Developing of friction stir welding process of high nitrogen containing stainless steel

采用载荷控制搅拌摩擦焊技术成功地实现了高氮奥氏体不锈钢板的对接焊。为了评估最佳搅拌摩擦焊条件的范围，采用了几个焊接参数。成功地生产出了全熔透无缺陷的对接焊接接头。搅拌区的维氏硬度高于基体金属。焊缝的屈服强度和抗拉强度均超过母材。研究了焊接接头的力学性能与热输入效应的关系。利用取向成像显微镜（OIM）对搅拌区晶粒尺寸和搅拌区中心的相组成进行了分析。

Butt welding of high nitrogen-containing austenitic stainless steels (HNS) plates was successfully performed using a load-controlled FSW machine. In order to assess the range of the optimum FSW conditions, several welding parameter were adopted. Full-penetrated and defect-free butt welded joints were successfully produced. The stir zone showed a higher Vickers hardness than the base metal. The yield strength and the tensile strength of the welds exceeded those of the base metal. The relationship of mechanical properties of joints and effect of heat input, experimentally acquired peak heat temperature, was examined. The grain size in the stir zone and the phase constituents in the stir zone center were analyzed by OIM (Orientation Imaging Microscopy).