JP2542350B2 - Skin pass method with continuous hot dip coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a skin pass mill that rotates a work roll by a drive device during release and rotates the work roll by friction with a strip without driving during reduction. The present invention relates to a skin pass method in a continuous hot dip galvanizing apparatus that prevents the strip from being narrowed or broken at the start of the reduction when the pressure is released again.

(Prior Art) In recent years, in a continuous hot dip galvanizing apparatus for strips, it has become common to install a skin pass mill or a tension leveler in the apparatus in order to produce a product of good quality.

However, these devices have individual drive sources,
Since it is expensive, a common drive source is used. FIG. 2 shows the drive system of the skin pass mill and the tension leveler by this common drive source. For the strip moving in the arrow direction, 1 is a bridle, 2 is a skin pass mill, 3 is a tension leveler, 4, Reference numerals 5 are bridles arranged in front of and behind the tension leveler 3.
The drive source 6 is provided on the bridle 5, and is connected to the bridle 4 and the skin pass mill 2 by a drive shaft 7.

The skin pass mill 2 has a drive shaft 7 as shown in FIG.
The bevel gear 8 is provided at the tip of the
A bevel gear 12 is also provided on one surface of the lower gear 9 of the pair of gears 9 and 10 via a shaft 11 so that these bevel gears 8 and 12 are fitted and the gears 9 and 10 are rotated. . Then, the opposite surfaces of the gears 9 and 10 and the upper and lower backup rolls 13 and 14 of the skin pass mill 2 are connected by different shafts 15 and 16, respectively,
The work rolls 17 and 18 are rotated. 19 is a strip.

The drive shaft 7 is provided with a first clutch 20, and the shaft 16 connecting the upper gear 10 and the upper backup roll 14 is provided with a second clutch 21. Both of these clutches can be manually operated individually by switching them, but normally, when the hydraulic pressure to open and reduce the skin pass mill 2 exceeds the set value, it automatically disengages, and below that set value. When it comes to, it will come in automatically. That is,
When the skin pass mill 2 is released, the clutches 20 and 21 will enter and the drive shaft 7 will move up and down the backup rolls 13 and 14.
Is rotated so that its peripheral speed matches the running speed of the strip 19, and when the skin pass mill 2 is pressed again, the work rolls 17 and 18 can start the skin pass at the same speed as the strip 19. . However, when the clutches 20 and 21 are pressed down the skin pass mill 2, both are disengaged, the upper and lower backup rolls 13 and 14 are in a non-driving state, and the strips 19 allow the work rolls 17 and 18 to rotate while skin pass. There is.

(Problems to be Solved by the Invention) By the way, in the continuous hot dip galvanizing apparatus, the skin pass mill 2 is opened when the plating is stopped or when passing through the welded portion of the strip 19 during plating. At this time, the switching type clutches 20 and 21 as described above
Therefore, when the skin pass is performed, the strip 19 may be narrowed or broken immediately after the skin pass is started.

In view of such a point, the present invention provides a skin pass method which does not have such a problem.

(Means for Solving the Problems) According to the present invention, a pair of gears 9, 10 vertically fitted to each other is connected to one side of a drive shaft 7 guided from a drive source of another device, and each of the upper and lower gears is connected. The opposite side of 9 and 10 and the upper and lower backup rolls 13 and 14 of the skin pass mill 2 have different axes.
By connecting 15 and 16, the upper and lower work rolls 17 and 18 are rotated, a first clutch 20 is connected to the drive shaft 7, and a second shaft 16 is connected to the upper gear 10 and the upper backup roll 14. A clutch 21 is provided, and both the clutches 20 and 21 automatically enter when the skin pass is released to rotate the upper and lower backup rolls 13 and 14, and when they are pressed down, both are automatically disengaged to cause friction with the strip 19. The upper and lower backup rolls 13 and 14 pass the skin while rotating, and both clutches 20 and 21 can be manually turned on and off. When the skin pass mill 2 is temporarily released and pressed down again, it can move up and down in front of the upper and lower work rolls 17 and 18 that are in contact with the backup rolls 13 and 14. By arranging the roll 22, the first clutch 20 is manually disengaged before the reduction of the skin pass mill 2, and the strip 19 is pushed up by the anti-clipping roll 22 while the second clutch 21 is kept on. When the upper work rolls 18 of the skin pass mill 2 are contact-rotated with each other, and the speeds of the upper and lower work rolls 17, 18 and the strip 19 are synchronized by this contact rotation, the skin pass mill 2 is held until the strips 19 come into contact with the lower work rolls 17. Second clutch after rolling down and contact
I tried to cut 21.

(Operation) As a result of various studies on the causes of narrowing and breaking of the strip occurring at the start of the skin pass mill reduction, the present inventors have found that the backup rolls 13, 14 of the skin pass mill 2 are
The rotation speed increases according to the strip passing speed, but since the mill does not have a correction mechanism that responds to diameter changes,
When the diameter of the backup rolls 13, 14 becomes smaller due to wear, the peripheral speed of the work rolls 17, 18 becomes slower than the speed of the strip 19, and as a result, the slack of the strip 19 occurs at the work rolls 17, 18 entrance side. It was found that, on the output side of the work rolls 17 and 18, the strip 19 was subjected to abnormal tension and was squeezed or broken. Therefore, in order to prevent the slack and the abnormal tension from being generated, the work rolls 17 and 18 may be rotated by the traveling strip 19 until the speeds are synchronized, and then the skin pass is performed.

As a method for rotating the work rolls 17 and 18, an anti-clipping roll 22 that can be moved up and down is arranged in front of these rolls, and the first clutch 20 is disengaged before reduction.
Moreover, if the strip 19 is pushed up by the anti-clipping roll 22 with the second clutch 21 in contact with the upper work roll 18 of the skin pass mill 2, the angle of wrapping the strip around the work roll 18 becomes large. The work roll 18 can be easily rotated. At this time, since the first clutch 20 is disengaged, the drive shaft 7 does not rotate the gears 9 and 10, but
Since the clutch 21 is included, the upper work roll 18 →
The rotation is transmitted to the lower work roll 17 through the path of the upper backup roll 14 → the fitted gears 10 and 9 → the lower backup roll 13 → the lower work roll 17. This contact is carried out until the speeds of the work rolls 17 and 18 and the strip 19 are synchronized, and then the strip 19 is pressed down until it comes into contact with the lower work roll 17, and after the contact, the second clutch 21 is disengaged. Rolls 17, 18 enter the skin pass at the same speed as strip 19.

(Example) A hot-dip galvanized steel strip having a plate thickness of 0.27 to 0.40 mm was passed through a continuous hot-dip galvanizing device at 180 m / min, and the peripheral speeds of the work rolls 17 and 18 of the skin pass mill 2 were made to match the steel strip speed. I passed the skin in both the closed state and the delayed state.

As shown in Fig. 1, the equipment arrangement before and after the skin pass mill 2 is that the bridle 1, tension leveler 3 and bridles 4 and 5 are arranged in the conventional manner, and anti-clipping is performed in front of the work rolls 17 and 18 of the skin pass mill 2. The roll 22 is movably supported by a hydraulic cylinder (not shown) so that the strip 19 can be pushed up. Further, a speedometer 23 is arranged on the upper backup roll 14, and the peripheral speed of the upper backup roll 14 and the strip 19 are arranged.
The speeds of the two can be compared.

As for the clutch, the first clutch 20 is disengaged and the second clutch 21
With work pieces turned on, rotate work rolls 17 and 18 to raise anti-clipping roll 22 and strip 19
After contacting the upper work roll 18, the hydraulic pressure for reduction is increased to close the work rolls 17, 18, and then
The second clutch 21 was disengaged. As a result, the work roll
It was normal when the peripheral speed of 17 and 18 was 180 m / min,
When it was set to 175 m / min, the strip 19 was narrowed down.

(Effects of the Invention) As described above, the skin pass method according to the present invention rotates the work roll of the skin pass mill with a strip,
Since the work roll and the strip speed are synchronized and the skin passes, the slack of the strip does not occur on the work roll entry side, and abnormal tension is not applied to the work roll exit side, resulting in narrowing or breakage. Can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a skin pass method according to the method of the present invention. FIG. 2 is a drive system diagram of a skin pass mill portion of the continuous hot dip galvanizing apparatus, and FIG. 3 is a partial front view of the skin pass mill. 1 ... Bridle, 2 ... Skin pass mill, 3 ... Tension leveler, 4, 5 ... Bridle, 6 ... Drive source, 7 ... Drive shaft, 8 ... Bevel gear, 9, 10 ... Gear, 11
…… Shaft, 12 …… Bevel gear, 13, 14 …… Backup roll, 15, 16 …… Shaft, 17, 18 …… Work roll, 19 …… Strip, 20 …… First clutch, 21 …… Second clutch,
22 …… Anti clipping roll, 23 …… Speedometer,

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-63-56308 (JP, A) JP-A-50-96425 (JP, A) Actually open Sho-60-110462 (JP, U) Actual-open Sho-51- 127929 (JP, U) Actually open 61-64156 (JP, U)

Claims (1)

(57) [Claims] 1. A pair of gears 9, 10 vertically engaged with each other is connected with a drive shaft 7 guided from a drive source of another device on one side, and the opposite faces of the upper and lower gears 9, 10 and a skin pass mill. Two upper and lower backup rolls 13 and 14 with different axes
By connecting 15 and 16, the upper and lower work rolls 17 and 18 are rotated, a first clutch 20 is connected to the drive shaft 7, and a second shaft 16 is connected to the upper gear 10 and the upper backup roll 14. A clutch 21 is provided, and both the clutches 20 and 21 automatically enter when the skin pass is released to rotate the upper and lower backup rolls 13 and 14, and when they are pressed down, both are automatically disengaged to cause friction with the strip 19. The upper and lower backup rolls 13 and 14 pass the skin while rotating, and both clutches 20 and 21 can be manually turned on and off. When the skin pass mill 2 is temporarily released and pressed down again, it can move up and down in front of the upper and lower work rolls 17 and 18 that are in contact with the backup rolls 13 and 14. By arranging the roll 22, the first clutch 20 is manually disengaged before the reduction of the skin pass mill 2, and the strip 19 is pushed up by the anti-clipping roll 22 while the second clutch 21 is kept on. When the upper work rolls 18 of the skin pass mill 2 are contact-rotated with each other, and the speeds of the upper and lower work rolls 17, 18 and the strip 19 are synchronized by this contact rotation, the skin pass mill 2 is held until the strips 19 come into contact with the lower work rolls 17. Second clutch after rolling down and contact
A method for skin-passing in a continuous hot dip galvanizing machine, which is characterized by cutting 21.