Microstructure and Hardness Distribution at the Brazed Joint of Brass

Abstract

Brass alloys are well suited for cutting and have superior thermal conductivity；they are widely used as materials for hot–water piping. For piping, brass alloys are combined with stainless steel with superior strength and corrosion resistance by brazing the joints. In recent years, brass with Bi and Sn addition has been developed. When brazing stainless steel and brass with Bi addition, its impact on brazeability is unknown. In the present study, we examined brazing that uses Ag–Cu–Ni brazing filler metal at a high–temperature range and aimed to examine the impact of the brazed joint structure on hardness distribution to determine brazeability.

Results showed that stainless steel and brass with BAg–13a can be brazed at a high–temperature range. However, because molten brazing filler metal reacted with the brass base material, we could not confirm the brazing filler metal layer. Compared with C3604, the brazing filler material exhibited wetness and spread on C6801；however, voids were confirmed. Bi in C6801 migrates to the brazing filler metal layer during the brazing and precipitates during the solidification. The Vickers hardness test showed similar hardness for each brazed joint.