METHOD AND APPARATUS FOR HEAT TREATING RAILS

摘要

The invention relates to the iron and steel industry, more specifically to methods and devices for heat treating railway rails. The method for heat treating rails includes preheating, postheating, and cooling. The technical result is achieved by means of heating that is carried out continuously and/or intermittently according to a set programme. Preheating is carried out to the austenitization start temperature (Ac1) without exceeding the austenitization end temperature (Ac3). Postheating is carried out by thermal cycling in the phase transformation region. In the intervals between the individual heating devices, retention is carried out to equalize the temperature over each cross section. The cooling speed is adjusted at different stages of the cooling regime. The claimed method is carried out on the proposed apparatus, which includes a preheating zone, a thermal cycling zone, a homogenization zone with individual heating devices having intervals and/or devices therebetween for equalizing the temperature over a cross-section, a cooling zone containing cooling modules with a unit for controlling and adjusting the cooling parameters, and a self-tempering zone. The technical result of the invention includes improved physical and mechanical properties, a rail head hardness of up to 415 НВ, and increased service life of the rails. Furthermore, the rails are of the required straightness after heat treatment, making it possible to exclude straightening in a roller straightening machine, and the range of adjustment of the heating and cooling speeds is extended, making it possible to heat treat rails made from different grades of steel.