JP5250823B2 - Plating adhesion amount control device and plating adhesion amount control method - Google Patents

Description

  The present invention relates to a plating adhesion amount control device and a plating adhesion amount control method used in a continuous plating line of an iron and steel plant, and in particular, when the plating adhesion amount is controlled mainly by the operation of a nozzle gap, the contact between the nozzle and the steel plate is controlled. The present invention relates to a plating adhesion amount control device and a plating adhesion amount control method for preventing and continuing plating adhesion amount control.

  The operation of the nozzle for changing the amount of plating attached to the steel sheet includes changing the nozzle pressure and changing the nozzle gap. Generally, it is better to manipulate and change the nozzle gap from the viewpoint of control responsiveness and gloss of steel plate plating. However, there is a problem that there is a risk that the nozzle and the steel plate come into contact by changing the nozzle position.

  In Patent Document 1, as a conventional method for controlling the plating adhesion amount, a control model for predicting the adhesion amount of plating from a state quantity to be controlled is provided, and a gas pressure for realizing a desired adhesion amount using this control model is provided. An example in which a combination of nozzle positions is calculated and output to a control target is shown.

  In Patent Document 2, a plurality of gap sensors for detecting the position of the steel sheet are provided in the width direction of the steel sheet, and while controlling the nozzle gap while detecting the nozzle gap, the plating adhesion amount is controlled. A control technique is shown.

Japanese Patent Laid-Open No. 10-018014 JP-A-8-302455

  However, in the method of Patent Document 1, since the nozzle is operated without considering the relative positional relationship between the nozzle gap and the steel plate, the risk of contact between the nozzle and the steel plate is output when an operation amount that narrows the nozzle gap is output. was there. When the nozzle and the steel plate come into contact with each other, it is necessary to stop the production line and replace the nozzle, which causes problems of productivity reduction, steel plate quality deterioration due to scratches, and nozzle replacement cost generation.

  In the method of Patent Document 2, since the actual value of the nozzle gap is detected by the gap sensor, it is possible to perform nozzle gap control that avoids contact between the nozzle and the steel plate. However, since it is necessary to install an expensive gap sensor, there is a problem that the price of the control system becomes expensive. Further, although the average steel plate position can be detected by the gap sensor, the vibration amplitude of the steel plate and / or the shape of the plate end (edge portion in the plate width direction) of the steel plate cannot be detected strictly. For this reason, in order to avoid the danger of contact between the nozzle and the steel plate, it is necessary to control the nozzle position according to a value obtained by adding a sufficient margin to the detected value of the steel plate position.

  The present invention is intended to solve such a conventional problem, and an object of the present invention is to use a special sensor for detecting the position of a steel sheet when the amount of plating is mainly controlled by a nozzle gap. Without preventing the contact between the nozzle and the steel plate, the plating adhesion amount is continuously controlled safely and the plating quality of the steel plate is improved.

In order to achieve the above object, the plating adhesion amount control device of the present invention immerses a continuously fed steel sheet in a hot dipping bath and blows a high-pressure gas from a nozzle immediately after pulling up, thereby unnecessary plating. A plating adhesion amount control device for controlling a plating plant for depositing a desired thickness of plating on a steel sheet by blowing off a steel sheet, a steel sheet position calculating means for calculating a steel sheet position, and a nozzle for attaching a desired plating amount to the steel sheet Control means for calculating and outputting pressure command value and nozzle position command value, steel plate thickness, steel plate thickness direction vibration amplitude, steel plate width direction warp amount, and steel plate nozzle twist amount If, to calculate the strip band is a value corresponding to the sum of the wavy shape amplitudes of the steel sheet ends, you position and correspondence between the command value and the front edge of the steel plate from the strip band of the nozzle position And a strip band calculating means for calculating a band edge and a back band edge you position and correspondence between the back edge of the steel sheet, by said control means takes in the Table band edge and the back band edge, the front side of the steel sheet In this case, the intersection of the nozzle and the band edge in the nozzle and the intersection of the nozzle and the band edge on the back side of the steel plate are determined, and when at least one of them intersects, the command value of the nozzle position is corrected and output.

  In the plating adhesion amount control method of the present invention, a steel plate continuously fed is immersed in a hot dipping bath, and immediately after being pulled up, high pressure gas is blown from a nozzle, and unnecessary plating is dropped to remove a desired thickness on the steel plate. A plating adhesion amount control method for controlling a plating plant for depositing a plating of a steel plate, a thickness of the steel plate, a vibration amplitude in the thickness direction of the steel plate, a warpage amount in the plate width direction of the steel plate, and a twist amount with respect to the nozzle of the steel plate Calculate and output the strip band, which is a value corresponding to the sum of the amplitude of the wavy shape at the end of the steel plate, and output the surface nozzle from the front side plating adhesion amount, nozzle pressure and steel plate speed measured by the plating adhesion meter. Calculate and output the estimated value of the distance on the front side of the steel plate, and calculate the estimated value of the distance between the back nozzle and the back side of the steel plate from the back side plating adhesion amount, nozzle pressure and steel plate speed measured by the plating adhesion meter. Output, estimate the position of the steel plate from the estimated value, the nozzle position on the front side of the steel plate, and the nozzle position on the back side of the steel plate, and output the value to the strip band at a value of 1/2 or more By adding or subtracting the value multiplied by, the front band edge on the steel plate front side and the back band edge on the back side of the steel plate are calculated and output, and the nozzle position is corrected by the front band edge and the back band edge. And

  In the present invention, the command amount of the nozzle position is specified based on the steel plate position and the strip band, the space where the steel plate can exist is specified, and the front side end (front band edge) and the back side end (back band edge) of this space And the position where the nozzle does not cross. Thereby, the contact between the steel plate and the nozzle can be prevented, and the nozzle gap can be controlled.

