Grain oriented electrical steel sheet

Patent metadata

Field	Value
Publication number	US-9799432-B2
Application number	US-201113814629-A
Country	US
Kind code	B2
Filing date	Aug 4, 2011
Priority date	Aug 6, 2010
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A grain oriented electrical steel sheet has a magnetic domain structure modified by strain introduction without a trace of treatment, in which noise generated when the grain oriented electrical steel sheet is used laminated on an iron core of a transformer is effectively reduced by: setting a magnetic flux density B 8 to 1.92 T or higher; then setting a ratio of average magnetic domain width of treated surface after strain-introducing treatment W a to average magnetic domain width before strain-introducing treatment W 0 as W a /W 0 <0.4; and setting a ratio of W a to average magnetic domain width of untreated surface W b as W a /W b >0.7; and further setting a ratio of average width of magnetic domain discontinuous portion W d in the untreated surface to average width of magnetic domain discontinuous portion in treated surface resulting from strain-introducing treatment W c as W d /W c >0.8; and setting W c <0.35 mm.

First claim

The invention claimed is:

1. A grain oriented electrical steel sheet with a forsterite film and a tension coating located over the forsterite film, which has a magnetic flux density B 8 of 1.92 T or higher and has a magnetic domain structure modified by strain introduction without a trace of treatment,
wherein the steel sheet is made from a slab having a chemical composition comprising C: 0.08 mass % or less and Si: 2.0 to 8.0 mass %,
a ratio of an average magnetic domain width in a treated surface after strain-introducing treatment W a to an average magnetic domain width before the strain-introducing treatment W 0 is 0<W a /W 0 <0.4, and a ratio of the average magnetic domain width W a to an average magnetic domain width in an untreated surface W b is W a /W b >0.7, and
a ratio of an average width of a magnetic domain discontinuous portion in the untreated surface W d to an average width of a magnetic domain discontinuous portion in the treated surface resulting from the strain-introducing treatment W c is W d /W c >0.8, and 0 mm<W c <0.35 mm.

2. The grain oriented electrical steel sheet according to claim 1 , wherein the strain-introducing treatment is electron beam irradiation.

3. The grain oriented electrical steel sheet according to claim 1 , wherein the strain-introducing treatment is continuous laser irradiation.

4. The grain oriented electrical steel sheet according to claim 1 , wherein the chemical composition further comprises Ni: 0.03 to 1.50 mass %.

5. The grain oriented electrical steel sheet according to claim 1 , wherein W c satisfies: 0.20 mm≦W c <0.35 mm.

Assignees

• Yamaguchi Hiroi
• Okabe Seiji
• Omura Takeshi
• Nakanishi Tadashi
• Jfe Steel Corp

Inventors

• Yamaguchi Hiroi
• Okabe Seiji
• Omura Takeshi
• Nakanishi Tadashi

Classifications

• C21D2201/05

  Grain orientation · CPC title

• C22C38/02

  containing silicon · CPC title

• C21D8/1294

  involving a localised treatment · CPC title

• C22C38/04

  containing manganese · CPC title

• C21D8/1261 Primary

  following hot rolling · CPC title