KR100742878B1 - Method for controlling entrance interval and entrance velocity according to thickness of a plate in heat treatment furnace - Google Patents

Abstract

The present invention is a process applied to the production of thick plate products in steel products, when charging the plate in the heat treatment furnace, and relates to a method for controlling the charging speed for each thickness and thickness of the heat treatment furnace.

In the heat treatment furnace charging interval and thickness charging speed control method of the present invention, a single drive method in which one motor is assigned to one roller at the charging side and the extraction side is adopted, and the charging speed and the furnace speed are calculated. By determining the optimal charging point and charging, the gap between the loaded plates can be reduced to within 2m, and if there is a difference in the thickness of the plates, the first loaded plate reaches the predetermined position and then the second plate is loaded. By driving the plates to run at different furnace speeds, you can quickly deal with emergency deliveries.

Heat treatment furnace, thick plate, single drive, charging point control, charging interval

Description

TECHNICAL FOR CONTROLLING ENTRANCE INTERVAL AND ENTRANCE VELOCITY ACCORDING TO THICKNESS OF A PLATE IN HEAT TREATMENT FURNACE}

1 is a block diagram showing a conventional heat treatment furnace.

Figure 2 is a block diagram showing a heat treatment furnace to which the present invention is applied.

Figure 3 is a block diagram for explaining a heat treatment furnace charging interval control method according to the present invention.

Figure 4 is a block diagram for explaining a charging speed control method for each thickness according to the present invention.

Figure 5 is a flow chart for explaining the charging and extraction process of the heat treatment furnace to which the present invention is applied.

(Explanation of symbols for the main parts of the drawing)

21: plate 22: ingress sensor

23: Charging standby table 24: Charging side drive motor

25: charging standby sensor 26: charging door

27: loading completion sensor 28, 32: single drive motor

29: roller 30: collective drive motor

31: Chain 33: Extraction complete sensor                 

34: extraction door 35: extraction table

The present invention relates to a charging control method applied to the production of thick plate products (hereinafter referred to as 'plate') of steel products, more specifically, the charging interval of the heat treatment furnace when charging the plate in the heat treatment furnace And it relates to a method for controlling the charging speed for each thickness of the plate.

In the plate manufacturing process, a thick plate product is charged into a heat treatment furnace heated to a high temperature in a thick plate factory, and after a predetermined time (reduction time: time existing in the heat treatment furnace) has elapsed after controlling the speed in the furnace according to the thickness of the plate. The quality of steel products is improved by extracting the plates and cooling them by air or water.

The heat treatment furnace used in the plate manufacturing process includes a burner control device for ignition or heating to raise the temperature, a roller table for transferring the plate, a motor, a sensor, and a programmable logic controller (PLC). Consists of.

In general, in charging the plate in the heat treatment furnace, the charging door is loaded at a high speed to prevent the furnace temperature from dropping during the charging door, and after charging, the plate speed and the effective distance of the heat treatment furnace are used to provide an appropriate furnace speed. Calculate and transfer the loaded plate in the heat treatment furnace according to this speed.

Hereinafter, a conventional heat treatment furnace will be described with reference to the accompanying drawings.                         

1 shows a conventional heat treatment furnace configuration. As shown in Fig. 1, a conventional heat treatment furnace is composed of a plurality of rollers, one group driving motor 15 is assigned to each of several rollers, and each motor is connected to each other by a clutch 16. That is, the group drive system which controls several rollers by one motor is employ | adopted. The standby table is provided with charging side drive motors 11 and 12 to drive the rollers of the charging standby table 13, and a charging door 14 is provided between the heat treatment furnace and the charging table, and the heat treatment furnace is extracted. An extraction door 17 is provided between the tables. Any number of rollers are connected to the collective drive motor 15 by a chain.

In this heat treatment furnace, the plate is driven to the charging side of the heat treatment furnace by the charging side drive motors 11 and 12 of the charging standby table 13. Subsequently, when the charging door 14 is opened and the collective drive motor in the charging side and the heat treatment furnace are connected to each other by a predetermined clutch device, the roller is operated by the collective drive motor to charge the plate into the heat treatment furnace. The length of the charging section can be selected depending on how many collectively driven motors on the charging side are connected. After charging, the charging side drive motors 11 and 12 are cut off, and the plate can be transferred at the furnace speed by driving the collective drive motor inside the heat treatment furnace.