  According to the present invention, in the plating adhesion amount control of the steel process line, the occurrence of contact between the nozzle and the steel plate is prevented, and the plating adhesion amount is controlled by the nozzle gap continuously, so that productivity can be improved. It becomes possible.

  In addition, according to the present invention, it is possible to control the amount of plating adhesion mainly by the nozzle gap. Therefore, compared with the case where the amount of plating adhesion is controlled by the nozzle pressure, the plating adhesion amount control response is increased, and the plating is controlled. It is possible to improve the surface quality of steel sheets and reduce quality defects.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating a configuration of a plating adhesion amount control system according to the present embodiment. The plating adhesion amount control system includes a plating adhesion amount control device 100 and a plating plant 150 that is controlled by the plating adhesion amount control device 100 to deposit a plating having a desired thickness on a steel plate (strip). First, after briefly explaining the configuration of the plating plant 150, the operation of the plating adhesion amount control device 100 and each part according to the present embodiment will be described in detail.

The plating plant 150 includes a plating bath (pot) 152 . In the plating bath (pot) 152 , hot dipping is stored. The steel plate 151 is continuously fed from the outside of the plating bath (pot) 152 at a steel plate speed (plate speed) V while being supported by the collecting roll 154, the stabilizing roll 155, and the sink roll 156, and immersed in the hot dipping. Is done. In the present embodiment, only the minimum required roles have been described, but a combination of roles may be configured by adding a support roll or the like. For example, zinc hot dipping is used as the hot dipping.

  The sheet warp in the width direction of the steel plate 151 can be changed by pushing and pulling the collecting roll 154 in the horizontal direction. In the state described above, the steel plate 151 fed at the steel plate speed V is once dipped in the hot dipping and then pulled up from the hot dipping. Then, immediately after the steel plate 151 is pulled up from the hot dipping, high pressure gas is blown from the nozzle 153, and unnecessary hot dipping is blown off, so that the amount of plating attached to the steel plate 151 is controlled to a desired value. Is done.

  The amount of plating that adheres to the steel plate 151 is roughly determined by the steel plate speed of the steel plate 151, the pressure of the gas blown from the nozzle 153, and the distance between the nozzle 153 and the steel plate 151. The distance between the front surface of the steel plate and the nozzle on the front side of the steel plate determines the amount of plating that adheres to the front side of the steel plate, and the distance between the back surface of the steel plate and the nozzle on the back side of the steel plate determines the back side of the steel plate. The amount of plating that adheres to the surface is determined.

  The relationship between the plating adhesion amount (W), the nozzle gas pressure (P), the steel plate speed (V), and the nozzle gap (D) is expressed by the relational expression of Formula 1 through constants a0 to a3.

[Equation 1]
ln (W) = f (P, V, D)
= A0 + a1 · ln (P) + a2 · ln (V) + a3 · ln (D)

  In the present specification, a model represented by the relational expression 1 is referred to as a plating adhesion amount prediction model. Note that the model represented by the relational expression 1 is an example of a plating adhesion amount prediction model, and an example of a plating adhesion amount prediction model in which the inverse of the nozzle height, the steel plate temperature, and the speed is added as an input may be used. .

  The continuous steel plate (strip) 151 is formed by connecting the front and back of a plurality of steel plates (coils) by welding at welding sites (welding points) 158, and is continuously processed. The welded part 158 usually corresponds to a switching part of the plating adhesion amount target value. The plating adhesion meter 157 is a device that measures the amount of plating actually attached to the steel plate 151, and how much plating is attached to the width direction part of the steel plate 151 on each of the front side and the back side of the steel plate 151. Output whether or not

  In the present embodiment, an example of so-called three-point scanning in which three measured values of the work side (WS), the center (CN), and the drive side (DS) are output on the front side and the back side of the steel plate 151 is shown. As a measurement form of the plating adhesion amount, an example of simply scanning in the width direction may be used. The plating adhesion meter 157 is attached at a location separated from the nozzle 153 by several tens to several hundreds of meters. Further, the measurement is performed while traversing the steel plate 151 in the width direction with respect to the steel plate 151 moving at the plate speed V. Therefore, it takes, for example, 1 to 2 minutes before the plating adhesion amount corresponding to the plating adhesion amount formed by the nozzle gas pressure P, the steel plate speed V, and the nozzle gap D at the position of the nozzle 153 is measured. And

  In the present embodiment, for the front side and the back side of the steel plate 151, for example, three measured values of the work side (WS), the center (CN), and the drive side (DS) are output. The plating adhesion meter 157 is attached at a location separated from the nozzle 153 by several tens to several hundreds of meters. Further, the steel plate 151 is moved at a plate speed V, and the steel plate 151 is measured while traversing in the width direction, and an average value of the measured values is output. Therefore, it takes, for example, 1 to 2 minutes before the plating adhesion amount corresponding to the plating adhesion amount formed by the nozzle gas pressure P, the steel plate speed V, and the nozzle gap D at the position of the nozzle 153 is measured. And

  Next, the plating adhesion amount control apparatus 100 will be described. The plating amount control device 100 includes a manufacturing information table 101 storing manufacturing information such as a steel type of a steel plate, a target value of plating amount, a plate thickness, a plate width, a length of a steel plate (coil length), and a target of the steel plate. A nozzle pressure preset table 102 in which the spray pressure of the nozzle 153 is stored with respect to the adhesion amount and the plate speed V is provided.

