Abstract: An iron-base, fine-grained, martensitic stainless steel alloy is disclosed. The alloy is essentially free of delta ferrite and provides very high hardness and good corrosion resistance. The alloy consists essentially of the following composition in weight percent. C about 0.20 to about 0.70 Mn about 5 max. Si about 1 max. P about 0.1 max. S about 0.03 max. Cr about 7.5 to about 15 Ni about 2 to about 5 Mo about 4 max. Co about 4 max. Cu about 1.2 max. Ti about 0.01 to about 0.75 Al about 0.2 max Nb about 1 max. about 2 max. N about 0.02 max. B about 0.1 max. The balance of the alloy is iron and the usual impurities. A composite article of manufacture is also disclosed that includes a case portion formed of the foregoing alloy.

Abstract: A martensitic alloy in which the ASTM grain size number is at least 5, including (wt. %) up to about 0.5% C, at least about 5% Cr, at least about 0.5% Ni, up to about 15% Co, up to about 8% Cu, up to about 8% Mn, up to about 4% Si, up to about 6% (Mo+W), up to about 1.5% Ti, up to about 3% V, up to about 0.5% Al, and at least about 40% Fe.

Abstract: An iron based, fine-grained, martensitic stainless steel essentially free of delta ferrite has a nominal composition of (wt. %): 0.05<C<0.15; 7.5<Cr<15; 2<Ni<5; Co<4; Cu<1.2; Mn<5; Si<1; (Mo+W)<4; 0.01<Ti<0.75; 0.135<(1.17Ti+0.6Zr+0.31Ta+0.31Hf)<1; V<2; Nb<1; N<0.02; Al<0.2; Al and Si both present such that (Al+Si)>0.01; B<0.1; P<0.1; S<0.03; and the balance essentially iron and impurities. This steel is different from other martensitic stainless steels because thermal mechanical treatment is used to refine the grains and precipitate a relatively uniform dispersion of fine, coarsening-resistant, MX-type particles. The steel combines high strength and impact toughness with good corrosion resistance.

Abstract: An iron based, fine-grained, alloy.

Abstract: An iron based, fine-grained, martensitic stainless steel essentially free of delta ferrite has a nominal composition of (wt. %): 0.05<C<0.15; 7.5<Cr<15; 2<Ni<5; Co<4; Cu<1.2; Mn<5; Si<1; (Mo+W)<4; 0.01<Ti<0.75; 0.135<(1.17Ti+0.6Zr+0.31Ta+0.31Hf)<1; V<2; Nb<1; N<0.02; Al<0.2; Al and Si both present such that (Al+Si)>0.01; B<0.1; P<0.1; S<0.03; and the balance essentially iron and impurities. This steel is different from other martensitic stainless steels because thermal mechanical treatment is used to refine the grains and precipitate a relatively uniform dispersion of fine, coarsening-resistant, MX-type particles. The steel combines high strength and impact toughness with good corrosion resistance.

Abstract: An iron based, fine-grained, alloy.

Abstract: An iron-based, corrosion-resistant, precipitation strengthened, martensitic steel essentially free of delta ferrite for use at high temperatures has a nominal composition of 0.05-0.1 C, 8-12 Cr, 1-5 Co, 0.5-2.0 Ni, 0.41-1.0 Mo, 0.1-0.5 Ti, and the balance iron. This steel is different from other corrosion-resistant martensitic steels because its microstructure consists of a uniform dispersion of fine particles, which are very closely spaced, and which do not coarsen at high temperatures. Thus at high temperatures this steel combines the excellent creep strength of dispersion-strengthened steels, with the ease of fabricability afforded by precipitation hardenable steels.