高氮奥氏体不锈钢连续驱动摩擦焊组织及性能研究

Research on Microstructure and Properties of Continuous Drive Friction Welded Joint of High Nitrogen Austenitic Stainless Steel

采用连续驱动摩擦焊方法对直径为73 mm,壁厚为7 mm的高氮奥氏体不锈钢环状管材进行了焊接试验。利用光学显微镜和扫描电镜对焊接接头显微组织和断口形貌进行了观察,利用硬度测试仪和拉伸试验机测试焊接接头的硬度和拉伸性能。试验结果表明:焊缝中心由带状组织组成,而热力影响区及热影响区组织呈流线型分布,同时还有σ相在晶界处析出。硬度曲线均呈现V曲线特征。拉伸试样均断裂于焊缝中心带状组织处,且断口为韧性断口。

The welding test of high nitrogen austenitic stainless steel ring pipe with diameter of 73 mm and wall thickness of 7 mm was carried out by continuous drive friction welding.The microstructure and fracture morphology of the welded joint was observed by optical microscope and scanning electron microscope.The hardness and tensile property of the welded joint were tested by hardness tester and tensile test machine,respectively.The results show that the band microstructure is found in the weld zone and the streamline microstructure is found in the thermomechanically affected zone and heat affected zone.At the same time,theσphase precipitates in the grain boundary in the thermomechanically affected zone.The hardness curve exhibits V curve characteristics.All the tensile specimens are failed in band microstructure of the weld center and the fracture is tough fracture.