JPH0816258B2 - Clad type non-oriented electrical steel sheet - Google Patents

Description

Detailed Description of the Invention

[Field of Industrial Application] The present invention relates to a non-oriented electrical steel sheet having excellent magnetic properties, particularly iron loss-magnetic flux density balance. [Prior Art] In recent years, as electrical equipment has become smaller, more efficient, and more energy efficient, the demand for low iron loss and high magnetic flux density is increasing even for non-oriented electrical steel sheets used as iron cores. It's starting. However, in order to realize such a low iron loss-high magnetic flux density, there are serious restrictions on the chemical composition, and although various improvements have been made from the past, the actual results are still not achieved. Is. That is, as is well known, magnetic properties such as iron loss and magnetic flux density greatly depend on chemical components, especially the amount of Si. Specifically, both the iron loss and the magnetic density decrease with the increase of the Si content. Therefore, if high Si steel is used to achieve the low iron loss, the magnetic velocity density will inevitably decrease. If Si is reduced to increase the magnetic flux density, the iron loss will increase at the same time. Conventionally, such restrictions on chemical components were considered to be unavoidable, and therefore the research target was limited to the improvement of grain size and texture, which are the secondary controlling factors of magnetic properties. . [Problems to be Solved by the Invention] However, in the case of accepting the restriction on the chemical composition which is the largest factor preventing the low iron loss-high magnetic flux density as in the conventional case, and when it is necessary to improve the secondary factor, It is true that there is a limit to the low iron loss-high magnetic flux density, and any of the techniques disclosed thus far has achieved sufficient low iron loss-high magnetic flux density. It is hard to say that In view of the above problems, the present invention aims to provide a steel sheet that overcomes the above-described restrictions on the chemical composition and that achieves an unprecedented low iron loss-high magnetic flux density. It was made based on the idea. [Means for Solving the Problems] Conventionally, for non-oriented electrical steel sheets, in order to smoothly carry out the magnetization process, in other words, in order not to inhibit the motion of the domain wall, all factors including the structure are Studies have been conducted in the direction of making it uniform. With respect to such a conventional idea, the present inventors reversed the idea and reconsidered the magnetic characteristics of the non-oriented electrical steel sheet from the viewpoint of nonuniformity. As a result, a clad type non-oriented electrical steel sheet which is completely different from the conventional non-oriented electrical steel sheet has been obtained as a low iron loss-high magnetic flux density material. That is, like a conventional non-oriented electrical steel sheet, a single layer over the entire pressure, if the same component, iron loss due to the increase of Si content, simultaneous decrease of magnetic flux density is inevitable, but the skin layer in the thickness direction. When a clad type electromagnetic steel sheet consisting of three layers (skin layer) -center layer (core layer) -skin layer (skin layer) is used, low iron loss can be obtained by changing the Si content of the skin layer and the core layer. The higher the Si side layer is, the lowering of the magnetic flux density that occurs at the same time can be supplemented by the low Si side layer having a high magnetic flux density, in other words, the high Si steel, the low Si steel, It was newly found that a so-called combined effect occurs in which the advantages of both are utilized and the drawbacks are complemented with each other. Further, as a result of further studies, by optimizing the components of each layer and the clad ratio, the magnetic properties are improved more than expected from the above composite effect through the interaction in the texture formation process between the skin layer and the core layer. It was concluded that the above can be achieved, and the present invention has been completed. Further, one of the properties required of the non-oriented electrical steel sheet is punchability. Generally speaking, the term "punching property" is evaluated by the wear of the punching die, and the factor affecting the magnetic properties is the shape of the sheared surface of the steel sheet punched and sheared by the die. That is, the magnetic characteristics after punching deteriorate due to this shape and residual strain. If the clearance of the mold is made small, the sheared cross-sectional shape is improved, but this is not economical because the mold wears quickly, and too small clearance gives residual strain to the steel sheet and deteriorates the magnetic properties. On the other hand, it was found that by clad the steel sheet into three layers as in the present invention, the shear cross-section shape was remarkably improved, and the magnetic characteristics when the motor core or EI core was actually manufactured were improved. The non-oriented electrical steel sheet of the present invention based on the above findings comprises a skin layer-core layer-skin layer in the thickness direction.
A clad type non-oriented electrical steel sheet having a layered structure, wherein the chemical composition of the skin layer and the core layer is% by weight, C: 0.0050% or less, Si: 0.7 to 3.4%, Mn: 0.1 to 1.0%, P: 0.15 % Or less, S:
0.015% or less, Al: 0.1 to 1.0%, N: 0.0050% or less,
Also, the Si content and Al content of the skin layer and the Si content of the core layer and
Al amount is [Si] + [Al] ≦ 3.5%

