JP2015151625A - wiping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove excessive molten metal from a surface of a steel strip without depending upon a gas jet flow.SOLUTION: There is provided a wiping device 1 which removes molten metal 5 from a surface of a steel strip 2 lifted from a molten metal bath 3. The wiping device 1 includes a solid wiper 7 made of metal having the same components with the molten metal 5. Excessive molten metal 5 can be removed from the surface of the steel strip 2 without using any gas jet flow by using the solid wiper 7. Further, the solid wiper 7 is made of the metal having the same components with the molten metal 5, so even when a surface layer part of the solid wiper 7 is molten and part of it sticks on the steel strip 2, the quality of the steel strip 2 is prevented from being spoiled.

Description

  The present invention relates to a wiping apparatus for removing excess molten metal from the surface of a steel strip pulled up from a molten metal bath.

  As equipment for continuously plating metal on a steel strip, a hot dipping equipment as shown in FIG. 8 is common. In the hot dipping equipment, after the steel strip 2 is continuously immersed in the molten metal bath 3, the direction is changed by the roll 4 in the bath installed in the molten metal bath 3 and is continuously pulled up from the molten metal bath 3. . A wiping device including a slit nozzle 6 is disposed in a portion after the steel strip 2 is pulled up from the molten metal bath 3. The slit nozzle 6 blows off the excess molten metal 5 adhering to the surface of the steel strip 2 by blowing a gas jet toward both surfaces of the steel strip 2, and the amount of molten metal adhering to the surface of the steel strip 2 is predetermined. Adjust to the value.

  In such a hot dipping facility, an improvement in the pulling speed of the steel strip 2 is required in order to improve productivity. When the pulling speed of the steel strip 2 is improved, the amount of the molten metal 5 adhering to the surface of the steel strip 2 at the position of the slit nozzle 6 increases, so that the gas jet blown by the slit nozzle 6 is made stronger. Therefore, it is necessary to blow off more molten metal 5. Further, for example, when it is desired to reduce the amount of molten metal deposited on the surface of the steel strip 2, that is, when it is desired to make the plating film thinner, it is necessary to increase the gas jet flow.

  However, when the gas jet is strengthened, the gas jet collides with the surface of the steel strip 2, or the gas jets on both surfaces of the steel strip 2 collide with each other outside the steel strip 2, thereby generating intense turbulence. When the molten metal 5 scattered from the surface of the steel strip 2 due to the turbulent flow adheres to the surface of the steel strip 2 at another portion, a splash flaw that is one of plating defects is generated. For such a problem, for example, Patent Document 1 proposes a technique related to installation of a shielding plate that prevents gas jets from colliding with each other outside the steel strip 2.

JP 2001-049417 A

  However, when the gas jet becomes stronger with an increase in the pulling speed of the steel strip 2, the technique described in the cited document 1 is not necessarily sufficient to suppress the turbulent flow, and as a result, splash soot is generated. There was a case.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to remove excess molten metal from the surface of the steel strip without depending on the gas jet, A new and improved wiping device is provided.

  In order to solve the above problems, according to one aspect of the present invention, a wiping device for removing molten metal from the surface of a steel strip pulled up from a molten metal bath is provided. The wiping device includes a solid wiper formed of a metal having the same component as the molten metal.

  The wiping device may further include a heater that heats the solid wiper. In addition, the above-described wiping device controls the pressing force when the solid wiper is pressed against the surface of the steel strip according to the sensor that detects the molten metal adhesion amount of the steel strip that has passed through the solid wiper and the molten metal adhesion amount. And a control means for performing the above.

  The solid wiper is divided into a plurality of portions in the width direction of the steel strip, and the width of the solid wiper can be adjusted to be approximately the same as the width of the steel strip by adjusting the overlapping width of the plurality of portions. May be. The wiping device may further include a slit nozzle that blows a gas jet onto the surface of the steel strip that has passed through the solid wiper.

