Non-oriented magnetic steel sheet and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-2017194082-A1
Application number	US-201515313284-A
Country	US
Kind code	A1
Filing date	Jul 2, 2015
Priority date	Jul 2, 2014
Publication date	Jul 6, 2017
Grant date	—

Abstract

A non-oriented magnetic steel sheet includes a specific chemical composition represented by, in mass %: Si: 3.0% to 3.6%; Al: 0.50% to 1.25%; Mn: 0.5% to 1.5%; Sb or Sn or both of them: [Sb]+[Sn]/2 is 0.0025% to 0.05% where [Sb] denotes an Sb content and [Sn] denotes an Sn content; P: 0.010% to 0.150%; Ni: 0.010% to 0.200%; C: 0.0010% to 0.0040%; and others. The thickness of the non-oriented magnetic steel sheet is 0.15 mm to 0.30 mm. the non-oriented magnetic steel sheet includes magnetic properties represented by, where t denotes a thickness (mm) of the non-oriented magnetic steel sheet: a magnetic flux density B50: “0.2×t+1.52” T or more; a magnetic flux density difference ΔB50: 0.08 T or less; core loss W10/50: 0.95 W/kg or less; and core loss W10/400: “20×t+7.5” W/kg or less. A ratio of a number of intergranular carbides precipitated in grains relative to a sum of the number of the intergranular carbides and a number of grain boundary carbides precipitated on grain boundaries is 0.50 or less.

First claim

1 . A non-oriented magnetic steel sheet, comprising:
a chemical composition represented by, in mass %: Si: 3.0% to 3.6%; Al: 0.50% to 1.25%; Mn: 0.5% to 1.5%; Sb or Sn or both of them: [Sb]+[Sn]/2 is 0.0025% to 0.05% where [Sb] denotes an Sb content and [Sn] denotes an Sn content; P: 0.010% to 0.150%; Ni: 0.010% to 0.200%; C: 0.0010% to 0.0040%; N: 0.0030% or less; S: 0.0020% or less; Ti: 0.0030% or less; Cu: 0.0500% or less; Cr: 0.0500% or less; Mo: 0.0500% or less; Bi: 0.0050% or less; Pb: 0.0050% or less; V: 0.0050% or less; B: 0.0050% or less; and balance: Fe and impurities, and magnetic properties represented by, where t denotes a thickness (mm) of the non-oriented magnetic steel sheet: a magnetic flux density B50: “0.2×t+1.52” T or more; a magnetic flux density difference ΔB50: 0.08 T or less; core loss W10/50: 0.95 W/kg or less; and core loss W10/400: “20×t+7.5” W/kg or less, wherein the thickness is 0.15 mm to 0.30 mm, and a ratio of a number of intergranular carbides precipitated in grains relative to a sum of the number of the intergranular carbides and a number of grain boundary carbides precipitated on grain boundaries is 0.50 or less.

2 . The non-oriented magnetic steel sheet according to claim 1 , wherein in the chemical composition,
P: 0.015% to 0.100%, Ni: 0.020% to 0.100%, or C: 0.0020% to 0.0030%, or any combination thereof is satisfied.

3 . A method of manufacturing a non-oriented magnetic steel sheet, comprising:
hot-rolling of a steel material to obtain a hot-rolled steel sheet; cold-rolling of the hot-rolled steel sheet to obtain a cold-rolled steel sheet; first annealing of the hot-rolled steel sheet before the cold-rolling is completed; and second annealing of the cold-rolled steel sheet, wherein the first annealing includes:
retaining the hot-rolled steel sheet in a first temperature range from 850° C. to 1100° C. for 10 seconds to 120 seconds, and
after the retaining, cooling the hot-rolled steel sheet at a rate of 5° C./s to 50° C./s in a temperature zone from 850° C. to 600° C.,
wherein the second annealing includes:
retaining the cold-rolled steel sheet in a second temperature range from 900° C. to 1100° C. for 10 seconds to 240 seconds, and
after the retaining, cooling the cold-rolled steel sheet at a rate of 10° C./s to 40° C./s in a temperature zone from 900° C. to 300° C., and
wherein the steel material comprises a chemical composition represented by, in mass %, Si: 3.0% to 3.6%; Al: 0.50% to 1.25%; Mn: 0.5% to 1.5%; Sb or Sn or both of them: [Sb]+[Sn]/2 is 0.0025% to 0.05% where [Sb] denotes an Sb content and [Sn] denotes an Sn content; P: 0.010% to 0.150%; Ni: 0.010% to 0.200%; C: 0.0010% to 0.0040%; N: 0.0030% or less; S: 0.0020% or less; Ti: 0.0030% or less; Cu: 0.0500% or less; Cr: 0.0500% or less; Mo: 0.0500% or less; Bi: 0.0050% or less; Pb: 0.0050% or less; V: 0.0050% or less; B: 0.0050% or less; and balance: Fe and impurities.

4 . The method of manufacturing the non-oriented magnetic steel sheet according to claim 3 , wherein hot-rolled sheet annealing is performed as the first annealing before the cold-rolling.

5 . The method of manufacturing the non-oriented magnetic steel sheet according to claim 3 , further comprising hot-rolled sheet annealing before the cold-rolling, wherein an intermediate annealing is performed as the first annealing during the cold-rolling.

6 . The method of manufacturing the non-oriented magnetic steel sheet according to claim 3 , wherein in the chemical composition,
P: 0.015% to 0.100%, Ni: 0.020% to 0.100%, or C: 0.0020% to 0.0030%, or any combination thereof is satisfied.

7 . The method of manufacturing the non-oriented magnetic steel sheet according to claim 3 , wherein a thickness of the cold-rolled steel sheet is 0.15 mm to 0.30 mm.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Murakami Kenichi
• Natori Yoshiaki
• Matsumoto Takuya
• Hori Hiroki
• Wakisaka Takeaki

Classifications

• C22C38/06

  containing aluminium · CPC title

• H01F1/16

  in the form of sheets (H01F1/147 takes precedence) · CPC title

• C22C38/04

  containing manganese · CPC title

• C21D8/1233

  Cold rolling · CPC title

• H02K1/02

  characterised by the magnetic material · CPC title