JP2622022B2 - Control device for strip adhesion - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the amount of adhered molten metal when continuously applying molten metal to a strip such as a steel strip.

2. Description of the Related Art In a typical prior art, a strip is wound around a sink roll which is immersed in a molten metal plating tank, and is guided upward. Above the plating tank, the amount of adhered deposit is controlled. For this purpose, wiping nozzle means for injecting gas is provided, and by adjusting the distance between the nozzle and the strip of the wiping nozzle means and the pressure of the gas blown out from the nozzle, the amount of adhered deposit is adjusted. When controlling the amount of adhesion, if the strip causes so-called canoeing and warps in a plane perpendicular to the longitudinal direction of the strip, the total adhesion of the front and rear surfaces of the strip is reduced in the width direction. Even if equal, on each surface
The deposition amount in the width direction has a different distribution in the width direction, which causes a problem in that the plating is peeled off during strip processing and a difference in corrosion resistance occurs. Thus, the distance between the nozzle of the wiping nozzle means and the strip is
Conventionally, a worker measures and a support roll provided downstream of a sink roll immersed in a plating tank is displaced so that the distance is uniform across the width of the strip. ing.

In such prior art, the working environment for measuring the distance between the nozzle of the wiping nozzle means and the strip is as follows.
It is extremely bad and dangerous, and the strip surface after the reflection is a mirror surface, so that it is difficult to measure the distance accurately with an optical distance measuring device, and furthermore, during such traveling. The above-mentioned strips vibrate with fluttering, and it is difficult to accurately measure the distance with a distance measuring device such as an electromagnetic type.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a strip adhesion control apparatus capable of accurately controlling the adhesion amount in the width direction of the strip.

Means for Solving the Problems The present invention relates to a plating tank in which molten metal to be plated is stored, a sink roll provided in the plating tank, and around which a strip is wound, and a sink roll in the plating tank. Immediately above the strip and downstream of the strip, the upper support roll contacting the same one surface as the strip contacting the sink roll, and the strip support between the sink roll and the upper support roll in the plating tank. A lower support roll provided in contact with the other surface so as to be displaceable toward the strip and away from the strip; a driving means for driving the lower support roll toward the strip and away from the strip; and A wiping nozzle hand that is located downstream of the strip in the running direction and injects gas from the nozzle to control the amount of adhesion A cooling means arranged downstream of the wiping nozzle means in the traveling direction of the strip to cool the strip, and a cooling means arranged downstream of the cooling means in the traveling direction of the strip to reduce the adhesion amount of the strip. Detecting means for detecting over the strip width direction; and, in response to the output of the detecting means, the ratio of the amount of adhesion on one surface of the strip to the total adhesion amount of the strip on the front and back surfaces in the width direction of the strip. One end, the center, and the other end are obtained, respectively, and the average value of the adhesion adhesion ratio at one end in the width direction of the strip and the adhesion adhesion ratio at the other end is obtained, and the width of the strip is obtained. A difference is obtained by subtracting the obtained average value from the attached adhesion ratio at the center in the direction, and the driving hand is set so that the difference becomes zero. Displaced driving the lower support roll control to the a plated coating weight of the control device of the strips, characterized in that it comprises a control means to equalize the plated deposition amount in the width direction of the strips.

According to the present invention, the molten metal to be plated, for example, zinc or aluminum, is stored in the plating tank. In the plated layer, the sink roll, the support roll, and the support roll are arranged in order from bottom to top. The support rolls are arranged in this order, and the strip to be attached is wound around a sink roll, the surface of the strip on the sink roll side is guided in contact with the upper support roll, and the other surface of the strip is the lower support. The lower support roll comes into contact with the roll, and the lower support roll can be displaced and driven by a driving means in a direction toward or away from the strip, and further, through the upper support roll, the strip after being mounted from the mounting tank is: The gas is jetted by the wiping nozzle means to control the adhered amount, and thereafter, the adhered amount is controlled by the detecting means. The control means is detected along the width direction of the strip, and the control means responds to the detection result of the adhesion amount in the width direction of the strip detected by the detection means, and strips the adhesion amount on one surface of the strip. The ratio of the total adhesion to the front and back surfaces is determined for one end, the center, and the other end in the width direction of the strip, respectively, and the ratio of the adhesion at one end in the width direction of the strip and the other end are determined. An average value of the adhered adhesion amount ratio is obtained, the average value thus obtained is subtracted from the adhered adherence amount ratio at the center in the width direction of the strip, and the difference between the nozzle of the wiping nozzle means and the strip is obtained as the subtracted value. By multiplying the interval, a distance in the thickness direction of the strip between both ends in the width direction of the strip and the central portion is calculated, and the calculated distance is calculated as follows. The driving means is controlled so as to be zero, and the lower support roll is driven for displacement. In this way, it is easy to make the amount of adhered deposition uniform across the width of the strip.