According to the conventional charging method, the charging section is divided into 10.8 m (L1), 16.2 m (L2), and 25.2 m (L3) according to the length of the plate, the length of the charging section can be set by appropriately selecting the clutch. have.

At the time of charging, the charging side drive motors 11 and 12 and the collective driving motor 15 in the heat treatment furnace are connected by the clutch 16 so that the charging table and the heat treatment furnace are interlocked so that the plate can be charged at high speed.

When charging is completed, the charging side drive motors 11 and 12 are cut off by the clutch 16, and the heat treatment furnace is driven by the collective drive motor 15 at a predetermined furnace speed. At this time, the distance between the plate loaded first and the plate completed is widened by the clutch selection range and the zone distance of the group drive motor (distance divided by the chain), and the charging is performed at this interval so that the plate between the plates There is a problem that the spacing of the gap is so wide that the heat treatment efficiency falls.

The reason is that, according to the conventional charging method, after any plate is charged, when the next plate is loaded, the charging is performed after the charging section is secured by the length of the charging standby plate. After charging, the distance between the first and second plates is increased. Considering the length of the limited heat treatment furnace, it is necessary to increase the production efficiency of the heat treatment furnace by charging more plates by narrowing the gap between the charged plate and the plates.

In addition, in controlling the furnace speed of the charged plate, since the entire heat treatment furnace is driven based on the furnace speed of the thickest plate among the loaded plates, only the plates having no thickness difference should always be charged at the time of charging. Therefore, there is a problem that it is not possible to load a plate having a large difference in thickness, so that the heat treatment furnace is required to be separately heat treated for such a plate, so that it is not possible to quickly process a plate with an urgent delivery date.

The present invention has been made under the above technical background, and adopts a single drive method in which one motor is allocated to one roller on the charging side and the extraction side, and the charging speed and the furnace speed are calculated, and the optimum charging time is determined from this. By determining and charging, the gap between the loaded plates can be reduced to within 2m, and in case of difference in the thickness of the plates, the plates can be processed at different speeds in the furnace to quickly process the delivery deadline. The purpose is to provide a charging speed control method for each thickness.

Charging method of the present invention for achieving the above object,

First, calculate the travel time in the heat treatment furnace of the first plate by dividing the moving distance in the heat treatment furnace of the loaded plate by the speed in the heat treatment furnace. Calculating a moving time at charging, and performing charging of the second plate before the first plate moves by the length of the second plate using the difference between the two moving times as the charging time point; And

When a plate with a difference in thickness is loaded, the first plate is charged according to the length of the loaded plate, and then a second charging plate is secured after securing a predetermined charging distance, and according to the thickness of each plate, the moving speed in the heat treatment furnace is determined. And controlling the differently.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2 shows a configuration of a heat treatment furnace to which the present invention is applied.

As shown in FIG. 2, the heat treatment furnace to which the present invention is applied includes a plurality of rollers 29, a charging standby table 23 installed on the charging side, a charging door 26, an extraction table 35 provided on the extraction side, and The extraction door 34 is comprised. The heat treatment furnace consists of a single drive section (A) on the inlet side, a group drive section (B) on the middle, and a single drive section (C) on the exit side. In the section A, a single driving motor 28 is provided for each roller, and in the section B, a plurality of rollers are driven simultaneously by the group driving motor 30 and the chain 31, In the section C, a single drive motor 32 is provided for each roller. A charging completion sensor 27 is provided on the charging side of the heat treatment furnace, and an extraction completion sensor 33 is provided on the extraction side. An entry sensor 22 and a charge wait sensor 25 are installed in the charge wait table 23 to detect position information of the plate, and the charge wait table 23 of the plate 21 is driven by the charge-side driving motor 24. Drive on the control panel is controlled. Each motor is provided with a sensor for measuring a moving distance.

