JP6740972B2 - Blade, deposit removing device including the blade, and molten metal plating device including the same - Google Patents

Description

The present invention relates to a blade, a deposit removing device including the blade, and a molten metal plating device including the blade.

Continuous hot-dip galvanizing of steel strips, which is a typical example of hot-dip galvanizing of metal strips, is generally performed by the following method.
FIG. 5: is a schematic block diagram of the hot dip galvanizing tank of a continuous hot dip galvanizing line. As shown in FIG. 5, the steel strip 1 is, if necessary, annealed or the like, and then continuously fed into the hot dip galvanizing bath in the plating tank 3 through the snout 2 so as to The sink roll 4 soaked in is converted to the upward direction, the support rolls 5a and 5b in the bath correct the warp and the position of the pass line, and then it is sent out of the bath. The steel strip 1 to which the plating is attached is sent out of the bath, and the amount of the coating attached is adjusted by a wiping nozzle or the like, and the plated layer is alloyed if necessary to obtain a product.

In such a hot dip galvanizing bath, impurities suspended in the plating bath are sink rolls 4 and support rolls 5a, 5b, that is, rolls arranged by being dipped in the plating bath (hereinafter referred to as "bath roll"). (Also referred to as "."), the adhered impurities are transferred to the steel strip 1 in contact with the sink roll 4 and the support rolls 5a and 5b, and defects such as flaws occur in the manufactured plated steel sheet.

Therefore, conventionally, the deposits adhered to the surface of the bath roll are removed by the deposit remover (wiper blade) to prevent the deposits from being transferred to the steel strip in contact with the bath roll. A technique for preventing the occurrence of defects in the plated steel sheet has been put into practical use.

As shown in FIG. 5, the deposit removing device of this type supports a blade 6 that comes into contact with the surface (outer peripheral surface) of the bath roll and scrapes off the deposit attached to the surface of the bath roll, and a blade 6 that supports the blade 6. The blade supporting member 7 and the elevating means (not shown) connected to the blade supporting member 7. Then, by applying a load to the blade 6 by the elevating means and pressing the blade 6 against the surface of the bath roll, it is configured to scrape off the deposits attached to the surface of the bath roll.

Patent Document 1 proposes an adhering matter removing device that improves the removability of the alloy layer adhering to the roll surface by providing a heating mechanism for forcibly heating the blade edge portion.

Japanese Utility Model Publication No. 4-127259

FIG. 6A is a sectional view showing the shape of a blade 30 which is an example of a conventional blade. As shown in FIG. 6( a ), the blade 30 has a tip portion 32 having a triangular cross-sectional shape that becomes narrower toward the tip.

The conventional blade 30 has a triangular shape with a pointed tip portion that comes into contact with the roll during bathing, and has a high ability to remove deposits at the start of use. However, as the passing amount of the steel strip increases or the usage period becomes longer, and the tip portion 32 is worn out as the tip portion 32 is brought into contact with the surface of the roll in the bath and abraded repeatedly (see FIG. b)), the contact area between the tip 32 and the bath roll increases.

When the contact area increases as described above, it is necessary to increase the load on the blade 30 in order to maintain the polishing ability of the blade 30. Therefore, it is necessary to control the contact surface pressure between the blade 30 and the in-bath roll, while taking into consideration the amount of steel strip threaded, the usage period of the blade 30, and the like. Further, when the load on the blade 30 is increased, the amount of polishing debris generated by abrasion of the tip portion 32 of the blade 30 is increased, and this polishing debris is transferred to the steel strip to cause harmful defects such as push defects. Leading to an increase.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a blade that can suppress a change in contact area even if the number of times of polishing a roll surface immersed in a molten metal bath increases. ..
In addition, in this specification, the cross-sectional shape of the blade means the shape of a cross-section perpendicular to the width direction of the blade (the length direction of the bath roll).

The features of the present invention for achieving such an object are as follows.
[1] A blade for removing a deposit adhered to the surface of a roll by contacting the tip with the surface of the roll immersed in a molten metal bath, wherein the shape of the tip is the width direction of the blade. A blade with a rectangular cross-section perpendicular to the blade.
[2] 100 kg of the following load, 0.002 kg / mm ² or more, has a contact area which is 0.003 kg / mm ² or less of the contact surface pressure, according to claim 1 blade.
[3] The blade according to [1] or [2], wherein the length of the blade in the width direction is longer than the body length of the roll.
[4] An adhering substance removing device equipped with the blade according to any one of the above [1] to [3] for removing adhering substances attached to the surface of a roll immersed in a molten metal bath.
[5] A molten metal plating apparatus including the deposit removing device according to [4].

According to the blade of the present invention, even if the number of times of polishing the surface of the roll immersed in the molten metal bath increases, the change in the contact area can be suppressed.
According to the blade of the present invention, the surface of the in-bath roll can be polished with a constant load from the start of use to the end of use.