  In addition, the plating adhesion amount control device 100 has the actual data such as the nozzle pressure P, the nozzle gap D, the steel plate speed V, the plating adhesion amount W detected by the plating adhesion meter 157 and the pressing amount of the collecting roll 154 from the plating plant 150. Stability determination means 104 for detecting whether or not the plating adhesion amount W detected from the steel plate 151 is a value (stable value) corresponding to the current nozzle pressure P, nozzle gap D, and steel plate speed V; The welding part passage determining means 105 for determining the passage and generating a start signal for switching to the control set value for the steel sheet to be processed next after passing the welding part, the actual data from the plating plant 150 and the stability determining means 104 The steel plate position where the stability establishment signal and the welding part passage determination means 105 take in the welding part passage signal and calculate the steel plate position Stripping means 106, strip band calculating means 107 for fetching the calculated steel plate position and the amount of plating adhesion in the front and back and width direction detected from the plating plant, and calculating the strip band by referring to the value of the strip band calculating table 108; Is provided.

  Further, the plating adhesion amount control device 100 takes in the output of the steel plate position calculating means 106, the strip band calculating means 107, and the nozzle pressure preset table 102, and is processed after passing the next welding site from the result data taken in from the plating plant 150. The control means 103 for calculating the preset command value and the corrected command value of the nozzle gap of the steel plate, and when the vicinity of the welded part 158 passes through the nozzle 153, the necessity is judged from the output of the control means 103, and the nozzle and the steel plate The nozzle is opened for the purpose of avoiding contact of the nozzle, and after the vicinity of the welded portion 158 has passed, the nozzle open / close means 110 for closing the nozzle again to the preset command value after passing through the welded portion, and the nozzle and strip band The proximity is acquired from the control means 103 and the alarm device 130 as required. And an alarm onset report means 109 to alarm the alarm.

  The plating adhesion amount control device 100 displays the nozzle gap set value, the steel plate position, the strip band value, the proximity between the steel plate and the strip band, etc., output from the control means 103 using the display device 120.

  Hereafter, the function of each part is demonstrated according to a figure.

FIG. 2 shows the configuration of the manufacturing information table 101. The manufacturing information table 101 stores the manufacturing information of the steel plate that is sent. FIG. 2 shows, as an example of manufacturing information, about the steel plate number HX0012352, the steel type is SS400 of carbon steel, the target adhesion amount is 60 g / m ² per side, and the values shown in FIG. Yes. When so-called differential thickness plating is performed in which the target adhesion amount differs between the front and back, the respective values may be stored in the form of the target adhesion amount (front) and the target adhesion amount (back).

  The form of a cold rolling mill is stored in the column of the pre-process of FIG. 2, and the tandem described in FIG. 2 is an example of a continuous rolling mill composed of a plurality of stands. In addition, there are reverse (reciprocating rolling mill consisting of a single stand), dual cold reverse (reciprocating rolling mill consisting of 2 stands) and the like. These are information related to the quality of the steel plate shape at the front and rear ends, and the best shape can be obtained with a tandem rolling mill capable of performing stable rolling. Actually, the previous process information may be further classified according to the name of the cold rolling mill plant that has been processed.

FIG. 3 shows the configuration of the nozzle pressure preset table 102. Preset values of nozzle pressure are stored in association with the target adhesion amount and the plate speed of the steel plate for each plating type (GI and GA in the example shown in FIG. 3). GI and GA are symbols indicating plating types, GI indicates hot dip galvanizing, and GA indicates alloyed hot dip galvanizing. FIG. 3 shows, as an example, when the plating type is GI, the target deposition amount is 50 g / m ² , the plate speed is 100 m / m (min) or less, the nozzle pressure preset value is 40 KPa , and the plate speed is 100 to 140 m / m (min). ) Shows an example in which 60 KPa is preset and 60 KPa is preset in a range where the plate speed is larger than 140 m / m (min).

  In general, the same pressure is often set for the front nozzle and the back nozzle in consideration of the influence on the vibration of the steel plate. From this, FIG. 3 shows an example in which the same pressure is set for the front nozzle and the back nozzle, but different values can be preset for the front nozzle and the back nozzle.

  FIG. 4 shows processing executed by the stability determination unit 104. In step S4-1, the tracking value L is initialized. In this flowchart, L indicates the distance that the stable state of control continues in the longitudinal direction of the steel sheet. In S4-2, it is determined whether any of the plate speed, the nozzle gap, or the nozzle pressure has changed. If changed, the process returns to S4-1 and the tracking L is initialized. If not changed, a value obtained by multiplying the plate speed V by the activation period Δt of the stability determining means 104 is added to L in S4-3, and is newly set to L.

  In S4-4, L is the distance L1 from the nozzle 153 and the plating adhesion meter 157, the product of the plate speed V and the time Tw when the plating adhesion meter 157 scans the plate in the width direction, and a value obtained by adding a margin M. Determine if greater than. In the case of being large, the plating plant 150 is controlled in the same state for a sufficiently long time, and the detected amount of plating adhesion from the plating adhesion meter 157 is the current nozzle pressure (P), nozzle gap (D), plate speed. It corresponds to V and the like. At this time, the stability determination means 104 determines the value taken in from the plating adhesion meter 157 as the adhesion amount detected in a stable state. Accordingly, in S4-5, the stability determination unit 104 outputs a stability determination signal. If not, the process returns to S4-2 and repeats the processes of S4-2 to S4-4.

  FIG. 5 shows a process executed by the weld site passage determination means 105. In S5-1, the tracking value L is initialized. In this flowchart, L indicates the distance from the top of the steel plate at the part being plated. In S5-2, a value obtained by multiplying the plate speed V by the activation period Δt of the welding part passage determining means 105 is added to L, and is newly set to L. In S5-3, it is determined whether L is larger than the steel plate length L2 fetched from the manufacturing information table 101. If not, the process returns to S5-2 and repeats the processes of S5-2 to S5-3. If it is larger, it means that the processing of the coil has been completed, so a welding part passage signal is output in S5-4.

