JP3467907B2 - Electrical steel sheet with excellent weldability and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to grain-oriented silicon steel sheets and non-oriented electrical steel sheets mainly used for iron cores of small transformers, iron cores of motors, etc. From the viewpoint of improvement, it proposes a magnetic steel sheet having excellent weldability and a method for manufacturing the same.

[0002]

2. Description of the Related Art Magnetic steel sheets are required to have high machining efficiency in punching and assembling in addition to magnetic properties such as magnetic flux density and iron loss. In particular, the cores of small transformers and small motors such as EI cores are formed by punching, laminating and welding a part of the end faces of the cores in order to efficiently finish complex shapes. .

To improve the efficiency of punching, Japanese Patent Publication Sho 49
-19078 (Electromagnetic steel sheet for laminated iron core with excellent punchability and weldability) and Japanese Patent Publication No. 51-34857 (electrical steel sheet coated with varnish) as an organic coating as an insulating coating ( Hereinafter, an organic coat) and a coating in which an organic substance and an inorganic substance are mixed (hereinafter referred to as a semi-organic coat) have been proposed, and these were effective in increasing the efficiency of punching.

However, by adopting such an organic coat or a semi-organic coat, at the time of welding the end faces of punched and laminated steel sheets, if the welding speed is increased, defects called blow holes are generated in the welded portion, and the workability of welding is extremely high. There was a defect that it decreased.

This defect is caused by the fact that the organic matter in the insulating coating is heated to a high temperature during welding and becomes a gas state, which springs out to the welded portion. As disclosed in JP-A-48586 (electrical steel sheet having a coating excellent in interlayer insulation resistance and heat resistance and its manufacturing method), the roughness of the steel sheet surface is increased to increase the amount of gas dissipated to areas other than the weld zone. Tari, (2) Japanese Patent Publication Sho 57-57953
Using a resin having a high heat resistance as disclosed in Japanese Patent Publication (electric iron plate having a heat-resistant insulating coating having excellent punchability and weldability) and CAMP-ISIJ Vol 7 (1994) p827,
(3) As disclosed in CAMP-ISIJ Vol 5 (1992) p903, a technique for reducing the O concentration as a component of steel and improving the shape of the welded portion has been proposed. However, all of these methods are due to the following reasons.
It has not reached the point of deteriorating the magnetic properties or significantly improving the weldability.

That is, (1) The method of increasing the roughness of the surface of the steel sheet inevitably causes a decrease in the space factor and also deteriorates the magnetic characteristics of the steel sheet, so that the magnetic characteristics of the actual product are significantly deteriorated. Let (2) When a resin with high heat resistance is used as an organic substance, the heat resistance temperature is up to 500 ° C, which is extremely low compared to the steel plate temperature of the welded portion of about 1600 ° C, and the improvement effect of weldability is limited. There is. (3) Regarding the decrease of O concentration in steel, the present steel has 10 ~
The value is 40PPM, which is sufficiently low, and the effect of improving the weldability is not great despite the efforts to reduce the O concentration.

[0007]

DISCLOSURE OF THE INVENTION The present invention eliminates the above-mentioned problems with regard to the weldability at the end faces of the laminate when the electromagnetic steel plates are punched, laminated, and then welded, and an electromagnetic steel plate having excellent weldability is provided. The purpose is to propose a manufacturing method thereof.

[0008]

First, an experimental example and an experimental result of the invention will be described.
Si: 0.35%, Mn: 0.25%, Al: 0.15%, P: 0.015%, and C: 0.001%, S: 0.002% as impurities.
A round bar of Al rotating at high speed was pressed against one surface of a non-oriented electrical steel sheet containing O: 0.003% and N: 0.003% to adhere Al. At that time, the pressing strength was changed to change the Al adhesion amount, but as a result of the analysis, the adhesion amount was 0.
02, 0.05, 0.10, 0.32, 4.3, 10.5, 32.7, 57.8, 240,
It was mg / m ² .

[0009] Including the steel sheet to which Al was not adhered, each of the steel sheets was laminated with a semi-organic coating consisting of half amount of acrylic resin and half amount of magnesium dichromate and a reducing agent baked on both sides of 4 g / m ^2. , TIG welding machine 2.6mm φTh−
Welding tests were carried out using a W electrode under the conditions of shielding gas: Ar and welding current: 120 A at a welding speed in the range of 20 to 120 cm / min. The result is shown in FIG. FIG. 1 is a graph showing the relationship between the amount of Al adhering to a steel sheet coated with a semi-organic coat and the maximum welding speed at which blowholes do not occur.

