JPS5925538A - Sheet steel member coated with insulating phosphate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet steel member coated with an insulating phosphate.

Magnetic cores used in generators, transformers, electric motors, etc.
Preferably, each sheet of laminated sheet-shaped steel stampings is coated with an insulating coating.

As is well known, this type of core is constructed from laminates rather than solid steel to minimize undesirable swirling currents.

Aluminum orthophosphate, also called aluminum phosphate, is used in diluted form as an inorganic coating material to produce an interlayer insulation medium on stamped parts of iron sheets and strips. Aluminum phosphate insulates between layers of laminated cores of motors, generators, transformers, etc.
Used to minimize eddies in this type of equipment. The coating solution before dilution consists of a mixture of phosphoric acid and alumina hydrate and contains approximately 63% by weight P2O5, 8% by weight Ano203, and 59% by weight H2O. This kind of φ material solution is, for example, [Alcophos J (Alk
It is commercially available under the trade name ophos and is widely used in the electrical equipment industry and is applied to electrical steel by equipment manufacturers or electrical steel suppliers.

The aluminum phosphate solution described above is usually further diluted with water prior to use. The concentration suitable for use depends on the desired resistivity and thickness as well as the coating equipment used to apply the coating, but is generally 0.5 to 4 parts by volume of the phosphate-aluminum solution to water. Concentration is the sum of parts by volume. The solution is applied to the steel using a felt or rubberized roll coater and then cured in a side-by-side oven.

Phosphate coatings of this type are well known in the art and are primarily used to coat hot rolled steel, as disclosed in U.S. Pat. No. 2,743,203 to Steinherz. The steel sheet is cured at a temperature of 165°C to 500°C and the water is thermally removed, leaving behind a thin phosphate coating that reacts with the ferrous metal surface of the sheet. The coating film thus obtained has a high insulation value and good surface properties. This coating has been determined to have the ability to resist various mechanical, thermal and chemical attacks encountered in electrical equipment or manufacturing processes.

However, in current practice, where it is common to use cold-rolled steel with a low reactivity surface, the temperature required for commercially available sheet steel to harden the unmodified phosphate film is approximately 64°C.
It is 0°C. Note: To achieve the above temperature for the steel and the same temperature for the phosphate coating, it depends on the furnace design, conveyor speed and layer thickness, and is usually much higher than the grade. The temperature must be set at a high temperature, usually between 425°C and 650°C. The curing temperature is high, and the process cost is high because the natural scum or electricity used in the oven is expensive, and when non-modified materials are used, the coating speed is slow, which increases labor costs. However, the cost of maintaining the equipment increases, and problems such as increased heat returning to the coating roll and increased risk of insufficient curing also arise.

Therefore, there is a long felt need for new coatings or improved coating methods that are simple, inexpensive, and yet provide interlayer film, insulation, and space factor properties comparable to prior art coatings or coating methods. I was 1 year old.

Accordingly, the present invention relates to a member made of ferrous sheet steel whose surface is coated with a hardened insulating phosphate coating ++g obtained from a water/8 solution consisting of 100 parts by volume of an aqueous aluminum phosphate solution and 15 parts by volume of nitric acid.

The phosphate coating used in the present invention (preferably based on the volume of the diluted phosphoric acid-aluminum solution, which is a solution prepared by adding 0.5 to 4 parts by volume of dilution water to 1 volume part of the phosphoric acid-aluminum aqueous solution) A mixture of dilute phosphate solution consisting of 12% total nitric acid.

Surprisingly, the addition of nitric acid as described above does not preserve the coating properties, insulation properties, and space factor properties of the unmodified phosphate coating, but it does reduce the commercially available properties necessary for curing the phosphate coating. The temperature of the sheet steel can be lowered by about 90°C. Lower curing temperatures have the added benefit of fewer handling problems and less energy requirements.

A variety of ferrous metal sorts can be treated with the present invention. Silicon-iron sheets with a silicon content of up to 7% can be treated according to the invention.

