(1) Saturation of the surface layer of steel articles with carbon to increase hardness and wear resistance (after quenching and tempering); the same as case hardening.
(2) Introduction of carbon (in the form of carbon-containing materials) into the molten steel produced in a steel-smelting plant to raise the carbon content to a specified level.
(3) Addition of carbon-containing materials to the charge during steel smelting by the carburization process for scrap.
(4) Formation of iron carbide, Fe3C, during blast-furnace smelting; it begins immediately after the reduction of iron oxides.