Lean austenitic stainless steel

Patent metadata

Field	Value
Publication number	US-9617628-B2
Application number	US-201414456026-A
Country	US
Kind code	B2
Filing date	Aug 11, 2014
Priority date	Nov 29, 2007
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

An austenitic stainless steel having low nickel and molybdenum and exhibiting comparable corrosion resistance and formability properties to higher nickel and molybdenum alloys comprises, in weight %, up to 0.20 C, 2.0-9.0 Mn, up to 2.0 Si, 16.0-23.0 Cr, 1.0-5.0 Ni, up to 3.0 Mo, up to 3.0 Cu, 0.1-0.35 N, up to 4.0 W, up to 0.01 B, up to 1.0 Co, iron and impurities, the steel having a ferrite number of less than 10 and a MD 30 value of less than 20° C.

First claim

What is claimed is:

1. An austenitic stainless steel consisting of, in weight percent:
up to 0.20 C,
2.0-9.0 Mn,
up to 1.0 Si,
16.0-23.0 Cr,
1.0-3.0 Ni,
up to 2.0 Mo,
0.1-0.35 N,
0.05 to 4.0 W,
up to 0.01 B,
up to 1.0 Co,
iron and
impurities,
the austenitic stainless steel having a ferrite number of at least 3 up to less than 10, and a MD 30 value less than 20° C.

2. The austenitic stainless steel according to claim 1 , wherein: 0.5≦(Mo+W/2)≦5.0.

3. The austenitic stainless steel according to claim 1 , having a PRE W value of greater than 22.

4. The austenitic stainless steel of claim 1 , having a PRE value greater than 22 and up to 30.

5. The austenitic stainless steel of claim 1 , having a ferrite number of 3 up to 5.

6. The austenitic stainless steel of claim 1 , having a MD 30 value less than −10° C.

7. The austenitic stainless steel of claim 1 , wherein C is limited to up to 0.08.

8. The austenitic stainless steel of claim 1 , wherein Mn is limited to 2.0-8.0.

9. The austenitic stainless steel of claim 1 , wherein Mn is limited to 3.0-6.0.

10. The austenitic stainless steel of claim 1 , wherein Cr is limited to 16.0-22.0.

11. The austenitic stainless steel of claim 1 , wherein Cr is limited to 17.0-21.0.

12. The austenitic stainless steel of claim 1 , wherein Cr is limited to 17.0-20.0.

13. The austenitic stainless steel of claim 1 , wherein Cr is limited to 16.0-18.0.

14. The austenitic stainless steel of claim 1 , wherein N is limited to 0.1-0.30.

15. The austenitic stainless steel of claim 1 , wherein N is limited to 0.14-0.30.

16. The austenitic stainless steel of claim 1 , wherein Mo is limited to 0.40-2.0.

17. The austenitic stainless steel of claim 1 , wherein Mo is limited to 0.5-2.0.

18. The austenitic stainless steel of claim 1 , wherein B is limited to up to 0.008.

19. The austenitic stainless steel of claim 1 , wherein W is limited to 0.05-0.60.

20. The austenitic stainless steel of claim 1 , wherein Mo is limited to 0.40-2.0 and having a MD 30 value less than −10° C.

21. The austenitic stainless steel of claim 1 , wherein Mo is limited to 0.40-2.0 and wherein 0.5≦(Mo+W/2)≦4.0.

22. The austenitic stainless steel of claim 21 , having a MD 30 value less than −10° C.

23. An austenitic stainless steel consisting of, in weight percent:
up to 0.20 C,
2.0-9.0 Mn,
up to 1.0 Si,
16.0-23.0 Cr,
1.0-3.0 Ni,
0.40-2.0 Mo,
0.1-0.30 N,
0.05 to 4.0 W,
up to 0.01 B,
up to 1.0 Co,
iron and
impurities,
the austenitic stainless steel having a ferrite number at least 3 up to 10, a PRE W value greater than 22 up to 30, and a MD 30 value of less than 20° C.

24. The austenitic stainless steel of claim 23 , wherein Mo is limited to 0.40-2.0 and wherein 0.5(Mo+W/2)≦4.0.

25. The austenitic stainless steel of claim 23 , wherein Mn is limited to 6.0-9.0.

26. An article of manufacture including an austenitic stainless steel consisting of, in weight percent:
up to 0.20 C,
2.0-9.0 Mn,
up to 1.0 Si,
16.0-23.0 Cr,
1.0-3.0 Ni,
up to 2.0 Mo,
0.1-0.35 N,
0.05 to 4.0 W,
up to 0.01 B,
up to 1.0 Co,
iron and
impurities, the austenitic stainless steel having a ferrite number of at least 3 up to less than 10, and a MD 30 value less than 20° C.

27. The article of manufacture of claim 26 , wherein the austenitic stainless steel has a MD 30 value less than −10° C.

28. The article of manufacture of claim 26 , wherein in the austenitic stainless steel Mo is limited to 0.40-2.0 Mo.

29. The article of manufacture of claim 26 , wherein the article is adapted for use in at least one of a low temperature environment and a cryogenic environment.

30. The article of manufacture of claim 26 , wherein the article is selected from the group consisting of a corrosion resistant article, a corrosion resistant architectural panel, a flexible connector, a bellows, a tube, a pipe, a chimney liner, a flue liner, a plate frame heat exchanger part, a condenser part, a part for pharmaceutical processing equipment, a sanitary part, and a part for ethanol production or processing equipment.

31. The austenitic stainless steel of claim 1 , wherein the ferrite number is calculated according to the following equation, in which elemental contents are weight percentages:
ferrite number=3.34×(Cr+1.5Si+Mo+2Ti+0.5Cb)−2.46×(Ni+30N+30C+0.5Mn+0.5Cu)−28.6.

32. The austenitic stainless steel of claim 23 , wherein the ferrite number is calculated according to the following equation, in which elemental contents are weight percentages:
ferrite number=3.34×(Cr+1.5Si+Mo+2Ti+0.5Cb)−2.46×(Ni+30N+30C+0.5Mn+0.5Cu)−28.6.

33. The article of manufacture of claim 26 , wherein the ferrite number of the austenitic stainless steel is calculated according to the following equation, in which elemental contents are weight percentages:
ferrite number=3.34×(Cr+1.5Si+Mo+2Ti+0.5Cb)−2.46×(Ni+30N+30C+0.5Mn+0.5Cu)−28.6.

Assignees

• Ati Properties Llc

Inventors

• Bergstrom David S
• Rakowski James M
• Stinner Charles P
• Dunn John J
• Grubb John F

Classifications

• C22C38/58 Primary

  with more than 1.5% by weight of manganese · CPC title

• C22C38/001

  containing N · CPC title

• C22C38/22

  with molybdenum or tungsten · CPC title

• C22C38/34

  with more than 1.5% by weight of silicon · CPC title

• C22C38/38

  with more than 1.5% by weight of manganese · CPC title