核级304L不锈钢钎缝显微组织结构及抗剪强度  

Microstructure and shear strength of brazed joint of nuclear grade 304L stainless steel

作　　者：孙效禹 蔡权 陈嘉诚 SUN Xiaoyu;CAI Quan;CHEN Jiacheng(CGNPC Uranium Resources Co.,Ltd.,Yangjiang 529500,Guangdong pro.,Chin)

机构地区：[1]中广核铀业发展有限公司,广东阳江529500

出　　处：《焊接技术》2023年第5期24-27,32,I0005,共6页Welding Technology

摘　　要：采用国内外厂家生产的BNi-7膏状镍基钎料真空钎焊核级304L不锈钢,通过扫描电镜、能谱分析仪、维氏显微硬度仪等设备研究钎缝显微组织、元素分布及显微硬度,并采用万能试验机检测钎焊接头抗剪强度。结果表明:不同厂家生产的钎料钎缝显微组织结构基本一致,主要由Ni(Cr,Fe)-P金属间化合物强化相、(Ni)_(SS)相及富镍的(Ni,Fe,Cr)_(SS)相组成,钎缝在富磷区域存在微小裂纹,其中P是导致裂纹产生的主要原因;不同厂家生产的钎料钎缝抗剪强度均满足使用要求且相差不大,国产钎料抗剪强度略高于国外钎料的。BNi-7钎焊接头拉伸时,裂纹平行于焊缝方向在富磷区域生长,富镍的(Ni,Fe,Cr)_(SS)相可有效阻止裂纹的生长。Vacuum brazing of nuclear grade 304L stainless steel with BNi-7 paste brazing filler metal produced by domestic and foreign manufacturers was used to study the microstructure,element distribution and microhardness of brazed joint by scanning electron microscope,energy spectrum analyzer,Vickers microhardness tester and other equipment.The shear strength of brazed joint was tested by universal test.The results showed that the microstructure of brazing solder welds produced by different manufacturers were basically the same,mainly composed of Ni(Cr,Fe)-P intermetallic compound enhanced phase,(Ni)_(SS) phase and nickel rich(Ni,Fe,Cr)_(SS) phase.There were micro cracks in the phosphorus-rich zone of brazing welds,and phosphorus was the main reason for the cracks.The shear strength of brazing solder seam produced by different manufacturers all met the requirements of use with little difference.The shear strength of domestic solder was slightly higher than that of foreign solder.During the stretching of BNi-7 brazing joint,the cracks growed parallel to the weld direction in the phosphorus-rich region,and the Ni-rich(Ni,Fe,Cr)_(SS) phase could effectively prevent the crack growth.

关 键 词：BNi-7钎料 304L不锈钢 显微组织结构 抗剪强度 

分 类 号：TG407[金属学及工艺—焊接]