Vacuum processing produces an extremely pure starting atmosphere for nitriding, eliminating the need for nitrogen purging, and provides excellent thermal and atmosphere uniformity. Owing to these highly controlled processing conditions, modern-day instrumentation can precisely run the nitriding process through maintaining the requisite nitriding potential. Fully-automated programmable cycles provide the highest quality product, including controlling “white layer.” The low thermal mass graphite hot zone allows rapid heat-up and cool-down, the latter accentuated by circulating nitrogen gas across a water cooled heat exchanger. Processing is considerably quicker and more economical than the traditional retort method. The horizontal, front-loading furnace design accommodates workloads up to 2500 pounds.