JPH01315104A - Electromagnetic steel plate with excellent self-caulking property - Google Patents

Abstract

PURPOSE:To enhance a self-caulking property of a steel-plate laminate by keeping a sulfur content in an electromagnetic steel plate as small as 0.01wt.% or smaller. CONSTITUTION:A surfur content in silicon steel is set to be 0.01wt.% or lower. In this case, since surfur is contained, MnS existing in the steel has a property to increase an easy-to-slide characteristic of the steel; as a result, a uniting force of laminated steel plates is reduced. Although a silicon content is not regulated, it is kept necessarily to be 4% or smaller because a rolling operation is executed. By this setup, a self-caulking property of a steel-plate laminate can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an electrical la steel sheet with improved self-clamping properties.

BACKGROUND OF THE INVENTION Electrical steel sheets are used as materials for iron cores of electric motors and transformers. When using it, for example, iron cores for small electric motors,
It is made through the process of pressing → laminating → skew (rotor only) → bundling.

Conventionally, these steps have been performed individually.

However, with the development of press technology, these steps have recently come to be performed within one press.

The binding performed in this press is significantly different from previous methods.

That is, up until now, welding methods, methods of drilling holes in the iron core and caulking with pins, and methods of tightening with bolts have been used. On the other hand, a recently developed binding method performed in a press is called an automatic binding method. In this method, as shown in Figure 3, a dent (4) is provided in the steel plate for the core (3), and when the steel plate for the core (3) is laminated, the dent (4) is
They are stacked on top of each other and bound together by the friction of the recessed walls.

The iron core built into the electric motor must have enough binding force to prevent it from disintegrating when photographed while the motor is running, and in the automatic tying method, it must be tied so that a binding force of 8hf/m% or more is usually obtained. It won't happen.

Problems to be Solved by the Invention As mentioned above, laminates such as iron cores laminated by the automatic interlocking method are required to have a cohesive strength that does not easily disintegrate.

In response to these demands, this invention has been developed based on the results of research into the material of steel sheets and the insulation coating applied to their surfaces in order to obtain excellent self-clamping properties. The present invention provides electromagnetic steel sheets that can be used.

That is, as a result of investigating the relationship between the chemical composition of a steel sheet and self-locking properties, the inventor found that in order to obtain good self-locking properties, the sulfur content in the silicon steel should be reduced. Furthermore, it is known that a thin film is preferable for the insulating film in terms of self-sealability. However, the insulating film is usually applied using a roll coater, and conventionally, in order to form a uniform film thickness, a thickness of 0.5 to 1.0 μm was usually used. Therefore, with conventional methods, it has not been possible to industrially reduce the thickness to 0.511 m or less.

However, since the applicant has developed an online film thickness meter,
The film thickness can be adjusted online to make it uniform during thin film formation, making it possible to form thin films industrially and uniformly.

Means for Solving the Problems In order to achieve the above object, the electric vi1 steel sheet of the present invention has the following features:
Electrical steel sheets with a sulfur content of 0.01 wt% or less in silicon steel, electrical steel sheets with an insulating coating of 0.3 m or less in thickness formed on the surface of the silicon steel sheet, and 0.01 wt% or less sulfur content.
．． 0.01 wt% or less on the surface of a silicon steel plate with a thickness of 0.01 wt% or less.
Made of electric V71 steel plate with an insulating coating of 3 μm or less.

In this invention, the reason why the sulfur content is limited is as follows. That is, the 11nS present in the steel due to sulfur content has a sandy quality that increases the slippage of the steel, and reduces the cohesive force of the laminated steel plate.

As a result of experiments, it was found that if more than 0.01 wt% of sulfur was contained, sufficient cohesive force could not be obtained, so 0.01 wt% was added.
The following was made. Although silicon content is not regulated,
Due to rolling, it is inevitably kept below 4%.

In addition, the insulating coating is made of one or more emulsions of acrylic resin, phenol resin, polystyrene resin, vinyl acetate resin, silicone resin, etc. as organic substances, and chromate, phosphate, etc. as inorganic substances. A composite coating material consisting of one or more types of colloidal silica, alkaline earth metal salts, etc. is used.

When a film is formed using this composite coating material, since it contains resin as an organic component, the frictional force of the steel plate is reduced due to the lubricating action of the resin. This lubrication effect is related to the thickness of the coating; the thicker the coating, the better the lubrication. Therefore, in order to improve the cohesive strength of laminated steel plates, the thinner the coating is, the better. According to experiments, it has been found that sufficient cohesive force can be obtained by using a thin film with a thickness of 0.3 terms or less.

Furthermore, by making the insulating coating thinner, the amount of gas generated due to resin decomposition during welding is reduced, and the occurrence of blowholes within the weld bead is reduced. Therefore, bundling by welding becomes easy.

