电磁脉冲焊304不锈钢/6061铝合金管材接头微观结构及性能

Microstructure and Properties of 304 Stainless Steel/6061 Aluminum Alloy Pipe Joints by Electromagnetic Pulse Welding

为了研究电磁脉冲焊接304不锈钢/6061铝合金异种管材焊接接头的显微组织与力学性能,在间隙为1.5 mm,电压为17 kV,频率为15 kHz,电流为640 kA工艺参数下对304不锈钢/6061铝合金管材采用电磁脉冲焊进行试验。通过光学显微镜(OM)、扫描电镜(SEM)、能谱分析仪(EDS)对焊后管材接头的微观形貌、元素分布和相组成进行了分析。采用硬度计和水压测试仪对接头表面显微硬度和耐压性能进行了测试。焊接后接头形貌良好无缺陷。焊接结合层界面发生了元素扩散,生成脆硬的金属间化合物(FeAl、FeAl_(2)及FeAl_(3)),平均硬度(HV)达到了647.35,水压测试后铝侧母材破裂。电磁脉冲焊接304不锈钢/6061铝合金异种管材可以获得成形良好且性能优异的接头。结合层中的金属间化合物增大了接头硬度,显著提高了焊缝的力学性能,使得焊接接头具有良好的耐压性、致密性和高硬度。

In order to investigate the microstructure and mechanical properties of dissimilar welded joints of 304 stainless steel/6061 aluminum alloy pipe by electromagnetic pulse welding, electromagnetic pulse welding experiment was carried out under the gap of 1.5 mm, voltage of 17 kV, frequency of 15 kHz and current of 640 kA. Microstructure, element distribution and phase composition of welded pipe joints were analyzed by optical microscope(OM), scanning electron microscope(SEM) and energy dispersive spectrometer(EDS). The surface microhardness and pressure resistance of the joint were tested by hardness tester and water pressure tester. After welding, the joint presents well morphology without defects. Element diffusion occurs at the interface of the welding bonding layer, and brittle intermetallic compounds(FeAl, FeAl_(2)and FeAl_(3)) are generated, with an average hardness of 647.35 HV. The base metal on the aluminum side is broken after hydrostatic testing. In conclusion, electromagnetic pulse welding of 304 stainless steel/6061 aluminum alloy dissimilar pipe can lead to well-formed joint with excellent performance. The intermetallic compound in the bonding layer promotes the increase of joint hardness, significantly improving the mechanical properties of the weld, which exhibits the desirable pressure resistance, compactness and high hardness.