Ferritic stainless steel sheet and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-11401573-B2
Application number	US-201816607420-A
Country	US
Kind code	B2
Filing date	Apr 13, 2018
Priority date	Apr 25, 2017
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

A ferritic stainless steel sheet having excellent corrosion resistance, formability, and ridging resistance and a method for manufacturing the same are provided. A ferritic stainless steel sheet has a chemical composition containing, in terms of mass %, C: 0.005 to 0.030%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.040% or less, S: 0.030% or less, Al: 0.001 to 0.150%, Cr: 10.8 to 14.4%, Ni: 0.01 to 2.50%, and N: 0.005 to 0.060%, with the balance being Fe and incidental impurities. The elongation after fracture is 28% or more, and the ridging height of a surface of a steel sheet to which a tensile strain of 23% has been applied in a rolling direction is 3.0 μm or less.

First claim

The invention claimed is:

1. A ferritic stainless steel sheet having a chemical composition consisting of, by mass %:
C: 0.005 to 0.030%,
Si: 0.05 to 1.00%,
Mn: 0.05 to 1.00%,
P: 0.040% or less,
S: 0.030% or less,
Al: 0.031 to 0.150%,
Cr: 10.8 to 14.4%,
Ni: 1.20 to 2.50%,
N: 0.005 to 0.060%,
optionally at least one element selected from the group consisting of Co, Cu, Mo, W, V, Zr, Nb, B, Mg, Ca, Y, REM, and Sb, and
a balance being Fe and incidental impurities,
wherein:
the steel sheet has an elongation after fracture of 28% or more, and
a surface of the steel sheet has a ridging height of 3.0 μm or less when a tensile strain of 23% is applied in a rolling direction to the steel sheet.

2. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
Co: 0.01 to 0.50%,
Cu: 0.01 to 0.80%,
Mo: 0.01 to 0.30%, and
W: 0.01 to 0.50%.

3. The ferritic stainless steel sheet according to claim 2 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
V: 0.01 to 0.10%,
Zr: 0.01 to 0.10%, and
Nb: 0.01 to 0.30%,
wherein a value of formula (1) below is 0.0 or less:
54×(V+Zr+Nb)−5×Mn−19×Ni+1.0  formula (1)

where, in formula (1) above, respective element symbols represent contents (mass %) of respective elements, or 0 when corresponding elements are not present.

4. The ferritic stainless steel sheet according to claim 3 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
B: 0.0003 to 0.0030%,
Mg: 0.0005 to 0.0100%,
Ca: 0.0003 to 0.0030%,
Y: 0.01 to 0.20%, and
REM (rare earth metal): 0.001 to 0.100%.

5. The ferritic stainless steel sheet according to claim 4 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

6. A method for manufacturing the ferritic stainless steel sheet according to claim 5 , the method comprising:
hot-rolling a steel slab having the chemical composition so as to form a hot-rolled sheet;
performing hot-rolled sheet annealing that includes holding the hot-rolled sheet at a temperature in a range of 900° C. or more and 1100° C. or less for 5 seconds to 15 minutes so as to form a hot-rolled and annealed sheet;
cold-rolling the hot-rolled and annealed sheet so as to form a cold-rolled sheet; and
performing cold-rolled sheet annealing that includes holding the cold-rolled sheet at a temperature in a range of 780° C. or more and 830° C. or less for 5 seconds to 5 minutes; thereby producing the ferritic stainless steel sheet of claim 5 .

7. The ferritic stainless steel sheet according to claim 3 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

8. The ferritic stainless steel sheet according to claim 2 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
B: 0.0003 to 0.0030%,
Mg: 0.0005 to 0.0100%,
Ca: 0.0003 to 0.0030%,
Y: 0.01 to 0.20%, and
REM (rare earth metal): 0.001 to 0.100%.

9. The ferritic stainless steel sheet according to claim 8 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

10. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
V: 0.01 to 0.10%,
Zr: 0.01 to 0.10%, and
Nb: 0.01 to 0.30%,
wherein a value of formula (1) below is 0.0 or less:
54×(V+Zr+Nb)−5×Mn−19×Ni+1.0  formula (1)

where, in formula (1) above, respective element symbols represent contents (mass %) of respective elements, or 0 when corresponding elements are not present.

11. The ferritic stainless steel sheet according to claim 10 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
B: 0.0003 to 0.0030%,
Mg: 0.0005 to 0.0100%,
Ca: 0.0003 to 0.0030%,
Y: 0.01 to 0.20%, and
REM (rare earth metal): 0.001 to 0.100%.

12. The ferritic stainless steel sheet according to claim 11 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

13. The ferritic stainless steel sheet according to claim 10 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

14. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition includes, by mass %, at least one selected from the group consisting of:
B: 0.0003 to 0.0030%,
Mg: 0.0005 to 0.0100%,
Ca: 0.0003 to 0.0030%,
Y: 0.01 to 0.20%, and
REM (rare earth metal): 0.001 to 0.100%.

15. The ferritic stainless steel sheet according to claim 14 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

16. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

17. A method for manufacturing the ferritic stainless steel sheet according to claim 1 , the method comprising:
hot-rolling a steel slab having the chemical composition so as to form a hot-rolled sheet;
performing hot-rolled sheet annealing that includes holding the hot-rolled sheet at a temperature in a range of 900° C. or more and 1100° C. or less for 5 seconds to 15 minutes so as to form a hot-rolled and annealed sheet;
cold-rolling the hot-rolled and annealed sheet so as to form a cold-rolled sheet; and
performing cold-rolled sheet annealing that includes holding the cold-rolled sheet at a temperature in a range of 780° C. or more and 830° C. or less for 5 seconds to 5 minutes; thereby producing the ferritic stainless steel sheet of claim 1 .

18. The ferritic stainless steel sheet according to claim 2 , wherein the chemical composition includes, by mass %, Sb: 0.001 to 0.500%.

Assignees

• Jfe Steel Corp

Inventors

• Nishida Shuji
• Ishii Tomohiro
• Yoshino Masataka
• Fujisawa Mitsuyuki

Classifications

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• C22C38/42

  with copper · CPC title

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• C21D8/0236 Primary

  Cold rolling · CPC title

• C21D8/0263

  following hot rolling · CPC title