Ferritic stainless steel sheet

Patent metadata

Field	Value
Publication number	US-11220732-B2
Application number	US-201716310956-A
Country	US
Kind code	B2
Filing date	Jun 15, 2017
Priority date	Jun 27, 2016
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

Provided is a ferritic stainless steel sheet excellent in shape of weld zone and corrosion resistance of a weld zone with a material of a different kind formed by performing welding with austenitic stainless steel.A ferritic stainless steel sheet having a chemical composition containing, by mass %,C: 0.003% to 0.020%, Si: 0.01% to 1.00%, Mn: 0.01% to 0.50%, P: 0.040% or less, S: 0.010% or less, Cr: 20.0% to 24.0%, Cu: 0.20% to 0.80%, Ni: 0.01% to 0.60%, Al: 0.01% to 0.08%, N: 0.003% to 0.020%, Nb: 0.40% to 0.80%, Ti: 0.01% to 0.10%, Zr: 0.01% to 0.10%, and the balance being Fe and inevitable impurities, in which relational expression (1) below is satisfied:3.0≥Nb/(2Ti+Zr+0.5Si+5Al)≥1.5  (1),here, in relational expression (1), each of the atomic symbols denotes the content (mass %) of the corresponding chemical element.

First claim

The invention claimed is:

1. A ferritic stainless steel sheet having a chemical composition containing, by mass %,
C: 0.003% to 0.020%,
Si: 0.01% to 1.00%,
Mn: 0.01% to 0.50%,
P: 0.040% or less,
S: 0.010% or less,
Cr: 20.0% to 24.0%,
Cu: 0.20% to 0.80%,
Ni: 0.01% to 0.60%,
Al: 0.01% to 0.08%,
N: 0.003% to 0.020%,
Nb: 0.40% to 0.80%,
Ti: 0.01% to 0.10%,
Zr: 0.01% to 0.10%, and
the balance being Fe and inevitable impurities,
wherein a combination of Ti, Nb, Zr, Si, and Al present in the chemical composition satisfy relational expression (1) below:
3.0≥Nb/(2Ti+Zr+0.5Si+5Al)≥1.5  (1),

where, in relational expression (1), each of the atomic symbols denotes the content (mass %) of the corresponding chemical element,
wherein a shape of a weld zone of the ferritic stainless steel sheet has no SAG or no UNDERCUT and wherein a case of a SAG is defined as a part of a weld fusion zone, of the ferritic stainless steel sheet, being 0.15 mm or more lower than the positions of two base metals butted on the right- and left-hand sides of the weld fusion zone, and a case of an UNDERCUT is defined as a thickness of the weld fusion zone at a position where the weld fusion zone is in contact with the base metal is 0.15 mm or more thinner than that of the base metal.

2. The ferritic stainless steel sheet according to claim 1 , wherein the combination of Ti, Nb, Zr, and Al present in the chemical composition satisfy relational expression (2):
2Ti+Nb+1.5Zr+3Al≥0.75  (2),

where, in relational expression (2), each of the atomic symbols denotes the content (mass %) of the corresponding chemical element, and
wherein the weld zone, after application of tensile stress according to JIS No. 5, has a surface quality defined by a maximum height roughness Rz of 10 μm or less.

3. The ferritic stainless steel sheet according to claim 2 , wherein the chemical composition further contains, by mass %, V: 0.01% to 0.30%.

4. The ferritic stainless steel sheet according to claim 3 , wherein the chemical composition further contains, by mass %, one or both of
Mo: 0.01% to 0.30% and
Co: 0.01% to 0.30%.

5. The ferritic stainless steel sheet according to claim 4 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

6. The ferritic stainless steel sheet according to claim 3 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

7. The ferritic stainless steel sheet according to claim 2 , wherein the chemical composition further contains, by mass %, one or both of
Mo: 0.01% to 0.30% and
Co: 0.01% to 0.30%.

8. The ferritic stainless steel sheet according to claim 7 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

9. The ferritic stainless steel sheet according to claim 2 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

10. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, V: 0.01% to 0.30%.

11. The ferritic stainless steel sheet according to claim 10 , wherein the chemical composition further contains, by mass %, one or both of
Mo: 0.01% to 0.30% and
Co: 0.01% to 0.30%.

12. The ferritic stainless steel sheet according to claim 11 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

13. The ferritic stainless steel sheet according to claim 10 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

14. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, one or both of
Mo: 0.01% to 0.30% and
Co: 0.01% to 0.30%.

15. The ferritic stainless steel sheet according to claim 14 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

16. The ferritic stainless steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, one or more of
B: 0.0003% to 0.0050%,
Ca: 0.0003% to 0.0050%,
Mg: 0.0005% to 0.0050%,
REM: 0.001% to 0.050%,
Sn: 0.01% to 0.50%, and
Sb: 0.01% to 0.50%.

Assignees

• Jfe Steel Corp

Inventors

• Kawabe Hidetaka
• Nishida Shuji
• Fujisawa Mitsuyuki
• Kami Chikara

Classifications

• C22C38/02

  containing silicon · CPC title

• C22C38/06

  containing aluminium · CPC title

• C22C38/52

  with cobalt · CPC title

• C22C38/46

  with vanadium · CPC title

• C22C38/50 Primary

  with titanium or zirconium · CPC title