In this heat treatment furnace, the plate 21 advances at high speed, for example, about 15 mpm (meter per minute) at the time of charging and extraction, and after charging, the furnace speed is calculated by calculating the furnace speed by the thickness of the plate 21. Proceed to (0-6mpm).

The heat treatment furnace is divided into a plurality of zones, and a position sensor is installed in each zone to compensate for the physical distance value.

The heat treatment furnace is heated by the burner installed in each zone, and heat treatment such as normalizing (890 degrees), quenching (910-930 degrees) and tempering (Tempering: 610-690 degrees) depending on the heat treatment method. There is a furnace heating method, and after extraction, the plate 21 heated by water or air cooling is cooled.

Next, the charging process will be described.                     

When the plate 21 reaches the entry sensor 22, the positional information of the plate 21 is received and the charging side drive motor 24 is automatically driven. As a result, the plate 21 is transferred to the charging standby table 23. When the plate 21 completely reaches the charging standby position, the furnace speed is calculated by the thickness of the plate 21, and the charging door 26 is opened. When the charging door 26 is opened, the single-drive motor 28 and the charging side drive motor 24 of the heat treatment furnace section A are simultaneously driven to load the plate 21 at high speed (15 mpm). . When the charging completion sensor 27 is turned on, charging is completely completed.

After charging, the plate 21 passes through the heat treatment furnace at a furnace speed calculated according to the thickness of the plate 21, and is heated in the heat treatment furnace for a predetermined ashing time. When the plate 21 thus transferred reaches the extraction completion sensor 33, the extraction door 34 is opened to extract the plate 21 to the extraction table 35, and the extracted plate 21 is cooled. The heat treatment is completed by passing through.

In the conventional heat treatment furnace charging method, the charging section is divided into 10.8 m or less, 16.8 m or less, and 25.2. M or less by length of the charging plate. If the length of the plate is 9.4 m, the charging section is 10.8 m or less and if there is no plate loaded first, the clutch of the collective drive motor corresponding to the length of 10.8 m is selected to Plate interlocks at high speed in conjunction. When the charging is completed, the chain interlocked with the charging side drive motor is broken, and the plate proceeds and is extracted at the speed of the furnace by connecting with the collective driving motor in the heat treatment furnace.

In the case of charging in this manner, the gap between the plates at the time of charging by the set distance for each charging section is opened, there is a problem that the production efficiency of the heat treatment furnace is lowered.

In addition, the conventional furnace speed control method is determined by the thickness of the plate, the criteria are as follows. When the total length of the heat treatment furnace is 52 m, the plate thickness is 20 mm, and the length is 10.8 m, the normalizing material rework time is as follows.

1.3 t (thickness) + 10 (minutes) = 1.3 x 20 + 10 = 36 minutes

The traveling distance in the heat treatment furnace is effective distance-charging distance = 52-10.8 = 41.4m, and the traveling speed is (traveling distance) / (overtime) = 41.4 / 36 = 1.15 mpm.

Next, with reference to Figures 3 and 4 will be described in the heat treatment furnace charging interval and plate thickness charging speed control method according to the present invention.

As shown in FIG. 3, case 1 represents a state in which the first plate has been charged at the position of the second plate, and case 2 represents a state in which the second plate has reached the charge standby position. Case 3 represents the case where the first plate proceeds at the furnace speed and the second plate reaches the charging point, and case 4 represents the state where the second plate is charged.

In Fig. 3, L1 is the length of the charge holding plate, L2 is the fixed distance between the charge holding plate and the charging completion point (6 m), L3 is the length in the heat treatment furnace of the charge holding plate (L1 = L3), L4 is the first The distance between the plate and the next plate to be loaded (≒ 2 m), the distance the first plate advances until the next waiting plate holds the charging distance, and P1, P2, P3, P4 and P5 are the plate movement positions . t1 is the charging speed (15 mpm: always constant) when charged in the charging standby plate, and t2 is the traveling speed (0-6 mpm) in the heat treatment furnace set by the thickness of the first plate loaded.

In the present invention, it is aimed to maintain the distance between the end of the first plate and the front of the second plate in the heat treatment furnace at 2 m or less.