  By using a solid wiper, it is possible to remove excess molten metal from the surface of the steel strip without using a gas jet. Further, by forming the solid wiper with a metal having the same component as the molten metal, even if the surface layer portion of the solid wiper melts and adheres to the steel strip, it is possible to prevent the quality of the steel strip from being impaired.

  As described above, according to the present invention, excess molten metal can be removed from the surface of the steel strip without depending on the gas jet.

It is a side view of the continuous molten metal plating apparatus containing the wiping apparatus which concerns on the 1st Embodiment of this invention. It is a front view of the continuous molten metal plating apparatus shown in FIG. It is a side view of the continuous molten metal plating apparatus containing the wiping apparatus which concerns on the 2nd Embodiment of this invention. It is a front view of the continuous molten metal plating apparatus containing the wiping apparatus which concerns on the 3rd Embodiment of this invention. It is a front view of the modification of the continuous molten metal plating apparatus shown in FIG. It is a side view of the continuous molten metal plating apparatus containing the wiping apparatus which concerns on the 4th Embodiment of this invention. It is a side view of the continuous molten metal plating apparatus containing the wiping apparatus which concerns on the 5th Embodiment of this invention. It is a side view of the continuous molten metal plating apparatus containing the wiping apparatus which concerns on a prior art.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a side view of a continuous molten metal plating apparatus including a wiping apparatus according to this embodiment. FIG. 2 is a front view of the continuous molten metal plating apparatus shown in FIG.

  As shown in FIGS. 1 and 2, the wiping device 1 according to this embodiment is installed in a portion after the steel strip 2 is pulled up from the molten metal bath 3. The wiping device 1 includes a pair of solid wipers 7 disposed on both sides of the steel strip 2. The solid wiper 7 is pressed against the surface of the steel strip 2 with a predetermined pressing force by a pressing means 8 such as a cylinder, thereby scraping off and removing the excess molten metal 5 adhering to the surface of the steel strip 2. In the wiping device 1, the amount of molten metal deposited on the surface of the steel strip 2 is adjusted to a predetermined value by the action of the solid wiper 7.

  Here, the solid wiper 7 is formed of a metal having the same component as the molten metal bath 3 and the molten metal 5 (hereinafter also referred to as a plated metal). The surface temperature of the steel strip 2 that has passed through the molten metal bath 3 still exceeds the melting point of the plated metal even at the position of the solid wiper 7. Therefore, the solid wiper melts in the surface layer portion of the solid wiper 7 pressed against the surface of the steel strip 2, and a part thereof adheres to the steel strip 2. However, since the solid wiper has the same component as the molten metal 5, it is possible to prevent the quality of the steel strip 2 from being impaired due to adhesion.

  It should be noted that the thickness of the plating metal that melts at the surface layer portion of the solid wiper 7 is thinner than the thickness of the excess molten metal 5 that is scraped off by the solid wiper 7. That is, the solid wiper 7 is smoothed by pressing the surface of the steel strip 2 as a solid, scraping off the excessive molten metal 5 and slightly melting the plated metal on the surface layer portion. It also has the effect of becoming.

  When using a solid wiper, unlike the case of using a gas jet from a slit nozzle, it is possible to stably remove excess molten metal 5 without generating turbulent flow. However, in the solid wiper, unevenness is likely to occur on the molten metal 5 on the surface of the steel strip 2 after scraping, as compared with the case where a gas jet is used. Therefore, in the present embodiment, the solid wiper 7 is formed of a metal (plating metal) having the same component as the molten metal bath 3 or the molten metal 5, so that the excess molten metal 5 can be stably removed and scraped off. The unevenness generated in the molten metal 5 on the surface of the steel strip 2 is smoothed, and the quality and appearance uniformity can be improved.

(Additional configuration: heater)
Further, the wiping device 1 may include a heater 9 for heating the solid wiper 7. For example, the heater 9 may be an electric heater. In this case, the heater 9 may be attached to the surface of the solid wiper 7, and the temperature of the solid wiper 7 may be raised by heat directly transmitted. Further, the heater 9 may be attached to a frame (not shown) that supports the solid wiper 7, and the solid wiper 7 may be heated by radiation. Alternatively, the heater 9 may be a circuit for causing the solid wiper 7 to generate heat when energized.

