US4054471A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing for cube-on-edge oriented silicon steel
Assignee: Allegheny Ludlum Corp
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Filing: 1976-06-17
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Granted: 1977-10-18
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Expires: 1996-06-17
Abstract
Abstract A process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1870 (G/O e ) at 10 oersteds. The process includes the steps of: preparing a melt of silicon steel containing from 0.02 to 0.06% carbon, from 0.0006 to 0.0080% boron, up to 0.0100% nitrogen, no more than 0.008% aluminum and from 2.5 to 4.0% silicon; casting said steel; hot rolling said steel; cold rolling said steel to a thickness no greater than 0.020 inch; decarburizing said steel to a carbon level below 0.005%; normalizing said steel at a temperature of from 1550° to 2000° F in a hydrogen-bearing atmosphere; applying a refractory oxide base coating to said steel; and final texture annealing said steel.
Inventors
- 👤 Amitava Datta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:32
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/12; C21D8/1244; C22; C22C; C22C38/00; C22C38/02; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783; C21D8/1255; C21D8/1272
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
214 words
In a process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1870 (G/O e ) at 10 oersteds, which process includes the steps of: preparing a melt of silicon steel containing from 0.02 to 0.06% carbon, from 0.015 to 0.15% manganese, from 0.01 to 0.05% of material from the group consisting of sulfur and selenium, from 0.0006 to 0.0080% boron, up to 0.0100% nitrogen, up to 1.0% copper, no more than 0.008% aluminum and from 2.5 to 4.0% silicon; casting said steel; hot rolling said steel; cold rolling said steel to a final gage no greater than 0.020 inch; normalizing said steel; decarburizing said steel to a carbon level below 0.005%; applying a refractory oxide base coating to said steel; and final texture annealing said steel; the improvement comprising the step of normalizing said cold rolled steel of final gage at a temperature of from 1550° to 2000° F in a hydrogen-bearing atmosphere, so as to recrystallize the cold rolled steel; and subsequently applying said refractory oxide base coating to said steel; said processed steel having a permeability of at least 1870 (G/O e ) at 10 oersteds; said normalize at a temperature of from 1550° to 2000° F contributing to the high permeability of said steel.
Claim 2
Dependent Claim
214 words
In a process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1870 (G/O e ) at 10 oersteds, which process includes the steps of: preparing a melt of silicon steel containing from 0.02 to 0.06% carbon, from 0.015 to 0.15% manganese, from 0.01 to 0.05% of material from the group consisting of sulfur and selenium, from 0.0006 to 0.0080% boron, up to 0.0100% nitrogen, up to 1.0% copper, no more than 0.008% aluminum and from 2.5 to 4.0% silicon; casting said steel; hot rolling said steel; cold rolling said steel to a final gage no greater than 0.020 inch; normalizing said steel; decarburizing said steel to a carbon level below 0.005%; applying a refractory oxide base coating to said steel; and final texture annealing said steel; the improvement comprising the step of normalizing said cold rolled steel of final gage at a temperature of from 1550° to 2000° F in a hydrogen-bearing atmosphere, so as to recrystallize the cold rolled steel; and subsequently applying said refractory oxide base coating to said steel; said processed steel having a permeability of at least 1870 (G/O e ) at 10 oersteds; said normalize at a temperature of from 1550° to 2000° F contributing to the high permeability of said steel.
Claim 3
Dependent Claim
14 words
The improvement according to claim 1, wherein said melt has at least 0.0008% boron.
Claim 4
Dependent Claim
22 words
The improvement according to claim 2, wherein said cold rolled steel is normalized at a temperature of from 1600° to 1900° F.
Claim 5
Dependent Claim
29 words
The improvement according to claim 2, wherein said cold rolled steel is heated to a temperature within said normalizing temperature range in a period of less than five minutes.
Claim 6
Dependent Claim
14 words
The improvement according to claim 4, wherein said period is less than three minutes.
Claim 7
Dependent Claim
20 words
The improvement according to claim 2, wherein said hydrogen-bearing atmosphere has a dew point of from -80° to +150° F.
Claim 8
Dependent Claim
20 words
The improvement according to claim 2, wherein said hydrogen-bearing atmosphere has a dew point of from 0° to +110° F.
Claim 9
Dependent Claim
16 words
The improvement according to claim 7, wherein said hydrogen-bearing atmosphere consists essentially of hydrogen and nitrogen.
Claim 10
Dependent Claim
40 words
The improvement according to claim 2, wherein said normalized steel is maintained in a hydrogen-bearing atmosphere for a period of at least 30 seconds within a temperature range between 1400° and 1550° F, to promote the decarburization of said steel.
Claim 11
Dependent Claim
14 words
The improvement according to claim 9, wherein said period is at least 1 minute.
Claim 12
Dependent Claim
35 words
The improvement according to claim 9, wherein said normalized steel is maintained in a hydrogen-bearing atmosphere having a dew point of from +20° to +150° F at said temperature range between 1400° and 1550° F.
Claim 13
Dependent Claim
35 words
The improvement according to claim 11, wherein said normalized steel is maintained in a hydrogen-bearing atmosphere having a dew point of from +40° to +110° F at said temperature range between 1400° and 1550° F.
Claim 14
Dependent Claim
31 words
The improvement according to claim 12, wherein said normalized steel is maintained in a hydrogen-bearing atmosphere consisting essentially of hydrogen and nitrogen at said temperature range between 1400° and 1550° F.
Claim 15
Dependent Claim
70 words
The improvement according to claim 2, wherein said cold rolled steel is normalized at a temperature of from 1600° to 1900° F in a hydrogen-bearing atmosphere having a dew point of from 0° to +110° F, and subsequently maintained in a hydrogen-bearing atmosphere having a dew point of from +40° to +110° F for a period of at least 30 seconds within a temperature range between 1400° and 1550° F.
Claim 16
Dependent Claim
47 words
The improvement according to claim 2, wherein said hot rolled steel has a thickness of from 0.050 to about 0.120 inch and wherein said hot rolled steel is cold rolled to a thickness of no more than 0.020 inch without an intermediate anneal between cold rolling passes.
Claim 17
Dependent Claim
58 words
The improvement according to claim 1, wherein said melt consists essentially of, by weight, 0.02 to 0.06% carbon, 0.015 to 0.15% manganese, 0.01 to 0.05% of material from the group consisting of sulfur and selenium, 0.0006 to 0.0080% boron, up to 0.0100% nitrogen, 2.5 to 4.0% silicon, up to 1.0% copper, no more than 0.008% aluminum, balance iron.
Claim 18
Dependent Claim
14 words
The improvement according to claim 16, wherein said melt has at least 0.0008% boron.
Claim 19
Dependent Claim
39 words
The improvement according to claim 1, wherein said oriented silicon steel has a permeability of at least 1890 (G/O e ) at 10 oersteds and a core loss of no more than 0.700 watts per pound at 17 kilogauss.
Claim 20
Dependent Claim
28 words
A cube-on-edge oriented silicon steel having a permeability of at least 1870 (G/O e ) at 10 oersteds, and made in accordance with the process of claim 2.
Claim 21
Dependent Claim
29 words
The improvement according to claim 2, wherein said normalize at a temperature of from 1550° to 2000° F is for a period of from ten seconds to ten minutes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-17 | 1981-04-18 | 1981-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-17 | 1985-04-18 | 1985-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-17 | 1989-04-18 | 1989-10-18 | $7700.00 | Window Closed / Lapsed |