It is also possible to process nickel-iron magnetic sheets with a nickel content of up to 85%. Other magnetic sheets with high iron content and alloyed with one or more other metals can also be processed.

Generally, sheets of this type are continuously cold rolled.

As used herein, the term "ferrous sheet steel" is intended to include all such materials.

The cured phosphate coating according to the present invention comprises a diluted aqueous aluminum phosphate solution, based on the volume of the diluted aqueous aluminum phosphate solution, from 1 to 15% by volume, preferably from 3 to 12% by volume, most preferably from 3 to 8% by volume. Obtained from a mixture of % HNO3 by volume.

If HNO3 is less than 1% by volume, no improvement in curing will be achieved. If HNO3 exceeds 15% by volume, the coating solution becomes excessively corrosive.

A diluted aqueous solution of aluminum or-114ate contains 100 parts by volume of an aqueous aluminum phosphate solution.

The aluminum phosphate composition is typically a mixture of phosphoric acid and alumina hydrate, with P2O5 as the active ingredient.
It can be expressed as having A Noah 03 and A Noah 03. The aluminum phosphate composition contains 28-68% by weight P2O5, preferably 0-65% by weight, and 5-12% by weight P2O5.
, preferably 7-10 heavy@ki A Noah 03 and 50-7
0% by weight water and preferably 50 to 400 parts by volume, most preferably 100 to 250 parts by volume of additional dilution water. If less than 50 parts by volume of water is added for dilution, it becomes difficult to uniformly apply the coating to electrical steel. If the amount of diluting water added exceeds 400 parts by volume, the thickness will become too thin and the insulation performance will deteriorate.

Therefore, the aqueous solution of the phosphate-aluminum composition is P2O
5 and AJ203. ! : The total solid content is 33 to 5.
5% and does not contain other substances such as zinc, zinc phosphate and nickel. However, an effective amount of a non-ionic steel wetting agent consisting of a material containing an alkyl group of suitable chain length attached to a group of the formula typically up to 1.5% by volume, preferably from 0.5 to 1.5% by volume, is used. It is also possible to use 2% by volume.

If the amount of wetting agent is less than 0.5% by volume, the steel cannot be softened and a phosphate coating cannot be attached.

The typical composition of nitric acid modified low temperature phosphate paints is P2O56
10 liters of an aluminum phosphate solution consisting of 6% by weight, 8.6% by weight of A4203 and 58.4% by weight of H2O;
It consists of 20 liters of H2O for additional dilution, about 0.6 liters of nonionic wetting agent, and 1.5 liters of HNO3, or about 5% by volume of HNO3 based on the above component composition. The term "nitric acid" as specified herein refers to HNO3 at a concentration of 65% or more, i.e. 69-71% of the reagent equivalent.
It is concentrated HNO3.

The nitric acid-modified phosphate coating composition of the present invention is generally applied to various types of cold-rolled electrical steel by roll coating techniques utilizing coated rubber or felt coating rolls. After applying this composition to the surface of the substrate sheet steel, the sheet steel and phosphate coating are heated to a temperature of about 0°C to about 10°C for a period sufficient to drive off most of the water. The applied coating film is cured and adheres to the substrate, becoming an integral part. When each sheet layer is stacked and used in an electromagnetic device,
The deposited coating provides good interlayer resistance to the substrate and improves eddy current losses.

Nitric acid-modified phosphate coating III can also be used in a multi-coat coating and can be overcoated over other basecoat phosphate coatings. 5. "Sheet steel quality J" refers to the crystallinity of the steel measured with a thermocouple, etc., and is not the crystallinity of the oven, which is usually at a much higher temperature than steel. .

The density of the nitric acid-modified phosphate coating of the present invention after curing is approximately
It is 1.59/cm. After curing, the coating film is AST
According to the Franklin test specified in M standard A-717, at least 2 ohm-(i/am).

