KR20030006128A - Bar moving speed optimization system for bar situation descaling header division use - Google Patents

Abstract

PURPOSE: A system for dividingly using descaling header per bar positions and optimizing bar proceeding speed is provided to prevent scaling defects at the front end of a coil by optimizing use patterns of the descaling header and proceeding speed of a bar, and prevent material defects of the front end part by securing temperature of the outlet side of a finish rolling mill of a strip. CONSTITUTION: The system for dividingly using descaling header per bar positions and optimizing bar proceeding speed is characterized in that the bar is proceeded to the maximum speed by increasing a descaling passing rate of the front end of a bar within the range that the bar is not collided with a first finish rolling mill as using all two rows of descaling headers in the front part of the bar and using only one row of the descaling header after the front end part of the bar passing through a follow point when rolling a thin sheet material in the hot rolling process, wherein the same rows of descaling headers as the descaling headers used in the previous rolling bar are not used at the part following the front end part of the bar in a material to be rolled in which two rows of the descaling headers are used only at the front end part of the bar.

Description

Bar moving speed optimization system for bar situation descaling header division use}

The present invention relates to the use of descaling header classification and bar progression speed optimization system for each bar position, and more particularly, a facility for removing an oxidation scale generated on the surface of a rolled bar in a rough rolling mill with a high-pressure cooling water during a hot rolling process. Use of descaling headers by location to optimize the usage pattern of the inscaling header and the speed of the bar to prevent the tip scale defect of the coil and to secure the exit temperature of the strip mill to prevent the material defects. Bar progress speed optimization system.

In general, in the hot rolling process, each rolling (rough rolling, finishing rolling) pass process and the process of proceeding to the next pass, as shown in FIG. 8, the scale of oxidation generated on the surface of the bar 10 due to contact with air is shown. The descaling header 13 of high pressure (150 kg / cm 2) is used to remove the pressure, the number of headers, the header height, the width of the nozzle pitch, and the like in the process. It is automatically designed in the upper calculator (not shown) for each characteristic.

At this time, the descaling work when the rough rolling (not shown) process and the finishing rolling 19 pass process is a matter that is directly connected to the quality of the product, it may be a particularly important process.

In the conventional operation method, however, the number of descaling headers 13 used from the front end to the end of the bar 10 is always used by the front row 13a and the rear row 13b, and the front row and the rear row. It has been used in three kinds.

This is because it is judged that the spraying of the descaling 13 should always be carried out at the same pressure, and the calculation itself is not displayed, and there is no big problem in use.

Therefore, using the header pattern selected according to the setting of the calculator as it is, proceed until the tip of the bar 10 passes the follow point (an imaginary point (25) designated by the calculator to control the speed of the bar). Adjust the speed. The descaling (13) header uses one or two rows to completely remove the scale, and has been operating to roll the speed pattern in synchronization with the first finishing mill (19) at the point of passing through the follow point (25). .

However, this operation method has the fastest speed at which the tip passes through the descaling header 13 when viewed in the longitudinal direction of the bar 10, and thus the moving speed of the bar 10 in a material material or a special material or a part of general steel. Increasing the speed, the oxidized scale was not completely removed, which provided a problem cause to cause scale defects in the product (coil: 22). There was a problem that the temperature is not secured as much as the target temperature.

On the other hand, Figure 9 shows the surface temperature distribution of the bar (10) when using only the heat transfer (13a) and the front and rear heat (13a, 13b) mixed in the state at a constant speed during high pressure desqueling spraying When spraying only the heat transfer 13a, the vertical stripe-shaped overlap part appeared, which caused early roll wear during the rolling operation, and the overall uniform temperature when spraying the front and rear heats 13a and 13b. It shows the distribution but the temperature in the center is extremely low.