  As described above, in the solid wiper 7, when pressed against the surface of the steel strip 2, the plating metal in the surface layer portion melts, and a part thereof adheres to the steel strip 2. However, when the original temperature of the solid wiper 7 is low and the temperature difference from the surface of the steel strip 2 is large, not only the plating metal does not melt at the surface layer portion of the solid wiper 7 but also the molten metal 5 on the surface of the steel strip 2. May adhere to the solid wiper 7 and solidify, causing irregularities in the molten metal 5 on the surface of the steel strip 2 and possibly deforming the solid wiper 7.

  Therefore, in the present embodiment, the temperature difference between the solid wiper 7 and the steel strip 2 is set within a predetermined range by installing the heater 9 and raising the temperature of the solid wiper 7 to an appropriate temperature below the melting point of the plating metal. Fit in. For example, when the ambient temperature of the wiping device 1 is high and the temperature difference from the steel strip 2 is small without raising the temperature of the solid wiper 7, the heater 9 may not be provided.

(Additional configuration: slit nozzle)
Further, the wiping device 1 may include a slit nozzle 6 provided in the subsequent stage of the solid wiper 7. The slit nozzle 6 blows a gas jet toward the surface of the steel strip 2. The slit nozzle 6 may be installed for the purpose of blowing off excess molten metal 5 that could not be removed by the solid wiper 7 by a gas jet, for example. Alternatively, the slit nozzle 6 may be installed for the purpose of further smoothing the unevenness generated in the molten metal 5 on the surface of the steel strip 2 after the excess molten metal 5 is removed by the solid wiper 7.

  That is, in the wiping apparatus 1, the slit nozzle 6 may be used as a molten metal adhesion amount adjusting means for removing excess molten metal 5 from the surface of the steel strip 2 together with the solid wiper 7, or the solid wiper 7 is excessive. It may be used as a smoothing means for smoothing the surface of the steel strip 2 after removing the molten metal 5. In any case, the gas jet blown by the slit nozzle 6 in the wiping device 1 may be weaker than the gas jet blown by the slit nozzle 6 installed in the conventional wiping device as shown in FIG. Therefore, in this embodiment, even when the slit nozzle 6 is installed in the wiping device 1, a splash flaw does not occur on the surface of the steel strip 2 due to the turbulent flow generated by the gas jet.

  As described above, in the first embodiment of the present invention, by using a wiping device including a solid wiper formed of a metal having the same component as the molten metal, the steel strip is not dependent on a gas jet. Excess molten metal can be removed from the surface. A slit nozzle may be added to the wiping device, and a gas jet may be sprayed for further adjustment of the amount of molten metal adhesion and smoothing of the surface of the steel strip, but in this case the gas jet is weaker than before. Therefore, the occurrence of defects such as splash wrinkles due to turbulent flow can be prevented.

  In addition, the wiping apparatus 1 which concerns on this embodiment is applicable, for example when using zinc, aluminum, etc. as a plating metal (molten metal).

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a side view of a continuous molten metal plating apparatus including the wiping apparatus according to the present embodiment.

  As shown in FIG. 3, in the present embodiment, a sensor 10 and a control unit 11 are additionally provided in the same wiping device 1 as in the first embodiment.

  The sensor 10 detects the molten metal adhesion amount of the steel strip 2 that has passed through the solid wiper 7 (and the slit nozzle 6). The sensor 10 may detect the molten metal adhesion amount using, for example, an on-line plating adhesion meter based on a general fluorescent X-ray method.

