石墨管与不锈钢管钎焊接头的组织和残余应力  

Microstructure and residual stresses of brazed graphite tubes and stainless steel tubes

作　　者：肖逸锋[1,2,3] 陈锦微 张汭 宋章 王晖 张乾坤[1,2,3] 吴靓 XIAO Yifeng;CHEN Jinwei;ZHANG Rui;SONG Zhang;WANG Hui;ZHANG Qiankun;WU Liang(School of Mechanical Engineering and Mechanics,Xiangtan University,Xiangtan 411105,China;Key Laboratory of Welding Robot and Application Technology of Hunan Province(Xiangtan University),Xiangtan 411105,China;Engineering Research Center of Complex Trajectory Processing Technology and Equipment of Ministry of Education(Xiangtan University),Xiangtan 411105,China)

机构地区：[1]湘潭大学机械工程与力学学院,湖南湘潭411105 [2]焊接机器人及应用技术湖南省重点实验室(湘潭大学),湖南湘潭411105 [3]复杂轨迹加工工艺及装备教育部工程研究中心(湘潭大学),湖南湘潭411105

出　　处：《材料科学与工艺》2024年第4期19-27,共9页Materials Science and Technology

摘　　要：为使石墨材料能够在空间核电散热装置中更充分地发挥其价值,本文采用BNi-2钎料真空钎焊连接等静压石墨管和304不锈钢管,研究了石墨/BNi-2/不锈钢接头在1010℃、保温90 min条件下的显微组织和不同冷却工艺对接头残余应力的影响。研究表明:在1010℃,保温90 min条件下,钎焊接头致密无裂纹,Cr元素在石墨侧与石墨基体反应形成Cr_(7)C_(3)反应层,在不锈钢侧形成了σ-FeCr扩散层,界面接头组成为石墨/Cr_(7)C_(3)/Ni(s,s)+Ni_(3)Si/σ-FeCr/不锈钢;经缓冷工艺处理的接头,常温剪切强度为28.38 MPa,比炉冷处理的接头剪切强度提高了22%;有限元数值分析结果表明,采用缓慢冷却的钎焊工艺可以有效缓解钎焊接头在冷却过程中产生的残余应力,符合剪切实验结果。In order to fully utilize the potential of graphite materials in space nuclear power heat sinks,the joining of graphite tube and 304 stainless steel tube have been prepared by brazing with BNi-2 filler material in a vacuum at 1010℃for 90 min.Microstructure and the effect of different cooling processes on the residual stresses of graphite/BNi-2/stainless steel joints under this process were investigated.The experimental results illustrate that under the condition of 1010℃and 90 minutes of insulation,the brazed joints exhibit a dense and crack⁃free structure.Moreover,part of Cr reacted with the graphite matrix to form Cr_(7)C_(3) reaction layer in the graphite side,while aσ-FeCr diffusion layer was formed on the stainless steel side.The interface microstructure of the brazed joints was graphite/Cr_(7)C_(3)/Ni(s,s)+Ni_(3)Si/σ⁃FeCr/stainless steel.Additionally,the room temperature shear strength of the joint treated by the temperature⁃controlled cooling process was 28.38 MPa,which was 22%higher than that of the furnace⁃cooled joint.The finite element numerical analysis results showed that the residual stresses generated during the cooling of brazed joints were effectively relieved when the temperature⁃controlled cooling process was used,which is in consistent with the shear test results.

关 键 词：镍基钎料 石墨管 不锈钢管 力学性能 有限元数值分析 钎焊 

分 类 号：TG454[金属学及工艺—焊接]