US Patent 7204952 Vacuum furnace for carburizing with hydrocarbons

Vacuum carburizing of ferrous workpieces is performed at low pressure in a vacuum furnace using a carburizing hydrocarbon as the carburizing medium. The furnace is constructed to be generally transparent to the carburizing hydrocarbon so that cracking tends to occur at the workpiece which functions as a catalyst to minimize carbon deposits. The carburizing hydrocarbon is supplied in liquid form to an injector which injects the liquid carburizing hydrocarbon as a vapor to produce a uniform dispersion of the carburizing hydrocarbon about the workpiece, resulting in uniform carburizing of the workpieces.