  The control means 11 is, for example, a controller or a computer, and the pressing means 8 presses the solid wiper 7 against the surface of the steel strip 2 according to the molten metal adhesion amount of the steel strip 2 detected by the sensor 10. Control the pressure. At this time, it is desirable that the control means 11 performs control so that the pressing means 8 on both sides of the steel strip 2 press the solid wiper 7 against the steel strip 2 with substantially equal pressing force. If the pressing force is different between the pressing means 8 on both sides, the steel strip 2 is pushed into one of the positions at the position of the solid wiper 7 and bent, so that the molten metal adhesion amount can be made uniform on both sides of the steel strip 2. This is because it becomes difficult.

  More specifically, for example, when the molten metal adhesion amount of the steel strip 2 detected by the sensor 10 is larger than a predetermined amount, the control means 11 increases the removal amount of the molten metal 5 by the solid wiper 7. Further, the pressing force of the solid wiper 7 by the pressing means 8 is increased. On the other hand, when the molten metal adhesion amount of the steel strip 2 detected by the sensor 10 is smaller than a predetermined amount, the control means 11 uses the pressing means 8 to reduce the removal amount of the molten metal 5 by the solid wiper 7. The pressing force of the solid wiper 7 is reduced.

  As described above, in the surface layer portion of the solid wiper 7 pressed against the surface of the steel strip 2, the plated metal is melted, and a part of the metal adheres to the steel strip 2. Therefore, as the operation in the continuous molten metal plating apparatus is continued, the solid wiper 7 is gradually scraped from the portion pressed against the steel strip 2 and its shape changes. Even if the pressing force by the pressing means 8 is constant, if the shape of the solid wiper 7 changes, the removal amount of the molten metal 5 by the solid wiper 7 varies. Therefore, in the present embodiment, the sensor 10 detects the amount of molten metal adhering to the surface of the steel strip 2, and the control unit 11 controls the pressing force of the pressing unit 8 based on the detected amount, thereby correcting the above fluctuation. The removal amount of the molten metal 5 by the solid wiper 7 can be kept at a predetermined value.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. 4 and FIG. FIG. 4 is a front view of a continuous molten metal plating apparatus including the wiping apparatus according to the present embodiment. FIG. 5 is a front view of a modification of the continuous molten metal plating apparatus shown in FIG.

  As shown in FIG. 4, in the present embodiment, in the wiping device 1 similar to the first embodiment, the solid wiper 7 is divided into a plurality of portions 7 a, 7 b, 7 c in the width direction of the steel strip 2. Yes. The portions 7a, 7b, and 7c partially overlap each other in the width direction of the steel strip 2, and cover the width direction of the steel strip 2 as a whole.

  In the illustrated example, of the three portions 7a, 7b, and 7c, the portion 7b is fixed, and the portions 7a and 7c can be moved by the moving means 12 such as a cylinder. The entire width of the solid wiper 7 can be increased by moving the portions 7a and 7c toward the outside in the width direction of the steel strip 2 and reducing the overlapping width with the portion 7b. Moreover, the whole width | variety of the solid wiper 7 can be narrowed by moving the parts 7a and 7c toward the width direction inner side of the steel strip 2, and enlarging the overlap width with the part 7b. Thus, in this embodiment, it is possible to adjust the width of the solid wiper 7 to be substantially the same as the width of the steel strip 2.

  As described above, as the operation in the continuous molten metal plating apparatus is continued, the solid wiper 7 is gradually scraped from the portion pressed against the steel strip 2 and its shape changes. If the width of the solid wiper 7 is larger than the width of the steel strip 2, a portion pressed against the steel strip 2 and a portion not applied to the surface of the solid wiper 7 are generated. In this case, the portion pressed against the steel strip 2 is gradually scraped, whereas the portion that is not so is hardly scraped, so that the shape of the solid wiper 7 is distorted. In this state, even if the steel strip 2 is made wider, it is difficult to uniformly remove excess molten metal 5 with the solid wiper 7. Therefore, in this embodiment, the solid wiper 7 is divided into a plurality of portions 7a, 7b, 7c, and the width of the solid wiper 7 is made substantially the same as the width of the steel strip 2 by adjusting the overlapping width of each portion. It is possible to adjust.

