JP6327218B2 - Reflow processing method for continuous tinning line - Google Patents

Description

  The present invention relates to a reflow processing method for a continuous tinning line.

  A tin-plated steel sheet is widely used as a surface-treated steel sheet for food cans and other general cans. In the production of this tin-plated steel sheet, a reflow treatment is usually employed in order to generate an Fe—Sn alloy layer and to improve glossiness and corrosion resistance.

  In order to control the temperature rise of the non-treated steel sheet within a predetermined range, the reflow treatment is generally performed by the use of induction reflow using resistance heating or induction reflow using induction heating for conduction reflow. is there. In addition, in order to control the degree of alloying of the Fe—Sn alloy layer, an alloying degree meter is introduced into the line to actually measure the degree of alloying, or the plate temperature of the steel sheet to be treated, which is the main factor of alloying, is increased It is necessary to control with accuracy.

  Conventionally, the control of the plate temperature of the steel plate to be processed is performed by confirming the gloss of the surface of the steel plate to be processed with the naked eye, or by applying image processing as described in Patent Document 1, It has been carried out by detecting and changing the set value of the plate temperature of the steel sheet to be processed on the alloying furnace outlet side. This is because it was difficult to measure the plate temperature of the steel plate to be processed using a contact-type thermometer because both the reflow and the induction reflow were charged to the steel plate to be processed. The emissivity of the surface tin is low, and the emissivity of the surface of the steel sheet to be processed varies greatly depending on the amount of metal tin, alloy tin or their ratio. This is because there was a problem that the target amount of alloy tin and alloying degree could not be obtained because it was not possible to measure accurately with use.

JP 09-256193 A

  However, when changing the plate temperature setting value of the steel plate to be processed on the conventional alloying furnace outlet side, there is a large personal error in the visual judgment, and the plate temperature of the steel plate to be processed in which there is no flow line in the image processing. The boundary temperature was simply found, and the alloy tin amount of the tin-plated steel sheet could not be accurately controlled by any means.

  Then, an object of this invention is to provide the reflow processing method of the continuous tinning line which can control the alloy tin amount of a tinning steel plate accurately.

  The present inventor has made extensive studies to achieve the above object, and in the reflow line of the continuous tin plating line of the steel sheet, using the radiation thermometer with the corrected emissivity, the alloying furnace exit side of the steel sheet to be processed Control the output power of the reflow so that the plate temperature of the steel plate to be processed becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed, and accurately control the plate temperature on the alloying furnace outlet side of the steel plate to be processed. Thus, it was learned that the amount of tin alloy in the tin-plated steel sheet can be controlled with high precision, and the present invention has been completed.

