Thermal treatment process for manufacturing edge layer of hardened long - nd flat products from unalloyed or low-alloyed steels

摘要

In order to heat treatment process for the production of edge layer of hardened long - or flat products, comprising the steps of cooling of the work piece to a temperature below the martensite starting temperature takes place, and a subsequent slow cooling of the core to improve the toughness properties of the workpiece that is to be improved, proposed according to the invention that the first cooling process in a plurality of repeating steps is carried out, wherein each process step of a cooling to a temperature below the martensite starting temperature takes place for the martensitic transformation in each case only a part of the workpiece edge region and a subsequent time phase to the relaxation of the already formed martensitic structure parts and / or edge regions is composed of the martensite / austenite.