焊接速度对Q&P980钢搅拌摩擦焊接头组织和性能的影响  

Effect of welding speed on microstructure and properties of Q&P980 steel friction stir welding joints

作　　者：郝政扬 王晨曦 王快社[1,2] 乔柯 王佳[1,2] 王文 孙琦 HAO Zheng-yang;WANG Chen-xi;WANG Kuai-she;QIAO Ke;WANG Jia;WANG Wen;SUN Qi(School of Metallurgical Engineering,Xi′an University of Architecture and Technology,Xi′an 710055,China;National and Local Joint Engineering Research Center for Functional Materials Processing,Xi′an 710055,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055 [2]功能材料加工国家地方联合工程研究中心,陕西西安710055

出　　处：《塑性工程学报》2024年第1期165-171,共7页Journal of Plasticity Engineering

基　　金：国家自然科学基金重点资助项目(52034005);国家自然科学基金面上资助项目(51974220);国家自然科学基金青年资助项目(52104383);陕西省教育厅青年创新团队建设项目(21JP058);陕西省教育厅专项科研项目(17JK0430)。

摘　　要：通过搅拌摩擦焊接对Q&P980钢进行焊接,固定转速为400 r·min^(-1),焊接速度分别为50 mm·min^(-1)(低焊速)和600 mm·min^(-1)(高焊速),采用光学显微镜、扫描电子显微镜、电子背散射衍射、显微硬度和拉伸性能测试等手段对焊接接头的微观组织和力学性能进行了表征,研究了焊接速度对接头微观组织和力学性能的影响。结果表明:相较母材,接头整体残余奥氏体含量降低,搅拌区晶粒明显细化和均匀化,有大量马氏体生成;热影响区晶粒略微粗大,显微硬度降低。与低焊速接头相比,高焊速接头峰值温度降低,材料流动范围较窄,热力耦合作用减弱;热影响区宏观尺寸减小,残余奥氏体含量增加,显微硬度提高,接头具有更好的变形协调性,接头抗拉强度和伸长率分别从1074 MPa、6.0%提高至1268 MPa、15.3%。The Q&P980 steel was welded by friction stir welding with the fixed rotation speed of 400 r·min^(-1) and welding speed of 50 min^(-1)(low welding speed)and 600 mm·min^(-1)(high welding speed),respectively.The microstructure and mechanical properties of the welded joints were characterized by optical microscopy,scanning electron microscopy,electron backscatter diffraction,microhardness and tensile property tests.The effects of welding speed on the microstructure and mechanical properties of the joints were studied.The results show that compared with the base metal,the overall retained austenite content of the joints is reduced,the grains in the stirring zone are obviously refined and homogenized,and a large amount of martensite are formed.The grains in the heat-affected zone are slightly coarse,and the microhardness decreases.Compared with the low welding speed joint,the peak temperature of the high welding speed joint decreases,the material flow range is narrow,and the thermal coupling effect is weakened.The macro-size of the heat-affected zone decreases,the content of retained austenite increases,the microhardness is higher,the deformation coordination of the joint is better.The tensile strength and elongation of the joint increase from 1074 MPa,6.0%to 1268 MPa,15.3%,respectively.

关 键 词：搅拌摩擦焊接 焊接速度 Q&P980钢 微观组织 力学性能 

分 类 号：TG457.11[金属学及工艺—焊接]