That is, in the control method of the present invention, by calculating the difference between the speed of the first plate in progress in the heat treatment furnace and the speed of the second plate loaded at a high speed, by charging the second plate before the charging section of the first plate is secured As in Case 4, the distance between the two plates shall be kept within 2 m.

Looking at the formula to determine the charging time is as follows. The loading point is the time when the end of the first plate passes through P5 past P2 and passes through P5 until the front of the second plate passes through P1 to reach P3.

Calculating how long the first and second editions reach the same conditions as Case 4,

Travel time of the first plate (t2) = travel distance / speed = (L1 + L4) / inner speed

Travel time of the second plate (t1) = travel distance / speed = (L1 + L2) / charge speed

Charging time = t2-t1.

That is, when the plate is loaded with the time obtained by subtracting the moving time of the second plate from the moving time of the first plate, the gap between the first plate and the second plate is adjusted under the same condition as in case 4.

Below, we look at the calculation process by substituting the actual plate length.

It is assumed that the thickness of the first plate is 20 mm, the length is 10 m, the length of the second plate is 10 m, and the length of the heat treatment furnace is 84 m.

First, calculating the ashing time and the traveling distance in the heat treatment furnace of the plate, as follows.

Working time = 1.3t (thickness) + 10 (minutes) = 1.3 x 20 + 10 = 36 (minutes)

Progress distance in heat treatment furnace = Effective distance-Loading distance + plate spacing

                      = 84-10 + 2 = 76 (m)

Therefore, the driving speed in the heat treatment furnace

(Travel distance) / (interest time) = 76.0 / 36 = 2.11mpm

When the movement time of the first plate is obtained based on the above-mentioned inner furnace driving speed,

Movement time t2 = travel distance / speed = (L1 + L4) / inner speed = (10 +2) /2.11 = 5.69 (min)

Movement time t1 = travel distance / speed = (L1 + L2) / charge speed = (10 + 6) / 15 = 1.06 (min),

The loading point of the second plate is t2-t1 = 5.69-1.06 = 4.63 (minutes).

In terms of moving distance, the charging point of the second plate can be made as in case 4 when the end of the first plate is charged at the position passing through P5, which is the distance traveled through P2 for 4.63 minutes.

Therefore, the travel distance = travel time x furnace speed = 4.63 x 2.11 = 9.7 (m) of the first plate. The starting point of the second plate is when the end of the first plate passes through P2 and reaches the point P5, which is 9.7 m, so that the distance between the first plate and the second plate can be maintained within 2 m.                     

Next, a charging speed control method for each plate thickness will be described with reference to FIG. 4. In FIG. 4, the symbols L1 to L4 and P1 to P6 are different from those of FIG. 3, and these symbols are valid only in FIG. More specifically, L1 to L4 are lengths which are arbitrarily divided by zones in the heat treatment furnace, and P1 to P6 are positions of two plates shown to explain the concept of the present invention.

As shown in FIG. 4, in the charging speed control method according to the thickness of the present invention, after the charging distance is secured for each case at the charging standby position, the plate loaded first passes through one or more zones, and then the thickness difference. The speed control mode is set, and then the plate is transferred at the speed of the two furnaces in the furnace by charging the second plate.

In FIG. 4, the case 1 is a case in which the length L of the charging plate is smaller than L1, and when the end of the first loading plate is in the P2 position, the thickness difference speed control mode is set to On and the thickness When a plate with a large difference is charged, the feed rate to the heat treatment furnace is controlled by two thicknesses after charging. In a similar manner, case 2 is where the length of the plate to be loaded (L) is greater than L1 and less than (L1 + L2), when the first plate is in the P4 position, charging of the second plate is possible, and case 3 When the length L of the plate to be loaded is larger than L1 + L2 and smaller than (L1 + L2 + L3), when the first plate is in the P6 position, the second plate may be loaded.

As such, by controlling the plate having a large thickness difference at two furnace speeds in the heat treatment furnace, flexible work is possible in the heat treatment furnace, and the heat treatment material urgently due to delivery can be processed at any time.                     

