Steel material and its manufacture

Abstract

The invention concerns a steel material which consists of a steel having the following chemical composition in weigh-%: 1.0-1.9 C, 0.5-2.0 Si, 0.1-1.5 Mn, 4.0-5.5 Cr, 2.5-4.0 (Mo+W/2), however max 1.0 W, 2.0-4.5 (V+Nb/2), however max 1.0. Nb, balance iron and impurities in normal amounts in the form of residual elements from the manufacturing of the steel, and with a microstructure, which in the hardened and tempered condition of the steel contains 5-12 vol-% MC-carbides, at least about 80 vol-% of the carbides having a size which is larger than 3 μm but smaller than 25 μm preferably smaller than 20 μm, and, prior to tempering, 0.50-0.70 weight-% carbon, which is dissolved in the martensite in the hardened condition of the steel. The material is intended for cold work tools, in the first place for homogenous rolls for cold rolling of meta, strips.

Dependencies are inferred from the claim text.