JPH0459926A - Magnetic characteristic improving device for grain oriented electrical steel sheet - Google Patents

Abstract

PURPOSE:To form compressive linear strains which have an effect of forming finer magnetic domains over a long period of time without wearing projecting teeth by instantaneously applying a compressive force to the grain oriented electrical steel sheet by means of a press provided with the projecting teeth having specific shape. CONSTITUTION:The press teeth provided to face receiving bases provided on both sides of a pass line are advanced and retreated to apply the compressive linear strains at spaced intervals to the grain oriented electrical steel sheet, by which the iron loss is decreased. The press teeth to apply the compressive force to the grain oriented electrical steel sheet mentioned above are formed as the linear projecting teeth having 20 to 3O0mum radius part in the sectional shape of the tips thereof and having no angles. The compressive linear strains having the effect of forming the finer magnetic domains are formed over an extremely long period of time in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for forming minute compressive linear strains at intervals on the surface of a grain-oriented electrical steel sheet to improve magnetic properties.

[Prior Art] It is important for grain-oriented electrical steel sheets to have low iron loss in response to the strong demand for energy-saving keys in electrical equipment such as transformers and electric motors.

As one method for improving iron loss characteristics, it is known to apply minute strains to the surface of a grain-oriented electrical steel sheet at intervals to subdivide the magnetic domains. For example, in Japanese Patent Publication No. 58-5968, microspheres are pressed onto the surface of a grain-oriented electrical steel sheet after finish annealing to form microstrains of 5 μ[[l or less] at intervals, subdividing the magnetic domains, and reducing iron loss. It is proposed to reduce the

It is known that it is effective to apply microstrain in a direction perpendicular to the rolling direction of a grain-oriented electrical steel sheet or in a direction at a predetermined angle to the rolling direction.

As an apparatus for industrially imparting linear minute strain to the surface of a grain-oriented electrical steel sheet, for example, Japanese Patent Application Laid-Open No. 60-96719 discloses a roll having minute protrusions made of a highly hard material arranged in a line in the axial direction. An apparatus has been proposed that uses a rotating roll to create minute dents on the surface of a grain-oriented electrical steel sheet. The rolls are installed in a continuous line as bridle rolls, deflector rolls, or dancer rolls to form minute dents in the grain-oriented electrical steel sheet being passed through.

According to Kone, the continuous formation of micro-strains at intervals in a grain-oriented electrical steel sheet is effective and effective.

By the way, when grain-oriented VA steel sheets are passed through a continuous line, it is difficult to uniformly form micro-strains across the entire width of the steel sheet using rolls due to fluctuations in steel sheet tension and the influence of the sheet shape. There is.

As a method for solving this problem, Japanese Patent Application Laid-open No. 1-156426 proposes to instantaneously apply compressive force to the Mi steel plate in the directional chamber to form a compressive linear strain using a press provided with protruding teeth. This may have the effect of making it difficult to be affected by tension fluctuations during steel sheet threading, and also having a large magnetic domain refining effect. We are thinking that a new crystal will be produced and played.

By the way, this press usually uses protruding teeth with a tip cross-sectional shape or a corner.In this case, since the hardness of the electromagnetic steel sheet in the direction +i is extremely high, the abrasion of the protruding teeth progresses relatively quickly.
It is necessary to reprocess the corner of the tip. Moreover, the recycling process increases costs and reduces productivity.

[Problems to be Solved by the Invention] The present invention aims to form compressive linear strain that produces a magnetic domain refining effect over a long period of time without wear of protruding teeth, while taking advantage of compressive linear strain formation by pressing. With the goal.

[Means for Solving the Problems] The present inventors have repeatedly conducted various experiments in order to create compressive linear strain over a long period of time that produces a magnetic domain refining effect. As a result, the compressive linear strain that produces the magnetic domain refining effect can be obtained even after long-term pressing, for example, over 600,000 times, and there is no need for regrinding, reducing costs and improving workability. It has been found that in order to make the teeth bend, it is sufficient to eliminate the corners at the tips of the press projection teeth and to make the cross-sectional shape of the tips of the teeth into a small radius shape.

The gist of the present invention is to advance and retreat press teeth provided opposite to pedestals provided across the sheet passing line, and to
! In a device that applies compressive linear strain to four plates at intervals to reduce iron loss, the cross-sectional shape of the tip of the press tooth that applies compressive force to the grain-oriented electrical steel plate is 20 to 300 um r. An apparatus for improving the magnetic properties of a grain-oriented electrical steel sheet characterized by linear protruding teeth without corners.