Next, with reference to the flow chart of Figure 5 will be described the operation sequence (operation sequence) of the charging speed control method according to the heat treatment furnace charging interval and thickness of the present invention.

After the operation is started and the plate to be charged is prepared (S11), it is determined whether the plate has arrived at the charging table (S12). When the plate arrives at the charging table, information of the arrived plate, for example, thickness, width, length, heat treatment temperature, etc. is received (S13), and when all the product information of the plate is received (S14), the furnace speed is calculated and set. (S15). The furnace speed is obtained by dividing the effective distance of the heat treatment furnace by the time of ash based on the thickness of the received plate information. Next, the plate is transferred to the charging wait table (S16). It is determined whether the plate has arrived at the charging table (S17), and when the plate has arrived at the charging table, it is determined whether the same plate is loaded continuously (S18). If it is not continuous charging in the step S18, the thickness difference setting mode is set to On (S19), and if it is continuous charging, the process goes to the next step. Next, it is determined whether the charging distance is secured by the length of the next plate from the position of the plate charged in the heat treatment furnace (S20). If the charging distance is secured in the step S20, the charging door is opened. (S21). When the opening of the charging door is completed (S22), the plate begins to be charged into the heat treatment furnace (S23). When the thickness difference setting mode is set to On in step S20, it is determined whether a charging distance corresponding to each case of FIG. 4 is secured from the position of the last loaded plate.

Next, when the charging of the plate is continued and the loading of the plate is completed at the charging standby position (S24), the charging door is closed (S25). When the closing of the charging door is completed (S26), the plate loaded at the preset furnace speed is driven (S27). By this driving, the plate is transferred along the heat treatment furnace at the furnace speed, and it is determined whether the plate has arrived at the extraction stage (S28). If the plate arrived at the extraction stage in the step (S28), the extraction door is opened (S29), and when the opening of the extraction door is completed (S30), the plate begins to be extracted at high speed (S31). After the plate is extracted from the heat treatment (S32), the extraction door is closed to complete the operation.

As described above, in the heat treatment furnace charging interval and thickness charging speed control method of the present invention, a single driving method in which one motor is allocated to one roller on the charging side and the extraction side is adopted. By calculating the speed and determining the optimum loading time from this, the distance between the loaded plates can be reduced to within 2 m. Accordingly, the spacing between the plates to be heat treated can be much shorter than in the prior art, and the efficiency of the heat treatment furnace is greatly improved. In addition, in the control method of the present invention, when there is a difference in thickness of the plate, the second plate is charged when the first plate passes a predetermined position according to an arbitrary case, and the two loaded plates are driven at different furnace speeds. By doing so, it is possible to quickly process the delivery deadline urgent material, thereby improving the productivity of the heat treatment furnace.

Claims (2)

A heat treatment furnace for performing a predetermined heat treatment on a plate loaded with a plurality of rollers provided with heating means, wherein a single drive section in which one motor is assigned to each roller is formed on the loading and extraction side, and a plurality of rollers are arranged in the middle. It is applied to the heat treatment furnace in which the group drive section in which one motor is assigned is formed. First, calculate the travel time in the heat treatment furnace of the first plate by dividing the moving distance in the heat treatment furnace of the loaded plate by the speed in the heat treatment furnace. Calculating a moving time at charging, and performing charging of the second plate before the first plate moves by the length of the second plate using the difference between the two moving times as the charging time point; And When a plate with a difference in thickness is loaded, the first plate is charged according to the length of the loaded plate, and then a second charging plate is secured after securing a predetermined charging distance, and according to the thickness of each plate, the moving speed in the heat treatment furnace is determined. Charging speed control method according to the heat treatment furnace charging interval and thickness characterized in that it comprises the step of controlling differently. The method of claim 1, The speed in the heat treatment furnace of the first plate is added to the length of the heat treatment furnace by the distance between the plates to be controlled, subtract the charging distance from this value to obtain the travel distance in the heat treatment furnace, and the value is determined by the first plate. Method for controlling the charging interval and charging speed by thickness of the heat treatment furnace, characterized in that obtained by dividing by the time to be treated in the heat treatment furnace.

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