Stainless steel and production method therefor

Patent metadata

Field	Value
Publication number	US-2017349984-A1
Application number	US-201515533499-A
Country	US
Kind code	A1
Filing date	Jul 2, 2015
Priority date	Dec 11, 2014
Publication date	Dec 7, 2017
Grant date	—

Abstract

Stainless steel that has excellent formability and ridging resistance and can be produced with high productivity is provided. The stainless steel comprises: a chemical composition containing, in mass %, C: 0.005% to 0.050%, Si: 0.01% to 1.00%, Mn: 0.01% to 1.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, and N: 0.005% to 0.06%, with a balance being Fe and incidental impurities; and a microstructure containing a martensite phase of 1% to 10% in volume fraction with respect to a whole volume of the microstructure.

First claim

1 . A stainless steel comprising:
a chemical composition containing, in mass %, C: 0.005% to 0.050%, Si: 0.01% to 1.00%, Mn: 0.01% to 1.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, and N: 0.005% to 0.06%, with a balance being Fe and incidental impurities; and a microstructure containing a martensite phase of 1% to 10% in volume fraction with respect to a whole volume of the microstructure.

2 . The stainless steel according to claim 1 ,
wherein the chemical composition further contains, in mass %, one or more selected from Cu: 0.1% to 1.0%, Mo: 0.1% to 0.5%, and Co: 0.01% to 0.5%.

3 . The stainless steel according to claim 1 ,
wherein the chemical composition further contains, in mass %, one or more selected from V: 0.01% to 0.25%, Ti: 0.001% to 0.05%, Nb: 0.001% to 0.05%, Ca: 0.0002% to 0.0020%, Mg: 0.0002% to 0.0050%, B: 0.0002% to 0.0050%, and REM: 0.01% to 0.10%.

4 . The stainless steel according to claim 1 ,
wherein mean elongation after fracture is 25% or more, in-plane anisotropy of elongation after fracture |ΔEl| is 3% or less, mean Lankford value is 0.70 or more, in-plane anisotropy of Lankford value |Δr| is 0.30 or less, and ridging height is 2.5 μm or less.

5 . A method for producing the stainless steel according to claim 1 , the method comprising:
hot rolling a steel slab having the chemical composition according to claim 1 into a hot rolled sheet; performing hot-rolled sheet annealing of holding the hot rolled sheet in a temperature range of 900° C. or more and 1050° C. or less for 5 seconds to 15 minutes, to form a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet into a cold rolled sheet; and performing cold-rolled sheet annealing of holding the cold rolled sheet in a temperature range of 850° C. or more and 950° C. or less for 5 seconds to 5 minutes.

6 . The stainless steel according to claim 2 ,
wherein the chemical composition further contains, in mass %, one or more selected from V: 0.01% to 0.25%, Ti: 0.001% to 0.05%, Nb: 0.001% to 0.05%, Ca: 0.0002% to 0.0020%, Mg: 0.0002% to 0.0050%, B: 0.0002% to 0.0050%, and REM: 0.01% to 0.10%.

7 . The stainless steel according to claim 2 ,
wherein mean elongation after fracture is 25% or more, in-plane anisotropy of elongation after fracture |ΔEl| is 3% or less, mean Lankford value is 0.70 or more, in-plane anisotropy of Lankford value |Δr| is 0.30 or less, and ridging height is 2.5 μm or less.

8 . The stainless steel according to claim 3 ,
wherein mean elongation after fracture is 25% or more, in-plane anisotropy of elongation after fracture |ΔEl| is 3% or less, mean Lankford value is 0.70 or more, in-plane anisotropy of Lankford value |Δr| is 0.30 or less, and ridging height is 2.5 μm or less.

9 . The stainless steel according to claim 6 ,
wherein mean elongation after fracture is 25% or more, in-plane anisotropy of elongation after fracture |ΔEl| is 3% or less, mean Lankford value is 0.70 or more, in-plane anisotropy of Lankford value |Δr| is 0.30 or less, and ridging height is 2.5 μm or less.

