JPS6230865A - Method and apparatus for producing metal hot dipped strip - Google Patents

Abstract

PURPOSE:To plate a strip to the coating weight uniform over the entire surface by adjusting the push-in of snap rolls according to the detected transverse warpage of the strip so that the space between the strip and wiping gas nozzles is made uniform. CONSTITUTION:The strip 2 past a metal hot dipping bath 4 is leveled by the snap rolls 8 and is further wiped to the prescribed plating thickness by the wiping gas nozzles 10. A transverse warpage detecting means 16 which is a sensor of a non-contact type is provided in the transverse direction above the extreme neighborhood of the above-mentioned nozzles 10 in this stage. The signal from the means 16 is fed to a control arithmetic part 18 which calculates the distance between the strip 2 and the nozzles 10 and sends the result of the calculation to an operation part 20 of a mechanism for driving the rolls 8. The rolls 8 are thereby pushed in by as much as the required amt. in the direction where the warpage is offset. The operation of the rolls 8 is preferably executed with the lower roll in order not to change the pass line.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method and apparatus for producing a hot-dip metal plated strip (hereinafter also simply referred to as a "hot-dip plated strip"), and in particular, a method and apparatus for producing a hot-dip metal plated strip (hereinafter also simply referred to as a "hot-dip plated strip"). The present invention relates to a method for manufacturing a molten metal plated strip in which the warpage in the width direction of the strip is adjusted to make the surface as flat as possible, thereby making the area weight of the molten metal coating uniform over the entire surface of the strip.

(Prior art) Hot-dip plating methods, such as the Sendzimir method as a typical example, have been widely used due to their rational line configuration, and other plating methods such as electroplating or Geiwa plating method It has the advantage of being considerably cheaper to manufacture than other products, and demand for it is expected to continue in the future.

On the other hand, the hot-dip plating method has a problem in that there is large variation in the amount of plating deposited on the front, back, or width direction of the strip to be treated. In other words, the basis weight of plated metal is normally determined based on the thinnest area, and therefore areas where sufficient plating will adhere will inevitably be over-plated, which increases costs. This puts them at a disadvantage.

This variation in the amount of plating deposited in the width direction is due to warpage in the width direction of the strip when adjusting the amount of plating deposited on the strip. This is because the spacing between the nozzle and the seven-node nozzle becomes uneven. Many proposals have already been made regarding methods of preventing warpage of the strip and maintaining a constant distance between the strip and the nozzle.

For example, JP-A-57-32358 and JP-A-57-
No. 32359 attempts to correct warping by changing the diameter of the snap roll, and is published in Japanese Patent Application Laid-open No. 5
No. 1-137627 and Nos. 55 to 128570 all attempt to prevent warping by attaching a crown to the roll. In addition, special public service No. 55-4810
In No. 1, the kunosoyeonpanoda is arranged in the width direction to prevent warping.

However, are they all on the first shape side? ]ll, and does not consider preventing warpage in response to various conditions that change over time during the plating process.

In this way, all conventional methods are concerned with straightening warpage in the width direction under static conditions, but in reality, it is necessary to straighten warpage due to changes in operating conditions such as plate thickness, line, etc., and equipment conditions such as wear and tear on rolls. The amount of correction must also vary from time to time, and no countermeasures have been found for this. In other words, in the past, there was no idea of equalizing the distance between the strip and the nozzle under dynamic conditions by constantly monitoring and constantly correcting warpage.

(Problems to be Solved by the Invention) Thus, an object of the present invention is to make the plating area weight as uniform as possible by constantly monitoring and constantly correcting warpage, and by equalizing the distance between the strip and the nozzle. An object of the present invention is to provide a method for manufacturing a hot-dip plated strip and an apparatus therefor.

Furthermore, another object of the present invention is to produce a hot-dip plated strip that can always maintain a constant coating weight in the width direction despite variations in operating conditions such as strip thickness, line speed, and equipment conditions such as roll wear. The purpose is to provide the law and its equipment.

(Means for Solving the Problems) Here, the gist of the present invention is to adjust the area weight of hot-dip plating by spraying a six-hole metal plating strip pulled out from a hot-dip metal plating bath through a snap roll. A method for manufacturing a hot-dip metal plated strip comprising: detecting warpage in the width direction of the strip at a position close to a wiping gas blowing position; A method for producing a hot-dip metal plated strip, characterized in that the push-in beak of the snap roll is adjusted in a direction that offsets warping.

The above snap roll consists of a pair of upper and lower rolls, and the upper and lower sides are fixed in order to keep the threading position constant, and the lower roll is not pushed into place. 7D-J' is preferable. Such snap rolls are not limited to any particular structure, but today the threading speed is quite high, so it is desirable to have a snap roll with good responsiveness.

According to another feature of the present invention, the present invention provides a molten metal plating bath in which a pair of upper and lower snap rolls are immersed, a wiping gas nozzle provided above the molten metal plating bath, and a wiping gas nozzle provided in the wiping gas nozzle. A means for detecting warpage in the width direction of the strip provided in close proximity to each other, receiving a signal from the warpage detection means to calculate the warpage in the width direction of the strip and calculating the pushing amount of the snap roll in a direction to offset the warpage. and a snap roll drive mechanism that receives a command from the control calculation device and displaces the snap roll by the calculated pushing amount, and after adjusting the pushing amount in this way, Detecting the fluctuation of the warpage of the snow roll by the warpage detection means, and sending the signal from the warpage detection means at that time to the control calculation device to obtain the latest relationship between the displacement amount of the snow roll and the fluctuation of the warpage. The control wave 1γ device (11) also has the function of storing the control wave as a basis for calculating the pushing amount.

