Silver Brazing Fly Out: Critical Causes and Fixes

Summary for silver brazing fly out Discussion

Silver brazing fly-out from the gap is the issue raised here: Arjun Prajapati asked why BAg-8 filler metal was flowing out of the joint between pure copper and nickel-plated SS304L during vacuum brazing at 830 °C for 40 minutes, and whether nickel plating or brazing parameters could be responsible. The thread excerpt provided contains only the question, so no named answerer or confirmed root cause is available in the source. Based on the question alone, the likely areas to investigate would be joint fit-up, capillary gap control, heating profile, and the interaction of the nickel plating with wetting and flow, but those are not stated as conclusions in the excerpt. Because the source does not include replies, no definitive remedy can be attributed from this page.

Q. We are doing BAg-8 silver brazing between Pure copper and Nickel plated SS304L, we found Brazing filler metal flown out on the surface during vacuum brazing at 830 °C 40 minutes.
Can you please let me know the reason behind this issue of filler metal flown out of the gap between surfaces to be brazed?
Is there any effect of Nickel plating or brazing parameters?

Arjun Prajapati
Metallurgical Engineer – Surat, India
February 9, 2022