  FIG. 6 shows the processing of the steel plate position detection means 106. First, the activation factor of the steel plate position detection means 106 is determined in S6-1. If the activation factor is a signal from the stability determining means 104, the actual value of the plating adhesion amount on the front side and the back side of the steel plate, the nozzle gap value on the front side and the back side of the steel plate, or the steel plate position are calculated in S6-2. The steel plate position is calculated as ΔD in FIG. The zero point (zero point) described in FIG. 7 corresponds to the steel plate position when the front and back nozzle gaps are zeroed.

  At this time, the front and back nozzles are equidistant across the zero point (zero point), and the front and back nozzle gaps have the same value. It is assumed that the steel plate is moved to the position illustrated in FIG. 7 by the change of the plate thickness or the operation of the collecting roll 154. At this time, the nozzle gap value output as the operation amount by the plating adhesion amount control device 100 is Dt and Db with reference to the zero point, but the actual distance between the nozzle and the plate is D′ t and D′ b. First, it is assumed that D′ t and D′ b are obtained, and then the steel plate position ΔD is calculated. D′ t and D′ b can be calculated by the relational expression of Expression 2 and the relational expression of Expression 3, respectively.

[Equation 2]
D′ t = f ⁻¹ (Wt, P, V) * (Dt + Db) / {f ⁻¹ (Wt, P, V) + f ⁻¹ (Wb, P, V)}

[Equation 3]
D′ b = f ⁻¹ (Wb, P, V) * (Dt + Db) / {f ⁻¹ (Wt, P, V) + f ⁻¹ (Wb, P, V)}

Here, Wt (average of WS, CN, DS) is the front adhesion amount, Wb (average of WS, CN, DS) is the back adhesion amount, P is the nozzle pressure, and V is the steel plate speed. Yes, f ⁻¹ (Wt, P, V) is the right side when the relational expression of Equation 1 is solved for D.

  Using this result, the steel plate position ΔD can be calculated by the relational expression of Formula 4 or the relational expression of Formula 5.

[Equation 4]
ΔD = D′ t−Dt

[Equation 5]
ΔD = D′ b−Db

  In FIG. 7, ΔD is defined as positive when it is on the right from the zero and negative when it is on the left. Then, the steel plate position calculated in step S6-4 in FIG. In step S6-5, the strip band calculating unit 107 is activated. When the activation factor is passing through the welded part in S6-1, a steel plate position movement amount is estimated in S6-3, and a new steel plate position is calculated. The amount of movement of the steel plate position varies depending on the combination form of the collecting roll 154 and the stabilizing roll 155, etc., but the plate thickness and plate thickness difference between the preceding steel plate and the subsequent steel plate through the welded part, This is expressed as a function using the operating amount of the pushing amount of the ting roll 154. Therefore, the movement amount ΔD of the new steel plate position is calculated by the relational expression of Equation 6.

[Equation 6]
ΔD = ΔDc−g (tf, tb, Δt, C)

  ΔDc is the current steel plate position, tf is the thickness of the preceding material, tb is the thickness of the following material, Δt is the thickness difference (tf−tb), and C is The pressing amount of the collecting roll 154.

  Thereafter, similarly, the steel plate position calculated in S6-4 shown in FIG. In step S6-5, the strip band calculating unit 107 is activated.

  FIG. 8 shows processing executed by the strip band calculating means 107. Before describing the processing executed by the strip band calculating means 107, the strip band will be described in detail with reference to FIG. FIG. 9 is a schematic view of the vicinity of the nozzle in the plating adhesion amount control device 150 as viewed from above, and the steel plate 151 is present at a position sandwiched between the front nozzle 901 and the back nozzle 902. As shown in FIG. 9, the steel plate 151 is warped in the plate width direction to some extent, and is further twisted with respect to the nozzle. In addition, it vibrates with a certain amplitude in the direction perpendicular to the nozzle (plate thickness direction). Furthermore, the edge portion may be wavy at a certain height due to the non-uniform length of the central portion and the edge portion (end portion) of the steel plate 151. The degree of wave amplitude (wave height) generally has a larger value at the front and rear end portions than the central portion of the steel plate 151, and the wave height tends to become larger when the previous process is a reverse mill.

  The sum of the warpage amount A1 in the plate width direction of the steel plate, the twist amount A2, the vibration amplitude A3, the wave height A4 of the edge portion, and the plate thickness A5 is hereinafter defined as a strip band. Further, the front band edge 904 and the back band edge 905 are defined as shown in FIG. The front band edge 904 is a part where the steel plate 151 is closest to the front nozzle, and the back band edge 905 is a part where the steel plate 151 is closest to the back nozzle. The crossing of the front nozzle 901 and the front band edge 904 or the back nozzle 902 and the back band edge 905 means that the nozzle and the steel plate are in contact with each other.

  In the process of FIG. 8, in S8-1, the steel type, the plate thickness, the plate width, and the previous process information are taken from the manufacturing information table 101. In S8-2, the steel plate vibration amplitude and edge shape for each layer are fetched from the strip band calculation table. FIG. 10 shows the configuration of the strip band calculation table 107. The strip band calculation table 107 includes a steel plate vibration amplitude storage table 1001 and an edge shape storage table 1002.

