Patent ID: 6818040
Filing Date: 2004-11-16
Classification: B22F,C21D,C22C

Abstract:
A powder metallurgy manufactured high speed steel with a high content of nitrogen in the form of a body formed through consolidation of alloyed metal powder, wherein the high speed steel, with reference to its chemical composition contains in weight-%1-2.5 C 1-3.5 N 0.05-1.7 Mn 0.05-1.2 Si 3-6 Cr 2-5 Mo 0.5-5 W 6.2-17 (V+2 Nb) balance iron and unavoidable impurities in normal amounts, and wherein the amount of, on one hand, the carbon equivalent, Ceq, expressed as Ceq=C+1214&it;N,and, on the other hand, the vanadium equivalent, Veq, expressed as Veq=V+2 Nb, are balanced relative to each other such that the amounts of said elements, expressed in terms of said equivalent, will lie within the area A1-B1-Cl-D1-A1 in the system of co-ordinates in FIG. 1, in which the Ceq/Veq-co-ordinates of the points A1-D1 areA1: 4.5/17 B1: 5.5/17 C1: 2.5/6.2 D1: 1.5/6.2 the high speed steel with reference to its structure, in the hardened and tempered condition of the steel, containing 12-40 vol-% of hard matter consisting of MX-particles, which are evenly distributed in the matrix of the steel, M in said matter of MX-type essentially consisting of vanadium and/or niobium, and X consisting of 30-50 weight-% carbon and 50-70 weight-% nitrogen.