FIG. 1 is a sectional view showing the shape of a blade according to an embodiment of the present invention. FIG. 2 is a front view of the blade shown in FIG. FIG. 3 is a sectional view showing the shape of the blade according to the embodiment of the present invention. FIG. 4 is a graph showing the relationship between the strip running length of the steel strip after polishing performed in the example and the detected number of polishing scraps detected. FIG. 5 is a schematic configuration diagram of a continuous hot-dip galvanizing line. FIG. 6 is a cross-sectional view showing the shape of an example of a conventional blade.

Hereinafter, an embodiment of a blade of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below.

In the present embodiment, a blade that removes deposits adhering to the surface of the roll immersed in the molten metal bath (molten metal plating bath) is assumed in the molten metal plating of the metal strip. More specifically, in continuous hot dip galvanizing, it is assumed that the blade removes deposits adhering to the surface of the sink roll immersed in the hot dip galvanizing bath.

FIG. 1 is a sectional view showing the shape of a blade 10 according to an embodiment of the present invention. Further, FIG. 2 is a front view of the blade 10.

As shown in FIG. 1, the tip portion (grinding portion) 12 of the blade 10 has a rectangular cross section.
As described above, in the present specification, the cross-sectional shape of the blade means the shape of a cross section perpendicular to the width direction of the blade (the body length direction of the bath roll). That is, the sectional view of the blade 10 shown in FIG. 1 corresponds to the sectional view taken along the line AA of the front view of the blade 10 in FIG.

The rear end of the blade 10 can be supported by a blade support member (not shown). The blade 10 is attached to the tip of a blade supporting member, and the blade supporting member is connected to an elevating means (not shown) to form an adhering substance removing device of the present invention. The blade supporting member and the elevating means are not particularly limited, and the same configurations as those of known publicly-known deposit removing devices can be adopted. For example, examples of the elevating means include a hydraulic cylinder and an air cylinder. Further, the molten metal plating apparatus of the present invention includes a molten metal bath and the above-mentioned deposit removing device.

When removing the deposits attached to the surface of the sink roll immersed in the molten metal bath using this deposit remover, the blade 10 attached to the tip by the elevating means of the deposit remover. The blade 10 is pressed against the surface (outer peripheral surface) of the sink roll to scrape off the deposits attached to the surface of the sink roll.

At this time, since the blade 10 has a rectangular cross-sectional shape at the tip portion 12, the number of times of polishing the surface of the sink roll immersed in the molten metal bath by pressing the tip surface of the tip portion 12 increases. However, the change in the contact area can be suppressed. Then, from the start of use to the end of use, the surface of the sink roll can be polished with a constant load.

Here, the contact surface pressure (polishing pressure) between the blade 10 and the sink roll is determined by the load (polishing load) applied to the blade 10 and the contact area between the sink roll. When the contact surface pressure is too high, the amount of wear of the blade 10 increases, the life of the blade 10 decreases, and the number of polishing scraps increases, so that harmful defects increase. On the other hand, if the contact surface pressure is too low, the polishing ability is lowered and the adhered substances cannot be sufficiently removed. Therefore, the contact surface pressure has an optimum range.

In this embodiment, the tip 12 of the blade 10, the contact area with the sink roll, the following load 100 kg, 0.002 kg / mm ² or more, it can achieve the 0.003 kg / mm ² or less of the contact surface pressure It is preferable that As a result, the polishing ability for the sink roll can be maintained, and the generation of polishing debris caused by the abrasion of the blade 10 can be suppressed better. Since the blade 10 has a rectangular cross-sectional shape at the tip portion 12, it is easy to maintain the contact surface pressure from the start of use to the end of use.

Further, in the present embodiment, the length L (see FIG. 1) of the tip portion 12 of the blade 10 is preferably 25 to 100 mm from the viewpoint of maintaining good strength and life of the blade 10. Further, the thickness T of the tip portion 12 of the blade 10 needs to be a certain thickness or more in order not to be deformed or destroyed by the force received from the sink roll during polishing. In the present embodiment, the thickness T of the tip portion 12 of the blade 10 is preferably 12 to 28 mm from the viewpoint of suppressing such deformation and destruction and maintaining the contact surface pressure within a favorable range. ..

The width W of the blade 10 in the width direction (see FIG. 2) can be determined according to the body length of the sink roll and the like. In the present embodiment, the widthwise length W is preferably longer than the body length of the sink roll. Specifically, the length W in the width direction is preferably 20 mm or more longer than the body length of the sink roll. When the tip 12 of the blade 10 is brought into contact with the surface of the sink roll to polish the surface of the sink roll, both ends in the width direction of the blade 10 are outside by 10 mm or more from both ends in the trunk length direction of the sink roll. It is preferable that the tip end portion 12 of the blade 10 is brought into contact with the surface of the sink roll in the state of being located at. As a result, it is possible to prevent uneven polishing of the sink roll in the cylinder length direction, and it is possible to maintain a satisfactory polishing ability over the entire width of the sink roll from the start of use to the end of use.

The blade 10 is preferably made of stainless steel.