(effect) The invention will now be further described with reference to the accompanying drawings.

The accompanying drawing schematically explains the method according to the invention, in which the strip 2 is exposed to a plating bath 4 at a rate of 1 JTI, changed direction at a roller 6, and then transferred to a snap roll 8. After undergoing straightening, wiping gas nozzle l
It is wiped off to a predetermined plating level by O, reaching the top roll 12, and the plating is completed.

During such hot-dip plating, the strip is first subjected to bending action by zinc rolls and snap rolls, thereby warping it in the width direction. For this reason, the distance between the strip and the nozzle varies in the width direction, resulting in variations in the amount of plating deposited.

Here, according to the present invention, near the wiping gas nozzle,
In the illustrated example, a widthwise warpage detection means 16 is provided directly above the wiping gas nozzle, and the widthwise warpage is detected by changing the pushing amount of the lower roll of the snap roll according to the amount of warpage detected by the means 16. It's about correction.

Although it has been known in the past to correct warpage in the width direction of the strip by using snap rolls, the reality is that the adjustment was performed by the operator based on experience and intuition. As long as such means are used, high-volume, high-speed production of products of uniform quality cannot be expected.

According to the present invention, when the warpage detection means is provided as described above, the signal from the widthwise warpage detection means 16, which is a plurality of non-contact type sensors arranged in the width direction immediately near the nozzle, is transmitted to the control calculation unit. is sent to the control calculation unit 18, which is
Eliminate noise signals and calculate distance to strip. This calculation result is transmitted to the operating unit 20 which is a snap drive device.
Then, the snap roll 8 is pushed in by the required amount according to the command from there.

The required amount of push-in described in - is calculated in advance, but as mentioned above, fluctuations in operating conditions and equipment conditions are always observed, so the control calculation device 18 constantly calculates the push-in amount. In response to this, the relationship of warpage displacement in the strip width direction must be updated.

Then, based on this latest relational expression, the push amount of the snap roll is calculated.

Here, it is desirable to perform the snap roll operation on the lower roll so as not to change the pass line. Furthermore, the present invention can be combined with automatic control that adjusts the nozzle blowing pressure and interval to achieve even more precise plating marks. ! Ilt control wholesale becomes iiJ function.

Thus, according to the invention, the distance between the strip and the wiping gas nozzle is always kept constant, and accordingly,
The basis weight can also be kept constant.

Next, the present invention will be explained in more detail by way of examples.

EXAMPLE Using the apparatus shown in the accompanying drawings, 18 dip-plated strips having a width of 914 cm were manufactured.

In this example, a non-contact laser sensor was used as a means for detecting warpage in the width direction of the strip, and was installed 10 cm above the wiping gas nozzle.

The snap rolls were driven hydraulically, the upper side was fixed, and the pushing amount of only the lower snap roll was adjusted.

The results obtained at this time are summarized in Table 1.

As is clear from the illustrated results, according to the present invention, the variation in the arrival stars at point a, point b, and point 0 of the strip is considerably reduced, compared to the case where the correction mechanism according to the present invention is not provided. The variation was almost halved.

Table 1 --b is defined.

(2) Conducted with a basis weight of 1,000 yen, and expressed as an average value for the Zanbuno public factor.

(The upper row of 3 liters of fabric weight is the upper roll side).The lower row is the fabric weight of the lower roll side.

[Brief explanation of the drawing]

The accompanying drawings are schematic illustrations of a hot-dip metal plating strip manufacturing apparatus according to the present invention. 2: Strip 4: Plating bath 8 varnish nut roll 10: Wiping nozzle 16:
Width warpage detection means

Claims (2)

[Claims] (1) In a method for manufacturing a molten metal plating strip, which comprises adjusting the area weight of the molten metal plating by spraying wiping gas onto the molten metal plating strip pulled out from the molten metal plating bath via a snap roll, the wiping gas spraying position is The strip is characterized by detecting warpage in the width direction of the strip at a nearby position, and adjusting the pushing amount of the snap roll in a direction to offset the warpage according to the detected amount of warpage in the width direction. A method for producing hot dip metal plated strip. (2) A molten metal plating bath provided by dipping a pair of upper and lower snap rolls, a wiping gas nozzle provided above the molten metal plating bath, and a strip width direction provided close to the wiping gas nozzle. a warpage detection means; a control calculation device that receives a signal from the warp detection means to calculate the warpage in the width direction of the strip and also calculates the pushing amount of the snap roll in a direction to offset the warpage; and the control calculation device. The snap roll drive mechanism displaces the snap roll by the calculated pushing amount in response to a command, and after adjusting the pushing amount in this way, the warpage detecting means detects fluctuations in warpage in the width direction of the strip. detecting the warpage and sending the signal from the warpage detection means at that time to the control calculation device to store the latest relationship between the displacement amount of the snap roll and the fluctuation amount of the warpage, and use it as the basis for calculating the pushing amount. A manufacturing apparatus for a hot-dip metal plating strip, wherein the control calculation device also has the function of: