High-strength, notch-ductile precipitation-hardening stainless steel alloy and method of making
AssigneeCRS Holdings, Inc.
InventorJames W. Martin
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Abstract
A precipitation hardenable, martensitic stainless steel alloy is disclosed consisting essentially of, in weight percent, about ______________________________________ C 0.03 max Mn 1.0 max Si 0.75 max P 0.040 max S 0.020 max Cr 10-13 Ni 10.5-11.6 Ti 1.5-1.8 Mo 0.25-1.5 Cu 0.95 max Al 0.25 max Nb 0.3 max B 0.010 max N 0.030 max Ce 0.001-0.025 ______________________________________ the balance essentially iron. The disclosed alloy provides a unique combination of stress-corrosion cracking resistance, strength, and notch toughness even when used to form large cross-section pieces. A method of making such an alloy includes adding cerium during the melting process in a amount sufficient to yield an effective amount of cerium in the alloy product.
Claims18
A precipitation hardenable, martensitic stainless steel alloy having a unique combination of stress-corrosion cracking resistance, strength, and notch toughness consisting essentially of, in weight percent, about
- ______________________________________ C 0.03 max Mn 1.0 max Si 0.75 max P 0.040 max S 0.020 max Cr 10-13 Ni 10.5-11.6 Ti 1.5-1.8 Mo 0.25-1.5 Cu 0.95 max Al 0.25 max Nb 0.3 max B 0.010 max N 0.030 max Ce 0.001-0.025 ______________________________________
- the balance essentially iron.
A method of preparing a precipitation hardenable, martensitic stainless steel alloy having a unique combination of stress-corrosion cracking resistance, strength, and notch toughness, said alloy consisting essentially of the following elements in the following approximate weight percents:
- ______________________________________ C 0.03 max Mn 1.0 max Si 0.75 max P 0.040 max S 0.020 max Cr 10-13 Ni 10.5-11.6 Ti 1.5-1.8 Mo 0.25-1.5 Cu 0.95 max Al 0.25 max Nb 0.3 max B 0.010 max N 0.030 max ______________________________________
- and the balance essentially iron, said method comprising the steps of:
- melting charge materials containing said elements in proportions sufficient to provide said weight percent amounts;
- and
- adding cerium to the alloy during the melting thereof, the ratio of the amount of cerium added to the amount of sulfur present in the alloy being at least about 1:1.
A precipitation hardenable, martensitic stainless steel alloy product having a unique combination of stress-corrosion cracking resistance, strength, and notch toughness, said alloy consisting essentially of, in weight percent, about
- ______________________________________ C 0.03 max Mn 1.0 max Si 0.75 max P 0.040 max S 0.020 max Cr 10-13 Ni 10.5-11.6 Ti 1.5-1.8 Mo 0.25-1.5 Cu 0.95 max Al 0.25 max Nb 0.3 max B 0.010 max N 0.030 max Ce up to 0.025 ______________________________________
- and the balance essentially iron, said alloy product being prepared by:
- melting charge materials containing C, Mn, Si, P, S, Cr, Ni, Ti, Mo, Cu, Al, Nb, B, N, and Fe in proportions sufficient to provide said weight percent amounts;
- and
- adding cerium to the alloy during the melting thereof, the ratio of the amount of cerium added to the amount of sulfur present in the alloy being at least about 1:1.
Dependencies are inferred from the claim text.