Reinforced durable tool steel, method for the production thereof, method for producing parts made of said steel, and parts thus obtained

摘要

The invention relates to a tool steel, whereby the composition thereof comprises the following expressed in wt. %: 0.8 <= C <= 1.5; 5.0 <= Cr <= 14; 0.2 <= Mn <= 3; Ni <= 5; V <= 1; Nb <= 0.1; Si+Al <= 2; Cu <= 1; S <= 0.3; Ca <= 0.1; Se <= 0.1; Te <= 0.1; 1.0 <= Mo+W/2 <= 4; 0.06 <= Ti+Zr/2 <= 0.15; 0.004 <= N <= 0.02. The rest of the composition is comprised of iron and impurities resulting from the production process, including 2.5 x 10-4 %2 <= (Ti + Zr/2) x N. The invention also relates to a process for producing a part made of the above-described steel wherein the production process is characterized by producing a liquid steel by melting a set of elements of the said composition with exception of titanium and/or zirconium and subsequently adding to the steel melt titanium and/or zirconium, whereby formation of local excessive concentrations of titanium and/or zirconium in the steel melt at any arbitrary moment being prevented. The liquid steel is then cast to obtain an ingot or a slab, the ingot or the slab is then subjected to plastic deformation by hot forming and subsequently a heat treatment in order to obtain the required part.