KR20080044600A - Two roll type apparatus for coating insulation film of non-oriented electrical steel sheet and coating method using it - Google Patents

Abstract

A two roll type apparatus for coating an insulation film of a non-oriented electrical steel sheet is provided to obtain a thick coating film with excellent coating quality while reducing damages of coating rolls at a line speed of about 300 to 400 mm/sec, and a coating method using the two roll type apparatus is provided. A two roll type apparatus for coating an insulation film of a non-oriented electrical steel sheet comprises: a fixed post(400) set up and fixed between a cooling zone(100) and a drying furnace(200) to which the strip moves such that an insulation coating is formed on the strip after decarburizing and annealing a strip(S); a lower lift(420) which is slantly fixed to the bottom face and supported through a lower connecting bar(410a) connected to the fixed post; an upper lift(450) which is connected to an upper portion of the fixed post and fixed by an upper connecting bar(410b) in a way that the upper lift has the same slope as the lower lift; upper and lower coating rolls(430,440) which are fixed to the upper and lower lifts, and which has a gap therebetween so that the strip passes through the gap; and nozzles(N) installed to an insulation coating solution onto upper and lower faces of the strip that is led in the upper and lower coating rolls.

Description

TWO ROLL TYPE APPARATUS FOR COATING INSULATION FILM OF NON-ORIENTED ELECTRICAL STEEL SHEET AND COATING METHOD USING IT}

1 is an exemplary view showing a conventional three roll type coating apparatus,

Figure 2 is an operating state showing the main portion of the coating apparatus shown in FIG.

Figure 3 is an illustration of a two roll type coating apparatus according to the present invention.

♧ description of the symbols for the main parts of the drawing ♧

400 .... Fixed post 420 .... Lower lift

430 .... Lower coating roll 440 .... Upper coating roll

450 .... Top Lift 460 ... Link

470 .... axis 480 .... operating cylinder

The present invention relates to a two-roll type insulating film coating apparatus of a non-oriented electrical steel sheet and a coating method using the same, and more particularly improved non-directional electrical coating to enable an excellent insulation coating coating with less damage to the coating roll It relates to a two-roll type insulating film coating apparatus of a steel sheet and a coating method using the same.

In general, the non-oriented electrical steel sheet used as iron cores for electric devices such as various motors, generators, safety devices, etc., is coated with an insulating coating on the surface of the sheet to minimize the power loss caused by eddy currents.

1 and 2 show a conventional three roll type coating apparatus 1 for coating an insulating film on an electrical steel bar, as shown, the three roll type coating apparatus 1 is composed of three rolls, respectively. , The upper roll 10 and the lower roll 20 having a symmetrical structure with each other.

The upper roll 10 and the lower roll 20 are installed on the stand 2 of the coating apparatus 1, the lower roll 20 can be elevated by the operation of the arm (3).

In addition, as shown in FIG. 2, the upper roll 10 includes the upper pick-up roll 11 and the coating liquid 4 picked up from the upper pick-up roll 11 to directly pick up the coating liquid 4 stored in the reservoir 14. It is supplied between the upper coating roll 13, the upper pick-up roll 11 and the upper coating roll 13 to be coated on the strip for electrical steel sheet (s) is supplied from the upper pick-up roll (11) to the upper coating roll (13) It consists of an upper transfer roll 12 to adjust the amount of the coating liquid (4) to be delivered. Typically, each roll is made of a cylindrical shape, the upper pick-up roll 11 and the upper coating roll 13 is made of a rubber material, the upper transfer roll 12 is made of a steel material.

Since the lower roll 20 has a symmetrical structure with the upper roll 10, the lower roll is not necessarily explained. However, the lower coating roll 23 is eccentrically disposed with respect to the upper coating roll 13 to reduce the load according to the load of the upper roll 10. Usually, the eccentric distance d is set to 2 to 5 mm.

On the other hand, the strip (s) is supported by the support roll 30 and drawn between the upper and lower rolls (10, 20), wherein the strip (s) at a predetermined angle with the support roll 30 at an angle It is called the inlet angle θ of the strip.

With reference to Figure 2 looks at the conventional electrical steel sheet insulation coating method using such a coating device.

Table 1 below shows the process conditions for each roll corresponding to a typical line speed of 200 to 250 mpm (mpm: travel per minute of the strip). Here, the circumferential speed ratio refers to a ratio (roll speed / line speed) of the roll speed to the line speed corresponding to the traveling speed of the strip s as a percentage (%).

