US2743203A - Phosphate coating for electrical steel - Google Patents

Phosphate coating for electrical steel Download PDF

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Publication number
US2743203A
US2743203A US244232A US24423251A US2743203A US 2743203 A US2743203 A US 2743203A US 244232 A US244232 A US 244232A US 24423251 A US24423251 A US 24423251A US 2743203 A US2743203 A US 2743203A
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US
United States
Prior art keywords
coating
sheets
aluminum hydrate
steel
die
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US244232A
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English (en)
Inventor
Hans A Steinherz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NLAANVRAGE7008624,A priority Critical patent/NL170624B/nl
Priority to NL80923D priority patent/NL80923C/xx
Priority to BE513679D priority patent/BE513679A/xx
Priority to BE513769D priority patent/BE513769A/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US244232A priority patent/US2743203A/en
Priority to GB17727/52A priority patent/GB717627A/en
Application granted granted Critical
Publication of US2743203A publication Critical patent/US2743203A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/10—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances metallic oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D37/00—Arrangements in connection with fuel supply for power plant
    • B64D37/02—Tanks
    • B64D37/06—Constructional adaptations thereof
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
    • C23C22/74—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process for obtaining burned-in conversion coatings

Definitions

  • the magnetic. coresv utilized in generators, transformers, electric motors, etc. are preferably made of laminated sheet .steel with a coating of insulating material on each :Hans :A'. Steinherz, Pittsburgh, Pa., assignor'to Westing- 1 house Electric Corporation, East Pittsburgh, :Pa., a corlamination.
  • these cores are r 0r laminate form instead of solid steel so that undesirable eddy currents are reduced to a minimum duringuse of the cores.
  • the edges either become rounded or chipped, depending 'upon'the degree 'of hardness of the'die face. This is particular'ly true when punching laminationsfrom' sheets of silicon steel which is relatively hard. As the punc'hand die edges become worn, small-burrs form on'the cut edges "of-the'punchings. The height ofthe, burr is proportional replaced.
  • the coating v possesses electrically insulating properties superior to many coatings now applied to punchings for motors and theilike.
  • the sheets are coated with an aqueous mixture containing as its essential'ingredients /2'% to 10% aluminum hydrate, 5% to 50% orthopho'sphoric acid (85% and the remainder being water, the pH of the solution being more acidic 'than018.
  • the proportion of aluminum hydrate to phosphoric acid .('H:'PO4) is maintained to provide at least 4.5 parts by weightof the phosphoric acid per part of the aluminum hydrate.
  • the sheets with the applied coating are "then 'pifssed'through an oven where they are heated to a temper'atu're ranging .from 135 C. 11p to 500 C. or higher. The heat drives off the water leaving a thin coating of aluminum phosphate reacted with the ferrous metal of "the'sheet.
  • the time in the oven of course depends upon "the degree of temperature, a'higher temperature requiring "les's'tim'e. "OrdinariIyJa few secondsare sutficient, though longer periods are beneficialin that they assure a complete reaction.
  • r'oll'of sheet steel or individual sheets are coated with an "tothe'wear'a't the edges of the punch and die. These burrs g are undesirable because they tend to cut through 'the insulatingcoating of the adjoining lamination when stacked,
  • Aluminum hydrate has the general formula AliOan'HzO "Where n is from 2 to 4 orgreater. I have secured good results with aluminumhydrate having the average formula A1203.3H20, also written Al(OH)3.
  • Sh'e'ets of'various ferrous base metals may be treated in accordance with the invention.
  • silicon-iron sheets "having up to 7% silicon may be coated therewith.
  • Nickeliron magnetic sheets with up to 85% nickel may be treated.
  • Other magnetic sheets containing a high proportion of iron, alloyed with OIIBIOFIIIOIG other metals may I be treated.
  • the term sheet steel will be employed hereconsiderable damage or destruction of-the core has 'occurred because of .the lack of insulation between lamina tions.
  • theburr may reach a hei'ghtwliich neces-' sitates an additional grinding step to remove them in order to insure against short circuiting.
  • the :burr height die must be'either replaced, or its faces reconditioned, :involving great expense and consumption of time.
  • Anobject-of this invention is thus to provide an improved alumina-phosphate base insulating coating tor sheets of magnetic material, which will enable a :greatly can becomes excessive (about 2 to 4 mils), the :punch and. v
  • Figure 1 is a schematicview, partly in section, of a form of apparatus that may be used in carrying out-the invention.
  • Fig. 2 is a fragmentary, greatly enlarged cross-section through a sheet of material prepared in accordance with p the invention.
  • a wetting agent may be added to the aqueous aluminum phosphate solution. This may be present in the order of from A to 2% of the weight of the "composition, the .amount depending upon the degree of cleanliness of the steel. Examples of' satisfactory wettingagen'ts are the alcohol sulfates, for example,
  • Percent Phosphoric acid 31 Aluminum hydrate 6 Water 62 Wetting agent l Patented Apr. 2,4, 1956 The aluminum hydrate was added to the acid-water mixture at a temperature of about 90 C.. It was completely dissolved in about five minutes with the aid of stirring. A clear, light yellow solution was formed.
  • the coated sheet strip was then heat-treated in the continuous baking oven 28 in which the air temperature was 485 C., the strip emerging from the oven at a temperature of about 135 C.
  • the speed of the strip through the oven was about 3 ft. per second and the length of the oven was 5 feet.
  • the strip 14 was pulled from the oven 28 by the tension control rolls 30 and 32 and then passed to a punch 34 and die 36.
  • Fig. 2 of the drawing there is illustrated a greatly enlarged cross-sectional view through an insulated steel strip 14 showing an insulating coating as applied by the process.
  • the coating 40 generally has a thickness in the order of 2% or less of the thickness of the sheets.
  • the heat treated insulating coating is so thin, it enables the laminatious to be formed into magnetic cores having a high space factor, that is, containing over 95% magnetic material.
  • the phosphate coating increased die life by a factor of nearly three, when compared to water glass, a standard coating material. Compared to bare or uncoated sheet, the coating of this invention enables nearly six times as many punchin gs to be made before the burr height reaches 4 mils.
  • Dielectric resistance tests of many punchings produced with the insulating coating of the invention have shown a median value of from 20 to 25 ohms per square centimeter per lamination. These resistance values are many times those of other commercially used insulating coatlugs.
  • the apparatus illustrated in Fig. l is an example of only one means of carrying out the invention.
  • the solution may be applied by spraying, flooding, or flow coating.
  • the tank 20 may be eliminated altogether and the sheet passed between rolls 24 and 26 with the solution being poured or dipped upon the rolls.
  • pH of the solution being more acid than 0.8, the ratio of I-IsPOr to aluminum hydrate being at least 4.5 to 1 by weight, and heat-treating the applied solution on the surface of the ferrous sheets at a temperature of from C.
  • An article of manufacture comprising a ferrous member and an insulating coating applied to the surface of the member, the coating being composed of the reaction product of the steel with a mixture of from /z% to 10% by weight aluminum hydrate, 5% to 50% by Weight phosphoric acid (85%) the ratio of HsPOr to aluminum hydrate being at least 4.5 to 1 by weight, and the applied mixture being heat-treated at a temperature of at least 135 C. for a period of time sufiicient to cause reaction to take place between the surface of the ferrous member and the applied mixture and not exceeding a temperature at which the coating decomposes.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Soft Magnetic Materials (AREA)
US244232A 1951-08-29 1951-08-29 Phosphate coating for electrical steel Expired - Lifetime US2743203A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NLAANVRAGE7008624,A NL170624B (nl) 1951-08-29 Werkwijze voor het bereiden van gesubstitueerde fenoxysalicylzuren, werkwijze voor het bereiden van een preparaat met farmacologische werking, dat deze verbindingen bevat, alsmede gevormde preparaten verkregen onder toepassing van deze werkwijze.
NL80923D NL80923C (nl) 1951-08-29
BE513679D BE513679A (nl) 1951-08-29
BE513769D BE513769A (nl) 1951-08-29
US244232A US2743203A (en) 1951-08-29 1951-08-29 Phosphate coating for electrical steel
GB17727/52A GB717627A (en) 1951-08-29 1952-07-14 Improvements in or relating to electrically insulating coatings for magnetic sheet material containing iron

