A STEEL AND A HEAT TREATED TOOL THEREOF MANUFACTURED BY AN INTEGRATED POWDER METALLURGICAL PROCESS AND USE OF THE STEEL FOR TOOLS

摘要

The invention relates to a steel having the following alloy composition in weight-%: 1.4-1.6 (C+N), max. 0.6 Mn, max. 1.2 Si, 3.5-4.3 Cr, 1.5-3 Mo, 1.5-3 W, wherein 6 < Weq < 9, and Weq = % W + 2 x % Mo, 3.5-4.5 V, max. 0.3 S, max. 0.3 Cu, max. 1 Co, a total amount of max. 1.0 of Nb + Ta + Ti + Zr + Al, a total amount of 0.5 of other elements, including impurities and accessory elements in normal amounts, balance iron, and with a microstructure substantially consisting of a martensitic matrix and in the matrix 2-15, preferably 5-10 volume-% undisssolved hard products having the particle size 0.1-3 mu m, said hard products being of MX-type, where M is V and X is C and/or N, wherein 40-60 % of the C and N content of the alloy is bound to vanadium as carbides and/or as carbo-nitrides, and a functional amount of hard products precipitated in the martensitic matrix after solution heat treatment of the steel at a temperature between 1000 and 1225 DEG C and tempering at least twice for at least 0.5 h at a temperature between 190 and 580 DEG C, and the use of the steel for tools for forming and/or cutting operations.