Inconel 690传热管GTAW对接焊接头组织及力学性能研究

对Inconel 690传热管材进行钨极气体保护焊(GTAW)对接焊,采用拉伸试验机、压扁试验机和光学显微镜测试和分析传热管焊接接头,同时利用ANSYS软件开展焊接接头在设计工况失压时的一次应力强度校核。研究结果表明:焊缝中心为树枝胞状晶,熔合线附近为粗大柱状晶。室温时接头的平均抗拉强度为619 MPa,平均屈服强度为292 MPa,350℃时接头平均抗拉强度为475 MPa,平均屈服强度为206 MPa,拉伸接头断裂从熔合区开始贯穿整个焊缝组织,呈塑性断裂。压扁试验和反向压扁试验结果表明管接头完好。通过ANSYS分析可知,设计工况下传热管接头350℃许用应力强度150 MPa限值可满足其一次应力强度要求,且裕量较大。

Study on microstructure and properties of GTAW butt welded joint of Inconel 690 heat transfer tube

Butt welding of Inconel 690 heat transfer tube is conducted by gas tungsten arc welding(GTAW).The tube welded joints are tested and analyzed by using the tensile tester,flattening tester and optical microscope.Meanwhile,the ANSYS software is used to carry out the primary stress intensity check of the welded joint when the pressure is lost in the design condition.The results show that the center of the weld is dendritic crystal,and the area near the fusion line is coarse columnar crystal.At room temperature,the average tensile strength and yield strength of the joint are 619 MPa and 292 MPa respectively.At 350℃,the average tensile strength and yield strength of the joint are 475 MPa and 206 MPa respectively.The fracture of tensile joint runs through the whole weld structure from the fusion zone,forming plastic fracture.The results of flattening test and reverse flattening test demonstrate that the tube joints are in good condition.Through ANSYS analysis,under the design condition,the allowable stress intensity of the heat transfer tube joint at 350℃is 150 MPa,which can meet the requirements of its primary stress intensity,and the margin is large.