That is, this invention is the following [1]-[ 5 ].
[1] In a reflow line of a continuous tin plating line for steel sheets, the steel sheet to be continuously plated is heated and heated by the output power of conduction reflow using resistance heating, and an alloying furnace A reflow treatment method of a continuous tin plating line for rapidly cooling the treated steel plate, measuring the temperature of the treated steel plate on the exit side of the alloying furnace with a radiation thermometer,
(1) Based on the plate width, plate thickness, line speed, metal tin amount target value, and alloy tin amount target value of the steel plate to be treated, the output power at the time of heating and heating by conduction reflow using the resistance heating is calculated. Set,
(2) The emissivity target value of the radiation thermometer is set based on the metal tin amount target value, the alloy tin amount target value, and the emissivity of tin , wherein the emissivity is determined by the heat radiation of the object. Is the ratio of the energy of the light emitted at the same temperature to the energy of the light emitted by the black body of the same temperature,
(3) using a preset alloy model, the metallic tin amount target value, the alloy of tin amount target value, the emissivity target value and the ratio in which emissivity correction target value and the emissivity of the tin, and Based on the sheet temperature on the alloying furnace entry side of the steel sheet to be treated, the target temperature value on the alloying furnace exit side of the steel sheet to be treated is calculated,
(4) Using a radiation thermometer in which the emissivity target value is set, the plate temperature on the alloying furnace outlet side of the steel plate to be processed becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed. In addition, by controlling the output power of the conduction reflow using the resistance heating, a part of the steel plate to be treated is passed through a reflow line,
(5) After passing a part of the steel plate to be treated through the reflow line, the amount of metal tin and the amount of alloy tin on the surface of a part of the steel plate to be treated were measured,
(6) the object to be treated metallic tin amount of a portion of the surface and metallic tin amount measured values obtained by actually measuring the alloy of tin content and alloy tin content measured value of the steel sheet, and based on the emissivity of the tin, the Correct the emissivity of the radiation thermometer,
(7) above using the metal tin content measured value and the alloy of tin content measured values, and the radiation thermometer corrected emissivity based on the emissivity of the tin portion of the surface of the treated steel sheet, wherein as sheet temperature alloying furnace exit side of the remainder of the treated steel sheet is a sheet temperature target value of the alloying furnace exit side of the object to be treated steel sheet, by controlling the output power of the conduction reflow with the resistive heating ,
The steel plate to be treated consists of a steel plate to be treated that is reflow-treated in advance and a steel plate to be treated that is reflow-treated after.
Against the processed steel sheet reflow process to <I> said preceding performs processing (1) above to (7),
<II> Measure the amount of tin plating adhesion of the steel sheet to be treated before reflow treatment and the amount of tin plating adhesion of the steel sheet to be treated after reflow treatment,
<III> Calculate the difference between the amount of tin plating adhesion of the steel sheet to be treated to be reflowed in advance and the amount of tin plating adhesion of the steel sheet to be treated to be reflowed after the reflow treatment,
<IV-1> When the difference is within a predetermined range, the emissivity based on the measured value of the metal tin amount and the measured value of the alloy tin amount for the steel sheet to be processed to be reflowed following the subsequent process. Using the radiation thermometer corrected, the sheet temperature on the alloying furnace outlet side of the steel sheet to be processed to be reflowed in the subsequent process is the alloying furnace outlet side of the steel sheet to be processed to be reflowed in advance. To control the output power of the conduction reflow using the resistance heating so that the plate temperature target value of
If <IV-2> the difference exceeds a predetermined range, relative to the treated steel sheet reflow process with the trailing, the process of (1) above to (7), continuous tin plating line Reflow processing method .
[2 ] In the reflow line of the continuous tin plating line of steel sheet, the steel sheet to be treated that has been continuously plated is subjected to the output power of conduction reflow using resistance heating and induction reflow using induction heating. A reflow treatment method for a continuous plating line in which the temperature of the heated steel sheet is passed through an alloying furnace, the temperature of the steel sheet to be treated is measured with a radiation thermometer, and the steel sheet to be treated is rapidly cooled. There,
(1) Conduction reflow using resistance heating and induction reflow using induction heating based on the plate width, plate thickness, line speed, metal tin amount target value and alloy tin amount target value of the steel plate to be treated Set the output power during heating and heating with
(2) The emissivity target value of the radiation thermometer is set based on the metal tin amount target value, the alloy tin amount target value, and the emissivity of tin , wherein the emissivity is determined by the heat radiation of the object. Is the ratio of the energy of the light emitted at the same temperature to the energy of the light emitted by the black body of the same temperature,
(3) using a preset alloy model, the metallic tin amount target value, the alloy of tin amount target value, the emissivity target value and the ratio in which emissivity correction target value and the emissivity of the tin, and Based on the sheet temperature on the alloying furnace entry side of the steel sheet to be treated, the target temperature value on the alloying furnace exit side of the steel sheet to be treated is calculated,
(4) Using a radiation thermometer in which the emissivity target value is set, the plate temperature on the alloying furnace outlet side of the steel plate to be processed becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed. In addition, by controlling the output power of the induction reflow using the induction heating and the induction reflow using the resistance heating, a part of the steel plate to be treated is passed through a reflow line,
(5) After passing a part of the steel plate to be treated through the reflow line, the amount of metal tin and the amount of alloy tin on the surface of a part of the steel plate to be treated were measured,
(6) the object to be treated metallic tin amount of a portion of the surface and metallic tin amount measured values obtained by actually measuring the alloy of tin content and alloy tin content measured value of the steel sheet, and based on the emissivity of the tin, the Correct the emissivity of the radiation thermometer,
(7) above using the metal tin content measured value and the alloy of tin content measured values, and the radiation thermometer corrected emissivity based on the emissivity of the tin portion of the surface of the treated steel sheet, wherein The reflow using the resistance heating and the induction heating are used so that the plate temperature on the alloying furnace outlet side of the remaining steel plate becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed . to control the output power of the induction reflow had,
The steel plate to be treated consists of a steel plate to be treated that is reflow-treated in advance and a steel plate to be treated that is reflow-treated after.
The treated steel sheet reflow process to <I> said preceding performs processing (1) above to (7),
<II> Measure the tin plating adhesion amount of the steel sheet to be treated before reflow treatment and the tin plating adhesion amount of the steel sheet to be treated after reflow treatment,
<III> Calculate the difference between the amount of tin plating adhesion of the steel sheet to be treated to be reflowed in advance and the amount of tin plating of the steel sheet to be treated to be reflowed after the reflow treatment,
<IV-1> When the difference is within a predetermined range, the emissivity is corrected based on the measured value of the metal tin amount and the measured value of the alloyed tin amount of the steel sheet to be processed to be reflowed following Using the radiation thermometer, the plate temperature on the alloying furnace outlet side of the steel sheet to be processed to be reflowed in the subsequent process is the same as that on the alloying furnace outlet side of the steel sheet to be processed to be reflowed in advance. so that the temperature target value, and controls the output power of the induction reflow using conduction reflow and the induction heating using the resistance heating,
If <IV-2> the difference exceeds a predetermined range, relative to the treated steel sheet reflow process with the trailing, the process of (1) above to (7), continuous tin plating line Reflow processing method.
[ 3 ] After correcting the emissivity of the radiation thermometer, the measured value of the metal tin amount, the measured value of the alloy tin amount, the corrected emissivity, the plate temperature and the emissivity of the steel plate to be treated on the alloying furnace entrance side The continuous tin according to [1] or [ 2] , wherein the alloying model is corrected based on a plate temperature of the treated steel plate measured using the radiation thermometer corrected for the alloying furnace. Reflow processing method for plating line.
[ 4 ] When actually measuring the amount of metallic tin and the amount of alloyed tin on the surface of a part of the steel sheet to be treated, a sample is taken from the steel sheet after passing through a tin plating line, and the specimen is taken from the collected sample. The reflow treatment control method for a continuous tin plating line according to any one of [1] to [ 3 ] above, in which the metal tin amount and the alloy tin amount on a part of the surface of the treated steel plate are measured.
[ 5 ] When measuring the amount of metal tin and the amount of alloy tin on a part of the surface of the steel sheet to be treated, the amount of metal tin on the surface of a part of the steel sheet to be treated using an alloying meter the actually measuring the alloy of tin content, the above-mentioned [1] to [4] reflow processing control method of the continuous tin plating line according to any one of.

  ADVANTAGE OF THE INVENTION According to this invention, the reflow processing method of the continuous tin plating line which can control the amount of alloy tin of a tin plating steel plate accurately can be provided.

