40mm厚铁素体不锈钢与16Mn钢异种电子束焊接接头显微组织结构研究

Study on Microstructure of Dissimilar Electron Beam Welded Joint between 40 mm Thick Ferritc Stainless Steel and 16Mn Steel

为了探究异种钢焊接接头的强度和使用性能,课题组对焊接接头不同位置处的显微组织结构进行研究。首先,电子束焊接将06Cr13Al铁素体不锈钢(FSS)对接连接到16Mn低合金钢厚板上;通过工艺优化,在电子束偏移向16Mn钢1.5mm时获得成型良好的焊接接头;采用光学显微镜、X射线衍射仪和扫描电子显微镜研究异种焊接接头不同位置处的显微组织,并测试异种接头硬度。结果表明:焊缝主要由粗大的柱状晶和中心轴向晶粒组成,显微组织由板条马氏体组成;16Mn钢的热影响区(HAZ)显微组织为羽毛状的上贝氏体和针状铁素体,铁素体不锈钢热影响区主要以粗大的铁素体和马氏体组成;焊缝区的显微硬度明显高于母材,焊缝不同厚度处的显微硬度没有明显的差异。焊接接头成型良好,未观察到缺陷。

In order to investigate the strength and performance of the dissimilar welded joints,the microstructure of the joint at different positions was studied.Electron beam welding was used to directly connect 06Cr13Al ferritic stainless steel to the 16Mn low alloy steel thick plates in a butt joint configuration.Through process optimization,a well-formed welded joint can be obtained with 1.5 mm beam deflection to 16Mn.The microstructure of dissimilar welded joints at different positions was investigated by optical microscopy,X-ray diffractometer and scanning electron microscopy,and the hardness of the heterojunction was tested.The results show that the weld metal is mainly composed of coarse columnar grains and central axial grains,the microstructure consists of lath martensite.The microstructure of the coarsegrained heat affected zone of 16Mn is upper bainite and acicular ferrite.The heat affected zone of ferritic stainless steel is mainly composed of coarse ferrite and martensite.The microhardness of weld metal is significantly higher than that of the base metal,and there is no significant difference in microhardness of the weld with different thicknesses.The welded joints were well formed and no defects were observed.