It shows a high resistance value of 6400hm-cm2/iam. As used herein, the term "cured" means that the phosphate coating has become a solid, non-stick coating. It is thought that HNO3 increases the activity of the iron surface during hardening, accelerates the reaction between the iron-containing sheet steel and the coating, producing iron phosphate, etc., and causing the deposition of aluminum phosphate.

Next, the present invention will be explained with reference to Examples.

Example 6 6.1% by weight P2O5 and 8.6% by weight AJ20
3 and 58.4% by weight of H2C at 25°C. , k 11Jlt is about 40 centipoise, specific gravity is 7.47, molecular weight is about 618 [trade name Alkophos C]
Monsanto Book Chemical Corporation 7 (MON
(commercially available from SanjO Chemical COo), 10 parts by volume of H2020 for addition dilution, and 7 parts by volume of H2020 for addition dilution.
A nitric acid modified phosphate coating composition was prepared consisting of a mixture of 1% Hf1035% or 0.05 x 30 parts by volume - 1.5 parts by volume of HNO3. In preparing the above composition, the acid was the last ingredient and mixed at 25°C.

Approximately 1% by volume nonionic phosphorus-containing medium chain length alkyl group wetting agent [trade name Vicshawet #
12 Victor Chemical Corporation (Vi
ctor Chemical Co., Ltd.] was added to the phosphate coating composition.

For comparison, unmodified phosphate coating compositions were made, or compositions containing the same components in the same amounts except that HNO3 was omitted. The Ryōei composition was roll-coated onto cold-rolled electrical steel, heated and cured, and then the insulation properties were measured. Both sets of oxides were also applied to armature punched parts and interlayer resistance was tested. The results are shown in Tables 1 and 2.

As can be seen from the table, the insulation properties and space factor properties of ■03 modified phosphate coating maintain the original values, and the curing temperature is higher than that of the unmodified phosphate coating of the seed yarn. The temperature has decreased by about 250°C.

Supplementary Procedures ■2
Snore (]5589922) Name of the invention Insulation + U grade salt-resistant seal coated l
-Relationship with the author case requiring the 3rd degree amendment in page 8 Address of patent applicant: Pennsylvania, United States of America.

Binzpurg Gateway Center (no street address) Name (711) Westinghouse Φ Electric Link Corporation Representative G.E. Nietveld Nationality
United States of America 4, agent address 2 people 4, 76 Kyomachi, Chuo-ku, Kobe [Bill Westinghouse Electric Japan KK]
6゜Symmetry of the amendment Description 7, Contents of the amendment The statement on page 13 is stated as attached.

Claims (1)

[Scope of Claims] 1. A ferrous sheet steel member coated with a hardened insulating phosphate coating, wherein the coating is coated with 100 parts by volume of aqueous aluminum phosphate and 1 to 15 parts by volume of nitric acid. A member characterized in that it is a coating film formed from an aqueous solution consisting of: 2. The member according to claim 1, wherein the aqueous aluminum phosphate is a mixture of phosphoric acid, hydrated aluminum, and water. The member according to claim 1 or 2, characterized in that 3.6 parts by volume to 8 parts by volume of nitric acid are used. 4. P2 containing 28-68% by weight of aqueous aluminum phosphate
A component according to claim 1, 2 or 6, characterized in that it consists of O5, 5-12% by weight of A-203 and 50-70% by weight of water. 5. Aqueous aluminum phosphate contains 60-35% by weight of P
The member according to claim 4, characterized in that it contains 2O5 and 7 to 10% by weight of A, z2o3. 6. The claim characterized in that the aqueous solution contains 50 to 400 parts by volume of additional dilution water and 3 to 12 volume % of nitric acid based on the total volume of aqueous aluminum phosphate and additional dilution water. The member according to any one of Items 1 to 5. B. The member according to claim 6, characterized in that 3 to 8% by volume of nitric acid is used. 8. The member according to claim 6 or 7, characterized in that the aqueous solution contains a maximum of 1.5% by volume of a wetting agent. 9. The member according to claim 6, 7 or 8, characterized in that 100 to 250 parts by volume of dilution water are used.