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对SMA490BW钢进行双丝MAG焊接,并研究了接头组织及力学性能。结果表明,SMA490BW钢双丝焊焊缝成型美观,无未熔合、夹渣等焊接缺陷。焊缝各层组织有差异,上层组织主要为先共析铁素体、针状铁素体、条状铁素体和粒状贝氏体组织;中层柱状晶组织有细化趋势;底层出现过热的魏氏组织。接头硬度和抗拉强度满足生产要求,焊接残余应力较小,接头疲劳性能优良,疲劳极限可达到420 MPa。
The double wire MAG welding of SMA490BW steel was carried out and the joint organization and mechanical properties were studied. The results show that the SMA490BW double wire welding seam is beautiful in appearance without any welding defects such as fusing and slag inclusion. There are differences in the microstructure of the weld layer. The upper layers mainly include pro-eutectoid ferrite, acicular ferrite, strip-shaped ferrite and granular bainite. The middle columnar crystal structure is refined, and the bottom layer is overheated Wei’s organization. Joint hardness and tensile strength to meet production requirements, welding residual stress is small, joint fatigue performance, fatigue limit up to 420 MPa.