In addition, in the said embodiment, although the aspect which removes the deposit adhered to the surface of the sink roll immersed in the hot dip galvanizing bath with the blade 10, it is not limited to this and the blade of this invention is assumed. Is also useful for removing deposits adhering to the surface of other rolls immersed in a molten metal bath such as a support roll.

In this example, the blade 20 having the cross-sectional shape shown in FIG. 3 was used to remove the deposits adhering to the surface of the sink roll immersed in the hot-dip galvanizing bath in the continuous hot-dip galvanizing line.

As shown in FIG. 3, the blade 20 according to this embodiment has a tip portion (grinding portion) 22 of the blade 20, a base body 24 of the blade, and a thickness gradually increasing from the tip portion 22 toward the base body 24. And the stepped portion R5. Since the blade 20 has the step portion, stress concentration can be avoided and strength can be secured.

The base body 24 of the blade has a length of 80 mm and a thickness of 50 mm. The tip portion 22 of the blade 20 has a rectangular cross section, and has a length of 30 mm and a thickness of 16 mm. The length of the blade 20 in the width direction is 100 mm longer than the body length of the sink roll.

The rear end of the blade 20 is supported by a blade supporting member (not shown), and the blade supporting member is connected to an air cylinder (not shown) to form an adhering matter removing device. The load applied to the blade 20 (contact surface pressure between the blade 20 and the sink roll) can be adjusted by the air cylinder.

Using the deposit removing device equipped with this blade 20, the tip 22 of the blade 20 was brought into contact with the surface of the sink roll, and the sink roll surface was polished to remove the deposit attached to the surface of the sink roll.

The polishing was performed by applying a load of 100 kg to the blade 20. The contact surface pressure at that time was 0.0028 kg/mm ² . Further, the polishing was performed by bringing the tip end portion 22 of the blade 20 into contact with the surface of the sink roll so that both ends of the blade 20 were located 50 mm outside of both ends of the sink roll in the body length direction. The results are shown in Fig. 4 (Example).

In addition, the result of polishing the surface of the sink roll by changing the load to be applied within the range of 80 to 120 kg using a conventional blade having a triangular cross-section as shown in FIG. 4 (comparative example).

As shown in FIG. 4, when the surface of the sink roll is polished by the blade 20 according to the present embodiment, the area where the deposit is detected in the steel strip passed through the sink roll after polishing is 200 m of the steel strip. It was possible to suppress the area to less than (average of 11 times of polishing). On the other hand, when the surface of the sink roll was polished with the conventional blade having a triangular cross-sectional shape, the deposit was detected even in the area of 200 m or more of the steel strip.

Further, the average polishing length per time was 1100 m/cycle when the blade 20 of the present example was used, whereas it was 1300 m/cycle when the conventional blade having a triangular cross-sectional shape was used. there were. Here, the polishing length is the length of the steel strip that has passed while pressing the blade 20 against the surface of the sink roll. In the conventional blade having a triangular cross-sectional shape, the polishing power decreases as the period of use increases, and the polishing length required to remove the deposits increases, so the average polishing length increases. On the other hand, with the blade 20 of the present embodiment, the average polishing length could be shortened because polishing was possible with a constant surface pressure regardless of the period of use.

Furthermore, when the amount of wear of the blade after 25 days from the start of use (the length worn from the lower end of the blade before the start of use) was measured, it was 19 mm when the blade 20 of the present example was used. On the other hand, the blade having a conventional triangular cross-sectional shape has a length of 25 mm.

From this, by using the blade 20 of the present embodiment, even if the number of polishing is increased, the change of the contact area can be suppressed, the contact surface pressure can be favorably maintained under a constant load, and the impurities adhered to the sink roll can be removed. It can be seen that the blade 20 can be properly removed, the generation of polishing dust on the blade 20 can be appropriately suppressed, and the transfer of these to the steel strip can be properly suppressed. Further, the blade 20 of the present embodiment has a long life, can reduce the number of times of replacement, and is excellent in economic efficiency.

1 Steel Strip 2 Snout 3 Plating Tank 4 Sink Roll 5a, 5b Support Roll 6, 10, 20, 30 Blade 7 Blade Support Member 12, 22, 32 Blade Tip Part

Claims (5)

A surface of a roll immersed in a molten metal bath, a blade for contacting the tip to remove deposits attached to the surface of the roll,
A tip portion, a base body, and a step portion whose thickness gradually increases from the tip portion toward the base body in a cross section perpendicular to the width direction of the blade,
A blade in which the shape of the tip portion is a rectangle in a sectional shape perpendicular to the width direction of the blade. The following load 100 kg, 0.002 kg / mm ² or more, has a contact area which is 0.003 kg / mm ² or less of the contact surface pressure, blade according to claim 1. The blade according to claim 1, wherein the length of the blade in the width direction is longer than the body length of the roll. An adhering substance removing device, comprising the blade according to any one of claims 1 to 3, for removing an adhering substance adhering to the surface of a roll immersed in a molten metal bath. A molten metal plating apparatus comprising the deposit removing device according to claim 4.

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