Examples Example 1 A composite coating material (consisting of chromic acid, acrylic resin, magnesium hydroxide, and aluminum hydroxide) was applied to the surface of an electrical steel sheet containing 0.5 wt% SL and 014 wt% SO to form a film. An insulating film with a thickness of O13, am was formed.

This electromagnetic steel sheet was slit to a width of 90++vr+ to form a hoop, and then a plurality of motor cores (1) having the shape shown in FIG. 1 were stacked and pressed automatically using a 200 ton press.

The depression (2) at this time has a round V shape as shown in FIG. Then, the cohesive strength after pressing was measured by the wedge method. This wedge method involves pushing a wedge between bound cores and expressing the pushing force when the cores are unbound.

On the other hand, in order to examine weldability, a stacked core without automatic interlocking was made and evaluated using TIG welding at the maximum welding speed at which blowholes do not occur. Also, the interlayer insulation resistance is JI
Measured by SC2550 (1986).

The above test results are shown in Table 1 together with the results of Examples 2 to 4 below.

The above is a comparative example of an electromagnetic steel sheet with an S content exceeding 0.010 wt%, but the cohesive strength is poor despite the thin insulation coating of 0.3 Am.

Example 2 An insulating coating having a film thickness of about 3 m was formed in the same manner as in Example 1 on an electrical steel sheet containing 5 wt% of SLo and 0.004 wt% of S. Then, a test was conducted in the same manner as in Example 1.

The results are shown in Table 1. From this result, it can be seen that just by reducing the S content, the cohesive strength was increased by four times compared to Example 1, and the self-locking property was excellent.

Example 3 An insulating film having a thickness of 0.5 Aim was formed in the same manner as in Example 1 on an electrical steel sheet containing 2 wt% of SiO and 0.08 wt% of S2O. Then, a test was conducted in the same manner as in Example 1.

The results are shown in Table 1. In this example, the insulation coating is 0.
This is a comparative example in which the film thickness exceeds 3 μm, and it can be seen that the cohesive force is low and the self-locking property is poor in this case as well.

Example 4 An insulating coating having a thickness of 0.2 terms was formed in the same manner as in Example 1 on an electrical steel sheet containing 0.2 wt% SL and 0.008 wt% S. Then, a test was conducted in the same manner as in Example 1.

The results are shown in Table 1. From this result, even though the S content was the same as in Example 3, the insulating coating was 0.3.
It can be seen that the binding force is significantly improved and the self-locking property is excellent just by making the comb thinner than itzm.

Example 5 The cohesive strength of a sampled material (uncoated material) containing 0.5 wt% Si and 0.014 wt% S was investigated using an automatic clamp press. The results are shown in Table 1.

In this example, there is no insulating coating and the S content is 0,0.
This is a comparative example where the content exceeds 1 wt%, but the cohesive strength is extremely small. Note that since this material was not coated with an insulating coating, it was meaningless to measure the weldability interlayer resistance, so it was not carried out.

Example 6 The cohesive strength of the material (uncoated material) containing SL O, 5 Wj% and S 0.004 wt% was investigated using an automatic clamp press in the same manner as in Example 5. The results are shown in Table 1. .

This embodiment is based on claim 1, but the binding force is 1
It can be seen that f/- of 5 is good. This result shows that reducing sulfur in steel is extremely effective for improving self-lockability.

Effects of the Invention The present invention can significantly improve the automatic locking properties of laminated steel sheets simply by keeping the sulfur content of the electromagnetic steel sheets low. Also,
By making the insulation coating thinner on the surface of the steel plate, excellent self-locking properties can be obtained. As a result, a strongly bound steel plate laminate can be obtained using the automatic clamping method, which is the simplest of the binding methods.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a motor core according to the embodiment of the present invention;
Figure 2 shows an enlarged view of the indentation of the self-locking part, Figure A is a plan view, Figure B is a cross-sectional view, and Figure 3 is a cross-sectional view showing the caulked part of electromagnetic steel sheets laminated by the self-locking method. be. 1...Motor core 2...Dent applicant Sumitomo Metal Industries Co., Ltd. agent Patent attorney Yoshihisa Oshida

Claims (1)

[Scope of Claims] 1. An electrical steel sheet with excellent self-locking properties in which the sulfur content in silicon steel is 0.01 wt% or less. 2. An electromagnetic steel sheet with excellent self-clamping properties, in which an insulating coating with a thickness of 0.3 μm or less is formed on the surface of a silicon steel sheet. 3. An electromagnetic steel sheet with excellent self-clampability, which has an insulating coating with a thickness of 0.3 μm or less formed on the surface of a silicon steel sheet with a sulfur content of 0.01 wt% or less.