Steel product hardened and tempered to a hardness of at least 58 HRc

摘要

A steel product hardened and tempered to a hardness of at least 58 HRc is a hot worked, fully dense, wear resistant, vanadium-rich, powder metallurgy cold work tool steel article with high impact toughness made from nitrogen atomised prealloyed powders, consisting essentially of 0.60 to 0.95 % carbon, 0.10 to 2.0 % manganese, 6.00 to 9.00 % chromium, 2.00 to 3.30 % vanadium V and up to 0.10 % phosphorus, up to 0.15 % sulphur, 2 % silicon max, up to 3.0 % molybdenum, up to 1.0 % tungsten, up to 0.15 % nitrogen, balance iron and incidental impurities, wherein the maximum carbon content does not exceed the amount given by the following formula %C maximum =0.60 + 0.177(%V-1.0) and of substantially all MC-type carbides, as defined herein, within the range of 4 to 8 percent by volume and the maximum size of the MC-type carbides does not exceed about 6 microns and the impact value is exceed 6.9 N. m.