Hsu Tai-I, Tsai Meng-Hsiu
Department of Health and Beauty, Shu Zen College of Medicine and Management.
Department of Mold and Die Engineering, National Kaohsiung University of Science and Technology;
J Vis Exp. 2019 Aug 13(150). doi: 10.3791/58633.
Friction stir spot welding (FSSW), a derivative of friction stir welding (FSW), is a solid-state welding technique that was developed in 1991. An industry application was found in the automotive industry in 2003 for the aluminum alloy that was used in the rear doors of automobiles. Friction stir spot welding is mostly used in Al alloys to create lap joints. The benefits of friction stir spot welding include a nearly 80% melting temperature that lowers the thermal deformation welds without splashing compared to resistance spot welding. Friction stir spot welding includes 3 steps: plunging, stirring, and retraction. In the present study, other materials including high strength steel are also used in the friction stir welding method to create joints. DP780, whose traditional welding process involves the use of resistance spot welding, is one of several high strength steel materials used in the automotive industry. In this paper, DP780 was used for friction stir spot welding, and its microstructure and microhardness were measured. The microstructure data showed that there was a fusion zone with fine grain and a heat effect zone with island martensite. The microhardness results indicated that the center zone exhibited a greater degree of hardness compared with the base metal. All data indicated that the friction stir spot welding used in dual phase steel 780 can create a good lap joint. In the future, friction stir spot welding can be used in high-strength steel welding applied in industrial manufacturing processes.
搅拌摩擦点焊（FSSW）是搅拌摩擦焊（FSW）的衍生技术，是一种1991年开发的固态焊接技术。2003年在汽车工业中发现了其工业应用，用于汽车后车门的铝合金。搅拌摩擦点焊主要用于铝合金以形成搭接接头。搅拌摩擦点焊的优点包括熔点降低近80%，与电阻点焊相比，可减少热变形焊接且无飞溅。搅拌摩擦点焊包括三个步骤： plunge（下压）、搅拌和回抽。在本研究中，搅拌摩擦焊方法还用于包括高强度钢在内的其他材料以形成接头。DP780是汽车工业中使用的几种高强度钢材料之一，其传统焊接工艺涉及电阻点焊。本文将DP780用于搅拌摩擦点焊，并测量了其微观结构和显微硬度。微观结构数据表明存在细晶粒的熔合区和岛状马氏体的热影响区。显微硬度结果表明，中心区的硬度比母材更高。所有数据表明，在双相钢780中使用的搅拌摩擦点焊可以形成良好的搭接接头。未来，搅拌摩擦点焊可用于工业制造过程中的高强度钢焊接。
