Where I did my apprenticeship Saunders Roe/BHC, they used salt baths to anneal and otherwise heat treat light alloy. The sheet metal grade most used was L72, what that is in todays terms I don't know. Anyway the process went something like,,,,,
1 Required part was cut to developed profile, including holes and tooling holes.
2 Part annealed in salt bath. Usually had a time stamp in ink, to indicate the working life of the heat treatment, from memory it wasn't long, 15 minutes rings a bell.
3 Part rushed to wherever it was due to be bent…fleet footed apprentices came in handy here. Most stuff was bent (formed) on a rubber die press, but the simpler parts were formed by hand, using bending bars etc. An inspector was standing by to ensure that the parts were formed within the allowed time.
Salt baths are unpleasant places and should be reserved for the professionals.
cheers
Bill