US4115161A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Processing for cube-on-edge oriented silicon steel
Assignee: Allegheny Ludlum Corp
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Filing: 1977-10-12
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Granted: 1978-09-19
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Expires: 1997-10-12
Abstract
Abstract A process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1870 (G/Oe) 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; recrystallizing the cold rolled steel at a temperature between 1300 DEG and 1550 DEG F in a hydrogen-bearing atmosphere having a dew point of from +50 DEG to +150 DEG F; 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 steel is heated to said temperature range of between 1300 DEG and 1550 DEG F at a heating rate of at least 1500 DEG F per minute and held within said temperature range for a period of at least 30 seconds.
Inventors
- 👤 Amitava Datta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:03
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/12; C21D8/1244; C21D8/1255; C21D8/1277; C21D8/1283
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
177 words
In a process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1870 (G/Oe) at 10 oersteds, which process includes the steps of: preparing a melt of silicon steel containing from 0.02 to 0.06% carbon, from 0.0006 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; recrystallizing the cold rolled steel at a temperature between 1300° and 1550° F. in a hydrogen-bearing atmosphere having a dew point of from +50° to +150° F.; 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 steps of heating said steel to said temperature range of between 1300° and 1550° F. at a heating rate of at least 1500° F. per minute; and holding said steel within said temperature range for a period of at least 30 seconds.
Claim 2
Dependent Claim
177 words
In a process for producing electromagnetic silicon steel having a cube-on-edge orientation and a permeability of at least 1870 (G/Oe) at 10 oersteds, which process includes the steps of: preparing a melt of silicon steel containing from 0.02 to 0.06% carbon, from 0.0006 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; recrystallizing the cold rolled steel at a temperature between 1300° and 1550° F. in a hydrogen-bearing atmosphere having a dew point of from +50° to +150° F.; 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 steps of heating said steel to said temperature range of between 1300° and 1550° F. at a heating rate of at least 1500° F. per minute; and holding said steel within said temperature range for a period of at least 30 seconds.
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
32 words
The improvement according to claim 2, wherein said steel is heated to said temperature range of between 1300° and 1550° F. at a heating rate of at least 2000° F. per minute.
Claim 5
Dependent Claim
33 words
The improvement according to claim 3, wherein said steel is heated to said temperature range of between 1300° and 1550° F. at a heating rate of from 2000° to 5000° F. per minute.
Claim 6
Dependent Claim
18 words
The improvement according to claim 3, wherein said recrystallizing occurs at a temperature between 1400° and 1500° F.
Claim 7
Dependent Claim
29 words
The improvement according to claim 3, wherein said steel is held within said temperature range of between 1300° and 1550° F. for a period of at least 60 seconds.
Claim 8
Dependent Claim
30 words
The improvement according to claim 6, wherein said steel is held within said temperature range of between 1300° and 1550° F. for a period of from 60 to 120 seconds.
Claim 9
Dependent Claim
23 words
The improvement according to claim 3, wherein said recrystallizing occurs in a hydrogen-bearing atmosphere having a dew point of +70° to +125° F.
Claim 10
Dependent Claim
16 words
The improvement according to claim 3, wherein said hydrogen-bearing atmosphere consists essentially of hydrogen and nitrogen.
Claim 11
Dependent Claim
46 words
The improvement according to claim 2, wherein said hot rolled steel has a thickness of from 0.050 to 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 12
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 13
Dependent Claim
14 words
The improvement according to claim 11, wherein said melt has at least 0.0008% boron.
Claim 14
Dependent Claim
38 words
The improvement according to claim 1, wherein said oriented silicon steel has a permeability of at least 1890 (G/Oe) at 10 oersteds and a core loss of no more than 0.700 watts per pound at 17 kilogauss -60Hz.
Claim 15
Dependent Claim
26 words
A cube-on-edge oriented silicon steel having a permeability of at least 1870 (G/Oe) at 10 oersteds, and made in accordance with the process of claim 2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-18 | 1982-03-20 | 1982-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-18 | 1986-03-20 | 1986-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-18 | 1990-03-20 | 1990-09-19 | $7700.00 | Window Closed / Lapsed |