Process conditions Upper and lower pickup roll Upper and Lower Transfer Roll Upper and Lower Coating Roll Diameter (mm) 200-220 240-260 250-280 Main Speed Ratio (%) 23-27 88-92 118-122 Rolling amount (kg) 115-125 95-105 95-105

On the other hand, when looking at the other process conditions, commonly used insulating coating solution is an organic and inorganic coating solution, specific gravity: 1.23 ~ 1.26, viscosity: 13 ~ 14cps, temperature: 24 ~ 34 ℃ conditions, the incoming strip (s ) Temperature is 28 ~ 40 ℃, strip entry angle is 3.0 ~ 4.5 °.

Under the above process conditions, the insulating coating solution was applied to the strip using a 1/2 reverse coating method in order to obtain the best coating thickness. Here, the 1/2 reverse coating method refers to the entire coating liquid 4 supplied to the coating rolls 13 and 23 while the coating rolls 13 and 23 are in sliding contact with each other in the direction in which the strips s travel. The rotational direction of the coating rolls 13 and 23 is determined so as to be delivered to the coating rolls, and the transfer rolls 12 and 22 rotate in the same direction as the coating rolls 13 and 23, while the entire amount of the coating liquid supplied is applied to the coating rolls 13. , 23, and the pickup rolls 11 and 21 rotate in the opposite directions to the transfer rolls 12 and 22 and transfer 1/2 of the coating liquid 4 picked up from the reservoir 14 to the transfer rolls. (12,22) is configured to be delivered to.

According to the 1/2 reverse coating method, when the amount of the coating liquid 4 picked up from the pickup rolls 11 and 21 is 1, 1/2 is transferred to the transfer rolls 12 and 22, and the coating is performed. The rolls 13 and 23 are also supplied with 1/2. Therefore, the coating roll is applied to the strip (s) about 1/2 of the coating liquid picked up by the pickup roll (11, 21).

However, despite the insulation coating at the highest circumferential ratio condition using the 1/2 reverse coating method as described above, the maximum thickness of the film that can be obtained after the insulation coating is only about 0.04 to 0.05 mils. There was a limit in obtaining the required thickness of 0.06 to 0.08 mils. In particular, the conventional thin film coating layer of about 0.04 ~ 0.05mils was not only the peeling phenomenon of the coating layer but also the appearance of the coating layer was often poor.

In addition, in the related art, there is a problem that the replacement cycle of the roll due to roll damage is short due to a high circumferential speed ratio of the coating roll.

In addition, the conventional line speed has been adjusted to 200 to 250mpm, and the improvement of the two-roll type coating technology to enable the thick film coating with excellent coating quality even at the line speed of 300 to 400mpm for the improvement of the production efficiency. It is required.

The present invention has been made in view of the above-mentioned problems in the prior art, which was created to solve this problem, while having no damage to the coating roll at a line speed of about 300 to 400 mm, the coating quality is excellent and the non-directional coating enables thick film coating. Its main purpose is to provide a two-roll type insulating film coating apparatus of electrical steel sheet and a coating method using the same.

The present invention provides a fixed post fixed between the cooling zone and the drying furnace to move the strip for insulation coating after decarburization, annealing, in order to achieve the above technical problem; A lower lift inclined to the bottom surface and supported by a lower connection bar connected to the fixed post; An upper lift connected to an upper end of the fixed post and fixed to have the same inclination as the lower lift by an upper connection bar; Upper and lower coating rolls fixed to the upper and lower lifts respectively and having a gap therebetween and a strip passing therebetween; It is characterized by providing a two-roll type insulating film coating apparatus of a non-oriented electrical steel sheet including a nozzle installed in the upper and lower strips of the strip to be introduced into the upper, lower coating rolls to apply an insulating coating liquid.

In this case, the upper lift is connected to one end of the shaft fixed to the upper end of the fixed post, it is also connected to the other end of the link and at the same time characterized in that it is installed to flow by the operating cylinder fixed to the upper connecting bar.

In addition, the upper and lower coating rolls are characterized by having a diameter of 300 ~ 350mm.

