Brazing Q&A

Q: We’ve been brazing 304L stainless steel using BNi-1a filler metal at 2130°F (about 1170°C) in our vacuum furnace. This process has worked well historically, but recently, we’ve encountered problems: The vacuum weakens to 3x10⁻² Torr above 2000°F (about 1100°C), and we’re seeing dark discolorations on the finished parts. What’s going wrong?

A: Several interrelated issues may be contributing to your recent brazing challenges. Loss of vacuum and surface discolora..