JP3209866B2 - Full process non-oriented electrical steel sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full process non-oriented electrical steel sheet having excellent magnetic properties, weldability, punchability, and space factor.

[0002]

2. Description of the Related Art Non-oriented electrical steel sheets are used for iron cores of electrical equipment such as small transformers and rotating machines. An iron core is manufactured by punching a non-oriented electrical steel sheet into a predetermined shape, laminating the sheets, and clamping them. One of the methods is welding.

[0003] The properties required for a non-oriented electrical steel sheet include excellent magnetic properties and excellent punchability, that is, 1
It is required that as many punches as possible per polishing can be achieved, that the weldability is excellent, that is, that welding can be performed at the fastest possible welding speed without causing defects such as blowholes in the welded portion, and that the space factor is high. Is done. Regarding the weldability, Japanese Patent Publication No. 49-6744 discloses that the surface of a steel sheet is given a roughness of 20 Hr.ms μinch or more, and has excellent punchability and weldability having a mixed film of an inorganic component and an organic resin thereon. Electrical steel sheets have been proposed. Also,
No. 19078 discloses that a steel sheet has a surface roughness of 2 μHma.
x An electrical steel sheet having a mixed coating of an inorganic component and an organic resin having excellent punching properties and weldability has been proposed. These ideas improve the punching property by the organic resin in the coating, while the weldability of the organic resin in the coating allows gas that is thermally decomposed during welding to escape from the gap formed on the rough surface between the steel sheets,
This is to suppress the occurrence of blow holes.

[0004] However, these methods have a drawback that the space factor is poor because a gap is provided between the steel plates. Therefore, it is not adopted as a small and highly efficient iron core requiring excellent magnetic properties. As such an iron core, an electromagnetic steel sheet in which a mixed film containing an inorganic component and an organic resin or a film containing only an inorganic component is applied to a normal smooth steel sheet surface is used. In this case, as shown in Japanese Patent Publication No. 49-6744, the welding speed must be reduced because blowholes occur in the inorganic / organic mixed film,
The inorganic coating has a problem of poor punchability.

In order to solve these problems, the present inventor disclosed in Japanese Patent Application Laid-Open No. 4-365843 [Sol.
0.15%, [B] / [N] = 0.5 to 2.5, the surface of a steel sheet containing one or two inorganic components of phosphoric acid type or chromic acid type and an organic resin content of 50% 400 mg / m ² and made so by applying a mixed coating ingredients adjusting inorganic and organic, magnetic properties, characterized in that the surface roughness Ra of 0.25μm or less, weldability, punching property, occupied A full process non-oriented electrical steel sheet with excellent moment is proposed.

[0006]

However, Japanese Patent Application Laid-open No.
The weldability of a steel sheet proposed in Japanese Patent Publication No. 365843 is not satisfactory, and the present invention further improves the above-mentioned conventional technology, and further improves the non-directional properties of magnetic properties, weldability, punchability, and space factor. It is intended to provide an electromagnetic steel sheet.

[0007]

That is, in the present invention, [C] is 0.005% or less by weight, and [Si] is 0.05 to 4%.
0%, [Mn] 0.1 to 1.5%, [P] 0.15% or less, [S] 0.01% or less, [Sol.Al] 0.15
% To 0.8% or less, [N] 0.01% or less,
[T. O] 0.02% or less On the surface of the steel sheet comprising the balance Fe and inevitable impurities, one or two inorganic components of phosphoric acid type or chromic acid type and an organic resin, and the content of the organic resin is 50%. Full process with excellent magnetic properties, weldability, punching properties and space factor, characterized by having an organic-inorganic mixed film of up to 700 mg / m ² and a surface roughness Ra of 0.25 μm or less. It is a non-oriented electrical steel sheet.

The present inventor has conducted intensive studies to improve the weldability of the steel sheet proposed in Japanese Patent Application Laid-Open No. 4-365843. As a result, an inorganic component containing one or two of a phosphoric acid type and a chromic acid type and an organic resin content of 50 to 700 mg / m
Inorganic and organic mixed film whose components are adjusted to be ² ,
It has been newly found that the weldability is improved when the steel is coated on a steel sheet containing Sol. Al in an amount exceeding 0.15% and the surface roughness Ra of the steel sheet is 0.25 μm or less.

