Ferritic stainless steel and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9863023-B2
Application number	US-201314437015-A
Country	US
Kind code	B2
Filing date	Oct 22, 2013
Priority date	Oct 22, 2012
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

Provided are a ferritic stainless steel having a corrosion resistance at a certain level or more and a temper-color removal performance at a certain level or more and a method for manufacturing the ferritic stainless steel. A ferritic stainless steel has a composition containing, by mass %, C: 0.001% to 0.030%, Si: 0.03% to 0.30%, P: 0.05% or less, S: 0.01% or less, Cr: more than 22.0% to 28.0%, Mo: 0.2% to 3.0%, Al: 0.01% to 0.15%, Ti: more than 0.30% to 0.80%, V: 0.001% to 0.080%, and N: 0.001% to 0.050%; Mn: 0.05% to 0.30% and Ni: 0.01% to 5.00%, or Mn: 0.05% to 2.00% and Ni: 0.01% to 0.30%; Nb: 0.05% or less as an optional component; and the balance being Fe and inevitable impurities, and the steel has a surface where TiN having a grain diameter of 1 μm or more is distributed at a density of 30 particles/mm 2 or more.

First claim

The invention claimed is:

1. A ferritic stainless steel having a composition containing, by mass %, C: 0.001% to 0.030%, Si: 0.03% to 0.30%, P: 0.05% or less, S: 0.01% or less, Cr: more than 22.0% to 28.0%, Mo: 0.2% to 3.0%, Al: 0.01% to 0.15%, Ti: more than 0.30% to 0.80%, V: 0.001% to 0.080%, and N; 0.001% to 0.050%; Mn: 0.05% to 0.30% and Ni: 0.01% to 5.00%, or Mn: 0.05% to 2.00% and Ni: 0.01% to 0.30%; Nb: 0.001% to 0.033%; and the balance being Fe and inevitable impurities, and
having a surface where TiN having a grain diameter of 1 μm or more is distributed at a density of 30 particles/mm 2 or more.

2. The ferritic stainless steel according to claim 1 ,
wherein the Mn content is 0.05% to 0.30%, and
the Ni content is 0.01% to less than 0.30%.

3. The ferritic stainless steel according to claim 1 ,
wherein NbN is precipitated on a surface of TiN having a grain diameter of 1 μm or more.

4. The ferritic stainless steel according to claim 1 ,
wherein, by mass %, the Mn content is 0.05% to 0.30%, the Ni content is 0.30% to 5.00%, and the N content is 0.005% to 0.030%.

5. The ferritic stainless steel according to claim 1 ,
wherein, by mass %, the Mn content is more than 0.30% to 2.00%, the Ni content is 0.01% to less than 0.30%, the S content is 0.005% or less, and the N content is 0.001% to 0.030%.

6. The ferritic stainless steel according to claim 5 ,
wherein [Mn] as the Mn content and [Si] as the Si content satisfy a formula (1):
[Mn]/[Si]>2.0  (1).

7. The ferritic stainless steel according to claim 1 ,
wherein the steel has a chemical composition further containing one or more components selected from the group consisting of, by mass %, Cu: 1.0% or less, Zr: 1.0% or less, W: 1.0% or less, and B: 0.1% or less.

8. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 1 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

9. The ferritic stainless steel according to claim 2 ,
wherein NbN is precipitated on a surface of TiN having a grain diameter of 1 μm or more.

10. The ferritic stainless steel according to claim 2 ,
wherein the steel has a chemical composition further containing one or more components selected from the group consisting of, by mass %, Cu: 1.0% or less, Zr: 1.0% or less, W: 1.0% or less, and B: 0.1% or less.

11. The ferritic stainless steel according to claim 3 ,
wherein the steel has a chemical composition further containing one or more components selected from the group consisting of, by mass %, Cu: 1.0% or less, Zr: 1.0% or less, W: 1.0% or less, and B: 0.1% or less.

12. The ferritic stainless steel according to claim 4 ,
wherein the steel has a chemical composition further containing one or more components selected from the group consisting of, by mass %, Cu: 1.0% or less, Zr: 1.0% or less, W: 1.0% or less, and B: 0.1% or less.

13. The ferritic stainless steel according to claim 5 ,
wherein the steel has a chemical composition further containing one or more components selected from the group consisting of, by mass %, Cu: 1.0% or less, Zr: 1.0% or less, W: 1.0% or less, and B: 0.1% or less.

14. The ferritic stainless steel according to claim 6 ,
wherein the steel has a chemical composition further containing one or more components selected from the group consisting of, by mass %, Cu: 1.0% or less, Zr: 1.0% or less, W: 1.0% or less, and B: 0.1% or less.

15. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 2 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

16. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 3 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

17. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 4 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

18. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 5 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

19. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 6 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

20. A method for manufacturing a ferritic stainless steel, comprising:
cold rolling and annealing a steel having a component composition according to claim 7 ; and
subsequently electrolytic pickling the steel for a pickling weight loss of 0.5 g/m 2 or more.

Assignees

• Jfe Steel Corp

Inventors

• Ishii Tomohiro
• Ishikawa Shin
• Ogata Hiroyuki
• Ota Hiroki

Classifications

• C21D8/00

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• C22C38/54

  with boron · CPC title

• C22C38/42

  with copper · CPC title

• C21D6/008

  containing Si · CPC title

• C21D6/005

  containing Mn · CPC title