EP0294134A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Manufacture of ductile high-permeability grain-oriented silicon steel
Assignee: Allegheny Ludlum Corp
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Filing: 1988-05-31
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Granted: —
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Expires: 2008-05-31
Abstract
Abstract For making a ductile boron-containing grain-oriented silicon steel, there is practiced, at a late stage in the making of the product either during the final texture anneal or a subsequent anneal, a high-temperature anneal in a reducing atmosphere with the use of a separating-agent coating, particularly magnesium oxide, which contains an effective amount of a compound of molybdenum and/or tungsten.
Inventors
- 👤 Douglas C. Dean
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 13:44
CPC Classifications
C; C21; C21D; C21D8/00; C21D8/12; C21D1/00; C21D1/68; C21D1/70; C21D3/00; C21D8/1277; C21D8/1283
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
67 words
A method of improving the ductility of grain-oriented silicon steel made by having boron present in the steel during a final texture annealing thereof, characterised in said method comprising conducting a high-temperature annealing heat treatment upon said steel in a reducing atmosphere while said steel is in physical contact with a coating material based upon magnesium oxide and containing a metallurgically suitable compound of molybdenum and/or tungsten.
Claim 2
Independent Claim
67 words
A method of improving the ductility of grain-oriented silicon steel made by having boron present in the steel during a final texture annealing thereof, characterised in said method comprising conducting a high-temperature annealing heat treatment upon said steel in a reducing atmosphere while said steel is in physical contact with a coating material based upon magnesium oxide and containing a metallurgically suitable compound of molybdenum and/or tungsten.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein said high-temperature annealing heat treatment is a separate step following the step of annealing said steel to develop grain-oriented texture therein.
Claim 4
Dependent Claim
16 words
A method according to claim 1 or 2, wherein said metallurgically suitable compound is tungstic acid.
Claim 5
Dependent Claim
16 words
A method according to claim 1 or 2, wherein said metallurgically suitable compound is molybdenum trioxide.
Claim 6
Independent Claim
30 words
A method according to any one of claims 1, 3 or 4, wherein said high-temperature annealing heat treatment is the step of annealing said steel to develop grain-oriented texture therein.
Claim 7
Independent Claim
22 words
A method according to any one of the preceding claims, wherein said coating material also contains boron in a metallurgically acceptable form.
Claim 8
Dependent Claim
26 words
A method according to claim 6, wherein said coating material contains, per one part by weight of boron, at least 2 parts by weight of molybdenum.
Claim 9
Dependent Claim
26 words
A method according to claim 6, wherein said coating material contains, per one part by weight of boron, at least 4 parts by weight of tungsten.
Claim 10
Independent Claim
103 words
A method of removing boron from steel in sheet form which comprises applying to said steel a coating based on magnesium oxide and containing at least one metallurgically acceptable compound of molybdenum and/or tungsten, said compound being present in such an amount as to be able to cause the boron of the steel to be reacted to form a boride of the formula X₂B₅, where X is molybdenum and/or tungsten, and then heating the steel under nonoxidizing conditions for a time and at a temperature sufficient to cause boron in said steel to be diffused out of said steel and to said coating.
Claim 11
Independent Claim
103 words
A method of removing boron from steel in sheet form which comprises applying to said steel a coating based on magnesium oxide and containing at least one metallurgically acceptable compound of molybdenum and/or tungsten, said compound being present in such an amount as to be able to cause the boron of the steel to be reacted to form a boride of the formula X₂B₅, where X is molybdenum and/or tungsten, and then heating the steel under nonoxidizing conditions for a time and at a temperature sufficient to cause boron in said steel to be diffused out of said steel and to said coating.
Claim 12
Dependent Claim
26 words
A method according to claim 9, wherein said heating is done for at least 2 hours at a temperature of at least 2100 degrees Fahrenheit (1149°C).
Claim 13
Dependent Claim
18 words
A method according to claim 9 or 10, wherein said heating is done for at least 4 hours.
Claim 14
Dependent Claim
24 words
A method according to claim 9, 10 or 11, wherein said metallurgically acceptable compound is molybdenum trioxide, tungsten trioxide, molybdic acid, or tungstic acid.
Claim 15
Independent Claim
23 words
A method according to any one of claims 9 to 12, wherein said steel in sheet form is a grain-oriented silicon electrical steel.
Claim 16
Independent Claim
27 words
A method according to any one of claims 9 to 13, wherein said heating is done concurrently with the final texture anneal provided to said silicon steel.
Claim 17
Independent Claim
29 words
A method according to any one of claims 9 to 13, wherein said coating and heating are done after the silicon steel has been given a final texture anneal.
Claim 18
Dependent Claim
51 words
A composition of matter for use in deboronizing steel, said composition being in the form of a dry powder or aqueous slurry made therefrom, said composition consisting essentially, on a dry-solids basis, of 5 to 20% by weight of an agent consisting of molybdenum and/or tungsten and the remainder magnesium oxide.
Claim 19
Dependent Claim
51 words
A composition of matter for use in deboronizing steel, said composition being in the form of a dry powder or aqueous slurry made therefrom, said composition consisting essentially, on a dry-solids basis, of 5 to 20% by weight of an agent consisting of molybdenum and/or tungsten and the remainder magnesium oxide.
Claim 20
Dependent Claim
19 words
A compositon according to claim 16 wherein said agent is molybdenum trioxide, tungsten trioxide, tungstic acid, and/or molybdic acid.
Claim 21
Dependent Claim
78 words
A process of deboronizing and ductilizing grain-oriented silicon electrical steel sheet or strip which is caused to contain, during a part of its final texture anneal heat-treatment step, a proportion of boron of the order of 30 parts per million, said process comprising applying to said steel a coating made from an aqueous slurry of 5 to 20 weight percent of an agent comprising tungsten trioxide, molybdenum trioxide, tungstic acid and/or molybdic acid, and the remainder magnesium oxide.
Claim 22
Dependent Claim
78 words
A process of deboronizing and ductilizing grain-oriented silicon electrical steel sheet or strip which is caused to contain, during a part of its final texture anneal heat-treatment step, a proportion of boron of the order of 30 parts per million, said process comprising applying to said steel a coating made from an aqueous slurry of 5 to 20 weight percent of an agent comprising tungsten trioxide, molybdenum trioxide, tungstic acid and/or molybdic acid, and the remainder magnesium oxide.
References Cited (Backward Citations)
No citation records indexed.
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