KR20040055978A - Control method for combination reflow brightening of tin plating process - Google Patents

Abstract

PURPOSE: A method for controlling combination reflow of tin plating process is provided to suppress variation of target temperature and prevent excess or deficiency of alloy amount and surface defects generated within the section by compensating shortage of input wattage of conductor roller for a certain section after operating from an induction heater. CONSTITUTION: The method is characterized in that the power shortage is actively compensation controlled in an induction heater(5) by operating changing time point of input wattage and electric power shortage of conduction heater between conductor rollers by the following expressions after judging a distance from input side conductor roller(1) to a welding point by welding point tracking if adjacent welding parts having different work specifications pass through the conductor rollers(1,2) arranged with being spaced apart from each other in a certain distance: {Expression 1} Q=¥í·A(C1+C2·TAVG)·ΔT (watts), where v is line speed (m/m), TAVG is average temperature between temperature in front of input side roller and target temperature, ΔT is increased temperature, C1 and C2 are coefficients, and A is sectional area of strip(4); {Expression 2} input electric power of conduction heater (QCH)=f·Q and input electric power of induction heater (QIN)=(1-f)·Q·η, where f(0¯1) is load distribution ratio between conduction heater and induction heater and η is efficiency of induction heater.

Description

CONTROL METHOD FOR COMBINATION REFLOW BRIGHTENING OF TIN PLATING PROCESS}

The present invention relates to a method for controlling a combination reflow in which energization and induction heating are mixed in a tin plating process of a steel mill.

In general, the material that has undergone the electro tin plating process undergoes a reflow melting process to form an alloy layer and improve weldability, corrosion resistance, and glossiness. Or induction heaters are added between the energizing rollers and heated to the melting point of tin, followed by rapid cooling.

In particular, the continuous line-type plating line processes the coil-type material, and by welding and providing coils of various material standards, continuous processing is possible in the plating process, and the strip between two energizing rollers in the combination reflow process The amount of current required for the heating is input to the current roller according to the load distribution in the current heating and induction heating periods, and the corresponding amount of power is applied to the induction heater for heating. It depends on the size of the material, ie the cross-sectional area and the feed rate.

By the way, a strip of several tens of meters is placed between the energizing rollers, and when the coil cross-sectional area is changed, that is, when the welding point of the leading and trailing material is placed between the two energizing rollers when the size of the preceding material and the following material is changed, the current is required for heating. Difficulties arise in the control of current.

Conventionally, as shown in FIG. 1, which shows an example of the coil-to-coil current control method by controlling the energization reflow, the preceding necessary to reach the target temperature To between the entry current supply roller 1DCR and the exit current supply roller 2CDR. When the required heat quantity (Q _before ) of the coil and the required heat quantity (Q _after ) of the trailing coil are different, the control change point occurs discretely at 1CDR or 2CDR, and the target temperature during the passing of the coil welding point between energizing rollers. The phenomenon that does not reach is generated, which causes problems such as poor surface quality or insufficient alloying amount.

The present invention has been made in view of the above-described problems of the prior art, and has been created to solve this problem. In the reflowing process during the continuous plating process, the impedance according to the material variation in the transition section in which the preceding coil and the following coil coexist simultaneously It is an object of the present invention to provide a combination flow control method of the tin plating process that can produce a product having a high quality surface quality by suppressing a change in target temperature by distributing and inputting an appropriate amount of electric power even if fluctuating.

1 is a timing diagram showing a coil-to-coil current control method by conventional energizing reflow control;

2 is a schematic configuration diagram of a combination reflow facility for explaining the present invention;

Figure 3 is a graph showing the temperature rising pattern for each distance from the induction rolling roll of the strip according to the present invention,

FIG. 4 is a timing diagram illustrating a distribution control method of reflow power between coils when a coil is transitioned in a thick-mold order according to the present invention.

FIG. 5 is a timing diagram illustrating a distribution control method of reflow power between coils when a coil is transitioned in the order of a material material to a material material according to the present invention. FIG.

Explanation of symbols on the main parts of the drawings

1 .... exit energizing roller 2 .... exit energizing roller

3 .... Muffle Furnace 4 .... Strip

5 .... induction heater 6 .... quench tank

Choke Core Coil

The present invention tracks the welding point when the preceding coil and the following coil are being transferred at an arbitrary speed, calculates the amount of heat required to raise the temperature of each coil, and changes the target temperature due to the current calculation error of the energizing heater in the transition section between the energizing rollers. The induction heater calculates the power compensation amount to suppress the power consumption, and based on this, the control method of changing the amount of power distribution so as to suppress the target temperature fluctuation of the reflow even when freely arranging the preceding and following coils is characterized by its configuration. do.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Figure 2 is a schematic configuration diagram of a combination reflow facility according to the present invention, Figure 3 is a graph showing the temperature rising pattern for each distance from the entrance conduction path of the strip by the present invention.

The reflow facility configuration of the electro-tin plating, which is the target process of the present invention, is conventionally shown in FIG.

