摘要
Inconel690镍基合金因其优异的抗晶间腐蚀能力而常应用于压水堆核电蒸汽发生器的管板堆焊隔离层。采用热丝TIG堆焊的方法在核电用SA508Gr.3Cl.2低合金钢表面堆焊Inconel 690镍基合金隔离层,并在焊后进行等温热处理以消除残余应力。采用OM、SEM、XRD对堆焊层和基体金属进行了组织表征,并对堆焊层和母材进行冲击韧性、硬度及拉伸性能进行测试和分析。研究结果表明,堆焊层组织在室温下的抗拉强度达到541.4 MPa,断后伸长率达到39.89%,基体低碳钢的抗拉强度为687.3 MPa,伸长率为20.8%。通过显微硬度测试得出堆焊层奥氏体组织平均硬度为140.8 HV,低于母材的159.5 HV。Inconel690堆焊层晶界附近析出的M23C6、NbC以及Ti C等碳化物相可对晶界产生钉扎作用,其在界面上的分布状态对提升堆焊层的高温力学性能和服役安全具有重要意义。
Inconel 690 nickel-based alloy is often used for the tube sheet isolated layer of PWR(pressurized water reactor)nuclear power steam generators due to its excellent intergranular corrosion resistance. The hot wire surfacing method was used to overlay the Inconel 690 nickel-based alloy insulation layer on the surface of SA508 Gr.3 Cl.2 low-alloy steel for nuclear power, and an isothermal heat treatment was used to eliminate residual stress after welding.The microstructure of the cladding and the base metal were characterized by OM, SEM, XRD, and the impact toughness, hardness and tensile properties of the surfacing layer were tested and analyzed.The results show that the tensile strength of the surfacing layer is 541.4 MPa at room temperature and the elongation after breaking is 39.89%. The tensile strength of the base low carbon steel is 687.3 MPa and the elongation is 20.8%. The microhardness test shows that the average hardness of the austenite microstructure of the surfacing layer is 140.8 HV, which is lower than 159.5 HV of the base material. Particles such as M23C6, NbC, TiC, etc.precipitated near the boundary of the surfacing layer are of great significance to improve the mechanical properties and service safety of the surfacing layer.
作者
郭彦兵
庞亚龙
鲁艳红
张旺
GUO Yanbing;PANG Yalong;LU Yanhong;ZHANG Wang(School of Materials,Shanghai Dianji University,Shanghai 201306,China;Shanghai Electric Group Nuclear Power Equipment Co.,Ltd.,Shanghai 201306,China;School of Materials and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《热加工工艺》
北大核心
2020年第11期6-10,15,共6页
Hot Working Technology
基金
国家自然科学基金面上资助项目(51975346)。
