Patent ID: 6180266
Filing Date: 2001-01-30
Classification: B32B,C22C,Y10S,Y10T

Abstract:
A cutting tool having a cutting edge made of a high speed tool steel consisting essentially of by weight C:0.6 to 1.8%, Si:1.2% max, Mn:0.5% max, Cr:3.5 to 5.0%, Mo:10% max, W:21% max, V:2 to 4% and Co:7 to 10%, the balance being Fe and incidental impurities, and the steel of the cutting edge comprising MC carbide grains each having a maximum equal value diameter of a circle ranging substantially 5 to 14 .mu.m, which equal value diameter of the circle being a diameter of any one of a circle being converted to the circle having the same cross sectional area as that of a cross sectional area of any one of the MC carbide grains, and the MC carbide grains having an equal value diameter of a circle ranging substantially 5 to 14 .mu.m have a ratio between short and long diameters ranging over substantially 0.3, wherein the ratio between short and long diameters is a value obtained by dividing a short diameter of any one of the MC carbide grains by a long diameter of the same.