Predictions of Carbon Fluxes During a Low Pressure Carburizing Treatment

This paper presents the qualitative assessment of a novel device developed for the regulation of carburizing processes in industrial vacuum furnaces. The proposed device involves a U-shaped thin wall iron tube: the outside surface of the tube is exposed to the carburizing atmosphere simultaneously with the workload, while the decarburizing gas mixture (here H₂ + H₂O) is circulated inside the tube. The outflow of decarburizing mixture is then continuously analyzed and eventually permits to determine the carbon potential and the transfer coefficient at the interface between the carburizing atmosphere and the workloads. To assess the principle, the probe has been used to compare the carburizing powers of different gases (propane, methane, ethylene, and acetylene) for a specific set of parameters. The results reported here, compared with microhardness and micrographies of the samples, indicate that the probe can indeed be used to carry out this task.