Solar Atmospheres announced that the U.S. Patent and Trademark Office issued U.S. Patent No. 8,088,328 covering Solar’s new vacuum gas-nitriding furnace design. The patent, including 14 claims, centers on an all-graphite hot-zone design featuring graphite heating elements, graphite gas baffles, graphite fan and graphite felt insulation housed in a vacuum-chamber enclosure. The advantage of the all-graphite hot zone is the combination of non-nitriding components that do not require retort teardown and scrubbing to restore nitriding constants, as with prior 330 alloy retorts.            

The low-mass hot zone provides rapid heating, and combined with an external gas blower and heat exchanger, allows fast heat up and cool down for nitriding cycles that are 50% faster than standard brick or retort designs. According to Roger A. Jones, corporate president of Solar Atmospheres, the new furnace has proved equally useful for bright tempering of alloys like H11, 13, D2 and bright annealing of brass alloys.