JPS611410A - Continuous descaling method - Google Patents

Abstract

PURPOSE:To improve the surface nature of a strip, and to reduce the cost of equipment by controlling a number of revolution of a brush roll and/or a disstance between the brush rolls, and also making a brush of the downstream side fine. CONSTITUTION:A strip passing through a rewinding machine 11, a shearing machine 12 and a welding machine 13 from a hot rolled coil is descaled by brush rolls 15-18 after cracking a scale by a scale breaker 14. The number revolution of the brush rolls 15-18 is controlled by controlling a number revolution of a motor by a strip passing speed signal. An interval of the brush rolls 15-18 is controlled by a hydraulic cylinder, etc. together with a roll supporting frame and the motor. These controls are adjusted so that phases of the brush rolls 15-18 become opposite successively, therefore, the strip is descaled smoothly. Accordingly, the strip whose surface nature is good is obtained, and also a pickling process equipment becomes unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for continuously removing surface scale formed on a hot rolled steel strip using a brush roll.

(Prior art) There is a method of removing surface scale generated on hot-rolled steel strip in a pickling device.

■ Waste liquid must be treated after pickling.

■ In order to improve productivity under slow removal reaction, the equipment will be long and the construction cost will be high.

■ Running costs increase due to heating the pickling solution and operating long equipment.

It has its drawbacks.

To solve this problem, a method is disclosed in JP-A-57-142710 E, in which scale is removed with a brush roll and then lightly pickled or liquid honed.
This is disclosed.

(Problems to be Solved by the Invention) In the method disclosed in JP-A-57-142710, a plurality of brush rolls are arranged above and below a hot-rolled strip conveyance path and are driven to rotate. When cleaning with a brush roll with brushes arranged in high density, the brushes press down on the scale and descaling is not completed completely. When applying a brush roll with brushes, the strip steel surface (
This has the disadvantage that the brush does not apply uniformly, resulting in uneven descaling.

The present invention has been made to solve the problems of the prior art as described above, and eliminates uneven descaling.

The purpose of the present invention is to provide a highly efficient descaling method with good surface quality of steel strip.

(First Means to Solve the Problem) The descaling method of the present invention is characterized in that a plurality of brush rolls each having brushes arranged at equal pitches in the circumferential direction of the rolls are arranged on the upper and lower surfaces of the hot rolled strip conveyance path. In the descaling device f, the brushes of each brush roll are rotated so that the brushes of the brush rolls shift the polishing pitch and uniformly polish the entire surface of the hot rolled steel strip being conveyed. The number and / 1 r, = is to control the distance between brush rolls.

(Function) FIG. 2 shows a cross section of the brush roll. Second
As shown in the figure (the number of cleaning changes per unit time of the brush roll 3 with brushes 2 fixed at equal pitches in the circumferential direction of the roll is as follows: the number of rotations of the brush roll 3 is N rotations for 7 seconds, the brush roll 3 is M is the number of flanges 2 fixed on the circumference of
The number of times the cleaning amount of this flagyl roll 3 fluctuates per unit time is MN times/second, assuming that the number of times per unit time is MN times/second.

Therefore, even if there are multiple brush rolls 3 on each of the upper and lower surfaces of the hot-rolled strip conveyor and the conveyor is rotating at a constant rotation speed, the number of rotations of the brush rolls must be controlled according to the speed of one strip to descale. Causes unevenness.

Furthermore, if the rotational speeds are not equal, uneven descaling will inevitably occur. This will be explained by taking as an example a case where there are two brush rolls on each of the upper and lower surfaces of the hot rolled strip conveyance path as shown in FIG.

Upper first brush roll 4 (reed or lower first brush roll 4'
] The number of rotations is N1 rotations/second, the number of brushes is M1 places/all around, the number of rotations of the upper second brush roll 5 (or the lower second flange roll 5') is fN2 rotations/second, and the number of brushes is M2 places/full circumference. The distance between the upper first brush roll 4 (or lower first brush roll 4' and upper second brush roll 5 (-ffi or lower second brush roll 5') is L1 □, and the steel strip 1
The sheet threading speed shall be KV meters/second. Here, 6 is a backup roll provided opposite to the brush roll.

In this case, the number of fluctuations in the cleaning amount per unit time of the first brush roll 4 is M, N times/second, and that of the second brush roll 5 is M2N2 times/second. Moat MlN, = 4
In the case of qM2N2, the threading speed is constant (here, M, N.

The difference between M2N2 and M2N2 causes descaling unevenness. M,N
.

If and M2N2 are equal.

The relationship is C, 2V M, N, M2N2, so that 012 is an integer in this formula.

M, N, , M2N2 or L1□, and the upper first brush roll 4. The phase of the upper second brush roll 5 is reversed [
If this is done, as shown in Figure 4, the descaling curve 7 caused by the upper first brush roll ζ and the descaling curve 8 caused by the second brush roll will complement each other, resulting in smooth descaling. Curve 9 is obtained.

