Solar Atmospheres, Souderton, Pa, recently announced it has successfully vacuum carburized a large gear required for a defense application that had previously not been successfully processed using atmospheric type equipment. Solar recently modified one of its large 10 Bar Quenching Furnaces to be able to vacuum carburize larger and more extensive loads.  By adding new instrumentation, carburizing nozzles, and an improved backfill system, this furnace, with a work zone that measures 48" wide x 72" long x 38" high and load capacity of 10,000 pounds, is capable of performing carburizing cycles on large parts and loads not previously thought possible in vacuum. The successful application was a large gear of 9310 Steel material with dimensions of 60" diameter x 13" high and a weight of 1900 pounds. The part was Low Pressure Vacuum Carburized to achieve an effective case depth of .070" followed by a temper, a minus 225°F freeze, and a second temper operation. Quenching was accomplished using a mixture of nitrogen and helium gasses.  Flatness was within .100" and roundness within .050", well within acceptable tolerances.  Solar Atmospheres anticipates that these types of results will further expand the applications for Low Pressure vacuum Carburizing.