FIG. 10A shows that when the exiting temperature is not secured (shown in FIG. 10B) and the exiting temperature is secured by using only one row of deceling 13 when rolling the thin material (PO material) and slowing the moving speed. The material of the bar 10 is compared with the temperature shown (shown in FIG. 10C).

If the exit temperature is not secured as shown in the figure (Fig. 10b), the processing crack (CRACK) occurred by coarse grains during rolling, but when the exit temperature is secured (Fig. 10c), it can be seen that a normal material can be obtained.

The present invention has been made to solve the above-mentioned problems in view of the above-mentioned problems, and an object thereof is a facility for removing an oxidation scale generated on the surface of a rolled bar in a rough rolling mill with a high-pressure cooling water during a hot rolling process. Optimized the use pattern of the scaling header and the moving speed of the bar to prevent the scale tip defect of the coil and to ensure the exit temperature of the strip mill to prevent the material defects. To provide a speed optimization system.

As a technical idea for achieving the above object of the present invention,

The number of descaling headers used during the hot rolling process of the hot rolled material is used for both front and rear rows, and after the front end of the bar passes the follow point, only one row of front and rear rows is used. An invention of a method of advancing the tip descaling header passing speed as fast as possible without causing a collision with the first finishing mill is presented.

1 is a flow chart showing a working flow chart of the rolling method for controlling the number of descaling headers and the bar speed by the use of the desqueling headers for each bar position and the bar progress speed optimization system.

FIG. 2 is a graph illustrating a bar speed pattern in a deskeling zone by the bar position descaling header classification and bar progress speed optimization system of the present invention; FIG.

Figure 3 is a graph showing the recuperation time of the bar surface temperature after the deskeling injection by the present inventors using the descaling header according to the bar position and bar progress speed optimization system,

Figure 4 is a graph showing the distribution of degradation of the bar surface and the direct temperature by using the descaling header according to the bar position according to the present invention and bar optimization speed optimization system,

FIG. 5 is a graph illustrating changes in temperature of the tip and tail ends based on the de-skelling header classification and bar progressing speed optimization system of the present invention.

FIG. 6 is a graph illustrating the number of descaling headers and the temperature change of the bar tip portion according to the bar speeds by the baring position descaling header classification and bar progress speed optimization system according to the present invention; FIG.

FIG. 7 is a graph illustrating an example of a position of a arrow point by using the descaling header according to the bar positions and the bar progress speed optimization system according to the present invention;

8 is a schematic diagram showing a finishing rolling process during hot rolling;

9 is a photograph showing a width direction temperature distribution of a bar according to the number of descaling headers;

10A, 10B, and 10C are graphs and photographs showing the relationship between the exit temperature and the material during rolling of a thin material.

<Description of the symbols for the main parts of the drawings>

10: bar 13: descaling header

13a, 13b: before and after heat 16: bar cutter

19: rolling mill 20: work roll

25: Following point 27: Bar detector

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawing using the descaling header according to the bar position and bar progress speed optimization system according to the present invention.

1 is a flow chart showing the flow chart of the rolling method for controlling the number of descaling headers and the bar speed by the system using the descaling header according to the bar position and bar progress speed optimization system, and FIG. 2 is a bar position according to the present invention. FIG. 3 is a graph illustrating bar speed patterns in a deskeling zone by the use of de-selling header classification and bar progression speed optimization system for each bar, and FIG. Figure 4 is a graph showing the time required for recuperation of the bar surface temperature after the deskeling spray, and FIG. 4 shows the distribution of deterioration of the bar surface and the direct temperature by the use of the deskeling header for each bar position and the bar progress speed optimization system. Figure 5 is a graph, Figure 5 shows the disc by the present invention using the descaling header for each bar position and bar progress speed optimization system Figure 6 is a graph showing the temperature change of the tip and tail end on the basis of the passing point of the ring, Figure 6 is according to the number and bar speed of the descaling header according to the present invention using the descaling header for each bar position and bar progress speed optimization system FIG. 7 is a graph illustrating changes in temperature of the tip of a bar, and FIG. 7 is a graph illustrating an example of a location of a blow point by using the descaling header for each bar position according to the present invention and a bar progress speed optimization system.

As shown, the upper calculator determines the number of use of the descaling header 13 and the two-row spray material 58 at the distal end. The speed of the bar 10 and the number of the descaling header 13 are determined according to the determination result. To determine and to roll and follow the points (48), 66 is composed of a system that allows to roll at a conventional spray pattern and bar travel speed.

This means that the heat that normally sprays only the tip portion during the operation process stops use after the tip portion, that is, when only the heat transfer 13a or the after heat 13b is continuously sprayed when the high pressure water is sprayed from the descaling header 13. As shown in Fig. 9, the temperature lowering part of the bar 10 due to the inter-nozzle overlap of the descaling header 13 causes local wear on the surface of the finishing roll 19 working roll 19-2. When using it, you can use it alternately between heat and heat.

In other words, if the first bar 10 was sprayed with heat, the next second bar 10 was sprayed with heat, so that the cooled part passed through the work roll 19-2 where the portion cooled by the overlap in the battlefield passed. To do that.

Therefore, in the case where only two rows are designated at the front end portion, it is configured to stop the heat of spraying only the front end portion after the tip portion passes.

According to the present invention configured as described above, when the upper calculator determines the number of use of the descaling header 13 and checks the spray pattern, the amount of spraying is as in the conventional case. Spraying in two rows (44), the speed of the bar (10) proceeds as directed by the calculator (46) proceeds to the follow point (48), and then the speed of the bar (10) at the synchronous speed with the first finishing mill (19) Deceleration (50) is to be rolled, and the injection of the descaling header 13 is terminated (54) and the end of the operation (56) at the time passing through the descaling header (13) of the bar (10).

In addition, when inputting into the first column using material 42 of the descaling header 13 from the upper calculator, it is determined whether only the first front end part is the second row injection material (58). When the rolling process is performed, and only the front end portion is a two-row spray material (58), the desqueling 13 is sprayed in two rows while calculating the follow point 66 according to the speed of the bar 10 in the calculator. And, the progression of the bar 10 proceeds at a maximum 64 speed within a range capable of preventing a collision with the first finishing mill 19.

Here, when the bar 10 arrives at the follow point 66, the speed decreases rapidly to synchronize the traveling speed with the first finishing mill 19, 50, and the descaling header 13 is sprayed 68 in one row. Rolling is in progress.

On the other hand, as shown in Figure (A) shown in FIG. 2, in the case of using only the heat transfer or post heat treatment of the descaling 13, the advancement speed of the bar cutter 16 advances to 90 MPM, and then the speed is increased to about 55 MPM after cutting the bar. At this time, the descaling header 13 is sprayed with only one heat to remove the scale, arrive at the follow point 25, and then speed down again to 32MPM, which is a synchronous speed with the first finishing mill 19. Proceed to enter the first filament rolling mill (19) is to have no difficulty.

◆ Example of use (museum PO material, thickness 1.4 <t <1.9mm material)

In Figure (B) of Figure 2 is a graph showing the working pattern when rolling the material in the Gwangyang 3 hot rolling mill.

This progresses while maintaining the speed at 90mpm as before, until the bar 10 passes through the cutter 16, and then proceeds from the cutting of the bar 10 to the follow point 25 to 68mpm (the conventional speed). 10 to 15mpm higher than the speed rise), and the descaling header 13 is sprayed in two rows, the speed is reduced sharply at the time passing through the follow point 25 to synchronize with the speed of the first finishing mill 19, The descaling header 13 stops the heat of spraying only the front end portion, so that only one heat is sprayed, as in the conventional case, to perform the rolling operation.

In addition, FIG. 3 is a graph showing the time when the surface temperature of the bar 10 is recuperated after descaling, and the graph shows the effect of the two-row spraying of the descaling 13.