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US244232A US2743203A (en) 1951-08-29 1951-08-29 Phosphate coating for electrical steel

Publications (1)

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US2743203A true US2743203A (en) 1956-04-24

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US244232A Expired - Lifetime US2743203A (en) 1951-08-29 1951-08-29 Phosphate coating for electrical steel

Country Status (4)

Country Link
US (1) US2743203A (nl)
BE (2) BE513769A (nl)
GB (1) GB717627A (nl)
NL (2) NL170624B (nl)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2979430A (en) * 1955-06-04 1961-04-11 Parker Rust Proof Co Heat resistant phosphate coatings, methods and articles produced therefrom
US3114661A (en) * 1961-04-24 1963-12-17 Lubrizol Corp Process for producing core laminations
US3198674A (en) * 1962-01-25 1965-08-03 Fiber Products Res Ct Inc Infrared absorbent aluminum phosphate coatings and method of manufacture
US3318731A (en) * 1962-02-03 1967-05-09 Hooker Chemical Corp Method of making electrically insulated ferrous magnetic sheet material
US3772060A (en) * 1970-12-11 1973-11-13 Ici Ltd Pre-treatment of metal substrates with complex halogen-containing phosphates of aluminum
US3948786A (en) * 1974-10-11 1976-04-06 Armco Steel Corporation Insulative coating for electrical steels
US3996073A (en) * 1974-10-11 1976-12-07 Armco Steel Corporation Insulative coating for electrical steels
DE2810155A1 (de) * 1977-03-09 1978-09-14 Centro Speriment Metallurg Ueberzugsloesung fuer elektrostahlbleche
FR2526814A1 (fr) * 1982-05-12 1983-11-18 Westinghouse Electric Corp Elements en feuilles d'acier revetus d'un phosphate isolant
EP0926249A1 (en) * 1997-12-19 1999-06-30 Armco Inc. Inorganic/organic insulating coating for non-oriented electrical steel
WO2001087798A2 (en) * 2000-05-19 2001-11-22 The University Of British Columbia Process for making chemically bonded composite hydroxide ceramics
WO2012041052A1 (zh) 2010-09-29 2012-04-05 宝山钢铁股份有限公司 一种无取向硅钢用无铬绝缘涂层涂料

