Advances in Vacuum Bright Annealing
91´«Ă˝ reports a significant improvement in bright annealing results and cycle times in their recently installed Model HFL-3648-LT Vacuum Furnace.  This furnace, with a hot zone measuring 36” wide x 30” high x 48” deep and a work load capacity of 2,500 pounds, has proven to be very successful in bright annealing various ferrous and non-ferrous materials in half of the cycle time required in other equipment, when processing materials under 1450°F.
This includes alloys traditionally not processed in a vacuum furnace. Â After an initial pump-down, a slightly positive atmosphere of a pre-programmed and a variable ratio of hydrogen/nitrogen is introduced. Â Since this furnace incorporates an extremely tight hot zone with a dual fan re-circulation system, faster heating and excellent temperature uniformity are achieved. Â Also, the protective atmosphere used minimizes any possible alloy depletion that might occur during the annealing process. Â This would include zinc in brass materials and lead in certain steel alloys. Â Following a final soak temperature, controlled cooling of the work is accomplished using an external 30 HP re-circulating gas system.