As shown, the time taken to recover the original temperature after descaling of the rolled bar 10 is about 7 seconds when the bar 10 temperature is 1,000 ° C.

Therefore, before descaling 13 is sprayed in two rows, the heat of the bar 10 is restored and another heat is used before the surface is oxidized, thereby significantly reducing the generation of oxidative scale on the surface.

4 shows the amount of temperature decrease on the surface of the bar 10 after descaling, the higher the desqueling pressure, and the slower the speed of the bar 10 is, the larger the amount of temperature decrease.

Therefore, in order to compensate for the temperature of about 13 DEG C, which is lowered by one more heat injection, the passage speed is increased to relatively reduce the amount of temperature decrease.

5 shows the temperature difference between the tip of the bar 10 and the tip of the bar 10 after passing through the descaling 13. In general, the oxidation of iron occurs much faster at high temperatures.

Therefore, since the temperature of the bar 10 of the bar 10 is descaled, the temperature is displayed at 1000 ° C. or less, so that even if only one heat is used, the scale flaw due to surface oxidation can be sufficiently prevented.

Figure 6 shows the change in temperature of the tip and tail end of the bar (10) appearing when rolling by the method according to the present invention and the conventional method, as shown in Figure (C) using a descaling header 13 in a row 10) When the speed is slowed down, the temperature distribution of the bar 10 shows that the temperature before and after the deceleration point of the follow point 25 decreases sharply compared with the target temperature (870 ° C.). As can be seen from the present invention, when the two-stage injection only the front end portion and the speed is faster, it can be seen that the temperature of the bar 10 is approaching the target temperature much more similarly.

FIG. 7 illustrates a follow point 25 position according to a rolling mill 19 specification of a Gwangyang three hot rolling mill, and the follow point 25 position corresponds to a finishing mill 19 and a bar detector 27 for each plant. The bar cutter 16 and the descaling header 13 appear differently, and the positions are all calculated and applied automatically by the upper calculator, so there is no problem in using the above-described method.

As described above, the present invention is a material of 1.4 ~ 2.4mm thickness among hot rolled coils, which causes scale flaws in the tip end caused by the scale not peeling off from the descaling header and defects in the material of the hot rolled coil according to the tip temperature exit of the finishing mill. It is effective to prevent.

In particular, the pickling coil is a product in which the normal oxide film of the hot rolled coil is removed, and defects which are not visible in the hot rolled coil state are connected to the defects after passing the pickling process, and the tip of the coil to which the present invention is applied is produced in the hot rolling process. It is possible to secure the surface quality of the cold rolled coil because there is no scale defect, and to improve the workability by preventing the material defect of the processing coil in which secondary demand is processed by securing the exiting temperature of the coil at the tip end of the coil. .

Claims (3)

The number of descaling (13) headers used in the rolling of the material in the hot rolling process is that the front end uses both rows, and after the front end of the bar (10) passes through the follow point (25), only one row of descaling (13) headers is used. Using the decelerating header classification and bar progress speed for each bar position, characterized in that the speed of passing through the distal end 13 of the bar 10 is as fast as possible without causing a collision with the first finishing mill 19. Optimization system. The method according to claim 1, wherein the same heat is not used after the front end of the bar 10 in the material in which the front end of the bar 10 uses only two rows of descaling headers. Speed optimization system for use and bar progression. The method according to any one of claims 1 to 4, wherein the number of use of the descaling (13) header when rolling within a thickness of 1.4 <t <1.9 mm as a thin material PO material among the rolled materials of the hot rolling process is used for both ends. After the front end of the bar 10 passes through the follow point 25, the speed of passing the front end desqueling 13 device of the bar 10 by using only one column of the descaling 13 header is the first finishing mill 19 System for decelerating headers by bar position and bar progress speed optimization system, characterized in that it proceeds as fast as possible without causing a collision with).