As shown in FIG. 1, it was found that the weldability of the steel sheet is remarkably improved by depositing 0.1 mg / m ² or more of metallic Al between the steel sheet surface and the semi-organic coat. As a result of the inventors' earnestly researching the reason for this, the main cause of generating blowholes during welding of steel sheets is
Oxygen in the organic matter contained in the insulating film.This oxygen combines with carbonic acid and hydrogen in the organic matter to generate CO and H ₂ O, and as a result, these gases generate blowholes in the weld. I got the knowledge that there is. Therefore, when metal Al is adhered to the steel plate surface, oxygen in the organic matter selectively combines with Al to generate Al ₂ O _3, which is harmful to the weldability of CO, H ₂ O, etc. It was found that the generation of gas was suppressed and the weldability was improved.

In addition to Al, Si is suitable as a component that selectively binds to oxygen in the organic matter. Further, these simple substances and alloys are not only present between the insulating coating and the steel sheet, but also in the insulating coating. Even if it exists, it turns out that it has the same effect.
The present invention has been achieved based on these new findings.

That is, the gist of the present invention is as follows. Has all or some of the ingredients
A magnetic steel sheet formed by coating an insulating coating made of a machine , between the steel sheet surface and the insulating coating, a total of 0.1 mg / m ^{2 to} 5.0 g / m ^{2 on} one side or both sides of the steel sheet. range of the amount of electromagnetic steel sheet with excellent weldability including the metal material for fixing the oxygen (first invention). All or some of the ingredients are organic
A magnetic steel sheet formed by coating an insulating coating made of a material ,
A magnetic steel sheet having excellent weldability, which comprises an oxygen-fixing metal substance in an amount corresponding to a total range of 0.1 mg / m ^{2 to} 5.0 g / m ^{2 in} the insulating coating (second invention). The electromagnetic steel sheet having excellent weldability according to the first invention or the second invention, wherein the metal substance that fixes oxygen is a simple substance of Si or Al or a mixture or alloy thereof. A total amount of 0.1 mg / m ^{2 to} 5.0 g / m ^{2 on} one or both sides of the steel plate ,
After attaching a metal substance that fixes oxygen, if all components
A method for producing an electromagnetic steel sheet having excellent weldability, characterized in that an insulating coating film, of which some of the components are organic, is formed (fourth invention). All components or part of components on steel plate surface
Is an organic insulating film with a total of 0.1 mg / m ²
A method for producing a magnetic steel sheet having excellent weldability, which comprises forming an insulating coating in which a metal substance that fixes oxygen is mixed , which corresponds to an amount in the range of up to 5.0 g / m ² (fifth invention).
The method for producing an electromagnetic steel sheet having excellent weldability according to the fourth invention or the fifth invention, wherein a simple substance of Si or Al or a mixture or alloy thereof is used as a metal substance for fixing oxygen (sixth invention).

[0013]

The operation of the present invention will be described below. The electromagnetic steel sheet targeted by the present invention is a semi-processed non-oriented electrical steel sheet for punching, laminating and welding, and strain relief annealing, and a full sheet for punching, laminating and welding. Non-oriented electrical steel sheet for process, grain-oriented silicon steel sheet, etc., which is further punched, laminated and welded and subjected to strain relief annealing as necessary,
It can be applied to any of these.

Here, as the composition of the non-oriented electrical steel sheet, the conventionally known C: 0.10 wt% or less, Si: 5.0 wt%
% Or less and Mn: 2.5 wt% or less, Al: 2.0 wt%
Below, P: 0.20 wt% or less, B: 0.005 wt% or less, Sb: 0.
A steel sheet that optionally contains at least one of 10 wt% or less, Sn: 0.20 wt% or less, Cu: 0.50 wt% or less, or Ni: 0.50 wt% or less is suitable. Steel slabs for non-oriented electrical steel sheets having such a composition are hot-rolled by a conventional method, then subjected to hot-rolled sheet annealing if necessary, and cold-rolled once or by multiple cold-rolling steps with intermediate annealing, The final plate thickness is used, and for full process, after finish annealing, for semi process, an insulating film is formed in a state where processing strain remains.

