JPH08193220A - Production of semiprocessed nonoriented silicon steel sheet - Google Patents

Abstract

PURPOSE: To produce a semiprocessed nonoriented silicon steel sheet minimal in anisotropy of magnetic properties by applying specific cold rolling to a steel sheet having a specific composition consisting of C, Si, Mn, P, S, Al, N, 0, and Fe. CONSTITUTION: A slab, having a composition consisting of, by weight, <=0.015% C, 0.05-1.0% Si, 0.1-1.5% Mn, <=0.15% P, <=0.03% S, <=1.0% sol.Al, <=0,.01% T.N, <=0.02% T.O, and the balance iron with inevitable impurities, is hot-rolled. The resulting hot rolled plate is subjected to hot rolled plate annealing at 700-1000 deg.C, if necessary. Then, this hot rolled plate is cold-rolled twice, while process-annealed between the cold rolling stages, to the final product thickness. At this time, the second cold rolling is done at 2-15% draft. Further, respective diameters of the upper and the lower work roll are made different from each other, and also (diameter of small-diameter roll)/(diameter of large-diameter roll)<=0.8 is satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-process non-oriented electrical steel sheet mainly used in rotating machines.

[0002]

2. Description of the Related Art Non-oriented electrical steel sheets are used for iron cores of rotating appliances such as motors for home appliances. Since the rotating machine is magnetized in all directions within the plane of the electromagnetic steel plate, if the anisotropy is large, problems such as uneven rotation of the rotating machine occur. Therefore, the non-oriented electrical steel sheet is required to have little anisotropy in magnetic properties. However, the non-oriented electrical steel sheet has more or less anisotropy, and in a normal manufacturing method, the characteristics in the rolling direction of the steel sheet (hereinafter referred to as L direction) are the width direction of the steel sheet (hereinafter C direction).
(Referred to as direction) characteristics.

In a method for producing a semi-process non-oriented electrical steel sheet by cold rolling twice with intermediate annealing, a method for producing a steel sheet having little anisotropy of magnetic properties is disclosed in Japanese Patent Laid-Open No.
-118014 gazette, the second cold rolling 100mm
A method has been proposed in which the product of the plate thickness t of the material to be rolled and the roll diameter D is performed with a roll diameter of less than φ so that D × t ≦ 70. However, although the anisotropy of the magnetic flux density is certainly reduced by this technique, in the embodiment, the L direction / C direction of B ₅₀ is 1.
It can only be reduced to about 023.

[0004]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention provides a method for producing a semi-process non-oriented electrical steel sheet with extremely small anisotropy of magnetic properties.

[0005]

That is, the gist of the present invention is as follows. (1)% by weight, [C]: 0.015% or less,
[Si]: 0.05 to 1.0%, [Mn]: 0.1
1.5%, [P]: 0.15% or less, [S]: 0.
03% or less, [Sol.Al]: 1.0% or less,
[T. N]: 0.01% or less, [T. O]: 0.0
After hot rolling a slab containing 2% or less of the balance iron and unavoidable impurities, two cold rollings with intermediate annealing are performed, and when the final product thickness is obtained, the second cold rolling is performed. Semi-process non-directionality, characterized in that the reduction rate is 2 to 15% and the work roll diameters of the upper work roll and the lower work roll are made different so that the small diameter roll diameter / the large diameter roll diameter ≦ 0.8. Manufacturing method of electrical steel sheet. (2) The method for producing a semi-processed non-oriented electrical steel sheet having excellent magnetic properties according to (1), wherein the hot rolled sheet is annealed at 700 to 1000 ° C.

The present inventor has made diligent efforts to develop a method for producing a semi-process non-oriented electrical steel sheet for a rotating machine having a small magnetic property anisotropy. As a result, during the second cold rolling, the anisotropy is remarkably reduced by making the diameters of the upper work roll and the lower work roll different from each other and performing the small diameter roll diameter / the large diameter roll diameter ≦ 0.8. Found.

In the experiment of FIG. 1, [C]: 0.003%,
[Si]: 0.09%, [Mn]: 0.2%, [P]:
0.09%, [S]: 0.0120%, [T. N]:
0.0055%, [T. O]: 0.016%, [Sol.A
l]: Molten steel containing 0.001% was continuously cast, followed by hot rolling. In the manufacturing process of the two-time cold rolling method in which the obtained hot-rolled sheet is sandwiched by intermediate annealing, the first cold rolling was performed to 0.532 mm, the intermediate annealing was performed, and the second cold rolling was performed at a cold rolling rate of 6%. ,
Finished to 0.500 mm. In the second cold rolling, the lower work roll has a roll diameter of 500 mmφ and the upper work roll has a roll diameter of 250 to 500 mmφ.
Epstein samples and ring samples were taken from the steel sheets obtained in this way with various values of large-diameter rolls to measure the magnetic properties in the L and C directions and subjected to strain relief annealing at 750 ° C x 2 hours for magnetic properties. investigated.

FIG. 1 shows the relationship between the small diameter roll diameter / large diameter roll diameter, the L direction / C direction of the magnetic flux density B ₅₀ , and the B ₅₀ of the ring sample. From this, the small roll diameter / large roll diameter is set to 0.
If done below 8, the L ₅₀ / B direction of B ₅₀ becomes smaller,
It can be seen that the anisotropy becomes smaller.

Next, the reasons for limiting the various conditions in the present invention will be described. [C]: When C exceeds 0.015%, not only is it harmful to the magnetic properties, but also the magnetic aging due to the precipitation of C becomes remarkable and the magnetic properties deteriorate, so 0.015% or less, preferably 0.010%. % Or less.

