A martensitic precipitation-hardenable stainless steel essentially consisting of, in weight percent, not more than 0.08% C, 0.5-4.0% Si, not more than 4.0% Mn, 5.0-9.0% Ni, 10.0-17.0% Cr, more than 0.3% and up to 2.5% Mo, 0.15-1.0% Ti, not more than 1.0% Al and not more than 0.03% N and the balance being...http://www.google.ca/patents/US5035855?utm_source=gb-gplus-sharePatent US5035855 - Martensitic precipitation-hardenable stainless steel