JPH0230318A - Control method for scale eliminating device for hot rolled coil - Google Patents

Abstract

PURPOSE:To effectively eliminate a scale of a hot rolled coil by deriving thickness of the scale to be ground from an elongation of the hot rolled coil in a scale eliminating device, power of a brush driving source, the number of stages of a brush, and a running speed of the coil, and executing a control so that said thickness enters into a range which is determined in advance. CONSTITUTION:A scale of a hot rolled coil 2 is eliminated by a scale eliminating device 1, and thereafter, it is brought to pickling. In such a case, an elongation epsilonof the coil 2 is varied by rollers 41, 42 and an elongation driving device 5. Subsequently, a first function (f) (epsilon) which goes to high by an increase of the elongation epsilon, a second function (g) (w) which goes to high by an increase of driving source power W, the number of stages N of brushes 611, 612 and a speed of the coil 2 are derived. Next, thickness t of the scale to be ground is derived from the expression I, and when t is outside of a scheduled range, it is allowed to enter into the range by varying and adjusting epsilon, W, N and V. In such a way, the scale of the hot rolled coil can be eliminated effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for controlling a hot-rolled coil scale removal apparatus that efficiently removes scale generated on the surface of a hot-rolled coil.

Conventional technology The hot-rolled coil, which is the base material to be cold-rolled, is hot-rolled at a predetermined high finishing temperature. , -ru'') are formed in a layered manner. This scale is removed by mechanical and chemical means before cold rolling.

In order to improve the efficiency of the descaling operation and subsequent operations, hot rolled coils are welded to perform the descaling operation. By welding the hot-rolled coil in this manner, scale removal work and the like can be performed continuously, and the work time can be shortened.

Problems to be Solved by the Invention However, even if the material conditions of the welded hot-rolled coils are different, it is difficult to significantly change the conditions of the chemical pickling section, the acid solution temperature, or the acid concentration. Materials with poor scale (removal of scale) properties require time and reduce productivity.

For this reason, a mechanical scale removal device is installed in front of the chemical pickling section, but because its conditions and effects are unclear, the scale removal capacity may become excessive or insufficient, resulting in In many cases, productivity improvement cannot be achieved.

As described above, in a scale removal operation that uses both mechanical scale removal and scale removal by pickling, it is particularly necessary to change the conditions for mechanical scale removal depending on the material conditions.

An object of the present invention is to provide a method for controlling a hot-rolled coil scale removal device that can operate scale removal by pickling most efficiently by controlling working conditions for mechanical scale removal. be.

Means for Solving the Problems The present invention provides a method for controlling a hot-rolled coil scale removal device in which pickling is performed after the scale of the hot-rolled coil is removed by the scale removal device, wherein the scale is removed from the hot-rolled coil. The elongation rate changing means changes the elongation rate 6 by angularly displacing the coil around an axis parallel to its width direction, and the hot-rolled coil surface is ground using a brush that is rotationally driven by a drive source. The first function f, which is installed in multiple stages in the longitudinal direction of the coil, becomes larger as the elongation rate ε increases.
(ε), a second function g (W) that increases as the power W of the brush drive source increases, the number of brush stages N used, and the running speed V of the hot-rolled coil. Determine the scale thickness Δt, and if Δt is outside the predetermined range, ε,
A scale removing apparatus for a hot rolled coil, characterized in that at least one of W, N, and V is changed: ll and scale removal is performed at ε, W, N, and V such that Δt is within the above range. This is a control method.

Function In the present invention, the scale of the hot rolled coil is removed by a scale removing device and then by pickling. This scale removing device is composed of elongation rate changing means and a plurality of brushes installed in the longitudinal direction of the hot rolled coil. Then, the thickness from which the scale is removed is Δt,
A first function f(ε) that increases as the elongation rate ε of the hot-rolled coil increases, and a second function g(W) that increases as the power W of the drive source that drives the brush increases.
, the number of stages of brushes used, N, and the running speed of the hot-rolled coil as ■, then Δt is expressed by the following equation.

If Δt determined according to the above formula is outside the predetermined range, the scale removing device
Δt is controlled to be within the above range by changing and adjusting the two.

Embodiment 1 Ca is a configuration block diagram of a scale removal apparatus 1 in which a control n method, which is an embodiment of the present invention, is implemented. After the tension applied to the hot-rolled coil 2 formed by the hot-rolling process is adjusted by the priddle roll 3a, the elongation that causes cracks and eyes to form in the scale generated on the surface of the hot-rolled coil 2 is performed. It passes through a scale breaker 4 which is a rate changing means. The elongation rate ε of the hot rolled coil 2 due to the scale breaker 4 is defined by the first equation.