[Function] The present invention will be described in detail below based on one embodiment with reference to the drawings.

In FIG. 1, 1 is a press body. 2 is the mold,
In this embodiment, a plurality of protruding teeth 3 are provided at intervals and substantially perpendicular to the sheet passing direction. Reference numeral 4 denotes a press advancing/retracting drive device which moves the protruding teeth 3 forward and backward with respect to the grain-oriented electromagnetic steel sheet 5 at high speed, and is connected to the mold 2. Reference numeral 6 denotes a rolling force control device, which is used to apply a compressive linear strain to the grain-oriented electromagnetic steel sheet 5 with a predetermined load using protruding teeth 3, such as an oil FiE cylinder, a fluid cylinder such as a pneumatic cylinder, a high-rigidity spring, etc. or used. In this embodiment, the rolling force control device 6 is provided below the pedestal 7.

The inventors of the present invention have repeatedly conducted various experiments, and have discovered that the protrusion teeth 3 can be formed as follows in order to stably form compressive linear strain that produces a magnetic domain refining effect over a long period of time.

That is, the cross-sectional shape of the tooth tip 3-1 of the protruding tooth 3 shown in FIG. 2 has no corners and is made into a small radius shape, or the small radius r is the tooth tip l! as shown in FIG. 3. If the radius of the 'r surface becomes large, the press load will increase, and compressive linear strain that produces the magnetic domain refining effect cannot be obtained, so the radius is set to 300 um or less.

In this case, the press load to obtain the compressive linear strain may vary depending on the number of protruding teeth 3 and the load capacity of the press machine in addition to the small radius r, or the number of protruding teeth 3 may be changed according to the industrial In order to obtain a processing speed of, for example, 20 mpm, 15 or more sheets were used, and the load capacity of the press was set at a maximum load of 300 TON, which is generally available and capable of continuous press processing. .

On the other hand, if the small radius r becomes small and the tooth tip becomes very sharp,
As shown in FIG. 4, tooth chipping occurs after a small number of presses, so the radius needs to be 20 μm or more.

The direction of the protruding teeth 3 relative to the grain-oriented electrical steel sheet 5 is preferably 290 degrees to 45 degrees with respect to the rolling direction of the grain-oriented electrical steel sheet W1tI4. Also, the interval between the protruding teeth 3 is 1 mII+
It is desirable to set it to 30+n+n or less.

Further, according to the apparatus of the present invention, new crystalline grains are not generated in the subsequent annealing at the location where compressive linear strain has been formed.

[Example] (Example 1) Using the device of the present invention, using a protruding tooth with a tooth tip cross-sectional radius of 280 IJm, a compression wire was formed by pressing on a finish-sintered Si: 3.20% grain-oriented electrical steel sheet. Shape distortions were formed at 5 mm intervals in a direction perpendicular to the rolling direction. Thereafter, annealing was performed at 800° C. for 2 hours, and magnetic properties (core loss, magnetic flux density) were measured.

Up to the 800,000th press, the magnetic properties were as shown in Table 1 when compressive linear strain was formed in the press.

Table 1 (Example 2) Using the apparatus of the present invention provided with protruding teeth with a tooth tip cross-sectional radius of 30 um, a Si:3.30% grain-oriented electrical steel sheet before decarburization annealing was pressed 1 million times continuously. The compressive linear strain is 6mm.
They were formed at intervals in a direction perpendicular to the rolling direction. The specimens were then decarburized and annealed, coated with an annealing separator, finished annealed, and their magnetic properties were measured. The results are shown in Table 2.

Table 2, Figure 4 is a graph showing the cross-sectional radius of the protruding tooth tip and the number of presses until tooth chipping occurs.

1...Press body, 2...Mold, 3...Protrusion teeth,
4... Press advance/retreat drive device, 5... Grain-oriented electromagnetic steel sheet, 6... Rolling force control device, 7... cradle.

Claims (1)

[Claims] 1. In a device that reduces iron loss by moving press teeth provided opposite to pedestals provided across the sheet threading line back and forth to apply compressive linear strain to grain-oriented electrical steel sheets at intervals, An apparatus for improving the magnetic properties of a grain-oriented electrical steel sheet, characterized in that the cross-sectional shape of the tip of the press tooth that applies compressive force to the grain-oriented electrical steel sheet is a linear protruding tooth with an r-section of 20 to 300 μm and no corners.