FIG. 1 is a diagram showing a configuration of a reflow line for carrying out the reflow processing method of the present invention. FIG. 2 is a flowchart showing the reflow processing method of the present invention. FIG. 3 is a histogram showing the accuracy of the alloy tin amount of the tin-plated steel sheet according to the example. FIG. 4 is a histogram showing the accuracy of the alloy tin amount of the tin-plated steel sheet according to the comparative example.

Hereinafter, embodiments of the present invention will be specifically described.
First, an example of a configuration of a reflow line for implementing the reflow processing method of the present invention shown in FIG. 1 will be described.

In the reflow line shown in FIG. 1 conductor roll 2 and no. A two-conductor roll 8, an alloying furnace 3 that keeps the steel plate 1 to be heated to a high temperature, an induction heater 4 that induction-heats the steel plate 1 to be treated, and a quench tank 7 that cools and solidifies tin that has been remelted by heating. A quench roll 6 for winding the steel plate 1 to be treated in the quench tank 7 is provided.
In the case where heating by induction reflow is not performed, the induction heater 4 can be omitted.

  Further, the reflow line shown in FIG. 1 includes a radiation thermometer 5 for measuring the plate temperature on the outlet side of the alloying furnace 3 and a radiation thermometer 9 for measuring the plate temperature on the inlet side of the alloying furnace 3. . The emissivity of the radiation thermometer 5 is set to the emissivity target value calculated based on the target value at the beginning of the reflow process, but after the reflow process starts, the emissivity (correction value) calculated based on the actually measured data is set. Use to correct emissivity. As the emissivity of the radiation thermometer 9, for example, the emissivity of tin is set.

  Further, in the reflow line shown in FIG. 1, an adhesion meter 31 for measuring the amount of tin plating of the steel plate 1 to be processed before the reflow treatment, a plate width detector 32 for measuring the plate width, and a plate thickness are measured. A sheet thickness detecting unit 33 for measuring the line speed, a line speed detecting unit 34 for measuring the line speed, an alloying degree meter 35 for measuring the degree of alloying of the steel sheet 1 after the reflow process, and after the reflow process The adhesion amount meter 36 for measuring the tin plating adhesion amount of the to-be-processed steel plate 1 can be provided.

Further, the reflow line shown in FIG. 1 includes, as a control unit, an input / output unit 20 for inputting / outputting data, a calculation unit 21 for performing calculation, an alloy tin amount target value, a metal tin amount target value, a plate Database 22 storing width, plate thickness, line speed, emissivity of tin, alloying progress speed correction coefficient for each steel type, input device 23 for inputting numerical values, memory for writing and storing calculation results Medium 24, display device 25 for displaying input numerical values and the like; 1 conductor roll 2 and no. A conduction reflow power supply unit 10 for supplying output power during heating and heating to the two-conductor roll 8; an induction reflow power supply unit 11 for supplying output power during heating and heating to the induction heater 4; and induction reflow power. An induction reflow power control unit 12 for controlling the output power of the supply unit 11 and a conduction reflow power control unit 13 for controlling the output power of the conduction reflow power supply unit 10 are provided.
If all the parameters necessary for the reflow process are stored in the database 22, the input device 23 can be omitted.
The display device 25 can be omitted.

  The to-be-treated steel sheet 1 plated with tin is No. After winding around the conductor roll 2, it enters the alloying furnace 3, then enters the quench tank 7 and winds around the quench roll 6. The two-conductor roll 8 is wound and the reflow process is finished. The plate temperature of the steel plate 1 to be treated is measured by a radiation thermometer 9 installed on the entry side of the alloying furnace 3 and a radiation thermometer 5 installed on the exit side of the alloying furnace 3.

At that time, it is called “conduction reflow”. 1 conductor roll 2 and No. 1 A current is passed through the steel plate 1 to be processed by the two-conductor roll 8 to heat the steel plate 1 to be heated and kept at a high temperature in the alloying furnace 3. If necessary, an induction heater 4 is installed between the alloying furnace 3 and the quench tank 7, referred to as induction reflow, a high-frequency current is passed through the steel plate 1 to be processed, and the steel plate 1 to be processed is heated by induction heating. May be.
Alloy steel is produced on the surface of the steel sheet 1 to be treated by heating the steel sheet 1 to be treated by conduction reflow, or by conduction reflow and induction reflow, and melting and quenching the metal tin on the surface of the steel sheet 1 to be treated. .
On the other hand, the emissivity ε ′ of the steel sheet varies greatly depending on the amount of metallic tin and alloy tin on the surface of the steel sheet 1 to be treated. Therefore, the emissivity is calculated from the metal tin amount and the alloy tin amount on the surface of the steel plate 1 to be processed, and the emissivity of the radiation thermometer 5 is corrected, so that the plate temperature on the outlet side of the measured alloying furnace 3 can be more accurately measured. Shall. The metal tin amount and the alloy tin amount on the surface of the steel plate 1 to be processed are the target values at the beginning of the sheet passing, and then, after a part of the steel plate 1 to be processed is reflow-treated, The actual measurement value obtained by actual measurement is used.

  Next, (1) to (7) of the reflow processing method for the continuous tin plating line of the present invention will be described.

(1) Setting of output power at heating temperature rise The setting of output power at heating temperature rise is based on the plate width, plate thickness, line speed, metal tin amount target value and alloy tin amount target value of steel plate 1 to be treated. Then, it is performed by setting the output power at the time of heating and heating by the conduction reflow or the conduction reflow and the induction reflow.

The calculation unit 21 acquires the plate width, plate thickness, line speed, metal tin amount target value, and alloy tin amount target value of the steel plate 1 to be processed through the reflow line from the database 22 via the input / output unit 20. Then, the output power of the conduction reflow power supply unit 10 is calculated and sent to the conduction reflow control unit 13, or the output power of the conduction reflow power supply unit 10 and the induction reflow power supply unit 11 is calculated, It is sent to the induction reflow control unit 13 and the induction reflow power control unit 12 to set the output power during heating and heating.
In this process, the plate width, plate thickness, and line speed of the steel plate 1 to be processed are obtained from the plate width detection unit 32, the plate thickness detection unit 33, and the line speed detection unit 34, respectively, instead of obtaining numerical values from the database 22. A numerical value may be acquired, or a numerical value input from an input device may be acquired. Moreover, instead of obtaining a numerical value from the database 22, one or both of the metal tin amount target value and the alloy tin amount target value of the steel plate 1 to be processed may obtain a numerical value input from the input device 23.
The plate width, plate thickness, line speed, metal tin amount target value, and alloy tin amount target value of the steel plate 1 to be processed acquired by the calculation unit 21 may be written and stored in the storage medium 24.

The output power of the conduction reflow power supply unit 10 or the output power of the conduction reflow power supply unit 10 and the induction reflow power supply unit 11 is W = ρ × C × LS × 60 × t × 10 ⁻³ × w × ( It is _{calculated |} required by T1-T2) * _APSn * _APSn-Fe . Where, W: output power (W), ρ: specific gravity of iron (kg / m ³ ), C: specific heat of iron (J / kg ° C.), LS: line speed (m / min), t: Plate thickness (mm), w: plate width (mm), T1: plate temperature (° C) on the alloying furnace entry side of the steel plate 1 to be treated, T2: plate temperature target value (° C) on the alloying furnace exit side, A _PSn , _APSn-Fe : Correction constants calculated based on actual results for each target value of metal tin and target value of tin of alloy.

(2) Setting the emissivity target value of the radiation thermometer 5 The emissivity target value of the radiation thermometer 5 is set based on the metal tin amount target value, the alloy tin amount target value, and the tin emissivity. This is done by setting an emissivity target value of 5.

The calculation unit 21 acquires, from the database 22, the metal tin amount target value and the alloy tin amount target value of the steel sheet 1 to be processed through the reflow line and the tin emissivity through the input / output unit 20. The emissivity target value of the thermometer 5 is calculated, sent to the radiation thermometer 5, and set.
In this process, one or both of the target value for the metal tin amount and the target value for the tin content of the steel plate 1 to be processed may be obtained by acquiring a numerical value input from the input device 23 instead of acquiring a numerical value from the database 22. In the case where it is stored in the storage medium 24, the numerical value may be read out and acquired therefrom. Moreover, instead of obtaining a numerical value from the database 22, the numerical value input from the input device 23 may be obtained for the emissivity of tin.
The calculator 21 writes the calculated emissivity target value of the radiation thermometer 5 in the storage medium 24 and stores it.

In a certain aspect, the calculating part 21 calculates the emissivity target value of the radiation thermometer 5 by the following formula.
_{ε p '= ε Sn * f} 1 (M PSn) * f 2 (M PFe-Sn)
here,
ε _p ′ is the emissivity target value of the radiation thermometer 5,
ε _Sn is the emissivity of tin,
M _PSn is the target amount of metal tin,
_MPSn-Fe is the target amount of alloy tin,
f ₁ (M _PSn ) is a function of M _PSn ,
f ₂ (M _PSn—Fe ) is a function of M _PSn—Fe ,
The operator * is an integration operator.

As an example, in more detail, f ₁ (M _PSn ) is f ₁ (M _PSn ) = α ₁ M _PSn + β ₁ , and f ₂ (M _PSn-Fe ) is f ₂ (M _PSn-Fe ). = Α ₂ M _PSn-Fe + β ₂ . Here, α ₁ , α ₂ , β ₁ , and β ₂ are constants calculated based on actual results.

(3) Calculation of the target plate temperature on the outlet side of the alloying furnace 3 of the processed steel plate 1 The target temperature value on the outlet side of the alloying furnace 3 of the processed steel plate 1 is calculated using a preset alloying model. , Metal tin amount target value, alloy tin amount target value, emissivity correction target value which is a ratio of emissivity target value and tin emissivity, and the temperature of the steel sheet to be processed 1 on the inlet side of the alloying furnace 3 Then, it calculates by calculating the plate temperature target value on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed.

First, the calculation unit 21 obtains the emissivity of tin from the database 22, reads and obtains the emissivity target value from the storage medium 24, calculates the emissivity correction target value by the following formula, and writes it in the storage medium 24. Remember me.
Here, instead of obtaining the emissivity of tin from the database 22, a numerical value input from the input device 23 may be acquired, and when stored in the storage medium 24, the numerical value is read therefrom. May be obtained.

E _P = ε _p '/ ε _sn
here,
E _P is the emissivity correction target value,
ε _p ′ is the emissivity target value of the radiation thermometer 5,
ε _sn is the emissivity of tin.

Next, the calculation unit 21 reads and acquires the emissivity correction target value from the storage medium 24, obtains the metal tin amount target value and the alloy tin amount target value of the steel plate 1 to be processed, and the alloying progress rate correction coefficient for each steel type. Is obtained from the database 22, the plate temperature (actually measured value) of the steel sheet to be treated 1 entering the alloying furnace 3 is obtained from the radiation thermometer 9 in which the emissivity of tin is set, and a preset alloying model is used. Then, a target plate temperature value on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed is calculated, written in the storage medium 24 and stored.
One or both of the metal tin amount target value and the alloy tin amount target value of the steel plate 1 to be processed may be acquired from the input device 23 instead of the numerical value from the database 22, or the storage medium. 24, the numerical value may be read out and acquired from the data, and the alloying progression speed correction coefficient for each steel type is input from the input device 23 instead of acquiring the numerical value from the database 22. A numerical value may be acquired.