  The solid wiper 7 is not necessarily divided into three, and may be divided into two, or four or more. In the above example, the solid wiper 7 is divided in the wiping device 1 similar to the first embodiment. However, the solid wiper 7 can be divided similarly in the wiping device 1 similar to the second embodiment.

(Modification)
FIG. 5 shows a modification of this embodiment. As described in the first embodiment, the slit nozzle 6 is not necessarily provided in the wiping device 1 in the embodiment of the present invention. However, in this embodiment, since the solid wiper 7 is divided into a plurality of parts, the shape of the solid wiper 7 becomes discontinuous at the boundary of the divided parts, and the molten metal 5 on the surface of the steel strip 2 has irregularities. Prone to occur. Therefore, as in the example shown in FIG. 5, the slit nozzle 6 is installed at the subsequent stage of the solid wiper 7 within the range corresponding to the boundary of the portion where the solid wiper 7 is divided at least, and the molten metal 5 on the surface of the steel strip 2 It is desirable to smooth the unevenness.

  In addition, also when the slit nozzle 6 is provided in the whole width direction of the steel strip 2 as in the example shown in FIG. 4, the molten metal 5 on the surface of the steel strip 2 generated at the boundary of the portion where the solid wiper 7 is divided. The unevenness is smoothed. However, for example, in the case where the unevenness of the molten metal on the surface of the steel strip 2 is acceptable except at the boundary of the portion where the solid wiper 7 is divided, the slit nozzle 6 is not as shown in the example shown in FIG. By limiting the arrangement position to the boundary portion, the gas jet sprayed on the surface of the steel strip 2 can be further reduced.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a side view of a continuous molten metal plating apparatus including the wiping apparatus according to the present embodiment.

  As shown in FIG. 6, in this embodiment, in the wiping device 1 similar to the first embodiment, a plurality of sets of solid wipers 7p and 7q that can be replaced with each other and can be independently replaced are provided. Installed. In the illustrated example, the solid wiper 7 p is pressed against the surface of the steel strip 2 by the pressing means 8, and the excess molten metal 5 is removed from the surface of the steel strip 2. On the other hand, the solid wiper 7q is arranged away from the surface of the steel strip 2.

  As described above, as the operation in the continuous molten metal plating apparatus is continued, the solid wiper 7 is gradually scraped from the portion pressed against the surface of the steel strip 2 and its shape changes. As the change of the shape progresses, it becomes difficult to use the same solid wiper 7 continuously, and the solid wiper 7 needs to be replaced.

  Therefore, in the present embodiment, by installing a plurality of solid wipers 7p and 7q and using one as a spare, it is possible to continue the operation even when the solid wiper 7 is replaced. In the illustrated example, when the solid wiper 7p becomes difficult to use due to a change in shape, the solid wiper 7q is instead pressed against the surface of the steel strip 2 by the pressing means 8, and the solid wiper 7p is separated from the surface of the steel strip 2. It is. As described above, since the solid wipers 7p and 7q can be exchanged independently of each other, the solid wiper 7p can be exchanged for a new one while the solid wiper 7q is being used. Thereafter, when the solid wiper 7q becomes difficult to use due to a change in shape, the new solid wiper 7p is used instead. Thus, in this embodiment, operation can be continued semipermanently without interrupting the pulling of the steel strip 2.

  Three or more sets of solid wipers 7 may be installed. In this case, the operation can be continued for a long time without replacing the solid wiper 7. In the above example, a plurality of sets of solid wipers 7 are installed in the same wiping apparatus 1 as in the first embodiment. However, in the wiping apparatus 1 similar to that in the second or third embodiment, the solid wiper is used. Multiple sets of 7 may be installed.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a side view of a continuous molten metal plating apparatus including a wiping apparatus according to this embodiment.

