GB798652A - Process for refining hot-rolled steel by further treatment - Google Patents

Abstract

798,652. Altering physical structure; working at specified temperatures; rolling. BOCHUMER VEREIN FUR GUSSSTAHLFABRIKATION AKT.-GES. Dec. 20, 1955 [Dec. 21, 1954], No. 36497/55. Class 83 (4). A process for refining and quality-improving by further treatment, steel which is hot rolled from billets or plate slabs and thereafter cooled without hardening, and, if required, already further worked in the cold to coil or bar form, is characterised in that, when subjected to further deformation by rolls or cylinders, the steel is heated by means of electric resistance heating in fractions of a second, preferably <SP>1</SP>/ 20 th of a second and less, to temperatures between 250‹ C. and slightly below AC3. The process enables a high rolling temperature to be chosen without prejudice to, e.g., a sorbitic structure obtaining from a previous heat treatment. Such structure can be still further improved by a heat treatment following the further deformation, such as air chilling or quenching or by tempering or annealing below AC3. The low voltage electric current, e.g. 10 volts, is supplied through the top roll to the bottom roll or vice versa, or by way of the rolls and an associated coiler or drawing pincers. The steel may be electrically heated and shaped either several times in immediate succession on a plurality of roll stands or by rolling to and fro uninterruptedly on one or two reversing stands. The electric current may be conducted by wheels connected to the rolls and immersed in a lead bath. Austenitic steels are electrically resistance heated to a temperature below that at which scaling begins.