High-silicon steel sheet and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10760143-B2
Application number	US-201615758826-A
Country	US
Kind code	B2
Filing date	Sep 8, 2016
Priority date	Sep 17, 2015
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A high-silicon steel sheet is excellent in terms of punching workability and magnetic property. The high-silicon steel sheet has a chemical composition containing, by mass %, C: 0.02% or less, P: 0.02% or less, Si: 4.5% or more and 7.0% or less, Mn: 0.01% or more and 1.0% or less, Al: 1.0% or less, O: 0.01% or less, N: 0.01% or less, and the balance being Fe and inevitable impurities, a grain-boundary oxygen concentration (oxygen concentration with respect to chemical elements segregated at grain boundaries) of 30 at % or less, and a microstructure in which a degree of integration P(211) of a {211}-plane of α-Fe on a surface of the steel sheet is 15% or more

P (211)= p (211)/ S ×100(%), wherein

S=p (110)/100+ p (200)/14.93+ p (211)/25.88+ p (310)/7.68+ p (222)/1.59+ p (321)/6.27+ p (411)/1.55, and
p(hkl): integrated intensity of a peak of X-ray diffraction of an {hkl}-plane.

First claim

The invention claimed is:

1. A high-silicon steel sheet having
a chemical composition containing, by mass %, C: 0.02% or less, P: 0.02% or less, Si: 4.5% or more and 7.0% or less, Mn: 0.01% or more and 1.0% or less, Al: 1.0% or less, O: 0.01% or less, N: 0.01% or less, and the balance being Fe and inevitable impurities,
a grain-boundary oxygen concentration comprising oxygen concentration with respect to chemical elements segregated at grain boundaries of 30 at % or less, and
a microstructure in which a degree of integration P(211) of a {211}-plane of α-Fe on a surface of the steel sheet is 15% or more,
wherein, a degree of integration P(hkl) of each crystal plane is defined by equation (1) on a basis of integrated intensities of various peaks obtained by using an X-ray diffraction method:
P (211)= p (211)/ S× 100(%)  (1)

wherein
S=p (110)/100+ p (200)/14.93+ p (211)/25.88+ p (310)/7.68+ p (222)/1.59+ p (321)/6.27 +p (411)/1.55, and

wherein
p(hkl): integrated intensity of a peak of X-ray diffraction of an {hkl}-plane.

2. The high-silicon steel sheet according to claim 1 , wherein the chemical composition further contains, by mass %, S: 0.010% or less.

3. The high-silicon steel sheet according to claim 1 , wherein the degree of integration P(211) is 20% or more.

4. The high-silicon steel sheet according to claim 2 , wherein the degree of integration P(211) is 20% or more.

5. The high-silicon steel sheet according to claim 1 , wherein a difference in Si concentration ΔSi between a surface layer of the steel sheet and a central portion in a thickness direction of the steel sheet is 0.1% or more.

6. The high-silicon steel sheet according to claim 2 , wherein a difference in Si concentration ΔSi between a surface layer of the steel sheet and a central portion in a thickness direction of the steel sheet is 0.1% or more.

7. The high-silicon steel sheet according to claim 3 , wherein a difference in Si concentration ΔSi between a surface layer of the steel sheet and a central portion in a thickness direction of the steel sheet is 0.1% or more.

8. The high-silicon steel sheet according to claim 4 , wherein a difference in Si concentration ΔSi between a surface layer of the steel sheet and a central portion in a thickness direction of the steel sheet is 0.1% or more.

9. A method of manufacturing the high-silicon steel sheet according to claim 1 , comprising:
performing hot rolling on a steel slab having a chemical composition containing, by mass %, C: 0.02% or less, P: 0.02% or less, Si: 5.5% or less, Mn: 0.01% or more and 1.0% or less, Al: 1.0% or less, O: 0.01% or less, N: 0.01% or less, and the balance being Fe and inevitable impurities,
optionally performing hot-rolled-sheet annealing,
performing cold rolling once, or more than once with a process annealing interposed between periods in which cold rolling is performed under a condition that at least one pass of final cold rolling is performed with rolls having an Ra of 0.5 μm or less, and
performing finish annealing including a gas-phase siliconizing treatment.

10. The method according to claim 9 , wherein the chemical composition further contains, by mass %, S: 0.010% or less.

11. The method according to claim 9 , further comprising an aging treatment performed at least once between passes of the final cold rolling at a temperature of 50° C. or higher for 5 minutes or more.

12. The method according to claim 10 , further comprising an aging treatment performed at least once between passes of the final cold rolling at a temperature of 50° C. or higher for 5 minutes or more.

13. A method of manufacturing the high-silicon steel sheet according to claim 3 , comprising:
performing hot rolling on a steel slab having a chemical composition containing, by mass %, C: 0.02% or less, P: 0.02% or less, Si: 5.5% or less, Mn: 0.01% or more and 1.0% or less, Al: 1.0% or less, O: 0.01% or less, N: 0.01% or less, and the balance being Fe and inevitable impurities,
optionally performing hot-rolled-sheet annealing,
performing cold rolling once, or more than once with a process annealing interposed between periods in which cold rolling is performed under a condition that at least one pass of final cold rolling is performed with rolls having an Ra of 0.5 μm or less, and
performing finish annealing including a gas-phase siliconizing treatment.

14. The method according to claim 13 , wherein the chemical composition further contains, by mass %, S: 0.010% or less.

15. The method according to claim 13 , further comprising an aging treatment performed at least once between passes of the final cold rolling at a temperature of 50° C. or higher for 5 minutes or more.

16. The method according to claim 14 , further comprising an aging treatment performed at least once between passes of the final cold rolling at a temperature of 50° C. or higher for 5 minutes or more.

17. A method of manufacturing the high-silicon steel sheet according to claim 5 , comprising:
performing hot rolling on a steel slab having a chemical composition containing, by mass %, C: 0.02% or less, P: 0.02% or less, Si: 5.5% or less, Mn: 0.01% or more and 1.0% or less, Al: 1.0% or less, O: 0.01% or less, N: 0.01% or less, and the balance being Fe and inevitable impurities,
optionally performing hot-rolled-sheet annealing,
performing cold rolling once, or more than once with a process annealing interposed between periods in which cold rolling is performed under a condition that at least one pass of final cold rolling is performed with rolls having an Ra of 0.5 μm or less, and
performing finish annealing including a gas-phase siliconizing treatment.

18. The method according to claim 17 , wherein the chemical composition further contains, by mass %, S: 0.010% or less.

19. The method according to claim 17 , further comprising an aging treatment performed at least once between passes of the final cold rolling at a temperature of 50° C. or higher for 5 minutes or more.

20. The method according to claim 18 , further comprising an aging treatment performed at least once between passes of the final cold rolling at a temperature of 50° C. or higher for 5 minutes or more.

Assignees

• Jfe Steel Corp

Inventors

• Okubo Tomoyuki
• Hiratani Tatsuhiko
• Oda Yoshihiko
• Nakajima Hiroaki

Classifications

• B21B1/222

  in a rolling-drawing process; in a multi-pass mill · CPC title

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title

• B21B3/02

  Rolling special iron alloys {, e.g. stainless steel} · CPC title

• B21B1/22

  for rolling {plates, strips,} bands or sheets of indefinite length (B21B1/42 takes precedence) · CPC title

• B21B1/227

  Surface roughening or texturing · CPC title