QUENCH AND TEMPER CORROSION RESISTANT STEEL ALLOY

• US 20170002447A1
• Filed: 08/12/2016
• Published: 01/05/2017
• Est. Priority Date: 10/24/2012
• Status: Active Grant

• Current Assignee: CRS Holding of America, LLC
• Original Assignee: CRS Incorporated (Carpenter Technology Corporation)
• Inventors: Wert, David E.
• Granted Patent: US 10,458,007 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B22F 1/00 Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• CPC Class Codes: B64C 25/00 Alighting gear air-cushion alighting gear B60V3/08
• CPC Class Codes: B64C 9/02 Mounting or supporting thereof
• CPC Class Codes: C21D 1/18 Hardening C21D1/02 takes precedence; Quenching with or without subsequent tempering quenching devices C21D1/62
• CPC Class Codes: C21D 2211/004 Dispersions; Precipitations
• CPC Class Codes: C21D 2211/008 Martensite
• CPC Class Codes: C21D 6/004 containing Cr and Ni
• CPC Class Codes: C21D 6/04 Hardening by cooling below 0 degrees Celsius
• CPC Class Codes: C21D 7/13 by hot working
• CPC Class Codes: C21D 8/005 of ferrous alloys C21D8/02 - C21D8/12 take precedence
• CPC Class Codes: C21D 9/0075 for rods of limited length of unlimited length C21D9/52
• CPC Class Codes: C22C 38/001 containing N
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/005 containing rare earths, i.e. Sc, Y, Lanthanides
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/04 containing manganese
• CPC Class Codes: C22C 38/06 containing aluminium
• CPC Class Codes: C22C 38/42 with copper
• CPC Class Codes: C22C 38/44 with molybdenum or tungsten
• CPC Class Codes: C22C 38/46 with vanadium
• CPC Class Codes: C22C 38/48 : with niobium or tantalum
• CPC Class Codes: C22C 38/50 : with titanium or zirconium
• CPC Class Codes: C22C 38/52 : with cobalt

Abstract

A quench and temper steel alloy is disclosed having the following composition in weight percent.

C0.2-0.5Mn0.1-1.0Si0.1-1.2Cr  9-14.5Ni2.0-5.5Mo1-2Cu  0-1.0Co1-4W0.2 max.V0.1-1.0Tiup to 0.5Nb  0-0.5Ta  0-0.5Al  0-0.25Ce  0-0.01La  0-0.01
The balance of the alloy is iron and the usual impurities including not more than about 0.01% phosphorus, not more than about 0.010% sulful, and not more than about 0.10% nitrogen. A quenched and tempered steel article made from this alloy is also disclosed. The steel article is characterized by a tensile strength of at least about 290 ksi, a fracture toughness (k_Ic) of at least about 65 ksi, good resistance to general corrosion, and good resistance to pitting corrosion.

Claims

1. A steel alloy comprising, in weight percent, about:

2. The alloy set forth in claim 1 which contains up to about 0.5% niobium and/or tantalum.

3. The alloy as set forth in claim 2 which contains up to about 0.01% cerium and up to about 0.01% lanthanum.

4. The alloy as set forth in claim 1 which contains not more than about 0.05% nitrogen.

5. The alloy set forth in claim 1 which contains about 9.5-12.5% chromium.

6. The alloy set forth in claim 1 which contains about 1.25-1.75% molybdenum.

7. The alloy set forth in claim 1 which contains about 2-3% cobalt.

8. The alloy set forth in claim 1 which contains about 3.2-4.3% nickel.

9. The alloy as set forth in claim 1 which contains at least about 0.3% vanadium.

10. The alloy as set forth in claim 1 which contains at least about 0.01% titanium.

11. The alloy as set forth in claim 1 which contains not more than about 0.7% copper.

15. A quenched and tempered steel article made from the alloy set forth in claim 1 which has a tensile strength of at least 290 ksi.

16. The steel article set forth in claim 15 which has a fracture toughness (K_Ic) of at least about 65 ksi√

in when tested in accordance with ASTM Standard Test Procedure E1290.

17. The steel article set forth in claim 16 which has sufficient general corrosion resistance such that the article does not rust after 200 hours when tested in accordance with ASTM Standard Test procedure B 117.

18. The steel article as set forth in claim 16 which has sufficient pitting corrosion resistance such that the article has a pitting potential of at least 90 mV when tested in accordance with ASTM Standard Test procedure G61 modified by using round bar samples.

12. A steel alloy consisting essentially of, in weight percent, about

13. The alloy as set forth in claim 12 which contains not more than about 0.7% copper.

14. The alloy as set forth in claim 12 which contains at least about 0.3% copper.

19. A structural component for an aerospace vehicle wherein the component is made from an alloy consisting essentially of, in weight percent, about

20. The aerospace structural component as set forth in claim 19 wherein the component is selected from the group consisting of one or more of landing gear, a rotatable shaft, an actuator, flap tracks, and slat tracks.

21. An alloy powder made from a steel alloy comprising, in weight percent, about:

22. The alloy powder as claimed in claim 24 wherein the steel alloy contains not more than about 4.0% nickel.