Lower-cost, ultra-high-strength, high-toughness steel

摘要

A non-stainless steel alloy includes, in combination by weight, about 0.20% to about 0.33% carbon, about 4.0% to about 8.0% cobalt, about 7.0 to about 11.0% nickel, about 0.8% to about 3.0% chromium, about 0.5% to about 2.5% molybdenum, about 0.5% to about 5.9% tungsten, about 0.05% to about 0.20% vanadium, and up to about 0.02% titanium, the balance essentially iron and incidental elements and impurities.

主权项

1. A non-stainless steel alloy comprising, in combination by weight:
about 0.20% to about 0.33% carbon, about 4.0% to about 8.0% cobalt, about 7.0% to about 11.0% nickel, about 0.8% to about 3.0% chromium, about 0.5% to about 2.5% molybdenum, about 0.5% to about 5.9% tungsten, about 0.05% to about 0.20% vanadium, and titanium up to about 0.02%, the balance essentially iron and incidental elements and impurities said alloy having a microstructure characterized by MC grain refinement particles by inclusion of principally M2C carbide particle precipitates wherein M2 is comprised of chromium (Cr), molybdenum (Mo), tungsten (W), and vanadium (V) in a predominately lath martensite matrix, said alloy further characterized by the combination of an ultimate tensile strength of at least about 1900 MPa, a KIC, high fracture toughness of at least about 100 to 140 MPa√m and enhanced stress KISCC corrosion cracking resistance as measured by ASTMF1624 or similar method of at least about 105 to 120 MPa√m.