FIG. 11 shows the configuration of the steel plate vibration amplitude storage table 1001. In FIG. 11, the vibration amplitude of the steel plate 151 is stratified by the steel type, tension, plate thickness, and plate width. For example, when the steel type is SS400, the tension is 1 kg / mm ² or less, the plate thickness is 1 mm or less, and the plate width is 900 mm, the vibration amplitude of the steel plate 151 is 4 mm. By taking in this value, the vibration amplitude A3 can be obtained.

FIG. 12 shows the configuration of the edge shape storage table 1002. In FIG. 11, the edge shape of the steel plate 151 is stratified by the form of the rolling mill, the plate thickness, and the plate width in the cold rolling, which is the previous process, with respect to the value of the wave height. ) And front and rear end portions (maximum wave height). For example, when the steel type is SS400, the tension is 1 kg / mm ² or less, the plate thickness is 1 mm or less, and the plate width is 900 mm, the value of the edge wave height of the steel plate 151 is 2 mm at the central portion of the steel plate 151 and 31 mm at the front and rear end portions. It is shown that. By taking in this value, the wave height value A4 of the edge portion can be obtained for each of the central portion and the front and rear end portions of the steel plate 151.

  Next, in S8-3 of FIG. 8, the actual adhesion amount detected by the plating adhesion meter 157 is taken in, and the warpage in the plate width direction of the steel sheet and the twist amount with respect to the nozzle are calculated. The warpage and the twist amount are calculated by, for example, the following using an adhesion amount actual result and a plating adhesion amount prediction model. That is, the warpage amount A1 is calculated by the relational expression of Expression 7, and the twist amount A2 is calculated by the relational expression of Expression 8. The abs in the following formula represents an absolute value.

[Equation 7]
A1 = f ⁻¹ (Ws, P, V)

Here, Ws is Ws = abs [{Wtc−Wbc + (Wbw + Wbd) / 2− (Wtw + Wtd) / 2} / 2], Wtc is the attached amount of table CN, and Wtw is the attached amount of table WS. Yes, Wtd is the surface DS adhesion amount, Wbc is the back CN adhesion amount, Wbd is the back WS adhesion amount, Wbw is the back DS adhesion amount, and f ⁻¹ (W, P, V) is the right side when the relational expression of Formula 1 is solved for D.

[Equation 8]
A2 = f ⁻¹ (Wn, P, V)

  Wn is Wn = abs {(Wtw−Wtd + Wbd−Wbw) / 2}.

  Based on the above A1, A2, A3, A4 and the plate thickness A5 fetched from the manufacturing information table 101, the strip band S is calculated in S8-4 according to the relational expression (9).

[Equation 9]
S = A1 + A2 + A3 + A4 + A5

  Since the edge portion wave height value A4 is different between the middle portion and the front and rear end portions (in the vicinity of the welded portion) of the steel plate 151, the strip band S also has a different value between the middle portion and the front and rear end portions. In S8-5, the front and back band edge values are estimated from the steel plate position taken in from the steel plate position calculating means 106 and the strip band values taken from the strip band calculating means 107 (steady and maximum). The values of the front and back band edges can be calculated by adding / subtracting the strip band value to / from the steel plate position. That is, using the notation of FIG. 7, the front band edge Bt is obtained by the following equation (10), and the back band edge Bb is obtained by the following equation (11).

[Equation 10]
Bt = ΔD−S / 2

[Equation 11]
Bb = ΔD + S / 2

  Then, the calculation result is output to the control means 103 in S8-6. Here, the front band edge Bt and the back band edge Bb are calculated by adding / subtracting a value obtained by multiplying the value of the strip band S by 1/2 to the steel plate position ΔD, but it is not necessarily strictly 1/2. If the value is close to ½, the same effect can be obtained. Also, in order to ensure the avoidance of the risk of contact between the nozzle and the steel plate, an appropriate margin may be taken, 1/2 may be set to a larger value by the margin, and this value may be multiplied. The front band edge corresponds to the movable limit (existence limit) position on the front side of the steel sheet, and the back band edge corresponds to the movable limit (existence limit) position on the back side of the steel sheet.

  FIG. 13 shows processing executed by the control means 103. In the embodiment of FIG. 13, the control means 103 executes setup control to calculate and output the set values of the nozzle gap and nozzle pressure of the steel plate processed after passing through the welded portion prior to passing through the welded portion of the steel plate 151. An example of this will be described. In step S <b> 13-1, the nozzle pressure preset value is fetched from the nozzle pressure preset table 102. In S13-2, a command value for the nozzle gap is calculated. The nozzle gap command value is obtained by transforming the relational expression of Equation 1 and solving for D, substituting the preset value of the nozzle pressure for P, the target adhesion amount taken from the manufacturing information table 101 for W, and the current speed of the steel plate 151 for V. This can be calculated. When the speed of the steel sheet to be processed after passing through the next welding site is known, this value may be substituted for V. In S13-3, the values of the front and back band edges (steady and maximum) are fetched from the strip band calculating means 107.

  In S13-4 of FIG. 13, it is determined whether the band edge of the stationary part of the steel plate 151 intersects with the nozzle. According to the notations and symbols in FIG. 7, the intersection determination between the front nozzle and the front band edge is performed based on whether or not the relational expression (12) is satisfied. This is performed depending on whether or not the above is satisfied.