In addition, the present invention is to coat the insulation coating liquid to 0.08 ~ 0.20mils when the insulation coating by using a two-roll coating device on the surface of the strip for non-oriented electrical steel sheet which is decarburized, annealed and drawn after cold rolling, the insulation coating liquid specific gravity 1.18 ~ 1.24, 12 ~ 12.9cps of inorganic insulating coating liquid is used.The upper and lower coating rolls used for coating are set to 300 ~ 350mm in diameter, 90 ~ 100% in circumferential ratio, and 110 ~ 140kg. , Strip entry angle: 4 ~ 6 °, inclination angle with upper and lower coating rolls about vertical: 5 ~ 11 °, eccentricity between rolls: 2 roll type insulating film coating device of non-oriented electrical steel sheet coated By providing a coating method using the above another technical problem can be achieved.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

3 is an exemplary view of a coating apparatus according to the present invention.

First, referring to the coating apparatus according to the present invention, the coating apparatus of the present invention as shown in Figure 3 is installed on the path that the strip (s) is moved from the cooling zone 100 to the drying furnace 200 pass roll 300 Insulating coating liquid is applied to both surfaces of the strip (s) proceeding through the coating method is a direct injection through the nozzle (N) and a direct coating using two coating rolls.

This coating device includes a fixed post 400 installed on the bottom surface.

At this time, the fixing post 400 is fixed to the upper and lower connection bars (410a, 410b) at intervals from each other.

In addition, a lower lift 420 is fixed to the lower connection bar 410a, and an upper lift 450 is fixed to the upper connection bar 410b.

In addition, the upper and lower lifts 420 and 450 are provided with a lower coating roll 430 and an upper coating roll 440, respectively.

Here, the upper and lower coating rolls (430, 440) will be described later, but have an eccentricity of 2 ~ 8mm with each other, the shaft center is installed to be offset, for this purpose, the upper and lower lifts (420, 450) are installed to be inclined, the inclination angle It is preferable to maintain 5-11 degrees with respect to the vertical line.

In addition, in the case of the upper lift 450, a means for adjusting the inclination angle may be further provided, which may be achieved by the link 460 and the operation cylinder 480.

That is, the center of the link 460 is fixed to the upper end of the fixed post 400 by the shaft 470, and both ends thereof connect the rear end of the upper lift 450 and the front end of the operation cylinder 480, respectively, One end of the connection bar 410b may be formed in such a way as to fluidly connect the lower end of the operation cylinder 480.

Thus, if necessary, the position of the upper coating roll 440 can be changed according to the working conditions. This is because the coating liquid has a large amount of stagnation on the upper surface of the strip (s), and the coating thickness is easily dropped without being stagnant on the lower surface, thereby facilitating the coating thickness. To adjust it.

And, although not shown, it is preferable that the dropped coating liquid is stored in a separate coating liquid container and then reused.

Therefore, the coating liquid is applied to the surface of the strip (s) that is advanced by the gap between the surface and the upper and lower coating rolls (430, 440).

Next, the process conditions of each roll according to the present invention are summarized as follows.

 Item  Roll diameter (mm) Strip Entry Angle (Based on Horizontal Line) Tilt angle between the top and bottom coating rolls (vertical line) Eccentricity between upper and lower coating rolls (mm) 2-roll type insulation coating condition  300-350  4-6 °  5-11 °  2-8 °

The strip for non-oriented electrical steel sheet, which is decarburized and annealed and drawn after cold rolling, is insulated coated by a two-roll type coating method unlike the conventional method, and the rolling reduction amount between the upper and lower coating rolls (430, 440) is set at 110 to 140 kg. It is desirable to.

First, look at the reason for maintaining the diameter of the upper and lower coating rolls (430,440) to 300 ~ 350mm.

When the diameters of the upper and lower coating rolls 430 and 440 are 300 mm or less, the upper and lower coating rolls 430 and 440 are buried in order to maintain the thickness of the coating liquid applied to the strip s about 0.08 to 0.20 mils. The amount of insulation coating must be excessively applied, which causes the coating liquid to flow down or the drying force to be reduced, resulting in a rough surface of the coating.

In addition, when the diameter of the upper and lower coating rolls 430 and 440 is 350 mm or more, an excessive amount of the insulating coating solution is applied to the surface of the strip s.

Therefore, in this case, it is necessary to lower the peripheral speed ratio to 100% or less to reduce the thickness of the insulating coating solution applied to the surface of the strip s.