On the other hand, as the grain-oriented silicon steel sheet, for example, conventionally known C: 0.005-0.15 wt%, Si: 2.0-4.5 wt%.
% And Mn: 0.002-0.15 wt%, S: 0.005-0.05 wt%, Se: 0.005-
0.05wt%, Te: 0.003-0.03wt%, Sb: 0.005-0.05wt
%, Sn: 0.03 to 0.5 wt%, Cu: 0.02 to 0.3 wt%, Mo: 0.
005 to 0.05 wt%, B: 0.0003 to 0.004 wt%, N: 0.001
~ 0.01wt%, Al: 0.005-0.05wt%, Ti: 0.001-0.05
A steel sheet containing at least one selected from wt% or Nb: 0.001 to 0.05 wt% is advantageously suitable. A steel slab for grain-oriented electrical steel sheets having such a composition is hot-rolled by a conventional method, then hot-rolled sheet is annealed if necessary, and then cold-rolled once or a plurality of cold-rolls sandwiching a central annealing is performed to obtain a final sheet. After thickening and decarburizing annealing, an annealing separator is applied, and after final finishing annealing, an insulating film is formed. At this time, by adjusting the components of the annealing separator, after the final finish annealing, it is possible to form an oxide layer on the surface of the steel sheet or suppress the formation of an oxide layer to bare the base metal surface. It is possible.

Further, the insulating coating targeted by the present invention is
An organic coat in which all components are organic or a semi-organic coat in which a part of components is organic, and an inorganic coat in which all components are inorganic are originally good in weldability, and therefore, to apply the present invention. It does not reach.

The essence of the present invention is to allow a metal substance for fixing oxygen in the organic substance to exist between the insulating coating and the steel plate or in the insulating coating. Here, a metal substance that fixes oxygen is one that has a lower free energy of formation of an oxide in a high temperature state than that of carbon or hydrogen,
Metallic substances such as V, Ti, Li, Ca are compatible, but at an inexpensive point
Al and Si are more preferable. And, they may be used alone or as a mixture, and their alloys may be used.

Further, even if the Si compound contains oxygen, such as silicone, since oxygen is fixed in the organic substance as a result of forming silica by the reaction, it is suitable as an oxygen-fixing metal substance in this case. .

As a method for adhering these oxygen-fixing metallic substances to the surface of the steel sheet, the method of pressing and sliding as in the above-mentioned experiment, the method of electroplating, the method of applying,
There are various methods such as spraying, but the effect is the same regardless of which method is used.

When an oxygen-fixing metal substance is contained in the insulating film, the surroundings of the powder are more preferable than the powder of Si or Al.
It is better to slightly oxidize it as SiO ₂ or Al ₂ O ₃ because stability in the coating solution is secured, but in this case also, the amount evaluated as a fixed metal substance of oxygen is strictly It goes without saying that only metal Si or metal Al is used.

As the amount of such a metal substance that fixes oxygen
Is 0.1 mg / m when applied between the insulating film and the steel plate²~
5.0 g / m²0.1 mg / m when included in the insulating film²
~ 5.0g / m²It is important to include a substantial amount of This
0.1 mg / m of metal substance²If it is less than, it will improve the weldability.
Poor, conversely 5.0 g / m ²If it exceeds, the space factor will be reduced.
It is not preferable because

[0022]

【Example】

Example 1 A rotating Si rod was pressed and slid on the surface of a forsterite coating of a grain-finished grain-oriented silicon steel sheet containing 0.35 mm of Si: 3.25% and Mn: 0.07%. To
After applying 130 mg / m ² of Si, a semi-organic coating consisting of calcium dichromate containing 40% of epoxy resin and styrene and a reducing agent was applied on both sides at 3 g / m ^{2 and} baked to make it a suitable example of the present invention. . 3g / same semi-organic coat as the above-mentioned conformity example directly on both sides of the same finish-annealed grain-oriented silicon steel sheet.
m ² Coating and baking was used as a comparative example. Both of them were punched out to a size of 100 x 100 mm, 300 sheets were laminated, and 2.6 mm φTh-W electrode was used. TI under shield gas: Ar, welding current: 80 A
Weldability was tested by the G welding method, and the maximum welding speed at which blowholes did not occur was determined. As a result, the maximum welding speed was 90 cm / min for the conforming example and 20 cm / min for the comparative example.

Example 2 A finish-annealed grain-oriented silicon steel sheet containing 0.50 mm thick Si: 2.5% and Mn: 1.5% was electrodeposited with 50 mg / m ^{2 of} Al on both sides, and then acrylic resin was applied on both sides. A semi-organic coat consisting of magnesium phosphate containing 30% of styrene and 5% of boric acid was applied and baked at ² g / m ^{2 as} a conforming example of the present invention. The same semi-organic coating as in the above-mentioned conforming example was applied to both sides of the same finish-annealed grain-oriented silicon steel sheet as a comparative example by coating and baking at ² g / m ² . Both of them were punched out to a size of 100 x 100 mm, 300 sheets were laminated and a 3.5 mm φTh-W electrode was used.
r, welding current: Weldability was tested by the TIG welding method under the condition of 100 A, and the maximum welding speed at which blowholes did not occur was determined. As a result, the maximum welding speed was 100 cm / min for the conforming example and 25 cm / min for the comparative example.

