The United States Patent and Trademark Office awarded patent number 9,540,721 to George Barbour, president of Heavy Carbon Co., for a method of carburizing that allows a carburizing process in a furnace at high temperatures in a protective atmosphere. The primary function of this method of carburizing is soot control with an atmosphere flow providing a constant low CH₄ to produce a strong reaction for a high-quality atmosphere regardless of carbon-potential setpoint.

This new method carburizes at a carbon potential well into the soot range while maintaining a controllable carbon potential with a stable CH₄. This stability maintains a constant reaction, cracking an air/gas mix in a self-heated retort to a temperature of 1825°F before entry into the furnace. The high carbon potential penetrates the steel surface at a rate up to 30% faster, saving time and money while producing higher-quality parts.

In addition to the speed at a higher carbon potential at high temperatures, the atmosphere will also penetrate lower-grade steels at lower temperatures without using ammonia to raise the HRC. The air/gas mix is cracked in a retort outside the furnace to form the atmosphere and is heated at the same high temperature of 1825°F before entry into the furnace. In this manner, the low furnace temperature does not hinder the reaction that must take place in the furnace.

Heavy Carbon Co. manufactures this patented system, which is known as the Endocarb System. It can be added to existing furnaces or built into a furnace at the time of manufacture.