FIG. 1 shows an example of the results of an experiment conducted by the present inventor. That is, [C] 0.002%, [Si] 0.
7%, [Mn] 0.21%, [P] 0.08%, [S]
0.002%, [Sol.Al] 0.001 to 0.8%,
[N] 0.002%, [T. O] 0.02% or less, a mixture of inorganic and organic components whose components are adjusted to contain 50 to 800 mg / m ² of magnesium dichromate and acrylic emulsion resin on the surface of a 0.5 mm-thick steel plate consisting of Fe and unavoidable impurities. The coating was applied at 1 g / m ² . The surface roughness Ra is 0.1.
It was 16 μm. Then, a groove shown in FIG. 2 was formed on a steel sheet, and 60 sheets were laminated to a thickness of 30 mm to prepare a welding test sample, and the groove was welded. The welding conditions were a welding current of 80 A, a welding speed of 10 to 200 cm / min, an arc length of 1.6 mm, and an electrode of 1.
6mmφ2% thorium-containing tungsten, Ar flow rate 12 liter / min, TI pressure 100 kgf / mm ²
G welding was performed. FIG. 1 shows the relationship between the content of Sol. Al, the content of the organic resin, and the highest welding speed at which blowholes do not occur. From this, [Sol.Al] 0.15
% To 0.8% or less, and the organic resin content is 50 to 70%.
It can be seen that the welding speed can be increased in the range of 0 mg / m ² .

Next, the conditions of the present invention and the reasons for limiting them will be described. [C]: C is not only harmful to the magnetic properties, but also causes significant magnetic aging due to precipitation of C, and generates CO gas at the time of welding. [Si]: Si is an element that reduces iron loss. If it is less than the lower limit of 0.05%, the iron loss deteriorates, and the upper limit is 4.0%.
If it exceeds 300, cold rolling becomes extremely difficult, so [Si] is set to 0.05 to 4.0%.

[Mn]: Mn increases the hardness of the steel sheet,
0.1% or more is added in order to improve the punching property. The upper limit of 1.5% is for economic reasons. [P]: P is also added to increase the hardness of the steel sheet and improve the punching property. If it exceeds the upper limit of 0.15%, embrittlement is remarkable. [S]: S becomes a sulfide such as MnS and deteriorates iron loss.

[Sol. Al]: When Sol. Al is contained in an amount exceeding 0.15%, when welding a magnetic steel sheet having a surface roughness Ra of 0.25 μm or less coated with a mixed film of an inorganic component and an organic resin. , Blowholes can be significantly reduced. If the upper limit of 0.8% is exceeded, the cost will increase significantly. [N]: Since N becomes a nitride such as AIN and deteriorates iron loss, [N] is made 0.01% or less. [T. O]: O becomes an oxide and deteriorates iron loss. O] is 0.02% or less.

When the surface roughness Ra of the steel sheet having the organic-inorganic mixed coating is more than 0.25 μm, Sol.
Has no effect on weldability. In addition, the space factor of the laminated iron core is deteriorated. Coating film: A mixed film of one or two of phosphoric acid and chromic acid and an organic resin. The inclusion of one or two of phosphoric acid type and chromic acid type has low surface tension, wettability,
Adhesion and insulation are improved, and organic resin is included
This is for improving the punchability.

The phosphoric acid compounds include, for example, phosphates of calcium, magnesium, aluminum and zinc or phosphates or divalent or trivalent oxides, hydroxides and carbonates of calcium, magnesium, aluminum and zinc. One or a mixture of two or more of dissolved salts, or one or more of titanium oxide, colloidal silica, colloidal alumina, boric acid, etc. added thereto. Next, the chromic acid type is one or two of a dichromate of calcium, magnesium, zinc, or a solution obtained by dissolving a divalent oxide, hydroxide, or carbonate such as calcium, magnesium, or zinc in chromic anhydride. It is a mixture of two or more kinds, or one or more kinds of them, such as titanium oxide, colloidal silica, colloidal alumina, boric acid, and an organic reducing agent.