10 . A method for producing the stainless steel according to claim 2 , the method comprising:
hot rolling a steel slab having the chemical composition according to claim 2 into a hot rolled sheet; performing hot-rolled sheet annealing of holding the hot rolled sheet in a temperature range of 900° C. or more and 1050° C. or less for 5 seconds to 15 minutes, to form a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet into a cold rolled sheet; and performing cold-rolled sheet annealing of holding the cold rolled sheet in a temperature range of 850° C. or more and 950° C. or less for 5 seconds to 5 minutes.

11 . A method for producing the stainless steel according to claim 3 , the method comprising:
hot rolling a steel slab having the chemical composition according to claim 3 into a hot rolled sheet; performing hot-rolled sheet annealing of holding the hot rolled sheet in a temperature range of 900° C. or more and 1050° C. or less for 5 seconds to 15 minutes, to form a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet into a cold rolled sheet; and performing cold-rolled sheet annealing of holding the cold rolled sheet in a temperature range of 850° C. or more and 950° C. or less for 5 seconds to 5 minutes.

12 . A method for producing the stainless steel according to claim 6 , the method comprising:
hot rolling a steel slab having the chemical composition according to claim 6 into a hot rolled sheet; performing hot-rolled sheet annealing of holding the hot rolled sheet in a temperature range of 900° C. or more and 1050° C. or less for 5 seconds to 15 minutes, to form a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet into a cold rolled sheet; and performing cold-rolled sheet annealing of holding the cold rolled sheet in a temperature range of 850° C. or more and 950° C. or less for 5 seconds to 5 minutes.

13 . A method for producing the stainless steel according to claim 4 , the method comprising:
hot rolling a steel slab having a chemical composition into a hot rolled sheet, the chemical composition containing, in mass %, C: 0.005% to 0.050%, Si: 0.01% to 1.00%, Mn: 0.01% to 1.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, and N: 0.005% to 0.06%, with a balance being Fe and incidental impurities; performing hot-rolled sheet annealing of holding the hot rolled sheet in a temperature range of 900° C. or more and 1050° C. or less for 5 seconds to 15 minutes, to form a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet into a cold rolled sheet; and performing cold-rolled sheet annealing of holding the cold rolled sheet in a temperature range of 850° C. or more and 950° C. or less for 5 seconds to 5 minutes.

14 . A method for producing the stainless steel according to claim 7 , the method comprising:
hot rolling a steel slab having a chemical composition into a hot rolled sheet, the chemical composition containing, in mass %, C: 0.005% to 0.050%, Si: 0.01% to 1.00%, Mn: 0.01% to 1.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, N: 0.005% to 0.06%, and one or more selected from Cu: 0.1% to 1.0%, Mo: 0.1% to 0.5%, and Co: 0.01% to 0.5%, with a balance being Fe and incidental impurities; performing hot-rolled sheet annealing of holding the hot rolled sheet in a temperature range of 900° C. or more and 1050° C. or less for 5 seconds to 15 minutes, to form a hot-rolled and annealed sheet; cold rolling the hot-rolled and annealed sheet into a cold rolled sheet; and performing cold-rolled sheet annealing of holding the cold rolled sheet in a temperature range of 850° C. or more and 950° C. or less for 5 seconds to 5 minutes.

15 . A method for producing the stainless steel according to claim 8 , the method comprising:
hot rolling a steel slab having a chemical composition into a hot rolled sheet, the chemical composition containing, in mass %, C: 0.005% to 0.050%, Si: 0.01% to 1.00%, Mn: 0.01% to 1.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.5% to 18.0%, Ni: 0.01% to 1.0%, Al: 0.001% to 0.10%, N: 0.005% to 0.06%, and one or more selected from V: 0.01% to 0.25%, Ti: 0.001% to 0.05%, Nb: 0.001% to 0.05%, Ca: 0.0002% to 0.0020%, Mg: 0.0002% to 0.0050%, B: 0.0002% to 0.0050%, and REM: 0.01% to 0.10%, with a balance being Fe and

Assignees

• Jfe Steel Corp

Inventors

• Mizutani Akito
• Yoshino Masataka
• Fujisawa Mitsuyuki
• Ta Ayako

Classifications

• C21D2211/005

  Ferrite · CPC title

• C21D9/46

  for sheet metals · CPC title

• C22C38/02

  containing silicon · CPC title

• C21D6/002

  containing Cr (C21D6/004 takes precedence) · CPC title

• C22C38/54

  with boron · CPC title