Brush rolls are placed on the upper and lower surfaces of the copper strip conveyance path, respectively.
) 2) Similarly, in the case of brush roll, the total number of rotations of the first brush roll is N1 rotations/second, and the number of brushes is fMi points/entire circumference.

If the distance between the first flag roll and the 1st +10- roll is Ll + 1°, the threading speed is v, and the constant is cii + 1, then M, N, =
M, N2−−,,,, = MiN i −,,,・
,, MnNnCl2V CI I
f l V Cn-1HV.

Here (C12,...+ "l 1+1 +
......The number of rotations N1 of each brush roll is set so that Cn-I n is all an integer.・・・＋Nl＋ ・・・
, Nn and/or brush roll spacing"+2+
``'+ ``l l+1 + ''・+ I'n-In is determined and controlled.

In the case of n brush rolls, the phase is changed by 2πh. In this case, the phase does not necessarily have to be changed by 2π74 sequentially from the upstream.

It is desirable that the roughness of the descaling brush in the present invention is coarser on the upstream side of the copper strip conveyance path and becomes finer as it goes downstream. In other words, on the upstream side, the main focus is on descaling, and on the downstream side, the main focus is on adjusting the surface of the copper strip and removing fine scale.

Efficient descaling is possible.

Here, the roughness of the brush is defined as shown in Table-1.

Table-1 (Example) Embodiments of the present invention will be described in detail using the drawings.

FIG. 1 shows a descaling process having four brush rolls each on the upper and lower sides. The hot-rolled coil is cut into strips by an unwinder 12. The steel strip 1, which has passed through the welding machine 13 and is connected to the preceding steel strip, cracks the scale with a scale breaker 14, and then passes through four upper and lower Nofrashi rolls 15 to 1.
8, the surface of the copper strip was cleaned by spraying, dried with a dryer 21 and a trowel, and wound up with a winder 22. Note that 19 indicates a pull-up roll. At that time, the steel wire diameter of each brush roll was as shown in Table 2.
Figure 5 shows the effect of applying the present invention to At-2 with a thickness of 25 mm and a width of 920 mm. The descaling speed, which was 138 mpm without rotation speed control, was improved by about 20% to 164 mpm with control. Also, controlling the brush rotation speed improved the surface quality of the copper strip by reducing excessive grinding. It was in good condition with no parts.

The rotational speed of the plano roll is controlled by controlling the rotational speed of a normal DC motor or a variable rotational speed AC motor using a signal t of the sheet passing speed obtained from a pulse generator or a plate speed meter.

The brush roll spacing is controlled by moving the brush roll, which is movable in one root direction, together with the brush roll support frame and motor, using a hydraulic cylinder or a worm gear. The amount of movement and position are determined using the signal of the threading speed obtained from a pulse generator or plate speed meter and the brush low J from a magnetic position detector, etc., in the same way as single rotation speed control.
L: Performed by position signal.

(Effects) By carrying out the present invention, (1) A copper strip with good surface quality without excessively ground parts can be efficiently obtained.

(2) There is no problem with waste acid treatment that occurs during the pickling and descaling process.

(3) A descaling effect equivalent to that of the pickling descaling process can be achieved with just a few brush rolls, making the equipment more compact.

It has the following effects.

[Brief explanation of drawings]

FIG. 1 shows a descaling process in one embodiment of the present invention. FIG. 2 shows a brush roll of the present invention. FIG. 3 shows the arrangement of the brush roll and backup roll. FIG. 4 shows the variation in the descaling rates of the two brush rolls and the summed descaling rate. FIG. 5 shows the effect of branmile rotational speed control. 1... Copper band, 2... Brush, 3... Brush roll, 4... Upper first brush roll, 4'... Upper first brush roll. 5... Upper second brush roll, 5'... Upper second brush roll, 6... Bank up roll, 7, 8.9...
- Descaling curve, 11... Rewinding machine, 12... Shearing machine, 13... Welding machine, 14... Scale breaker-115 to 18... Brush o -ib, 19-0/
Z tutu up. -2,, 2013, Nib2. 21... Dryer, 22... Winding machine.

Claims (2)

[Claims] (1) In a descaling device in which a plurality of brush rolls each having brushes arranged at equal pitches in the circumferential direction of the rolls are arranged on the upper surface and lower surface of a hot rolled strip conveying path and are driven to rotate, the brush rolls on each brush roll are Continuous descaling characterized in that the number of rotations of each brush roll and/or the distance between the brush rolls is controlled so that the surface of the hot rolled steel strip being conveyed is uniformly polished as a whole by shifting the polishing pitch. Method. (2) The continuous descaling method for hot-rolled steel strip according to claim 1, characterized in that the brushes of the brush roll are made finer toward the downstream side.