Claims
- 1. A grain-oriented silicon steel containing Cr and Bi as steel constituents and having a forsterite coating on its surface,wherein said steel and said forsterite coating combined together contain about C≦30 wtppm, Si: 2.0-4.5 wt %, Al: 0.005-0.03 wt %, N: 0.0015-0.006 wt %, Mn: 0.02-0.5 wt %, Cr: 0.1-1.0 wt %, and Bi: 0.001-0.15 wt %, and wherein the steel sheet has a magnetic flux density of B8≧1.96T.
- 2. A decarburization annealed silicon steel sheet having a chromium spinel sub-scale, wherein said sheet and sub-scale comprise about C≦30 wtppm, Si: 2.0-4.5 wt %, Al: 0.01-0.05 wt %, N: 0.003-0.012 wt %, Mn: 0.02-0.5 wt %, Cr: 0.1-1.0 wt %, and Bi: 0.005-0.20 wt %.
- 3. The steel sheet defined in cliam 2, wherein said subscale comprises 0.35 -0.95 g/m3 of oxygen.
- 4. The steel sheet defined in claim 2, having a chromium-spinel layer having a peak intensity layer I1 due to the (202) plane of FeCr2O4, as compared to the peak intensity layer I0 of fayalite, wherein the ratio I1/I0 is 0.2 -0.5.
Priority Claims (2)
Number |
Date |
Country |
Kind |
10-264765 |
Sep 1998 |
JP |
|
11-168317 |
Jun 1999 |
JP |
|
Parent Case Info
This application is a division out of parent application Ser. No. 09/398/586, filed Sep. 17, 1999, now U.S. Pat. No. 6,287,392, granted Sep. 11, 2001.
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