Embodiment FIG. 1 is an overall system diagram of an embodiment of the present invention.
Strip 1 of metal, for example, steel, passes through molten metal 3, for example, zinc or aluminum, stored in plating tank 2, and its surface is plated. Wiping nozzle means 4 controls the amount of deposition. Thereafter, the strip is cooled by the cooling means 5, the amount of sticking is detected by the detecting means 6 over the width direction of the strip 1, and the control means 7 responding to the output of the detecting means 6
Controls the driving means 8. The strip 1 is introduced into the plating tank 2 through a snout 9 and is wound around a sink roll 10 having a horizontal line. An upper support roll having a horizontal axis just above the sink roll 10 in the plating tank 2
11 are provided. In addition, the upper support roll 11 is located downstream of the strip sink roll 10, and
1 (the surface on the left side near the upper support roll 11 in FIG. 1). In the plating tank 2, a lower support roll 12 having a horizontal axis is disposed between the sink roll 10 and the upper support roll 11. The lower support roll 12 contacts the other surface of the strip 1 (the right surface near the lower support roll 12 in FIG. 1). The sink roll 10 and the upper support roll 11 are provided rotatably in the molten metal 3, and their various line positions are provided so as not to be displaced. The lower support roll 12 is provided so as to be rotatable around a horizontal axis, and is driven by a driving means 8 in a direction toward the strip 1 (to the left in FIG. 1) and in a direction away from the strip 1 (to the right in FIG. 1). It is provided so as to be displaceable.

The wiping nozzle means 4 described above is disposed downstream of the plating tank 2 in the traveling direction 13 of the strip 1. The wiping nozzle means 4 has elongated nozzles 4a and 4b in the width direction of the strip 1 for injecting gas such as air toward both front and back surfaces of the strip 1. The amount of adhesion of one is controlled. The nozzles 4a and 4b extend in the width direction of the strip 1 (perpendicular to the plane of FIG. 1). The strip 1 after the adhered amount is controlled by the wiping nozzle means 4 is wound around guide rolls 14, 15, 16 and passes through the cooling means 5 described above, where it is cooled, and thereafter detected. Guided to means 6. The detecting means 6 has a structure for detecting the amount of the strip 1 attached over the width direction of the strip 1, for example, irradiating an X-ray toward the surface of the strip 1, and measuring the intensity of the reflected X-ray. Then, there is a configuration for detecting the adhesion amount.

FIG. 2 is a sectional view of the strip 1 as viewed from the vicinity of a section line II-II in FIG. When the lower support roll 12 is advanced toward the strip 1 as shown by an arrow 17, the warping which is the canoeing of the strip 1 is caused as shown in FIGS. 2 (1) to 2 (5). Occurs. As shown in FIG. 3, the canoeing amount d corresponds to the pushing amount of the lower support roll 12 in the direction of the arrow 17. In the range A1 where the pushing amount of the lower support roll 12 is zero (that is, when the distance between the strip 1 and the lower support roll 12 is zero) or is small, the canoeing amount d is mainly affected by the sink roll 10, and As shown in FIG. 1A, the upper support roll 11 is concave and the lower support roll 12 is convex. The canoeing amount d refers to the distance between both ends of the strip 1 and the center position of the strip 1 in the thickness direction. Reference numerals 19 and 20 in FIG. 2 indicate plating layers.

When the lower support roll 12 is pushed in the direction of arrow 17, there is a position l1 where the canoeing amount d becomes zero in the range A2 in FIG. 3, and in this state, the cross section of the strip 1 becomes the second position.
The result is as shown in FIG.