In one embodiment, an alloying model represented by the following formula is used as a preset alloying model.
Fe _Sn = A * (T1-T2) * E _P * K + B
here,
Fe _sn is the degree of alloying (%),
T1 is the plate temperature (° C.) of the steel sheet 1 to be treated on the entry side of the alloying furnace 3;
T2 _P is a target plate temperature (° C.) on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed.
E _P is the emissivity correction target value (the ratio of the emissivity epsilon _sn emissivity target value epsilon _{p 'and} tin corrected radiation thermometer),
K is an alloying speed correction factor for each steel type,
A and B are constants, respectively.
The operator “*” is an integration operator.

  The constants A and B are constants specific to each steel type having different components, and are calculated based on the record of the degree of alloying.

In another aspect, an alloying model represented by the following formula is used as a preset alloying model.
Fe _sn '= C * (T1-T2 _P ) * E _P * K + D
here,
Fe _sn 'is the amount of alloy tin (g / m ² ),
T1 is the plate temperature (° C.) of the steel sheet 1 to be treated on the entry side of the alloying furnace 3;
T2 _P is a target plate temperature (° C.) on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed.
E _P is the emissivity correction target value (the ratio of the emissivity epsilon _sn emissivity target value epsilon _{p 'and} tin corrected radiation thermometer),
K is an alloying speed correction factor for each steel type,
C and D are each a constant,
The operator “*” is an integration operator.

  The constants C and D are unique constants for each steel type having different components, and are calculated based on the actual amount of alloy tin.

(4) Partial reflow line passing plate of the steel plate 1 to be processed The reflow line passing plate of the steel plate 1 to be processed is an alloy of the steel plate 1 to be processed using the radiation thermometer 5 in which the emissivity target value is set. The output power of the conduction reflow power supply unit 10 or the conduction reflow power supply unit 10 and the plate temperature on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed become the target temperature value on the outlet side of the alloying furnace 3. This is done by controlling the output power of the induction reflow power supply unit 11 and passing a part of the treated steel plate 1 through the reflow line.

  While passing a part of the steel plate 1 to be processed through the reflow line, the calculation unit 21 starts from the radiation thermometer 5 in which the emissivity target value is set, and the temperature of the steel plate 1 on the outlet side of the alloying furnace 3 (actual measurement). Value), and the sheet temperature (actually measured value) of a part of the alloying furnace 3 exiting the steel sheet 1 to be processed is read from the storage medium 24 and acquired. The output power of the conduction reflow power supply unit 10 or the conduction reflow power supply unit 10 and the induction reflow power supply unit 11 is calculated so as to reach the temperature target value, and the conduction reflow power control unit 13 or the conduction reflow is calculated. The output power to the control unit 13 and the induction reflow power control unit 12 and the output power of the conduction reflow power supply unit 10 or the conduction reflow power supply unit 10 and Set the output power of the induction reflow power supply unit 11, for heating an object to be processed steel sheet 1.

(5) Actual measurement of metal tin amount and alloy tin amount of steel plate 1 to be processed Actual measurement of metal tin amount and alloy tin amount of steel plate 1 to be processed is carried out after passing a part of the steel plate 1 to be processed through a reflow line. This is done by actually measuring the amount of metallic tin and the amount of alloyed tin on the surface of a part of the treated steel sheet 1.

  Once the reflow line is stopped and the reflow process is performed, a sample is taken from a part of the steel sheet 1 to be processed, the amount of metal tin and alloy tin on the surface of the sample is measured, and the amount of metal tin is measured. Values and measured values of alloy tin are obtained.

  In the case where the adhesion amount meter 36 and the alloying degree meter 35 are installed in the reflow line, the calculation unit 21 does not stop the reflow line. The amount of metal tin on the surface of a part of the treated steel sheet 1 after obtaining the amount of tin plating adhesion from the adhesion amount meter 36 and the degree of alloying from the alloying degree meter 35 and performing the reflow treatment An actual measurement value and an alloy tin amount actual measurement value are calculated, written in the storage medium 24, and stored.

(6) Correction of the emissivity of the radiation thermometer 5 The correction of the emissivity of the radiation thermometer 5 is performed by actually measuring the amount of metal tin and alloy tin on the surface of a part of the steel plate 1 to be processed. This is performed by correcting the emissivity of the radiation thermometer 5 based on the actually measured value, the actually measured amount of tin alloy, and the emissivity of tin.

The arithmetic unit 21 reads and acquires the measured value of the metal tin amount and the alloy tin amount of the surface of a part of the surface of the steel sheet 1 after the reflow process is performed, and acquires the tin emissivity. Obtained from the database 22, the emissivity (correction value) of the radiation thermometer 5 is calculated and sent to the radiation thermometer 5.
In this process, instead of reading out and acquiring the measured metal tin amount and the measured alloy tin amount on a part of the surface of the steel sheet 1 to be processed from the storage medium 24, the numerical value input from the input device 23 is acquired. Alternatively, instead of obtaining the emissivity of tin from the database 22, a numerical value input from the input device 23 may be acquired, and when stored in the storage medium 24, the numerical value is read from the input device 23. You may get it.
The computing unit 21 may write and store the calculated emissivity (correction value) of the radiation thermometer 5 in the storage medium 24.

In one certain aspect, the calculating part 21 calculates the emissivity (correction value) of the radiation thermometer 5 by the following formula.
ε ′ = ε _Sn * f 1 (M _Sn ) * f 2 (M _Fe-Sn )
here,
ε ′ is the emissivity (correction value) of the radiation thermometer 5,
ε _sn is the emissivity of the tin surface, M _Sn is the measured amount of metallic tin,
M _Fe—Sn is a measured value of the amount of alloy tin,
f ₁ (M _Sn ) is a function of M _Sn ,
f ₂ (M _Fe—Sn ) is a function of M _Fe—Sn ,
The operator “*” is an integration operator.

