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针对2mm厚的3A21防锈铝合金和3 mm厚的304不锈钢采用对接的方式进行了不等厚板电子束扫描焊接。通过拉伸试验机、维氏硬度测试仪和扫描电镜等设备对接头的力学性能和断口形貌进行了测试和分析。结果表明:在合适的工艺下铝-钢异种金属电子束扫描焊接接头成形良好,无气孔、裂纹等缺陷;电子束流和电子束偏移距离对接头的力学性能有较大的影响,接头力学性能最大可达112.6 MPa,接近铝母材的87%。焊接接头由钢侧熔化区、铝-钢界面连接区和铝侧熔化区三部分组成,铝-钢界面连接区主要由脆硬的Fe-Al金属间化合物组成,是接头的薄弱环节。硬度的分布与接头的形貌有关,铝-钢界面连接区的硬度最大,铝侧和钢侧熔化区的硬度都分别要比铝母材和钢母材的硬度高,接头的断裂方式为韧脆混合型断裂。
For the 2mm thick 3A21 rust-proof aluminum alloy and 3 mm thick 304 stainless steel butt-welded plate with unequal-thickness electron beam scanning. Tensile testing machine, Vickers hardness tester and scanning electron microscope and other equipment on the mechanical properties and fracture morphology were tested and analyzed. The results show that the formation of aluminum-steel dissimilar metal-based electron beam scanning welded joint is well formed without any defects such as pores and cracks under the proper process. The electron beam current and the electron beam migration distance have a great influence on the mechanical properties of the joint. Performance up to 112.6 MPa, close to 87% of aluminum base metal. The welded joint is composed of steel melt zone, aluminum-steel interface and aluminum melt zone. The aluminum-steel interfacing zone is mainly composed of brittle Fe-Al intermetallic compound, which is the weak point of joint. The distribution of hardness is related to the shape of the joint. The hardness of the aluminum-steel interfacial connection zone is the highest, and the hardness of the aluminum-side and steel-side molten zone is respectively higher than that of aluminum base metal and steel base metal. Crisp hybrid fracture.