This process consists of heating over AC3 temperature (usually 900°C), followed by air cooling. It can be done with or without controlled atmosphere and the result is a perlitic evenly and fine structure. It is used especially after hot processing (forging, rolling, extrusion) for eliminating the band structure and obtaining a uniform perlitic structure very good for the final heat treatment (hardening, carburizing, etc.).
It is suitable for most of the steels after hot processing and can be made in the following furnaces: