JPH0576376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement of a back tension device used in a device for descaling and shape correction in pre-pickling treatment of ordinary steel and special steel.

<Conventional technology> Normally, an oxide film is formed on the surface of the steel strip after hot rolling, and in the case of special steel, it is hardened. Annealing and removal of surface oxide film (hereinafter referred to as scale) are performed. This scale is hard and brittle, so conventionally, in order to remove this scale, a steel ball is shot onto the steel plate surface using shot blasting to crack the scale on the steel plate surface, and then sulfuric acid and nitric acid are used to crack the scale on the steel plate surface. Chemical removal methods using chemicals such as , hydrochloric acid, and boronic acid were used.

However, in recent years, users' requirements for the surface of steel sheets have become stricter, and when shot blasting is used on the surface of steel sheets, it leaves dents, so it is necessary to reduce the size of the shot particles and use bending rolls in combination to crack the scale. This shortens the pickling time. Since this bending requires applying high tension to the steel plate, pinch rolls are installed on the entry side.

As shown schematically in FIG. 4, such conventional pickling pretreatment equipment includes a fog cooling tank 2 and a water quench 3 disposed at the rear of an annealing furnace 1.
A scale breaker 4 is disposed on the outlet side, a dryer 5 for drying the strip is disposed behind the scale breaker 4, and a bridle 6 for controlling the speed of the line is disposed behind the dryer 5. . And scale breaker 4
consists of a pinch roller 7a which applies back tension to the steel plate on its entry side, and a bending roll unit 8 consisting of three bending rolls located at the center.

To explain the scale breaker 4 in more detail, the pinch roll 7a is generally lined with rubber, holds the strip 11 with a hydraulic cylinder 10, and backs the strip 11 by performing drag operation with a DC motor (not shown). It gives tension. In addition, bending roll unit 8
has two upper pairs of back-up rolls and one lower pair of back-up rolls, and the amount of reduction can be set by an electric motor (not shown) according to the thickness of the plate. moreover,
The leveling roll unit 9 is installed to correct the bending caused by the sudden bending of the plate by the bending roll unit 8.The leveling roll unit 9 is installed to correct the bending caused by the sudden bending of the plate by the bending roll unit 8.The leveling roll unit 9 is installed to correct the bending caused by the sudden bending of the plate by the bending roll unit 8. It's summery. In addition, these bending roll units 8 and leveling roll units 9 are all non-driven, and the plate bending resistance due to these rolls appears as an increase in the tension of the strip 11, and this tension is caused by the rear bridle 6. It is designed to be able to be pulled. Furthermore, a water cooling nozzle (not shown) is installed inside the scale breaker 4 to spray water onto the strip 11 from the inlet to the outlet in order to prevent push-in damage due to scale build-up.

<Problems to be Solved by the Invention> The various facilities described above have the following drawbacks.

1 The strip 11 heated in the annealing furnace 1 is rapidly cooled by cooling water and enters the pinch roll 7a (or bridle roll) in a wet state, so if a large tension is to be applied, the strip 11 will be damaged by the rolls. A slip occurs between the strip 11 and the strip 11, making control difficult.At the same time, the strip curvature due to the bending roll unit 8 also changes, making uniform braking or leveling difficult.

2. If a large amount of rolling force is to be applied to the strip 11 using the pinch rolls 7a, the rolls must be made of steel, which will cause scratches on the product.

3. If the surface of the pinch roll 7a is rubber-lined, as mentioned in 1), slips will occur between the roll and the strip 11, causing uneven wear on the roll, and the life of the roll will be extremely shortened. becomes shorter. Furthermore, if a bridle roll is used instead of the pinch roll 7a, the diameter of the roll becomes large and the amount of equipment increases.

4 When the surface of the pinch roll 7a is rubber-lined, the upper roll is opened when the part where strips of different thickness are joined passes, but if the temperature is high due to insufficient cooling, the roll may burn out. There is a risk of being damaged, making stable operations difficult.

5 For bridle rolls, strip 11
When the joined portion passes, the upper roll cannot be opened like the pinch roll 7a. Furthermore, if the temperature at the joint is insufficient and the temperature is high, there is a risk that the rolls will be burnt out, making stable operation difficult.

In view of the above-mentioned problems, the present invention enables more effective braking or leveling by applying tension to the strip within the leveling roll or bending roll, and provides stable braking at all times even when the strip is wet. The purpose of the present invention is to provide a back tension device for a scale breaker that can be operated.

<Means for solving the problem> A scale breaker bag is provided downstream of the water quench and on the inlet side of a scale breaker having bending rolls and leveling rolls, and applies tension to the strip within the scale breaker. The tensioning device consists of three rolls arranged in a staggered manner, including an upper roll that can move up and down and a pair of lower rolls that clamp the strip and forcefully bend the strip.

<Operation> A mechanical loss (energy) called bend loss is generated by forcibly bending the strip by a plurality of rolls arranged in a staggered manner, and this mechanical loss generates back tension in the strip. This energy is different from pinch rolls that use rolling force and friction,
Generates tension regardless of the type of strip.

<Example> Hereinafter, a preferred example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a pickling pretreatment facility using a back tension device according to this embodiment, and FIG. 2 is an explanatory diagram showing the configuration of the back tension device according to this embodiment. Note that the same parts as those explained in the prior art are denoted by the same reference numerals.
Duplicate explanations will be omitted.

As shown in both figures, the back tension device 7 provided on the inlet side of the scale breaker 4 is of a three-roll type, and has an upper roll 13 and two lower rolls 14. The upper roll 13 has a rubber lining 12 on its outer periphery, and is rotatably held via a bearing 15 in a bearing box 18 that can be raised and lowered.
It is connected by a pin 30 to a rod end 19 screwed into the rod of a hydraulic cylinder 20 fixed to the hydraulic cylinder 20 . On the other hand, the two horizontally arranged lower rolls 14 have their surfaces coated with ceramic and are rotatably held in a bearing box 17 fixed to the frame 21 via bearings 16. These upper roll 13 and lower roll 14 are rotationally driven separately, and the upper roll 13
is driven by a DC motor 26 via a universal joint 22, a reducer 24, and a coupling 25, and the two lower rolls 14 are driven by a DC motor 29 via a universal joint 23, a distribution reducer 27, and a coupling 28. Driven by

In such a configuration, the upper roll 13 is pressed downward by the cylinder 20 while the upper roll 13 is pressed downward.
And by driving the two lower rolls 14,
The strip 11 can be bent and clamped to obtain back tension. In this case, 2mm
If a hydraulic cylinder 20 capable of bending the strip 11 up to 6 mm is used, the bending resistance will reach 2000 Kg to 8000 Kg in terms of tension. This value can be freely changed depending on the roll arrangement and roll diameter. The above-described embodiment has a simple structure and is designed to provide both a bending effect and a pinch roll effect in order to obtain the maximum effect. Moreover, the pinch roll effect is equivalent to two pinch rolls.

In the above-mentioned embodiment, in order to further enhance the pinch roll effect, the lower roll 14 is coated with a ceramic coating in order to increase the coefficient of friction in a wet state, and to prevent the occurrence of push-in scratches.
The rubber lining 12 was applied only to the upper roll 13. At this time, the tension generated in the lower roll is N×p×b× if the strip is 1m wide.
M=0.1×60×100×2=1200Kg, the tension generated in the upper roll is N×p×b×M=0.05×60×
100 x 2 = 600Kg, and a total pinch roll effect of 1800Kg can be expected.

Tension 1800Kg due to this pinch roll effect
If the tension due to the bending effect mentioned above is added to this, the result is 3800Kg to 9800Kg. As described above, the device of this embodiment can obtain a back tension of 3800 kg even with a thin material, which is a sufficient value for use in this type of scale breaker.

For comparison, let us estimate the back tension of the pinch roll method according to the prior art. For pinch rolls with rubber lining, the maximum linear pressure is currently considered to be 50 to 90 kg/cm due to the strength limitations of the rubber, so if the strip is 1 m wide, the tension is N x p x b = 0.05×90×100＝
450Kg, and even if the upper and lower rolls are driven, it weighs about 900Kg. Therefore, according to the conventional method, it is necessary to arrange three to four pinch rolls in tandem.

FIG. 3 shows a back tension device 40 according to another embodiment. In this back tension device 40, two back up rolls 31 are disposed on each of the three upper and lower rolls 32, so that the diameters of the upper and lower rolls 32 can be reduced.

As explained above, according to the back tension device of this embodiment, it is possible to obtain the effect of three to four conventional pinch rolls. Moreover, since the rolls are arranged in a staggered manner, the rolling force is 30% to 40% higher than that under direct pressure such as pinch rolls, so the capacity of the hydraulic cylinder for rolling must be relatively small. I can do it.

Note that such a back tension device is useful not only as a scale breaker but also as a tension leveler, a leveler, and the like.

<Effects of the Invention> As explained above in detail along with the examples, by using the back tension device according to the present invention, it is possible to effectively apply a large back tension to the strip through the bending effect and the pinch roll effect. Furthermore, since no slip occurs between the roll and the strip, control is easy, and the curvature of the strip does not change due to the bending roll unit, making uniform braking or leveling easy. Further, since a large back tension can be obtained with a small rolling force, the strip does not suffer from pressure damage, and furthermore, since the strip does not slip, uneven wear of the roll does not occur and the life of the roll is extended. Furthermore, since there is no need to provide a rubber lining to the lower roll, if the upper roll is opened when the strip joint passes, the roll will not burn out even at high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of pickling pretreatment equipment equipped with a back tension device according to an embodiment of the present invention;
FIG. 2 is an explanatory diagram showing the configuration of the back tension device, FIG. 3 is an explanatory diagram showing the configuration of the back tension device according to another embodiment, and FIG. 4 is an explanatory diagram showing the configuration of the back tension device according to the prior art. It is a schematic diagram of the equipment. In the drawing, 4 is a scale breaker, 7 is a back tension device, 8 is a bending roll unit, 9 is a leveling roll unit, 11 is a strip, 13 is an upper roll, 14 is a lower roll, 40
is a back tension device.

Claims (1)

[Claims] 1. A scale breaker back tension device that is installed downstream of the water quench and on the inlet side of a scale breaker having bending rolls and leveling rolls and applies tension to the strip in the scale breaker, which clamps the strip. A back tension device for a scale breaker, comprising three rolls arranged in a staggered manner, including an upper roll that can move up and down and a pair of lower rolls that are arranged in a staggered manner to forcefully bend the strip. .