多孔不锈钢薄壁管与316L不锈钢的真空钎焊连接特性

Bonding Characterization of 316L and Porous Stainless Steel Thin Pipes by Vacuum Brazing

摘要:

采用镍基BNi7焊膏为钎料,对多孔不锈钢薄壁管与316L不锈钢成功实现真空钎焊连接,并用扫描电子显微镜(SEM)和x射线衍射仪(XRD )对接头界面组织结构进行观察和分析。结果表明焊缝的主要相是Ni-Cr 固溶体和Ni-P金属间化合物。测试连接件的整体拉伸性能,焊接温度980℃及焊接时间615min得到焊接件的最大室温拉伸强度245MPa。在同等条件下,延长保温时间或者提高焊接温度都不能进一步提高焊接强度。这主要是因为浓度梯度引起的熔融的钎料和母材基体的互扩散所致。

Abstract:

Vacuum brazing of porous stainless steel tube and 316L stainless steel has been successfully performed using BNi-7 brazing paste as a filler metal. Ni-Cr solid solution and Ni-P intermetallics were the main phases in the brazing seam. And the interface microstructure of the joint was observed by means of SEM and EDS. The experimental results showed that the highest tensile strength of 245 MPa was acquired from the joint brazed at 980℃ for15min. Longer processing time or higher processing temperature than these conditions did not further improve the joint strength. This is ascribed to the interdiffusion between molten liquid of the filler and solid base metal due to concentration gradients.