Example 3 A non-oriented electrical steel sheet having a finish of 0.50 mm and containing Si: 0.1% and Mn: 0.2%, which had been annealed, was electroplated with 150 mg / Al.
After depositing m ^2, a semi-organic coat consisting of magnesium dichromate containing 20% of an epoxy resin and a reducing agent was applied and baked at 1 g / m ^{2 on} both sides to obtain a conforming example A of the present invention. Average grain size: 0 on both sides of the same finish annealed non-oriented electrical steel sheet.
The same semi-organic coat as in the above-mentioned conforming example A except that it contained 15% of Al powder of 5 μm was applied and baked at 1 g / m ^{2 to} obtain the conforming example B of this invention. The same semi-organic coating as in the above-mentioned conforming example A was applied to both surfaces of the same finish-annealed non-oriented electrical steel sheet as a comparative example of 1 g / m ² coating and baking. These three members were punched out to a size of 100 x 100 mm, 300 sheets were laminated, and 2.5 mm φTh-W electrode was used.
Weldability was tested by the G welding method, and the maximum welding speed at which blowholes did not occur was determined. As a result, the maximum welding speed was compliant example A: 150 cm / min, compliant example B: 160 cm / min, comparative example: 25 cm / min.

Example 4 Degreased Si: 0.45% after 0.50 mm thick skin pass rolling,
Mn: 0.30% non-oriented electrical steel sheet with an organic coating consisting of calcium dichromate containing 20% silicone on both sides and a reducing agent at 1 g / m ²
Coating and baking This is a compatible example of the present invention. After the same skin pass rolling, apply the same organic coat as the conforming example except that silicone is not contained on both sides of the degreased non-oriented electrical steel sheet.
g / m ² Coating and baking was used as a comparative example. Both of them were punched out to a size of 100 x 100 mm, 300 sheets were laminated, a 2.9 mm φTh-W electrode was used, and a weldability test by the TIG welding method was performed under the conditions of shielding gas: Ar and welding current: 120 A. The maximum welding speed without blowholes was determined. As a result, the maximum welding speed was 80 cm / min for the conforming example A and 25 cm / min for the comparative example.

[0026]

INDUSTRIAL APPLICABILITY The present invention is an electromagnetic steel sheet comprising a steel sheet surface coated with an insulating coating containing a metal substance for fixing oxygen. According to the present invention, an organic or steel sheet for improving punchability is provided. It improves the weldability of laminated end faces of electromagnetic steel sheets coated with an insulating coating containing organic substances, and greatly contributes to improving the processing efficiency of iron core manufacturing.

[Brief description of drawings]

1 is a graph showing the relationship between the maximum welding speed without generation of Al deposition amount and blanking low halls in steel sheet forms a semi-organic coating object.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-4-272166 (JP, A) JP-A-4-157180 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 22/00-22/86 C22C 38/00 303 C23C 30/00

Claims (6)

(57) [Claims] 1. All or some of the components are made of organic substances.
Comprising an insulating coating an electromagnetic steel sheet consisting forms the, between the steel sheet surface and the insulating film, the amount of one or a range of ^{0.1 mg / m 2 ~5.0 g /} m 2 in total at both sides of the steel sheet the electromagnetic steel sheet with excellent weldability including the metal material for fixing oxygen. 2. All or some of the components are made of organic substances.
The composed insulating coating an electromagnetic steel sheet consisting forms the, in an amount corresponding to a range of total ^{0.1 mg / m 2 ~5.0 g /} m 2 in the insulating film, contain a metal material which fixes the oxygen Magnetic steel sheet with excellent weldability. 3. The metal substance for fixing oxygen is a simple substance of Si or Al, or a mixture or alloy thereof.
Alternatively, the electromagnetic steel sheet having excellent weldability according to item 2. 4. A total of 0.1 m on one or both sides of the steel plate
in an amount ranging from ^{g / m 2 ~5.0 g / m} 2, after the deposition of the metal material for fixing the oxygen, a portion of all the components or ingredients organics
A method for producing an electromagnetic steel sheet having excellent weldability, which comprises forming an insulating coating made of 5. The entire composition or a part of the composition on the steel plate surface.
Is an organic insulating film with a total of 0.1 mg / m ²
A method for producing a magnetic steel sheet having excellent weldability, which comprises forming an insulating coating mixed with an oxygen-fixing metal substance in an amount in the range of up to 5.0 g / m ² . 6. The method for producing a magnetic steel sheet having excellent weldability according to claim 4 or 5, wherein a simple substance of Si or Al or a mixture or alloy thereof is used as a metal substance for fixing oxygen.