[Equation 12]
Dt <-Bt

[Equation 13]
Db <Bb

  When at least one of the nozzles intersects with the strip band, the command value of the nozzle gap is changed in a direction to avoid contact in S13-5. That is, for the nozzle gaps that intersect, the command value of the front nozzle gap is limited so that Dt is larger than -Bt on the front side, and the back nozzle gap of Db is larger than Bb on the back side. Limit the command value. Regarding the fact that the target adhesion amount cannot be satisfied due to the limitation of the nozzle gap operation, it is conceivable to reduce the speed of the steel plate 151 or increase the nozzle pressure according to the relationship indicated by the plating adhesion amount prediction model. In step S13-6, the nozzle pressure command value, the calculated nozzle gap command value, the strip band value, and the proximity (distance) between the nozzle 153 and the band edge are output. The proximity between the nozzle and the front band edge is calculated by the relational expression (14), and the proximity between the nozzle and the back band edge is calculated by the relational expression (15).

[Formula 14]
Lt = Dt + Bt
= Dt + ΔD-S

[Equation 15]
Lb = Db−Bb
= Db-ΔD-S

  If the nozzle and the band edge of the steady portion of the steel plate 151 do not intersect in S13-4, the process proceeds to S13-6 without performing the process in S13-5.

  FIG. 14 shows processing executed by the nozzle open / close means 110. In S <b> 14-1, the proximity of the front band edge and the front nozzle and the proximity of the back band edge and the back nozzle calculated for the maximum value of the strip band are fetched from the control unit 103. In S14-2, it is determined whether the steel plate 151 and the band edge intersect with the nozzle. The intersection determination may be performed in the same manner using the relational expression of Expression 12 and the relational expression of Expression 13. The strip band is maximized because the front and rear ends of the steel plate 151, that is, in the vicinity of the welded portion 158, and in the case of crossing, in S14-3, a process for increasing the nozzle gap by timing near the welded portion 158 (nozzle open) ) And after the vicinity of the welded portion 158 has passed the position of the nozzle 153, a process (nozzle close) is performed to reduce the nozzle gap value calculated by the control means 103. As a result, automatic control can be continued while avoiding contact between the nozzle and the steel plate in the vicinity of the welded portion.

  FIG. 15 shows processing executed by the alarm notification means 109. In S15-1, the distance between the front band edge and the front nozzle and the distance between the back band edge and the back nozzle are fetched from the control means 103. The distance is calculated by the relational expression of Expression 14 and the relational expression of Expression 15. In S15-2, it is determined whether or not the front band edge and the front nozzle and the back band edge and the back nozzle are close to each other by a predetermined value or more. The proximity limit value used for the determination is input in advance by the user of the plating adhesion amount control apparatus 100. If it is determined that at least one of the front side and the back side is close, an alarm signal is output to the alarm device 130 in S15-3. Then, an alarm is issued from the alarm device 130. As a specific method of alarm, sound, blinking of light, display on an operation display, etc. can be considered, and an appropriate means may be selected according to the system. Upon receiving the alarm, the operator can take safety measures such as manually opening the nozzle.

  FIG. 16 shows a display example when the output of the control means 103 is displayed on the display device 120. In the display example of FIG. 16, information necessary for the operator to control the plating plant by avoiding contact between the nozzle and the steel plate, such as the nozzle gap, the steel plate position, and the strip band value, is displayed in one screen. Has been. By monitoring the value of the strip band, the proximity between the nozzle and the band edge, etc. with the display device, the operator can perform the plating adhesion amount control while grasping the transition of the strip band. Using such monitor information, the operator can know the timing of appropriate manual intervention during automatic control, as well as the warpage in the plate width direction of the steel plate, the vibration amplitude of the steel plate, and the degree of bad shape at the end of the steel plate. It can be used as a reference for parameter adjustment to obtain. Further, it can be used as a reference when adjusting the proximity limit value when the alarm is issued or the contents of the strip band calculation table 108.

  In the present embodiment, the edge shape of the steel plate 151 is set to a value associated with the plate width and thickness, and is taken from the edge shape storage table 1002, but is actually measured by a shape meter provided for the cold rolling process, which is the previous process. The values obtained may be used. In this case, the plating adhesion amount control device 100 automatically constructs the edge shape storage table 1002 associated with the steel plate number if the shape measurement value of the steel plate taken in by the cold rolling mill control device can be taken in via the network. can do. Alternatively, the edge shape storage table 1002 may be constructed by the operator acquiring information on the cold rolling process and inputting the information to the plating adhesion amount control device 100.

  As another embodiment of the present invention, FIG. 17 shows a case where the nozzle opening is gradually reduced when the control means 103 closes the nozzle gap and the nozzle and the strip edge are close to each other. An example will be described in which the control means 103 executes setup control to calculate and output the set values of the nozzle gap and nozzle pressure of the steel plate to be processed next before passing through the welded portion of the steel plate 151.

  In step S <b> 17-1, the nozzle pressure preset value is fetched from the nozzle pressure preset table 102. In S17-2, a command value for the nozzle gap is calculated. The nozzle gap command value is obtained by transforming the relational expression of Equation 1 and solving for D, substituting the preset value of the nozzle pressure for P, the target adhesion amount taken from the manufacturing information table 101 for W, and the current speed of the steel plate 151 for V. This can be calculated. If the speed of the steel sheet to be processed after passing through the welding site is known, this value may be substituted for V. In S17-3, the values of the front and back band edges (steady and maximum) are taken in from the strip band calculation means 107. In S17-4, it is determined whether or not the band edge of the steady portion of the steel plate 151 is close to the nozzle after control.

  According to the notation and reference of FIG. 7, the proximity determination between the front nozzle and the front band edge is performed according to whether the following equation 16 is satisfied, and the proximity determination between the back nozzle and the back band edge is performed according to the following equation 17: Is done depending on whether you are satisfied.