However, if the rotational speed of the coating roll is set lower than the traveling speed of the strip s, the surface of the coating roll is severely damaged (a phenomenon in which the surface of the coating roll is dragged without being linked with the speed of the strip, resulting from excessive friction between the strip and the roll contact portion. Premature damage to the roll surface) occurs.

Next, look at the reasons for limiting the strip entry angle (horizontal basis) to 4-6 degrees.

When the strip entry angle (horizontal line reference) is set to 4 degrees or less, the force applied by the strip s is excessive, resulting in premature damage as well as roughening of the coating surface due to overloading the lower coating roll 430, resulting in thickness variation between the upper and lower portions. .

When the strip entry angle (horizontal line reference) is 6 degrees or more, fine scratches occur due to poor contact between the strip and the pass roll 300, and thickness deviations occur on the upper and lower coating surfaces.

When the inclination angle (vertical line reference) between the upper and lower coating rolls 430 and 440 is set to 5 degrees or less, the center of the upper and lower coating rolls 430 and 440 is closer to the vertical line, and the pressure is applied to the upper and lower coating rolls 430 and 440. It is unsuitable because the force is increased so that the friction force with the strip is increased and the coating layer is formed unevenly.

On the other hand, when the inclination angle (vertical line reference) between the upper and lower coating rolls (430, 440) is set to 11 degrees or more, the center line between the upper and lower coating rolls (430, 440) coincides with the force applied to the lower coating roll (430) too much. The coating layer is uneven due to the strip (s) and the slip, and the surface coating of the lower coating roll 430 is excessive, causing a problem of having to replace the coating roll early.

In addition, when the eccentricity (mm) between the upper and lower coating rolls (430, 440) is set to 2 mm or less, the center of gravity of the upper and lower coating rolls (430, 440) is coincident with the pressure applied to the lower coating roll (430) to increase the roll surface. In addition to damage, the lower coating layer of the strip becomes rough, whereas when the eccentricity (mm) between the upper and lower coating rolls (430, 440) is 8 mm or more, the strip (s) due to excessive separation of the center of gravity between the upper and lower coating rolls (430, 440). ) An uneven insulation coating layer applied to upper and lower surfaces is caused.

Therefore, it is desirable to design appropriately for the conditions described above.

Hereinafter, exemplary embodiments will be described, and reference numerals will be omitted for convenience of description.

EXAMPLE

Insulation coating is C: 0.04 ~ 0.07wt%, Si: 2.5 ~ 4.0wt%, Mn: 0.5 ~ 0.25wt%, P: 0.03wt%, S: 0.02wt%, Al: 0.1wt%, N: 0.01wt Cold rolled strip for non-oriented electrical steel sheet (steel grade: PN23) composed of% residual Fe and other unavoidable impurities (steel grade: PN23) to a thickness of 0.5 mm, and the rolled strip was held for 2-4 minutes at a temperature of 860-1,100 ° C. After the decarburization and annealing, and then using a two-roll coating apparatus was carried out by the method of continuously applying an insulating coating liquid to the surface of the strip by a forward coating method.

In order to coat the insulation coating liquid at 0.08 to 0.20 mils at the line speed of 300 to 400mpm, the inorganic coating liquid is used as the inorganic coating liquid having a specific gravity of 1.18 to 1.24 and the viscosity of 12 to 12.9 cps. The upper and lower coating rolls have a diameter of 300 ~ 350mm, circumferential speed ratio: 90 ~ 100%, rolling reduction: 110 ~ 140kg, strip drawing angle: 4 ~ 6 degrees, inclination angle with upper and lower coating rolls about vertical: 5 ~ 11 degrees, eccentricity between rolls: 2 ~ 8mm In order to evaluate the quality of the coated insulating film, the film appearance, insulation, adhesion, corrosion resistance, weldability, and weldability after stress relief annealing were compared to evaluate the quality of the coated insulation film. The comparison method is as follows.

That is, Stress Relief Annealing (SRA) was heat-treated at 750 ° C. for 2 hours in a dry 100% N ₂ gas atmosphere.

At this time, the surface appearance was evaluated by visual observation of stains, streaks, and the like, and the film appearance was evaluated as good as there were no stains and streaks.

Insulation is evaluated by the storage current value (Amps) when the current is input through 0.5V, 1.0A under 300psi pressure, but in the case of SAR, 0.10 ~ 0.14Amps is good, about 0.14 ~ 0.90Amps. It was determined that the surface was defective, and in the case of SAR after 0.40 Amps or less, it was considered good, and when it was above 0.14 Amps.

