postcarburizing

Postcarburizing is a heat-treatment procedure in which carbon is diffused into the surface of a steel part after it has been formed and finished, in order to create a hard, wear-resistant outer layer while preserving a tougher interior. It is used when surface durability is needed without compromising core toughness.

The process typically involves heating the component in a carbon-rich environment at elevated temperature for a controlled period to allow carbon diffusion to the surface. After carburizing, the part is usually quenched to harden the surface and then tempered to relieve stresses and achieve the desired hardness. Postcarburizing can be performed using gas carburizing, vacuum carburizing, or salt bath methods, and may be followed by precision finishing to meet dimensional tolerances.

The depth of the carburized case depends on temperature, time, and alloy composition. Postcarburizing offers benefits for parts with complex geometries or tight final tolerances, enabling surface hardening without extensive machining to remove decarburized zones. However, it can introduce distortion, residual stresses, and potential surface contamination if not carefully controlled, and it adds processing cost.

Applications include gears, shafts, bearings, cam profiles, and other wear-prone steel components used in automotive and industrial equipment. Related processes include conventional carburizing, carbonitriding, and other diffusion-based heat treatments.