[Equation 16]
Dt <− (Bt + δB1)

[Equation 17]
Db <(Bb + δB2)

  If at least one of the nozzles is close to the strip band, in S17-5, the nozzle is not controlled to the target value all at once, but is gradually brought closer to the target value. As the moving speed of the nozzle, it is conceivable to multiply the normal moving speed by a constant, for example, about 1/5. By reducing the nozzle gap operating speed, it becomes possible for the operator to pay close attention to the movement, and when there is a risk of contact between the nozzle 153 and the steel plate 151, backup such as switching the nozzle control to manual is possible. In step S17-6, the nozzle pressure command value, the nozzle gap command value calculated by reducing the moving speed, the strip band value, and the proximity (distance) between the nozzle 153 and the band edge are output. In S17-4, when the band and the band edge of the steady portion of the steel plate 151 do not intersect, the process proceeds to S17-6 without performing the process of S17-5.

  The plating adhesion amount prediction model and various tables described in this specification are stored in a storage unit (not shown) provided in the plating adhesion amount control device.

  It can be widely applied to the control of the coating amount in the steel process line.

It is a figure which shows the structure of the plating adhesion amount control system which concerns on this invention. It is a figure which shows the structure of the manufacture information table of the plating adhesion amount control apparatus which concerns on this invention. It is a figure which shows the structure of the nozzle pressure preset table of the plating adhesion amount control apparatus which concerns on this invention. It is a flowchart which shows the process of the stability determination means based on this invention. It is a flowchart which shows the process of the welding site | part passage determination means based on this invention. It is a flowchart which shows the process of the steel plate position calculation means based on this invention. It is a figure which shows the relative relationship between a nozzle position and a steel plate position. It is a flowchart which shows the process of a strip band calculation means. It is a schematic diagram explaining a strip band. It is a figure which shows the structure of a strip band calculation table. It is a figure which shows the structure of a steel plate vibration amplitude storage table. It is a figure which shows the structure of an edge shape storage table. It is a flowchart which shows an example of a process of a control means. It is a flowchart which shows the process of a nozzle open close means. It is a flowchart which shows the process of an alarm alerting means. It is a figure which shows an example of the display screen of a display apparatus. It is a flowchart which shows another example of the process of a control means.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Plating adhesion amount control apparatus, 101 ... Manufacturing information table, 102 ... Nozzle pressure preset table, 103 ... Control means, 104 ... Stability determination means, 105 ... Welding part passage determination means, 106 ... Steel plate position calculation means, 107 ... Strip Band calculation means 108 ... Strip band calculation table 109 ... Alarm reporting means 110 ... Nozzle open / close means 120 ... Display device 130 ... Alarm device 150 ... Plating plant 151 ... Steel plate (strip) 152 ... Plating Bathtub (pot), 153 ... Nozzle, 157 ... Plating adhesion meter, 158 ... Welded part

Claims (12)