That is, there is a muffle furnace (3) between the entry energizing roller (1) and the exit energizing roller (2) to preserve the temperature of the strip (4), and the temperature is rapidly increased just before the acquisition to reach the target temperature. There is an energizing heater, and then there is a quench tank (6) is configured to be quenched in the molten state of the plated tin.

In addition, in the case of the entry and exit side energizing rollers 1 and 2 for supplying AC power, choke core coils 7 and 8 are provided outside the energizing rollers 1 and 2 so as to concentrate current therebetween. It will be provided.

The temperature rising pattern of the typical combination reflow type side entry roller 1 to the quench tank 6 is shown in the graph of FIG. 3.

The drawn strip 4 is heated according to the material information and the feed rate of the strip 4 so as to start heating from the entry energizing roller 1 to reach the target temperature To just before entering the quench tank 6. The calculation of the input amount can be obtained from the following required calorific value (Q) equation.

(Required calorie type)

Here, v: line feed (mpm), T _AVG : average temperature between the starting roller and the target temperature, ΔT: elevated temperature, C1, C2: coefficient, A: strip cross-sectional area.

The calculated power consumption (Q) is divided into load by the energizing heater and the induction heater, and is calculated as follows.

Input heater power (Q _CH ) = fQ

Induction heater input power (Q _IN ) = (1-f)

Where f (0 ~ 1): load ratio of energized heating and induction heating, and η: efficiency of induction heater.

For the same material, only the feed rate of the strip 4 is a factor that changes the required heat quantity and input power. If the size of the material varies, the required heat quantity must be calculated variably.

4 and 5 show a detailed control method thereof. The detailed control method is shown in FIG.

When the size of the preceding coil and the following coil is different, the electrical resistance by the strip 4 becomes non-uniform and varies linearly when the welding point, which is the connection between the coils, passes through the energizing rollers 1 and 2.

The input current of the energizing heater can be obtained by calculating the electrical resistance of the material and conducting a current corresponding to the amount of heat required for the temperature increase.The welding point of two materials having different materials, that is, having different electrical resistance, may be located between the energizing rollers (1, 2). At this time, if the input current of the energizing heater is changed, the thickness of the material falls short of the target temperature. In the case of the material, the temperature rises and the reflow failure occurs in some material sections before and after the welding point.

Therefore, the change in the amount of power of the energizing heater is always made mainly of the material having a large electrical resistance when the welding point is located between the energizing rollers 1 and 2.

This is to prevent overheating in the material change section by the current of the energizing heater.

As shown in FIG. 4, when the preceding coil is a thick material and the trailing coil is a thin material, the welding point is changed at the moment of passing through the entrance energizing roller 1, and as shown in FIG. 5, the preceding coil is a thin material and the trailing material. If the coil is humul recognition is changed to the preceding coil energization outlet roller (2) the input power after completely through to the Q from Q _{after_CH before_CH.}

When input power changes due to material change of the opening 5, inducing unlike tongjeonga heat welding point induction is started to enter the opening (5) immediately changes from Q to Q _{before_IH after_IH.}

At this time, in the transition section through which the welding point between the current passing rollers 1 and 2 passes, the power required for the temperature rise is insufficient for the thick material. In the induction heater 5, during this section, the induction heater according to the welding point transfer information. Compensation is made in (5) and the compensation amount is as follows.

Compensation amount (Q _compen ) = ｜ Q _{after_CH} -Q _{before_CH} ｜

Regardless of the electrical resistance, the compensation amount is calculated by calculating the compensation amount in the material section located in the transition section by tracking the welding point irrespective of the variable electrical resistance input to the reflow until the welding point completely passes between the energizing rollers (1, 2). By compensating for the amount of heat by the induction heater 5 that is operated, the target temperature To immediately before being obtained into the quench tank 6 can be kept constant even when adjacent coils having different material specifications pass the transition section.

As described above, when the welding part between adjacent coils having different cross sections according to the present invention passes between the energizing rollers, the power amount of the energizing heater when the strip resistance and the required heat quantity by the welding point tracking is changed, the resistance is changed in a constant section. The change of power amount of the induction heater is made between the energizing rollers, and the shortage of the energizing roller input power is compensated by calculating the compensation in the induction heater for a certain period to suppress the fluctuation of the target temperature and the amount of alloys that can be generated within this period. It is possible to prevent excessive shortage and surface quality defects.

Claims (1)

In the combination reflow process of the continuous electroplating process, When adjacent welds with different material specifications pass through the energizing rollers arranged at a distance from each other, the distance from the entry energizing roller to the welding point is determined by the welding point tracking. Combination flow control method of the tin plating process characterized in that by calculating the electric power shortage of the heat to actively compensate for it in the induction heater. (One) Where v is the line feed (mpm), T _{AVG is the} average temperature between the starting roller and the target temperature, ΔT is the elevated temperature, C1, C2 is the coefficient, and A is the strip cross-sectional area. (2) Input heater power (Q _CH ) = fQ Induction heater input power (Q _IN ) = (1-f) (Where f (0 ~ 1): load ratio of energized heating and induction heating period, η: efficiency of induction heater) (3) Compensation amount (Q _compen ) = ｜ Q _{after_CH} -Q _{before_CH} ｜