[Si]: Si is an element that reduces iron loss. If it is less than 0.05%, the iron loss is too bad, and the upper limit of 1.0% is that the magnetic flux density is lowered. [Mn]: Mn is added in an amount of 0.1% or more in order to increase the hardness of the steel sheet and improve punchability. The upper limit of 1.5% is due to economic reasons.

[P]: P is also added to increase the hardness of the steel sheet and improve the punchability. If the upper limit of 0.15% is exceeded, embrittlement becomes remarkable. [S]: S becomes a sulfide such as MnS and deteriorates iron loss, so the content was made 0.03% or less.

[Sol.Al]: The upper limit of 1.0% causes a decrease in magnetic flux density. [T. N]: T. N becomes a nitride such as AIN and deteriorates iron loss, so N is made 0.01% or less. [T. O]: T. O forms an oxide and deteriorates iron loss, so the content is made 0.02% or less.

Reduction ratio of the second cold rolling: If the reduction ratio of the second cold rolling is less than 2% or more than 15%, the magnetic flux density of the ring sample decreases. When the diameters of the upper work roll and the lower work roll of the second cold rolling are made different, and the small diameter roll diameter / large diameter roll diameter ≦ 0.8: small diameter roll diameter / large diameter roll diameter ≦ 0.8, magnetic The anisotropy of properties can be significantly reduced. Hot-rolled sheet annealing temperature: Hot-rolled sheet annealing is performed as necessary,
Below the lower limit of 700 ° C, there is no effect of improving the magnetic properties, and above the upper limit of 1000 ° C, the cold ductility deteriorates.

[0014]

【Example】

[Example 1] [C]: 0.002%, [Si]: 0.38%, [M]
n]: 0.2%, [P]: 0.08%, [S]: 0.0
032%, [T. N]: 0.0039%, [T. O]:
Molten steel containing 0.015% and [Sol.Al]: 0.001% was continuously cast, and subsequently hot-rolled. In the manufacturing process of the two-time cold rolling method in which the obtained hot-rolled sheet is sandwiched by intermediate annealing, the first cold rolling was rolled to 0.532 mm, the intermediate annealing was performed, and the second cold rolling was performed at a cold rolling rate of 6%. The final product thickness was 0.500 mm. In this second cold rolling, an experiment was conducted in which the diameters of the upper work roll and the lower work roll were changed, and the values of the small diameter roll / the large diameter roll were changed. From the steel sheet thus obtained, Epstein samples and ring samples were measured for magnetic properties in the L and C directions, and stress relief annealing was performed at 750 ° C. for 2 hours to investigate the magnetic properties. Upper work roll diameter at this time, lower work roll diameter, small diameter roll diameter / large diameter roll diameter, L direction / C direction of magnetic flux density B ₅₀ and B of ring sample
₅₀ relationships are shown. From this, it is understood that when the small diameter roll diameter / large diameter roll diameter is 0.8 or less, the L direction / C direction of the magnetic flux density B ₅₀ is small and the anisotropy is small.

[0015]

[Table 1]

Example 2 The same hot-rolled sheet as in Example 1 was not annealed, and was annealed at 600 ° C. and 750 ° C.
The first cold rolling was rolled to 0.549 mm, then annealed,
A second cold rolling was performed at a cold rolling rate of 9% to give a final product thickness of 0.500 mm. In this second cold rolling, a lower work roll of 500 mmφ was used and an upper work roll of 3 mm was used.
An experiment was conducted with a diameter of 40 mm and a diameter of a small roll / a large roll of 0.68. From the steel sheet thus obtained, Epstein samples and ring samples for L-direction and C-direction magnetic property measurement were sampled and subjected to stress relief annealing at 750 ° C. for 2 hours to investigate the magnetic properties. The relationship between the annealing temperature of the hot rolled sheet, the L direction / C direction of the magnetic flux density B ₅₀ and the B ₅₀ of the ring sample at this time is shown. From this, it is understood that in the case of the present invention example, the anisotropy is small and a high magnetic flux density can be obtained. Further, it can be seen that when the hot-rolled sheet annealing is performed at 700 to 1000 ° C., the magnetic properties are more excellent.

[0017]

[Table 2]

[0018]

As described above, according to the present invention, it is possible to manufacture a semi-process non-oriented electrical steel sheet having little magnetic property anisotropy.

[Brief description of drawings]

[1] of the second small-diameter cold rolling roll diameter / large-diameter roller diameter and B ₅₀ L direction / C direction is a diagram showing the relationship between the ring specimen B _50.

Claims (2)

[Claims] 1. In weight%, [C]: 0.015% or less, [Si]: 0.05 to 1.0%, [Mn]: 0.1 to 1.5%, [P]: 0. .15% or less, [S]: 0.03% or less, [Sol.Al]: 1.0% or less, [T. N]: 0.01% or less, [T. O]: 0.02% or less and hot rolling a slab consisting of the balance iron and unavoidable impurities, and then cold rolling twice with intermediate annealing sandwiched between them to obtain the final product thickness. Cold rolling, reduction ratio 2-1
Manufacturing of semi-processed non-oriented electrical steel sheet characterized in that the work roll diameters of the upper work roll and the lower work roll are made different, and the work roll diameters are made smaller / larger roll diameter ≦ 0.8 while being set to 5%. Method. 2. The hot-rolled sheet according to claim 1,
A method for producing a semi-processed non-oriented electrical steel sheet having excellent magnetic properties, characterized by performing hot-rolled sheet annealing at 00 to 1000 ° C.