A plating plant that attaches plating of the desired thickness to the steel sheet by immersing the steel plate that is continuously sent in the hot dipping bath, blowing high pressure gas from the nozzle immediately after pulling up, and blowing off unnecessary plating. A plating adhesion amount control device for controlling,
Steel plate position calculating means for calculating the steel plate position;
Control means for calculating and outputting a command value for nozzle pressure and a command value for nozzle position for attaching a desired plating amount to the steel sheet, and
Strip that is a value corresponding to the sum of the thickness of the steel sheet, the vibration amplitude in the thickness direction of the steel sheet, the amount of warpage in the width direction of the steel sheet, the amount of twist with respect to the nozzle of the steel sheet, and the amplitude of the wavy shape at the end of the steel sheet strip calculating a band to calculate a back band edge you corresponds a movable limit position of the back side of the steel plate position and table band edge from the strip band you movable limit position and corresponds in front of steel sheets A band calculating means,
The control means takes in the front band edge and the back band edge, determines the intersection of the nozzle and band edge on the front side of the steel sheet and the intersection of the nozzle and band edge on the back side of the steel sheet, and at least one of them intersects In this case, the plating adhesion amount control device corrects and outputs the command value of the nozzle position. Storage means for storing a plating adhesion amount prediction model describing at least a relationship between a steel plate speed, a nozzle pressure, a distance between the nozzle and the steel plate, and a plating adhesion amount adhering to the steel plate;
Equipped with a plating adhesion meter that measures the amount of plating attached to the steel sheet,
The steel plate position calculating means estimates the distance between the front nozzle and the steel plate front side calculated by inputting the front side plating adhesion amount, nozzle pressure and steel plate speed of the steel plate measured by the plating adhesion meter into the plating adhesion amount prediction model. The estimated value of the distance between the back nozzle and the steel plate back side calculated by inputting the value, the back side plating adhesion amount of the steel plate measured with the plating adhesion meter, the nozzle pressure and the steel plate speed into the plating adhesion amount prediction model, and the steel plate The plating adhesion amount control device according to claim 1, wherein the position of the steel plate is estimated from the position of the front nozzle and the position of the back nozzle of the steel plate. A stability determining means for determining whether or not the value of the plating adhesion amount measured by the plating adhesion meter is a stable value corresponding to the current nozzle pressure, nozzle position, and steel plate speed;
A welded part passage determining means for determining that a welded part connecting the steel plates passes through the nozzle position, and
The plating adhesion amount control device according to claim 2, wherein the steel sheet position calculation means is activated at any one of a timing at which a stable adhesion amount is detected and a timing at which the welded portion passes a nozzle position. The strip band calculating means calculates a front band edge on the steel plate front side and a back band edge on the steel plate back side by adding or subtracting a value obtained by multiplying the strip band by a value of 1/2 or more to the steel plate position. It outputs. The plating adhesion amount control apparatus of any one of Claims 1-3 characterized by the above-mentioned. The strip band calculating means calculates the strip band using the amplitude of the wavy shape at the end of the steel plate in the vicinity of the welded portion of the steel plate, and then adds a value obtained by multiplying the strip band by a value of 1/2 or more to the steel plate position. Or, by subtracting, the front band edge on the steel plate front side and the back band edge on the steel plate back side are calculated and output,
Determine the proximity based on the distance between the front nozzle position and the front band edge calculated as the command value, and determine the proximity based on the distance between the back nozzle position and the back band edge calculated as the command value. A value calculated as a command value at a timing when the vicinity of the welded part passes through the nozzle position when the proximity of the welded part exceeds a predetermined allowable value and the vicinity of the welded part finishes passing through the nozzle position 5. The plating adhesion amount control device according to claim 1, further comprising a nozzle open / close means that closes the nozzle to the top. Equipped with an alarm device that issues an alarm upon receiving an alarm signal,
Determine the proximity based on the distance between the front nozzle position and the front band edge calculated as the command value, and determine the proximity based on the distance between the back nozzle position and the back band edge calculated as the command value. The plating adhesion amount control device according to any one of claims 1 to 5, further comprising an alarm notification means for outputting an alarm signal to the alarm device when the proximity of the electrode exceeds a predetermined allowable value. . Determine the proximity between the front nozzle and the front band edge and the proximity between the back nozzle and the back band edge,
When at least one of them is close, the change amount of the command value of the corresponding nozzle position in unit time is set to a value smaller than the normal change amount so that the operator can manually intervene in the nozzle position control. The plating adhesion amount control apparatus according to any one of claims 6 to 6.   8. A display device that displays the calculation results of the steel plate position, strip band, front band edge, and back band edge together with operation information including the nozzle position and nozzle pressure on the same screen. The plating adhesion amount control apparatus of any one of these. Control the plating plant that attaches the plating of the desired thickness to the steel sheet by immersing the steel plate that is continuously sent in the hot dipping bath, blowing high pressure gas from the nozzle immediately after pulling up, and blowing off unnecessary plating. A plating adhesion amount control device,
Storage means for storing a plating adhesion amount prediction model describing a relationship between at least the speed of the steel sheet, the nozzle pressure, the distance between the nozzle and the steel sheet, and the adhesion amount of the plating adhering to the steel sheet;
Strip that is a value corresponding to the sum of the thickness of the steel sheet, the vibration amplitude in the thickness direction of the steel sheet, the amount of warpage in the width direction of the steel sheet, the amount of twist with respect to the nozzle of the steel sheet, and the amplitude of the wavy shape at the end of the steel sheet Strip band calculating means for calculating a band and calculating a front band edge corresponding to the movable limit position on the front side of the steel sheet from the steel plate position and the strip band and a back band edge corresponding to the movable limit position on the back side of the steel sheet; With
The nozzle position and nozzle pressure for depositing the desired plating on the steel sheet, with the constraint that the nozzle on the front side of the steel sheet and the front band edge do not intersect and the nozzle on the back side of the steel sheet and the back band edge do not intersect A control means for calculating the combination of the above using the plating adhesion amount prediction model,
A plating adhesion amount control device characterized by comprising. Control the plating plant that attaches the plating of the desired thickness to the steel sheet by immersing the steel plate that is continuously sent in the hot dipping bath, blowing high pressure gas from the nozzle immediately after pulling up, and blowing off unnecessary plating. A plating adhesion amount control method,
Strip that is a value corresponding to the sum of the thickness of the steel plate, the vibration amplitude in the thickness direction of the steel plate, the amount of warpage in the plate width direction of the steel plate, the amount of twist with respect to the nozzle of the steel plate, and the amplitude of the wavy shape at the end of the steel plate Calculate and output the band,
Calculate and output the estimated value of the distance between the surface nozzle and the steel sheet front side from the surface side plating adhesion amount of the steel sheet measured with the plating adhesion meter, the nozzle pressure and the steel sheet speed,
Calculate and output the estimated value of the distance between the back nozzle and the steel plate back side from the back side plating adhesion amount of the steel plate measured with the plating adhesion meter, the nozzle pressure and the steel plate speed,
Estimate and output the position of the steel plate from these estimated values, the nozzle position on the front side of the steel plate, and the nozzle position on the back side of the steel plate,
By adding or subtracting a value obtained by multiplying the strip band by a value of 1/2 or more to the position of the steel plate, the front band edge on the steel plate front side and the back band edge on the steel plate back side are calculated and output,
Correct the nozzle position by the front band edge and the back band edge,
The plating adhesion amount control method characterized by this. Calculate the nozzle pressure and nozzle position command values so that the desired plating adheres to the steel sheet,
Calculate the distance between the front nozzle position and the front band edge calculated as a command value, and the distance between the back nozzle position and the back band edge calculated as a command value,
The intersection of the front nozzle and the front band edge and the intersection of the back nozzle and the back band edge are determined using the sign of the distance,
The plating adhesion amount control method according to claim 10, wherein, when at least one of the intersections intersects, the intersection is eliminated by restricting a change amount of the command value of the corresponding nozzle position. Calculate the nozzle pressure and nozzle position command values so that the desired plating adheres to the steel sheet,
Calculate the distance between the front nozzle position and the front band edge calculated as a command value, and the distance between the back nozzle position and the back band edge calculated as a command value,
The proximity of the front nozzle and the front band edge and the proximity of the back nozzle and the back band edge are determined using the sign of the distance,
When at least one of the proximity between the front nozzle and the front band edge and the proximity between the back nozzle and the back band edge is close, the amount of change in the unit time of the command value of the corresponding nozzle position is set to a small value. The plating adhesion amount control method according to claim 10, wherein manual intervention of an operator in nozzle position control is enabled.

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