steel. The intermetallic compounds layer is composed of Al_8Fe_2 Si,a few [Al,Fe,Si]phases and a few Al_8Fe_2 Si phases and a few Al_(13)Fe_4 phases with a total thickness of 4-5 μm. The tensile strength of as-welded joints reaches 163 MPa,and the fracture occurred in weld seam. After the joint being annealed at 280 ℃ for 30 min,the microstructure of intermetallic compounds layer doesn't bring out obvious changes,which consists of Al_8Fe_2 Si,a few [Al,Fe,Si] phases and a few Al_8Fe_2 Si phases. The thickness of compound layer in annealed joint increases to 9-10 μm.The tensile strength of annealed joint increases to 185 MPa,and the fracture occurs in aluminum base metal.
出处
《焊接》
2018年第3期15-18,共4页
Welding & Joining
基金
国家自然科学基金青年基金项目(51505197)
关键词
铝/钢焊接
退火热处理
微观组织
抗拉强度
aluminum/steel welding
annealing treatment
microstructure
tensile strength
