钎焊工艺对75Ni8排锯钢基体性能影响的研究

摘要

探究钎焊工艺对75Ni8排锯钢钎焊后力学性能和显微组织的影响.实验共选用7种钎料进行感应钎焊,借助力学试验机、冲击试验机、维氏硬度计、金相显微镜等进行力学性能和显微组织分析.结果表明:三明治HL861钎焊接头的剪切强度最高,为164.87 MPa;CT737冲击韧性最高,为50.08 J/cm2;距离钎缝近的母材区域维氏硬度下降较快,最低为1 176 MPa,原始母材的维氏硬度为4 468.91 MPa;金相观察发现:距离钎缝近的区域母材组织粗大,而原始母材组织细小均匀.75Ni8排锯钢钎焊后的组织和性能受温度影响较大,当加热时间变长,回火温度超过600℃时,组织转变为回火屈氏体.%The mechanical properties and microstructures of 75Ni8 gang saw steel are investigated by changing the brazing processes.The experiments select 7 kinds of brazing materials for induction brazing.The mechanical properties and microstructure are analyzed by using mechanical test machine,impact tester,Vickers hardness tester,metallographic microscope and so on.The results show that the shear strength of sandwich HL861 brazed joint is the highest,reaching 164.87 MPa,and that the impact toughness of CT737 is the highest,reaching 50.08 J/cm2.The Vickers hardness of the 75Ni8 base material area near the brazing seam is decreased rapidly,whose nadir is 1 176 MPa,while the original Vickers hardness is 4 468.91 MPa.The metallographic observation finds that the organization of the 75Ni8 base material near the brazing seam is coarse and the original is fine and uniform.The organization and property of 75Ni8 gang saw after welding are influenced by temperature.When the heating time becomes longer and the tempering temperature exceeds 600 ℃,the microstructure changes to the tempered troostite.