Process for controlling carbon content of injection molding steels during debinding

A process for controlling the carbon content in a metallic piece molded by injection or other process comprising,

• a) heating said shaped piece under a substantially pure hydrogen atmosphere only up to a temperature sufficient to remove low molecular weight constituents,
• b) replacing said substantially pure H.sub.2 atmosphere with a substantially pure nitrogen atmosphere and heating the pieces to a temperature higher than that in step a), sufficient to remove binder without effecting carburization or decarburization,
• c) maintaining the temperature in the enclosure at substantially the same temperature in step b) while subjecting the pieces to an atmosphere comprising from 15% to 100% vol. hydrogen, the complement being nitrogen, then
• d) replacing said atmosphere by substantially pure nitrogen, and
• e) heating the pieces to a temperature sufficient to further eliminate the remaining binder.