[Si] +

[Al] ≧ 1.7% ([Si] + [Al])-(

[Si] +

[Al]) ≧ 0.5% where [Si]: Si content of the skin layer (wt%) [Al]: Al content of the skin layer (wt%)

[Si]: Si content of the core layer (% by weight)

〔Example〕

Using the steels A to G shown in Table 1, the clad material slabs shown in Table 2 were produced. Also, as a comparative material, an ordinary single-layer material having a component equivalent to the clad material from the components of the skin layer and core layer of each clad material and the clad ratio (equivalent component single-layer material)
The components were calculated to obtain the slabs of Steels H to Z shown in Table 1. These slabs were hot-rolled under the conditions shown in Table 2 to a finished sheet thickness of 2 mm, then hot-rolled sheet annealed (some parts are omitted), pickled, and then cold-rolled to a sheet thickness of 0.5 mm. Finishing annealing was performed to obtain a predetermined clad material electromagnetic steel sheet and equivalent component single-layer electromagnetic steel sheet. Table 3 shows the results of measuring the magnetic properties of both of the ring samples (inner diameter 33φ-outer diameter 45φ).
The magnetic properties of 15 to 15) are equivalent to the magnetic flux density B compared to the single layer material of the equivalent component.
0.02 T or more high magnetic flux density at _{50 (ΔB 50} ≧ 0.02T), the iron loss W
0.25 w / kg or more _15/50 reduce iron loss (ΔW _15/50 ≦ -0.25w / k
g), it can be seen that the clad electromagnetic steel sheet according to the present invention has an extremely excellent magnetic flux density-iron loss balance. On the other hand, the comparative material (No. 16 to 19) has ΔB ₅₀ : -0.013
~ 0.008T, ΔW _15/50 : -0.12 to -0.05w / kg, all of which have magnetic properties equivalent to or slightly lower than the equivalent component single layer material with magnetic flux density B ₅₀ , and iron loss W _15/50 somewhat. Low degree,
It can be seen that an excellent magnetic flux density-iron loss balance cannot be obtained with the clad electromagnetic steel sheet outside the scope of the present invention. [Advantages of the Invention] As described above, the non-oriented electrical steel sheet of the present invention has both low iron loss and high magnetic flux density, which have not been realized so far, at the same time. Since it can be obtained by the method, it has a great industrial value, and in particular, it is an extremely effective invention that can meet the recent demands for downsizing, high efficiency, energy saving, etc. in electric devices.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the structure of the clad material and the clad ratio. FIG. 2 is a graph showing the influence of the amount of Si + Al in the skin layer and the core layer on the magnetic flux density of the clad material and its limiting range. FIG. 3 is a graph showing the influence of the amount of Si + Al in the skin layer and the core layer on the iron loss of the clad material and its limiting range. Fig. 4 shows the skin layer and core layer of Si +
3 is a graph showing a limited range of the present invention regarding Al. FIGS. 5 (a) and 5 (b) and FIGS. 6 (a) and 6 (b) are graphs showing the influence of the clad ratio on the magnetic properties of the clad material and its limited range.

Claims (1)

[Claims] 1. A clad type non-oriented electrical steel sheet having a three-layer structure consisting of a skin layer, a core layer and a skin layer in the thickness direction, wherein the chemical composition of the skin layer and the core layer is% by weight, and C: 0. .
0050% or less, Si: 0.7 to 3.4%, Mn: 0.1 to 1.0%, P: 0.15%
Below, S: 0.015% or less, Al: 0.1 to 1.0%, N: 0.0050% or less, and the Si content and Al content of the skin layer and the Si content of the core layer
Amount and Al amount are [Si] + [Al] ≦ 3.5% [Si] + [Al] ≧ 1.7% ([Si] + [Al]) − ([Si] + [Al]) ≧ 0.5% , [Si]: Si content of the skin layer (wt%) [Al]: Al content of the skin layer (wt%) [Si]: Si content of the core layer (wt%) [Al]: Core layer Al content (wt%) is satisfied, the balance is Fe and unavoidable impurities, and the clad ratio R (%) is 5% ≤ R ≤ 30%, where R (%) = ([skin layer Sheet thickness] / [total sheet thickness]) × 100. A clad type non-oriented electrical steel sheet.