When the lower support roll 12 is further pushed in the direction of the arrow 17, the strip 1 is curved so as to be convex on the upper support roll 11 side and concave on the lower support roll 12 side (FIG. 2 (3)). The state shown by.

When the lower support roll 12 is further pushed in the direction of the arrow 17, at the position l2 of the lower support roll 12 in the range A3 in FIG. 3, as shown in FIG. Is reduced to zero, and then the lower support roll 12 is further pushed in, as shown in FIG.
As can be seen, the canoeing amount d increases.

In the present invention, the control means 7 drives the lower support roll 12 by controlling the driving means 8 so that the canoeing amount d becomes zero in the above-mentioned range A2.

When the distance between the nozzle 4a and the strip 1 in the wiping nozzle means 4 is D, the traveling speed of the strip 1 is V, and the pressure of the gas injected from the nozzle 4a to the surface of the strip 1 is P, the detecting means 6 The thickness Z of the plating layer detected as described above is as shown in the first equation.

Z = D ^a V ^b V ^c (1) where a, b, and c are constants. The same applies to the other nozzle 4b. Since the thickness of the front and back plating layers is required to be the same except in the case of so-called differential pressure plating, in which the thickness of the front and back plating layers is different, the distance D between the nozzle 4a and the strip 1 is The interval between 4b and strip 1 is set to be the same.

As is apparent from the first formula, the thickness Z of the plating layer is:
Since the fluctuation varies in accordance with the distance D between the nozzle 4a and the strip 1, the distribution of the adhered adhesion amount in the plate width direction of the strip 1 in which canoeing occurs becomes uneven in the width direction. This indicates that, in a strip where canoeing occurs, the canoeing amount d can be obtained from the measured value of the amount of adhesion in the width direction.
The canoeing amount d is expressed by the following equation (2) using the ratio of the amount of the attached adhesion on one surface of the strip to the total amount of the attached adhesion of the strip on the front and back surfaces, and the distance D.

Here, as shown in FIG. 2 (1), ZWF, ZCF, ZD
F represents the adhesion amount of one end WS, the center CN, and the other end DS of one surface of the strip 1 respectively, ZWB, ZWB
CB and ZDB are at one end W on the other surface of the strip 1.
The adhesion amounts of S, the center CN, and the other end DS are shown. The plating weight ratio on the right side of the second equation
ZCF / (ZCF + ZCB), ZWF / (ZWF + ZWB), ZDF / (ZDF + ZD
B) is the center CN in the width direction of the strip, one end WS,
The ratio of the adhesion amount at the other end DS is shown.

According to the detection means 6, the adhesion amount ZWF, ZCF, ZDF; ZW
B, ZCB, and ZDB are detected, and from these detection values, the adhesion amount ratio is determined at one end WS in the width direction of the strip and at the center.
The distance D between the nozzle 4a and the strip 1 corresponding to the adhered amount can be obtained from the first equation, and the canoeing amount d can be obtained from the second equation. Can be.

The control means 7 controls the driving means 8 so that the canoeing amount d becomes zero as described above and controls the lower support roll 12.
Is driven for displacement. As a result, the ratio of the adhered adhesion amount at the center portion CN in the width direction of the strip 1 is calculated by calculating the average value of the ratio of the adhered adhesion amount at one end portion WS in the width direction of the strip 1 and that at the other end portion DS. It is controlled by the control means 7 so that they are equal, that is, the difference becomes zero.

As described above, the adhesion amount is required to be uniform over the entire surface over the entire width. However, as is apparent from the second equation, even when the adhesion amount is not uniform, the ratio Is greatly deviated from 0.5, the canoeing amount becomes zero if the ratio is the same in the width direction. For this reason, even if the canoeing amount is zero, it may not be possible to express a substantially uniform adhesion amount on the front and back over the entire width of the strip. However, as described above, the distance between the nozzle 4a and the strip 1 and the nozzle 4b
The distance between the strip 1 and the strip 1 is set to be the same. Therefore, even if canoeing occurs, the ratio is maintained at approximately 0.5 at the center CN of the strip 1 in the width direction. When it becomes zero, it is possible to realize a substantially uniform adhesion amount on both sides over the entire width. Furthermore, as described above, the canoeing amount can be reduced to zero even if the ratio deviates greatly from 0.5, so that the so-called differential thickening in which the thickness of the front and back plating layers is different also in the width direction of the plate. A uniform attachment amount can be realized over the entire width.