As an example, more specifically, f ₁ (M _Sn ) is f ₁ (M _Sn ) = α ₃ M _Sn + β ₃ , and f ₂ (M _Fe—Sn ) is f ₂ (M _Fe—Sn ). = Α ₄ M _Fe-Sn + β ₄ . Here, α ₃ , α ₄ , β ₃ , and β ₄ are constants calculated based on actual results.

  The radiation thermometer 5 obtains the emissivity (correction value) from the emissivity calculation calculation unit 12 and corrects the emissivity.

(7) Output power control The output power is controlled by adjusting the emissivity based on the measured value of the amount of metal tin and the amount of alloy tin measured on a part of the surface of the steel sheet 1 and the emissivity of tin. The output of the conduction reflow 15 is used so that the plate temperature on the outlet side of the alloying furnace 3 of the remaining steel plate 1 to be processed becomes the target temperature on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed. This is done by controlling the power or the output power of the conduction reflow 15 and the induction reflow 16.

  While passing the remaining portion of the steel plate 1 to be processed through the reflow line, the calculation unit 21 calculates the plate temperature (actually measured value) on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed from the radiation thermometer 5 whose emissivity is corrected. The plate temperature (actually measured value) of the remaining steel plate 1 on the alloying furnace outlet side obtained and obtained from the storage medium 24 becomes the target plate temperature on the outlet side of the alloying furnace 3 of the steel plate 1 to be acquired. As described above, the output power of the conduction reflow power supply unit 10 or the conduction reflow power supply unit 10 and the induction reflow power supply unit 11 is calculated, and the conduction reflow power control unit 13 or the conduction reflow control unit 13 and the induction are calculated. It is sent to the reflow power control unit 12 and the conduction reflow power supply unit 10 or the conduction reflow power supply unit 10 and the induction riff Set the output power of over the power supply unit 11, for heating an object to be processed steel sheet 1.

In the reflow treatment method of the present invention, the gloss of the surface of the steel sheet 1 to be treated on the outlet side of the alloying furnace 3 is confirmed with the naked eye, and the set value of the plate temperature on the outlet side of the alloying furnace 3 of the steel sheet 1 to be treated is changed. Since the image processing is not performed to detect the flow line on the surface of the steel plate 1 to be processed and the set value of the plate temperature on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed is not changed, Since there is no room for entering and the boundary temperature of the plate temperature of the steel plate to be processed where there is no flow line is simply found, the plate temperature on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed can be accurately controlled.
Moreover, since the reflow processing method of this invention can control the plate | board temperature of the alloying furnace 3 exit side of the to-be-processed steel plate 1 with a sufficient precision, it can improve the precision of the alloy tin amount of the obtained tin-plated steel plate. I can expect. Furthermore, by improving the accuracy of the degree of alloying, the accuracy of the degree of alloying can also be improved, improving the gloss and corrosion resistance, which are the quality of the tin-plated steel sheet, and unnecessary in the reflow and induction reflow. It can be expected to contribute to power saving by suppressing heating.

(Correction of alloying model and update of target temperature at alloying furnace outlet side)
The reflow processing method of the present invention is based on the measured alloying amount of metal tin and the measured amount of tin alloy, the emissivity (correction value) of the radiation thermometer 5, the alloying furnace 3 entrance side of the steel plate 1 to be processed. When the alloying model is corrected based on the sheet temperature and the sheet temperature on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed, and the target temperature value on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed is updated, It is preferable because the temperature of the treated steel sheet 1 on the outlet side of the alloying furnace 3 can be measured with higher accuracy and the temperature of the processed steel sheet 1 on the outlet side of the alloying furnace 3 can be controlled more accurately.
The plate temperature target value on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed is obtained by using a preset alloying model, a metal tin amount target value, an alloy tin amount target value, an emissivity target value, and an emissivity of tin. Is calculated from the emissivity correction target value, which is the ratio of the above, and the plate temperature of the steel sheet to be processed 1 on the entry side of the alloying furnace 3.
By replacing the metal tin amount target value, the alloy tin amount target value and the emissivity target value of the formula representing the alloying model with the metal tin amount actual value, the alloy tin amount actual value and the emissivity (correction value), respectively. If the alloying model is corrected and the target temperature of the alloying furnace 3 exit side is updated, the temperature of the alloying furnace 3 exit side can be controlled more accurately. Can be controlled more accurately.

  By replacing the metal tin amount target value, alloy tin amount target value and emissivity target value of the equation representing the alloying model with the metal tin amount actual value, alloy tin amount actual value and emissivity (correction value), respectively, (3) Calculate the plate temperature target value on the outlet side of the alloying furnace 3 of the steel plate 1 to be processed (new plate temperature target value) on the outlet side of the alloying furnace 3 The output power of the reflow is controlled so that the plate temperature of the treated steel plate 1 on the outlet side of the alloying furnace 3 becomes a new plate temperature target value.

(Update of the target plate temperature on the alloying furnace exit side due to the difference in the amount of tin plating)
It should be noted that the portion of the steel plate 1 to be reflow processed in advance (the steel plate to be processed to be reflowed in advance) and the amount of tin plating adhering to the portion to be reflowed (following and reflow processing) When the difference from the amount of tin plating applied to the steel plate to be treated is within a predetermined range, the target temperature on the outlet side of the alloying furnace 3 of the steel plate to be treated and reflowed, and the radiation The emissivity target value and emissivity (correction value) of the thermometer 5 may be set to the same value as the steel plate to be processed in advance, but if the difference exceeds the processing range, it is preceded. (1) to (7) above (1) to (7) for the steel sheet to be reflow-treated after the processes (1) to (7) described above are performed on the steel sheet to be reflow-treated. It is preferable to perform the process.