Here, 1. is the unit length of the hot rolled coil before being input to the scale breaker 4, and i is the length of the unit length output from the scale breaker 4. scale breaker 4,
Tension is applied to the hot-rolled coil 2 by the priddle rolls 3a, 3b3C, and a space is provided between the two rolls 41.42 in the traveling direction of the hot-rolled coil 2, and the roll 41.4 is attached to the hot-rolled coil 2.
2 is a device that applies pressure in a direction perpendicular to the direction of movement to stretch the material and form cracks in the scale.

The scale of the hot-rolled coil 2, which has been cracked by the scale breaker 4, is mechanically removed by the grinding device 6. The number of passes of the grinding devices 61 to 6 rI is controlled by the brush driving device 7, and the number of passes is controlled to increase when the scale is thick.

As this brush 611612 rotates and slides on the hot rolled coil 2, the scale is ground. Brush 611,6
12 are driven by brush drive sources 611a and 612a, and the power W of the brush drive sources 611a and 612a is controlled by the brush drive device 7.

After the scale on the hot-rolled coil 2 is removed by the grinding device 6, the hot-rolled coil 2 passes through the priddle roll 3d and moves to the next step, a pickling step.

In the pickling step, scale is removed by passing the hot rolled coil 2 through a pickling tank containing hydrochloric acid or sulfuric acid. It is made to pass through the pickling tank for a predetermined time (for example, 5 to 10 seconds). This pickling time is determined by the capacity of the equipment before and after the pickling, and depending on the scale thickness, extending the pickling time, that is, lowering the hot-rolled coil passing speed, will reduce productivity and must be avoided. The scale is ground by a scale remover until the scale thickness is completely removed by the equipment.

FIG. 2 is a configuration diagram for explaining the relationship between the scale removal device 1 and the pickling film gIi11. Each hot rolled coil 2 manufactured by hot rolling is welded before being sent to the scale removing device 1 in order to continuously perform scale removal and subsequent processes. The hot-rolled coil 2 is sent to the descaling device 1 via the inlet loop 10a. In the scale removal equipment 1 and the pickling equipment 11, it is necessary to take care to allow the hot-rolled coil 2 to pass through it continuously. A coil storage device is required. In this embodiment, an inlet loop 10a and an outlet loop 10b are used as this storage device. These loops can move in the directions of arrows 12a to 12d, and by changing the storage amount of the hot-rolled coil 2, the scale removal equipment 1 and the pickling equipment 11 can be maintained even during welding of the hot-rolled coil. The hot rolled coil 2 can be passed through continuously. Further, the direction of the hot rolled coil 2 is changed by deflation crawlers 13a to 13d and sent to a predetermined facility.

Next, an embodiment of the control method according to the present invention will be described below. FIG. 3 is a control flowchart for realizing a subwriting method according to an embodiment of the present invention.

The processing of each step will be explained below. First, in step S1, the number N of stages through which the hot rolled coil 2 passes through the grinding device 6 is initially set. This initial setting value is determined by the temperature during hot rolling of the hot rolled coil 2. The scale thickness ground by the grinding device 6 is roughly determined by the number of stages,
As the number of stages increases, more scale is removed. When the number of stages is set in step S1, step s2
Then, the influence coefficient f(ε) of the scale grinding amount is calculated from the elongation rate ε of the hot rolled coil 2 due to the scale breaker 4.

In step S3, the electric power supplied to the grinding device 6 is set, and the influence coefficient g(W) of the amount of grinding by the grinding device 6 is calculated. 1! A certain constant value is initially selected for the force W, and is adjusted after calculating Δt, which will be described later.

When the power supplied to the grinding device 6 increases, the brush 6
The pressing force on the hot rolled coil 2 of 11,612 becomes stronger, and more scale is ground.

In step s4, the running speed ■ of the hot rolled coil 2 is set. The running speed (2) is set to the slower value of the line speed of the inlet side of the scale removing device 1 and the line speed of the mountain opening equipment capacity.

Once the parameters determining the scale thickness to be ground are set in steps 51 to S4, step S
In step 5, the scale grinding amount Δt is calculated according to the second equation.

In step S5, when the scale grinding amount Δt is calculated,
In step S6, it is determined whether the grinding amount Δt is within the scale thickness range generated in the hot rolled coil 2. If the scale thickness is outside the range, for example, if the scale grinding amount Δt is larger than the scale thickness generated in the hot rolled coil 2, or if the scale grinding amount Δt is smaller than the scale thickness generated in the hot rolled coil 2, When the scale thickness is i% that cannot be removed by the pickling equipment 11, step s is performed.
6, the process advances to step S1, and the above-mentioned parameters are set again.