In addition, the adhesiveness (mmφ) is evaluated as the minimum arc diameter without film peeling when the specimen is annealed 180 ° by bending around an annular bar having an arc of 10, 20, 30 to 100 mmφ after annealing, but is peeled off at 20 mm when peeled at 10 mm. When it is usually, when peeling at 30 ~ 100mm was judged as bad. Corrosion resistance was observed by visual observation with the presence of rust on the surface of the film when left indoors for 1 year and exposed outdoors for 3 months.

The weldability and appearance are shown in the weld bead after TIG welding (welding current: 150A, electrode: pure-W (3.2 mmφ), electrode gap: 0.35 mm, welding speed: 15 mm / sec). Hole formation was evaluated by visual observation.

Finally, the film peeling was judged by the presence or absence of adhesion of the film peeling powder which appeared when the adhesive tape (polypropylene) was attached to the film after the stress relief annealing.

As a result of the experiment, under the same rolling reduction conditions, the diameter of the upper and lower pick-up rolls was 300 to 350 mm, the circumferential speed ratio was 15 to 22%, the diameter of the upper and lower transfer rolls was 360 to 410 mm, and the peripheral speed ratio was 80 to 87%. When the diameter of the upper and lower coating rolls was 390 to 420 mm and the peripheral speed ratio was 100 to 110%, the quality of the insulating coating layer was excellent.

That is, as can be seen in Table 3 below, the appearance of the insulation coating, insulation, corrosion resistance, weldability was found to be excellent, the peeling phenomenon or insulation of the film after the stress relief annealing was found to hardly decrease.

 division  Before stress relief annealing  After stress relief annealing  Outer appearance Insulation (Amps) Adhesiveness (mmφ) Corrosion resistance  Weldability Film peeling phenomenon Insulation (Amps) inside Outdoor  quality  Good  0.1-0.13  10  Good  Good  Good  none  0.1-0.3

As described in detail above, the present invention is less damage of the coating roll even at a line speed of about 300 ~ 350mpm and minimizes the damage of the coating roll surface portion and minimizes the damage to the coating roll surface, the production failure due to the early replacement of the coating roll It saves time and improves the coating process.

Claims (4)

A fixed post 400 which is fixed between the cooling zone 100 and the drying furnace 200 to which the strip s moves after the decarburization and annealing are coated; A lower lift 420 fixed to the bottom surface and supported by a lower connection bar 410a connected to the fixed post 400; An upper lift 450 connected to an upper end of the fixed post 400 and fixed to have the same inclination as the lower lift 420 by an upper connection bar 410b; Upper and lower coating rolls 430 and 440 fixed to the upper and lower lifts 420 and 450 and having a gap therebetween and a strip s passed therebetween; 2-roll type insulation of the non-oriented electrical steel sheet characterized in that it comprises a nozzle (N) is installed to apply an insulating coating liquid to the upper and lower surfaces of the strip (s) drawn into the upper and lower coating rolls (430,440) Film coating equipment. The method according to claim 1; The upper lift 450 is connected to one end of the link 460 fixed to the shaft 470 at the upper end of the fixed post 400, and is connected to the other end of the link 460 and the upper connection bar 410b. 2 roll type insulating film coating apparatus of the non-oriented electrical steel sheet, characterized in that the flow is installed by the working cylinder 480 fixed to. The method according to claim 1 or 2; The upper and lower coating rolls (430, 440) is a two-roll type insulating coating device of a non-oriented electrical steel sheet, characterized in that having a diameter of 300 ~ 350mm. In order to coat the insulation coating liquid with 0.08 to 0.20 mils when the insulation coating is carried out by using a two-roll coating apparatus on the surface of the strip for non-oriented electrical steel sheet which is decarburized, annealed and drawn after cold rolling, Insulating coating liquid uses inorganic insulating coating liquid having a specific gravity of 1.18 to 1.24 and viscosity of 12 to 12.9 cps. Upper and lower coating rolls used for coating are set to diameter: 300 ~ 350mm, circumferential speed ratio: 90 ~ 100%, rolling reduction: 110 ~ 140kg, Strip inlet angle: 4 ~ 6 °, inclination angle with upper and lower coating rolls about vertical: 5 ~ 11 °, eccentricity between rolls: 2 roll type insulation of non-oriented electrical steel, characterized in that coating is set to Coating method using film coating device.

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