  The tin plating adhesion amount can be obtained by temporarily stopping the reflow line, collecting a sample from the steel plate 1 before the reflow treatment is performed, and actually measuring the tin plating adhesion amount on the surface of the collected sample. When the adhesion amount meter 31 is installed in the reflow line, measurement can be performed without stopping the reflow line, which is preferable.

In addition, the predetermined range of the difference between the amount of tin plating adhesion of the steel sheet to be processed to be reflowed in advance and the amount of tin plating adhesion of the steel sheet to be processed to be reflowed later can be appropriately set. for example, preferably set to ± 0.1 g / ^{m 2,} more preferably to ± 0.05 g / ^{m 2,} and even more preferably from ± 0g / ^{m 2.}

400 coils of steel plate 15tonf to be processed with a plate thickness of 0.08 to 0.6 mm, a plate width of 450 to 1100 mm, and a tin adhesion amount of 1.0 to 14 g / m ² are prepared, passed through a reflow line, and reflow processed. did.
Of the above 400 coils, 200 coils were reflow processed by the reflow processing method of the present invention (Example), and the remaining 200 coils were visually radiated by the operator using a radiation thermometer with a constant emissivity. Judgment was made and reflow processing was performed (comparative example).
FIG. 3 shows the deviation ratio between the target value and the actual measurement value of the alloy tin amount of the coil reflow-treated by the reflow treatment method of the present invention. FIG. 4 shows the alloy tin amount of the coil reflow-treated by the conventional reflow treatment method. The deviation ratio between the target value and the actual measurement value is shown. 3 and 4, the numbers on the horizontal axis represent the median value of each class, and each class represents −5% or more and less than + 5% of the median value.
The deviation ratio between the target value of the alloy tin amount of the coil reflow-treated by the reflow treatment method of the present invention and the measured value is 1σ = 8% variance, and the target value of the alloy tin amount of the coil reflow-treated by the conventional reflow treatment method The deviation rate from the measured value is 1σ = 14% dispersion, and it was found that the accuracy of the alloy tin amount of the tin plating of the steel plate to be treated can be remarkably improved by the reflow treatment method of the present invention.

1: Steel plate to be treated 2: No. 1 conductor roll 3: alloying furnace 4: induction heater 5: radiation thermometer 6: quench tank roll 7: quench tank 8: No. 1 2 conductor roll 9: radiation thermometer 10: conduction reflow power supply unit 11: induction reflow power supply unit 12: induction reflow power control unit 13: conduction reflow power control unit 20: input / output unit 21: calculation unit 22: database 23: input device 24: storage medium 31: adhesion meter 32: plate width detector 33: plate thickness detector 34: line speed detector 35: degree of alloying meter 36: adhesion meter

Claims (5)