In step S6, if the scale grinding amount Δt is within the scale thickness range, scale removal is performed according to the parameters set in steps 51 to s4.

FIG. 4 is a graph showing the relationship between the temperature during hot rolling and the scale thickness generated in the hot rolled coil 2.

In the fourth [2I], the horizontal axis indicates the temperature when the hot rolled coil 2 is hot rolled, and the vertical axis indicates the scale thickness generated in the hot rolled coil 2. The line e1 in FIG. 4 is a line showing the relationship between the temperature during hot rolling and the scale thickness, and the thickness of the scale generated on the surface of the hot rolled coil 2 is almost uniform depending on the temperature during hot rolling. and its thickness increases as the temperature increases.

A line 12 indicated by a broken line in FIG. 4 is a line representing the thickness of the scale to be ground by the grinding device 6, and the thickness of the scale to be ground by the hot-rolled coil 2 differs depending on the number of stages N of the grinding device 6. That is, the number of stages N of the grinding device 6 is roughly determined by the winding temperature when the hot rolled coil 2 is hot rolled. For example, when the temperature is in the range of t1 to t2, the number of stages N of the grinding device 6 is 1. , the number of stages N is set to 2 when the temperature is within the range of temperature t2 to temperature t3. In this way, the amount of scale grinding in the grinding device 6 is determined by the number of stages N, and the scale remaining after grinding in the grinding device 6 is removed by the pickling equipment in the post-process of the scale removing device 1.

FIG. 5 is a graph for explaining the elongation rate ε of the scale breaker 4, which is determined by the temperature during hot rolling. As the winding temperature during hot rolling increases, the scale becomes thicker, so it is necessary to increase the elongation rate ε of the hot rolled coil 2 depending on the winding temperature during hot rolling. Therefore, when the winding temperature during hot rolling of the hot rolled coil 2 is determined, the scale breaker 4
In order to obtain the elongated skewer shown in the middle line 13, the elongation is controlled by the elongation drive 5, and the cracks give an eye to the scale of the hot-rolled coil 2. As described above, by changing the elongation rate ε given to the hot-rolled coil 2 depending on the winding temperature during hot rolling, grinding in the grinding device 6 can be easily performed.

As described above, according to this embodiment, by controlling the operating conditions of the scale remover, the scale removal by the scale remover and the pickling equipment can be operated efficiently at all times.

Effects of the Invention As described above, according to the present invention, the thickness Δt of the scale to be ground is determined from the elongation rate ε, the power W of the brush drive source, the number of stages of the brush °N, and the running speed ■ of the hot-rolled coil. Since Δt is controlled to fall within a predetermined range, scale can be removed efficiently.

[Brief explanation of the drawing]

The first section is a configuration block diagram of the scale removal device 1 in which a control method according to an embodiment of the present invention is implemented, and FIG. 2 is a configuration diagram for explaining the relationship between the scale removal device 1 and the pickling equipment 11. , FIG. 3 is a control method according to an embodiment of the present invention and a control flowchart to be realized, FIG. 4 is a graph showing the relationship between the temperature during hot rolling and the scale thickness generated on the hot rolled coil, and FIG. FIG. 5 is a graph for explaining the elongation rate ε of the scale breaker 4 determined by the temperature during hot rolling. 1... Scale removing device, 2... Hot rolled coil, 3a
~3d...Pridle roll, 4...Scale braking force, 5...Elongation rate drive device, 6...Grinding device, 7...Brush drive device

Claims (1)

[Claims] In a method of controlling a hot-rolled coil scale removing device, the scale remover removes scale from the hot-rolled coil and then pickles the hot-rolled coil, the scale removing the hot-rolled coil by its width. Grinding is performed using an elongation rate changing means that changes the elongation rate ε by angular displacement around an axis parallel to the direction, and a brush that is rotationally driven by a drive source on the surface of the hot rolled coil. The first function f, which is installed in multiple stages in the longitudinal direction, becomes larger as the elongation rate ε increases.
(ε), a second function g(W) that increases as the power W of the brush drive source increases, the number of brush stages N used, and the running speed V of the hot-rolled coil. The thickness Δt of the scale is calculated from Δ_t=N・f(ε)・g(W)/V, and if Δt is outside the predetermined range, ε,
A method for controlling a scale removing apparatus for a hot rolled coil, characterized in that at least one of W, N, and V is adjusted to perform scale removal operation at ε, W, N, and V such that Δt is within the above range. .