汽车轮辋用钢搅拌摩擦焊接头组织及力学性能

目的 为搅拌摩擦焊在轮辋钢的应用提供理论数据。方法 选用厚度为4.5 mm的江铃汽车V362轮辋钢板B380CL，采用不同的焊接参数，获得搅拌摩擦焊接头，对焊缝宏观成形及微观组织进行分析，研究焊接参数对组织的影响；通过进行拉伸试验和硬度测试，分析焊接参数对焊接接头性能的影响；对接头焊缝进行X-Ray无损探伤。结果 当搅拌头旋转速度为950 r/min，焊接速度分别为37.5, 47.5, 60 mm/min时，均能形成焊接接头。焊接速度为47.5 mm/min时，焊缝宏观成形较好，微观组织无缺陷，微观组织为铁素体和珠光体，抗拉强度最高，超过母材；焊接接头各区域微观组织硬度较母材高，伸长率较焊接速度为37.5 mm/min时的接头高。结论 搅拌摩擦焊实现轮辋钢的对接，该研究中旋转速度950 r/min，焊接速度47.5 mm/min为最佳工艺参数，接头抗拉强度超过母材。

Microstructure and Mechanical Properties of Automotive Wheel Steel Friction Stir Welded Joints

The paper aims to provide theoretical basis for application of friction stir welding in wheel steel. Wheel steel plate B380CL with a thickness of 4.5 mm of Jiangling Motors was used to obtainfriction stir welding joint with different welding parameters to analyze macroscopic forming and macro-structure of the joint and research influences of welding parameters on microstructures; tensile test and hardness test were carried out to analyze influences of welding parameters on performance of joint. In addition, it was assured to test the defect of the joint by the X-Ray. The result showed that at rotation speed of 900 r/min, travel speed of v1=37 mm/min, v2=47.5 mm/min, v3=60 mm/min, the welded joint could be formed. At travel speed of v2=47.5 mm/min, the macroscopic formation was better than others, with the Ferrite and the Pearlite forming and no defect and the highest of the tensile strength, which exceeded the base metal; and hardness of the weld-associated zone and the elongation of the joint were higher than the joint at travel speed of v1=37.5 mm/min. Friction stir welding could realize the butt-welded of wheel steel. In this study, the tensile strength of the joint exceed the base metal withthe best parameters: rotation speed of 950 r/min andwelding speed of 47.5 mm/min.