Articles fabricated from cold-worked and case- hardened essentially co-free stainless steel alloys and methods of fabrication thereof

A method for fabricating an article, comprising the steps of:

• forming a billet consisting essentially of a stainless steel composition of
• manganese 2.00 wt. %-24.00 wt. %
• chromium 19.00 wt. %-30.00 wt. %
• molybdenum 0.50 wt. %-4.00 wt. %
• nitrogen 0.25 wt. %-1.10 wt. %
• carbon ≤1.00 wt. %
• phosphorus ≤0.03 wt. %
• sulfur ≤1.00 wt. %
• nickel <22.00 wt. %
• cobalt <0.10 wt. %
• silicon ≤1.00 wt. %
• niobium ≤0.80 wt. %
• oxygen ≤1.00 wt. %
• copper ≤0.25 wt. %
• balance iron;
• annealing the billet;
• cold working the billet to form the article;
• and
• without annealing of the article, subsequently case hardening the article at a single case hardening temperature to form a surface layer on a top surface thereof, wherein case hardening comprises at least one of boriding, carburizing, nitriding, carbonitriding, or a combination thereof without formation of borides, carbides, nitride, and carbonitrides,
• wherein (i) the surface layer comprises a surface hardness of at least 350 HV, and (ii) the article comprises an articulating orthopedic device comprising a first element comprising a first articular surface and a second element comprising a second articular surface configured to articulate with the first articular surface, the first and second elements consisting essentially of the stainless steel composition, and wherein the first and second articular surfaces each comprise the surface layer comprising the stainless steel composition and further comprising at least one of carbon, nitrogen, or boron diffused therein.