Inorganic/organic insulating coating for nonoriented electrical steel

A technology of insulating coating and electrical steel sheet, which is applied in the direction of coating, inorganic material magnetism, process efficiency improvement, etc., can solve problems such as uneven and discontinuous welds, poor fluidity of weld pools, etc. Effects of environmental concerns, high surface resistivity, improved adhesion and chalking resistance

Inactive Publication Date: 2004-08-11
ARMCO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

All of these soluble silicate based insulating coatings provide good surface resistivity and heat resistance, but they impair weld pool fluidity during gas tungsten arc welding, resulting in uneven and discontinuous welds

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0038] The coating of fully finished non-oriented electrical steel sheet according to the invention was carried out as an example in the laboratory with an acidic aqueous suspension comprising a monoaluminum phosphate solution, an inorganic silicate particle, a acrylic latex, and a water-miscible organic solvent. This aqueous suspension, hereinafter referred to as Invention Coating I, was prepared in the following manner. 21.1 parts of acrylic resin, based on 100 parts of total solids on a dry basis, were added to a mixing vessel. This acrylic latex is manufactured by Union Carbide Corporation, UCAR EmulsionSystems, Cary, North Carolina, and sold under the tradename UCAR Vehicle 443. It contains 41 wt% styrene-acrylic polymer and approximately 59 wt% water. The average particle size of the styrene-acrylic polymer particles in the latex was 0.15 μm. A water-soluble organic solvent, diethylene glycol monobutyl ether, is then added to the propylene latex. Such solvents are ma...

example 2

[0065] Non-oriented electrical steel sheet samples were coated in the experiments with the inventive coating II and the commercial phosphate coating I described above in Example 1 and tested for water absorption in a humidified atmosphere. Each coating was applied and cured as described in Example 1. Weigh the sample weight before coating, and weigh again after the coating is cured to determine the coating weight, expressed in g / m2 steel sheet unit. The coated samples were then placed in a humidity chamber at a temperature of 21°C and a relative humidity of 99-100% (non-condensing) for 48 hours. Immediately after removal from the humidity chamber, weigh the specimen again and convert the weight gain or water absorption of each coating to a percentage of the original coating weight. The results are summarized below.

[0066] water absorption

[0067] (coating weight%)

[0068] Invention Coating II 9

[0069] Commercial Phosphate Coating I 26

[007...

example 3

[0073] Two non-oriented electrical steel coils (approximately 15 tonnes) with a thickness of 0.47 mm were coated on a coating line with an aqueous acidic suspension having the same composition as the inventive coating II in Example 1. Water was added to adjust the specific gravity of the coating suspension to 1.125. The coating was applied to both surfaces of a steel plate moving at a line speed of 23 m / min with a grooved rubber metering roll. The line speed was limited to 23m / min because thin coating streaks or bare streaks would form at faster speeds. After coating, the coating was cured by passing the steel panels through a 12 m long furnace with an open flame gas burner. The residence time of the steel plate in the furnace is about 30 sec, and the maximum metal temperature is about 329°C. After passing through the curing furnace, the steel plate is cooled to close to room temperature, and the steel plate is coiled at the end of the coating line. The cured coating has a ...

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Abstract

The present invention relates to a nonoriented electrical steel sheet coated on both surfaces with a cured insulative coating for providing a high level of surface resistivity to minimize interlaminar power losses. The cured insulative coating on the steel sheet includes, based upon 100 parts by dry weight, 20-60 parts of aluminum phosphate, 20-70 parts of at least one inorganic particulate silicate and 10-25 parts of an acrylic resin. The cured coating is formed from an acid aqueous suspension that may include up to 1 part by weight of a water-soluble organic solvent per each part of the resin. The aqueous suspension has a pH of about 2-2.5, a silicate particle size of 0.3-60 mu m, a resin particle size of less than 1 mu m, less than about 0.5 wt. % unreacted phosphoric acid and a specific gravity of about 1.0-1.3. The silicate may be one or more from the group consisting of aluminum silicate, aluminum potassium silicate and magnesium silicate. After curing, the coating has a thickness on each sheet surface of 0.5-8 mu m. The insulative coated nonoriented electrical steels may be used to minimize power losses in laminated magnetic cores of motors, generators, transformers, and other electrical equipment.

Description

Background of the invention [0001] The present invention relates to an inorganic / organic insulating coated semi-finished or fully finished non-oriented electrical steel to provide a high level of surface resistivity to minimize interlayer power loss. More specifically, the insulating coating is formed from an acidic aqueous suspension comprising a monoaluminum phosphate solution, at least one inorganic silicate particulate and an organic acrylic latex. The insulation-coated non-oriented electrical steel of the present invention can be used to minimize power loss in magnetic cores of motors, generators, transformers and other electrical equipment. [0002] Non-oriented electrical steel sheets for medium or large electric motors and transformers are provided with an insulating coating to provide a high level of surface resistivity so that power losses between layers are reduced when laminations formed of electrical steel are used in the as-punched state. to minimum. This high ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C22/17C04B28/34C21D8/12C22C38/00C23C22/20C23C22/74H01F1/18
CPCH01F1/18C04B2111/00525C23C22/74C04B28/34C21D8/1283Y10T428/12951Y10T428/31678Y10T428/31833Y02P10/20C04B14/04C04B24/2641C23C28/00
Inventor D·S·劳德米尔克J·L·布朗
Owner ARMCO INC
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