The operation of the control means 7 will be described with reference to FIG. After moving from step n1 to step n2, the attachment amount is detected by the detecting means 6 at each of one end WS, the center CN, and the other end DS in the width direction of the front and back surfaces of the strip 1 by the detecting means 6. Measure and detect. Thus, the canoeing amount d is calculated from the above-described second equation. At step n4, it is determined whether or not the canoeing amount d is positive. If it is positive, as shown in the range A2 in FIG.
Is advanced in the direction of arrow 17 to make the canoeing amount d zero. When the canoeing amount d is negative, the process moves from step n4 to step n6, whereby the support roll 12 moves in the range A2 with the arrow 17.
The canoe is reversed in the reverse direction, and the canoeing amount d is made zero. By setting the canoeing amount d to zero, the strip 1 can pass between the two nozzles 4a, 4b at equal intervals and between these nozzles 4a, 4b, so that the entire width of the strip 1 can be reduced. The plating is deposited with a uniform thickness throughout.

Advantageous Effects of the Invention As described above, according to the present invention, a strip is wound around a sink roll in a plating tank, guided to wiping nozzle means via a lower support roll and an upper support roll, and thereafter, the adhered adhesion amount is reduced. Detecting means detects the width of the strip in the width direction, and in response to the output of the detecting means, the control means controls the lower support roll so that the canoeing amount calculated based on the adhesion adhesion amount becomes zero. Is driven by the driving means in the direction toward the strip or away from the strip, so that the amount of adhesion of the strip can be accurately and uniformly formed in the width direction. Therefore, as described in the above-mentioned prior art, there is no need for the operator to measure the distance between the nozzle of the wiping nozzle means and the strip in a bad environment near the wiping nozzle means, and the workability is improved.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of one embodiment of the present invention, FIG. 2 is a sectional view of the strip 1 taken along a section line II-II in FIG. 1, and FIG. FIG. 4 is a graph showing the relationship between the canoeing amount d and the canoeing amount d.
5 is a flowchart for explaining the operation of FIG. 1 ... strip, 2 ... plating bath, 3 ... molten metal,
4 wiping nozzle, 5 cooling means, 6 adhesion adhesion amount detecting means, 7 control means, 8 driving means,
10 …… Sink roll, 11 …… Upper support roll, 12 ……
Lower support roll

Continuation of the front page (56) References JP-A-62-30865 (JP, A) JP-A-3-138344 (JP, A) JP-A-3-115555 (JP, A) JP-A-3-17249 (JP) , A)

Claims (1)

(57) [Claims] 1. A plating tank for storing a molten metal to be plated, a sink roll provided in the plating tank, around which a strip is wound, and a strip roll just above the sink roll in the plating tank. On the downstream side of the upper support roll contacting the same one surface as the surface contacting the sink roll of the strip, and contacting the other surface of the strip between the sink roll and the upper support roll in the plating tank, Leaning towards the strip,
And a lower support roll provided to be displaceable in a direction away from the strip, a driving means for driving the lower support roll closer to the strip and displaced in a direction away from the strip, and disposed downstream of the plating tank in a running direction of the strip relative to the plating tank. Wiping nozzle means for injecting gas from a nozzle to control the amount of adhesion, cooling means arranged downstream of the wiping nozzle means in the running direction of the strip, and cooling the attached strip; and cooling means. Detecting means for detecting the amount of sticking of the strip over the width direction of the strip, and responding to the output of the detecting means to detect the amount of sticking of the strip on one surface of the strip. The ratio of the amount of the strip to the total amount of adhesion on the front and back surfaces is expressed as one of the widths of the strip. Parts, respectively obtained for the central portion and the other end, an average value of the plated deposition amount ratio in the plated deposition amount ratio and the other end portion at one end in the width direction of the strips,
The difference is obtained by subtracting the obtained average value from the adhesion amount ratio at the central portion in the width direction of the strip, and the lower support roll is displaced and driven by controlling the driving means so that the difference becomes zero. A control unit for making the amount of adhesion of the strip in the width direction uniform, a control device for controlling the amount of adhesion of the strip.