Abstract
In recent years, the use of ferritic stainless steel and a Ni-based brazing foil has been required in an environment where low cost and high quality are required at the same time. However, when brazing stainless steel and brazing foil, the formation of Cr–B intermetallic compounds and a Cr depletion zone were confirmed, and there was concern that the corrosion resistance around the brazed layer would decrease. Therefore, the brazing times of SUS444 / MBF20® brazed joint with excellent corrosion resistance were compared at 5 minutes, 1 hour, and 3 hours using the corrosion resistance evaluation by electrochemical method and the microstructure observation by EPMA analysis. From the results of the polarization curve, the corrosion resistance at the brazing time of 3 hours was the best. Results of microstructure observation, it was confirmed that the formation of the Cr-depletion zone was suppressed when the brazing time was 1 hour and 3 hours. From these results, it was suggested that good corrosion resistance of the brazed joint was obtained by long time brazing. These results provide new insights in determining future brazing conditions.