  As shown in FIG. 7, in the present embodiment, in the wiping device 1 similar to the first embodiment, the solid wiper 7 has a downward slope from the steel strip 2 side toward the opposite side of the steel strip 2. Formed. Due to this gradient, excess molten metal 5 scraped off from the surface of the steel strip 2 by the solid wiper 7 flows down along the lower surface of the solid wiper 7 and is returned to the molten metal bath 3. In order to prevent the molten metal 5 from solidifying on the lower surface of the solid wiper 7, the temperature of the solid wiper 7 may be maintained at a temperature close to the melting point of the plating metal by the heater 9.

  Next, examples of the present invention will be described. In this example, the wiping device 1 according to the first embodiment described with reference to FIG. 1 is applied to the case where hot-dip zinc is continuously plated on a steel strip, and a steel strip pulling speed that can be realized and The amount of molten zinc deposited on the steel strip was verified. In the wiping device 1, a heater 9 and a slit nozzle 6 are installed. The temperature of the solid wiper 7 was kept at 300 to 350 ° C. by the heater 9. Further, the same verification was performed on the wiping apparatus according to the related art described with reference to FIG. In Examples 1 and 2 and Comparative Examples 1 to 3, the setting of the pulling speed, the amount of adhesion, and the flow velocity of the gas jet from the slit nozzle is as follows.

Of the pulling speed and deposition amount conditions shown in Table 1, the conditions of Comparative Example 1 (pulling speed 150 mpm, deposition amount 40 g / m ² ) are standard conditions in a hot dip galvanizing facility using a conventional wiping apparatus. is there. Therefore, in Comparative Example 1, even in a conventional wiping apparatus without a solid wiper, the flow velocity of the gas jet may be 140 m / s, and the steel strip could be galvanized without generating splash soot. In Example 1 in which the fixed wiper was used under the same conditions, the steel strip could be galvanized without generating splash wrinkles. In Example 1, since the solid wiper 7 was installed, the gas jet was not required.

  In Example 2, the steel strip pulling speed was increased from the conventional 150 mpm to 300 mpm. Even in this case, the wiping device 1 was able to galvanize the steel strip without using a gas jet and without generating splash soot. On the other hand, in Comparative Example 2 in which the same conditions were set, the flow velocity of the gas jet must be increased to 250 m / s as the molten metal adhering to the steel strip increases as the steel strip pulling speed increases. As a result, splash wrinkles occurred.

In Example 3, the amount of molten zinc deposited on the steel strip was reduced from the conventional 40 g / m ² to 20 g / m ² . Even in this case, the wiping device 1 was able to galvanize the steel strip without using a gas jet and without generating splash soot. On the other hand, in Comparative Example 3 in which similar conditions were set, in order to blow off more molten zinc, the flow rate of the gas jet had to be increased to 200 m / s, and as a result, splash soot was generated.

  From the examples and comparative examples described above, the embodiment of the present invention can improve the steel strip pulling speed or reduce the amount of molten metal deposited on the steel strip without causing defects such as splash wrinkles. It can be said that it was proved to be effective for

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Wiping apparatus 2 Steel strip 3 Molten metal bath 4 Roll in bath 5 Molten metal 6 Slit nozzle 7 Solid wiper 8 Pressing means 9 Heater 10 Sensor 11 Control means 12 Moving means

Claims (5)

A wiping device for removing molten metal from the surface of a steel strip pulled up from a molten metal bath,
A wiping apparatus comprising a solid wiper formed of a metal having the same component as the molten metal.   The wiping apparatus according to claim 1, further comprising a heater for heating the solid wiper. A sensor for detecting a molten metal adhesion amount of the steel strip that has passed through the solid wiper;
The wiping apparatus according to claim 1, further comprising: a control unit that controls a pressing force when the solid wiper is pressed against the surface of the steel strip in accordance with the molten metal adhesion amount. .   The solid wiper may be divided into a plurality of portions in the width direction of the steel strip, and the width of the solid wiper may be adjusted to be substantially the same as the width of the steel strip by adjusting the overlapping width of the plurality of portions. The wiping device according to any one of claims 1 to 3, wherein the wiping device is possible. The wiping apparatus according to claim 1, further comprising a slit nozzle that blows a gas jet on a surface of the steel strip that has passed through the solid wiper.

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