HARDENED MARTENSITIC STEEL HAVING A LOW COBALT CONTENT, PROCESS FOR MANUFACTURING A PART FROM THIS STEEL, AND PART THUS OBTAINED

摘要

A steel characterized in that its composition is percentages by weight: C=0.18-0.30% Co=1.5-4% Cr=2-5% Al=1-2% Mo+W/2=1-4% V=traces-0.3% Nb=traces-0.1% B=traces-30 ppm Ni=11-16% where Ni7+3.5 Al Si=traces-1.0% Mn=traces-2.0% Ca=traces-20 ppm Rare earths=traces-100 ppm if N10 ppm, Ti+Zr/2=traces-100 ppm where Ti+Zr/210 N if 10 ppmN20 ppm, Ti+Zr/2=traces-150 ppm O=traces-50 ppm N=traces-20 ppm S=traces-20 ppm Cu=traces-1% P=traces-200 ppm the remainder being iron and inevitable impurities resulting from the smelting. A process for manufacturing a part from this steel, and part thus obtained.