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2120212A (en) * 1936-01-10 1938-06-07 Curtin Howe Corp Phosphated metal coating
US2357269A (en) * 1942-04-22 1944-08-29 David A Russell Art of treating ferrous metal articles
US2465247A (en) * 1946-10-24 1949-03-22 Westinghouse Electric Corp Composition for and method of producing phosphate films on metals
US2484242A (en) * 1946-04-03 1949-10-11 Westinghouse Electric Corp Coating ferrous metal sheets with an insulating film
US2501349A (en) * 1946-05-10 1950-03-21 Westinghouse Electric Corp Insulation for magnetic material
US2501846A (en) * 1945-10-03 1950-03-28 Armco Steel Corp Production of silicon steel sheet stock having the property of high surface resistivity
US2564864A (en) * 1948-07-02 1951-08-21 Parker Rust Proof Co Method of and solution for increasing resistance to corrosion

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2120212A (en) * 1936-01-10 1938-06-07 Curtin Howe Corp Phosphated metal coating
US2357269A (en) * 1942-04-22 1944-08-29 David A Russell Art of treating ferrous metal articles
US2501846A (en) * 1945-10-03 1950-03-28 Armco Steel Corp Production of silicon steel sheet stock having the property of high surface resistivity
US2484242A (en) * 1946-04-03 1949-10-11 Westinghouse Electric Corp Coating ferrous metal sheets with an insulating film
US2501349A (en) * 1946-05-10 1950-03-21 Westinghouse Electric Corp Insulation for magnetic material
US2465247A (en) * 1946-10-24 1949-03-22 Westinghouse Electric Corp Composition for and method of producing phosphate films on metals
US2564864A (en) * 1948-07-02 1951-08-21 Parker Rust Proof Co Method of and solution for increasing resistance to corrosion

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2979430A (en) * 1955-06-04 1961-04-11 Parker Rust Proof Co Heat resistant phosphate coatings, methods and articles produced therefrom
US3114661A (en) * 1961-04-24 1963-12-17 Lubrizol Corp Process for producing core laminations
US3198674A (en) * 1962-01-25 1965-08-03 Fiber Products Res Ct Inc Infrared absorbent aluminum phosphate coatings and method of manufacture
US3318731A (en) * 1962-02-03 1967-05-09 Hooker Chemical Corp Method of making electrically insulated ferrous magnetic sheet material
US3772060A (en) * 1970-12-11 1973-11-13 Ici Ltd Pre-treatment of metal substrates with complex halogen-containing phosphates of aluminum
US3948786A (en) * 1974-10-11 1976-04-06 Armco Steel Corporation Insulative coating for electrical steels
US3996073A (en) * 1974-10-11 1976-12-07 Armco Steel Corporation Insulative coating for electrical steels
DE2810155A1 (de) * 1977-03-09 1978-09-14 Centro Speriment Metallurg Ueberzugsloesung fuer elektrostahlbleche
FR2526814A1 (fr) * 1982-05-12 1983-11-18 Westinghouse Electric Corp Elements en feuilles d'acier revetus d'un phosphate isolant
EP0926249A1 (en) * 1997-12-19 1999-06-30 Armco Inc. Inorganic/organic insulating coating for non-oriented electrical steel
US5955201A (en) * 1997-12-19 1999-09-21 Armco Inc. Inorganic/organic insulating coating for nonoriented electrical steel
WO2001087798A2 (en) * 2000-05-19 2001-11-22 The University Of British Columbia Process for making chemically bonded composite hydroxide ceramics
WO2001087798A3 (en) * 2000-05-19 2002-10-31 Univ British Columbia Process for making chemically bonded composite hydroxide ceramics
WO2012041052A1 (zh) 2010-09-29 2012-04-05 宝山钢铁股份有限公司 一种无取向硅钢用无铬绝缘涂层涂料

Also Published As

Publication number Publication date
BE513769A (nl)
BE513679A (nl)
NL170624B (nl)
GB717627A (en) 1954-10-27
NL80923C (nl)

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