In a reflow line of a continuous tin plating line for steel sheets, the steel sheet to be treated that has been continuously plated is heated and heated by the output power of conduction reflow using resistance heating and passed through the alloying furnace. And, the reflow treatment method of the continuous tinning line for measuring the plate temperature of the treated steel sheet on the alloying furnace outlet side with a radiation thermometer, and quenching the treated steel plate,
(1) Based on the plate width, plate thickness, line speed, metal tin amount target value, and alloy tin amount target value of the steel plate to be treated, the output power at the time of heating and heating by conduction reflow using the resistance heating is calculated. Set,
(2) The emissivity target value of the radiation thermometer is set based on the metal tin amount target value, the alloy tin amount target value, and the emissivity of tin , wherein the emissivity is determined by the heat radiation of the object. Is the ratio of the energy of the light emitted at the same temperature to the energy of the light emitted by the black body of the same temperature,
(3) using a preset alloy model, the metallic tin amount target value, the alloy of tin amount target value, the emissivity target value and the ratio in which emissivity correction target value and the emissivity of the tin, and Based on the sheet temperature on the alloying furnace entry side of the steel sheet to be treated, the target temperature value on the alloying furnace exit side of the steel sheet to be treated is calculated,
(4) Using a radiation thermometer in which the emissivity target value is set, the plate temperature on the alloying furnace outlet side of the steel plate to be processed becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed. In addition, by controlling the output power of the conduction reflow using the resistance heating, a part of the steel plate to be treated is passed through a reflow line,
(5) After passing a part of the steel plate to be treated through the reflow line, the amount of metal tin and the amount of alloy tin on the surface of a part of the steel plate to be treated were measured,
(6) the object to be treated metallic tin amount of a portion of the surface and metallic tin amount measured values obtained by actually measuring the alloy of tin content and alloy tin content measured value of the steel sheet, and based on the emissivity of the tin, the Correct the emissivity of the radiation thermometer,
(7) above using the metal tin content measured value and the alloy of tin content measured values, and the radiation thermometer corrected emissivity based on the emissivity of the tin portion of the surface of the treated steel sheet, wherein as sheet temperature alloying furnace exit side of the remainder of the treated steel sheet is a sheet temperature target value of the alloying furnace exit side of the object to be treated steel sheet, by controlling the output power of the conduction reflow with the resistive heating ,
The steel plate to be treated consists of a steel plate to be treated that is reflow-treated in advance and a steel plate to be treated that is reflow-treated after.
<I> The processing (1) to (7) is performed on the steel sheet to be processed to be reflowed in advance.
<II> Measure the amount of tin plating adhesion of the steel sheet to be treated before reflow treatment and the amount of tin plating adhesion of the steel sheet to be treated after reflow treatment,
<III> Calculate the difference between the amount of tin plating adhesion of the steel sheet to be treated to be reflowed in advance and the amount of tin plating adhesion of the steel sheet to be treated to be reflowed after the reflow treatment,
<IV-1> When the difference is within a predetermined range, the emissivity based on the measured value of the metal tin amount and the measured value of the alloy tin amount for the steel sheet to be processed to be reflowed following the subsequent process. Using the radiation thermometer corrected, the sheet temperature on the alloying furnace outlet side of the steel sheet to be processed to be reflowed in the subsequent process is the alloying furnace outlet side of the steel sheet to be processed to be reflowed in advance. To control the output power of the conduction reflow using the resistance heating so that the plate temperature target value of
<IV-2> When the difference exceeds a predetermined range, reflow of a continuous tin plating line for performing the processes (1) to (7) on the steel sheet to be processed to be reflowed following the above process. Processing method. In the reflow line of a continuous tin plating line for steel plates, the temperature of the steel plate to be treated that is continuously fed is heated by the output power of the induction reflow using induction heating and the induction reflow using induction heating. And passing through the alloying furnace, measuring the sheet temperature of the treated steel sheet on the alloying furnace exit side with a radiation thermometer, and a reflow treatment method of a continuous plating line for rapidly cooling the treated steel sheet,
(1) Conduction reflow using resistance heating and induction reflow using induction heating based on the plate width, plate thickness, line speed, metal tin amount target value and alloy tin amount target value of the steel plate to be treated Set the output power during heating and heating with
(2) The emissivity target value of the radiation thermometer is set based on the metal tin amount target value, the alloy tin amount target value, and the emissivity of tin , wherein the emissivity is determined by the heat radiation of the object. Is the ratio of the energy of the light emitted at the same temperature to the energy of the light emitted by the black body of the same temperature,
(3) using a preset alloy model, the metallic tin amount target value, the alloy of tin amount target value, the emissivity target value and the ratio in which emissivity correction target value and the emissivity of the tin, and Based on the sheet temperature on the alloying furnace entry side of the steel sheet to be treated, the target temperature value on the alloying furnace exit side of the steel sheet to be treated is calculated,
(4) Using a radiation thermometer in which the emissivity target value is set, the plate temperature on the alloying furnace outlet side of the steel plate to be processed becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed. In addition, by controlling the output power of the induction reflow using the induction heating and the induction reflow using the resistance heating, a part of the steel plate to be treated is passed through a reflow line,
(5) After passing a part of the steel plate to be treated through the reflow line, the amount of metal tin and the amount of alloy tin on the surface of a part of the steel plate to be treated were measured,
(6) the object to be treated metallic tin amount of a portion of the surface and metallic tin amount measured values obtained by actually measuring the alloy of tin content and alloy tin content measured value of the steel sheet, and based on the emissivity of the tin, the Correct the emissivity of the radiation thermometer,
(7) above using the metal tin content measured value and the alloy of tin content measured values, and the radiation thermometer corrected emissivity based on the emissivity of the tin portion of the surface of the treated steel sheet, wherein The reflow using the resistance heating and the induction heating are used so that the plate temperature on the alloying furnace outlet side of the remaining steel plate becomes the target temperature on the alloying furnace outlet side of the steel plate to be processed . to control the output power of the induction reflow had,
The steel plate to be treated consists of a steel plate to be treated that is reflow-treated in advance and a steel plate to be treated that is reflow-treated after.
<I> About the to-be-processed steel plate to be reflowed in advance, the processes (1) to (7) are performed,
<II> Measure the tin plating adhesion amount of the steel sheet to be treated before reflow treatment and the tin plating adhesion amount of the steel sheet to be treated after reflow treatment,
<III> Calculate the difference between the amount of tin plating adhesion of the steel sheet to be treated to be reflowed in advance and the amount of tin plating of the steel sheet to be treated to be reflowed after the reflow treatment,
<IV-1> When the difference is within a predetermined range, the emissivity is corrected based on the measured value of the metal tin amount and the measured value of the alloyed tin amount of the steel sheet to be processed to be reflowed following Using the radiation thermometer, the plate temperature on the alloying furnace outlet side of the steel sheet to be processed to be reflowed in the subsequent process is the same as that on the alloying furnace outlet side of the steel sheet to be processed to be reflowed in advance. To control the output power of the induction reflow using the induction heating and the induction reflow using the induction heating so as to become the temperature target value,
<IV-2> When the difference exceeds a predetermined range, reflow of a continuous tin plating line for performing the processes (1) to (7) on the steel sheet to be processed to be reflowed following the above process. Processing method. After correcting the emissivity of the radiation thermometer, the measured value of the metal tin amount, the measured value of the alloy tin amount, the corrected emissivity, the plate temperature and the emissivity on the alloying furnace entrance side of the steel plate to be processed were corrected. The reflow processing method for a continuous tinning line according to claim 1 or 2 , wherein the alloying model is corrected based on a plate temperature on the alloying furnace outlet side of the steel plate to be processed measured using the radiation thermometer. . When actually measuring the amount of metal tin and the amount of alloy tin on the surface of a part of the steel plate to be treated, a sample is taken from the steel plate after passing through the tin plating line, and the steel plate to be treated is taken from the collected sample. The reflow treatment control method for a continuous tin plating line according to any one of claims 1 to 3 , wherein the amount of metal tin and the amount of alloy tin on a part of the surface are measured. When actually measuring the amount of metal tin and the amount of alloy tin on the surface of a part of the steel sheet to be treated, the amount of metal tin and the tin of alloy on a part of the surface of the steel sheet to be treated using an alloying degree meter The reflow processing control method for a continuous tinning line according to any one of claims 1 to 4 , wherein the amount is actually measured.

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