Further, as the organic resin to be mixed with the inorganic film, a water-soluble or emulsion-type acrylic resin and its copolymer, vinyl acetate resin and its copolymer, butadiene-styrene copolymer, amino resin, alkyd resin Phenol resin, maleic anhydride copolymer, epoxy resin, or a modified product thereof. Organic resin content: If the content exceeds the upper limit of 700 mg / m ² , blow holes are likely to occur, and the welding speed cannot be increased. If it is less than the lower limit of 50 mg / m ² , the punching properties will deteriorate.

[0016]

Embodiment No. 1 in Table 1 A steel ingot having 1 to 5 steel components was melted in vacuum and hot rolled. Then, the hot rolled sheet was cold rolled.
Finished to a thickness of 50 mm, and subjected to continuous annealing at 900 ° C. × 1 minute. Thereafter, the components were adjusted so as to contain dichromic acid as an inorganic component and acrylic emulsion resin as an organic resin in an amount of 30 to 800 mg / m ² , and applied to a steel sheet so as to have various roughnesses. Then, the magnetic characteristics and the surface roughness were measured.

On the other hand, in the welding test, a groove as shown in FIG. 2 was formed on the sample, 60 sheets were laminated to a thickness of 30 mm, and the groove was welded. The welding conditions were: welding current 80A, welding speed 1
0-200cm / min, arc length 1.6mm, electrode 1.6mmφ
Tungsten containing 2% thorium, Ar flow rate 12 liters
TIG welding was performed under the conditions of / min and a tightening pressure of 100 kgf / mm ² . Then, the fastest welding speed at which blowholes did not occur was investigated. Further, in the punching test, under the conditions of a carbide die, a clearance of 5%, and a punching oil: light oil, the number of punching times at which the burrs were 50 μm or more was investigated.

No. 1 to 5, [Sol.
Al] exceeds 0.15%, it can be seen that the fastest welding speed at which blowholes do not occur increases. No.
According to the comparison of 2, 4, 6, and 7, [Sol. Al] in the steel has an effect on the weldability because the surface roughness Ra is 0.25 μm.
It can be seen that the case is as small as below. No. 4, 8 ~
The 11 Comparison of the amount of the organic resin blowholes are likely to occur becomes higher than 700 mg / m ^2, the fastest welding speed causing no Burohoru slows down when less than 50 mg / m ^2, punching property becomes worse You can see that.

[0019]

[Table 1]

[0020]

As described above, the full-process non-oriented electrical steel sheet of the present invention has excellent magnetic properties, weldability, punching properties, and space factor.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between [Sol. Al] in steel, the content of organic resin in a steel sheet surface coating, and the fastest welding speed at which blowholes do not occur.

FIG. 2 is a view showing a shape of a groove formed on a sample for welding test.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazufumi Hanzawa 1-1, Hibata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Corporation Yawata Works (72) Inventor Rokuro Kono 2, Otemachi 2 Chiyoda-ku, Tokyo -6-3 Inside Nippon Steel Corporation (56) References JP-A-4-365843 (JP, A) JP-A-3-229820 (JP, A) JP-A-5-299227 (JP, A) JP-A-2-118020 (JP, A) JP-B-59-20731 (JP, B2) JP-B-49-6744 (JP, B1) JP-B-49-19078 (JP, B1) (58) (Int.Cl. ⁷ , DB name) C22C 38/00 303 C22C 38/06 H01F 1/18

Claims (1)

(57) [Claims] [C] 0.005% or less, [Si] 0.05 to 4.0 as weight%.
%, [Mn] 0.1 to 1.5%, [P] 0.15% or less, [S] 0.01% or less, [Sol.Al] more than 0.15% to 0.8%, [ N] 0.01% or less, [T. O] 0.02% or less The surface of a steel sheet comprising Fe and unavoidable impurities is composed of one or two inorganic components of phosphoric acid or chromic acid and an organic resin, and the content of the organic resin is 50 to 700mg / m ²
And a surface roughness Ra of 0.2
A full-process non-oriented electrical steel sheet having an excellent magnetic property, weldability, punching property, and space factor, having a particle size of 5 μm or less.