JPH02303611A - rolling mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rolling mill equipped with a backup roll having a tapered piston type variable roll crown mechanism for rolling metal plates or metal strips. .

[Conventional technology]

For example, thin copper strips used for tinplate must have high flatness in order to meet the quality standards required for tinplate, or to improve threadability and increase production efficiency. is required. In order to improve the flatness of thin steel strips, a rolling mill is equipped with a roll crown variable mechanism that changes the roll crown of the work roll. The flatness is controlled (hereinafter referred to as shape control).

As one of the methods for carrying out shape-controlled rolling of the thin steel strip mentioned above, it is known to use a four-layer rolling mill equipped with backup rolls having a tapered piston type variable roll crown mechanism. The structure of the backup roll used in this rolling mill is shown in a longitudinal sectional view in FIG. As shown in FIG. 8, the backup roll 2 has a taper of 3 (!
:, 7- A sleeve 4 shrink-fitted to the taper 3, a hydraulic chamber 5 located at both ends of the taper 3 and composed of the taper 3 and the sleeve 4, and a taper piston 7 disposed within the hydraulic chamber 5. It consists of This back unroll 2
To explain in more detail, the taper 3 is provided with a hydraulic oil supply passage lO, and the taper piston 7 is passed through the rotary joint 11 arranged at the axial end of the taper 3.
Hydraulic oil for operating the roller is sent from the hydraulic oil hydraulic unit 12 to the hydraulic chamber 5, so that the taper piston 7 can move in the roll axis direction. Further, a slip ring 13 is provided at the other shaft end of the taper 3, and a piston position sensor 14 is provided in the hydraulic chamber 5. A position signal from the piston position sensor 14 is sent to the taper piston control panel 16 through a piston position sensor signal line 15 provided on the taper 3 and the slip ring 13. The operator of the rolling mill presses the operation switch 17 while checking this signal.
To! and performs taper piston control.

FIG. 9 shows the grinding flat of the back-up roll 2 equipped with a tapered piston 7. . Figure 9 (
As shown in →, the taper piston 7 in the hydraulic chamber 5 is
Apply hydraulic oil and push toward the center of the roll shaft to deform the backup roll 2 into a trapezoid shape. Next, in this state, the surface of the roll is ground to make the surface of the backup roll 2 flat, as shown in FIG. 9(b). 1. As shown in FIG. 9(C), the taper piston 7 is moved toward both ends of the roll shaft so that a convex crown is formed on the surface of the roll.

FIG. 10 shows the position of the tapered piston 7 in the hydraulic chamber 5 in the roll axis direction, the roll profile, and the work roll 1 when the shape of the thin steel strip 9 is controlled using the backup roll 2 ground as described above. The profile and the crown state of the thin steel strip 9 in a plate shape are shown. 20
is the work roll profile, which shows the state of the roll profile under rolling load.

(1) As shown in FIG. 10(a), when the taper piston 7 in the hydraulic chamber 5 is located at the outermost position from the roll center, the backup roll profile 19 is in the most convex state, and the work roll profile 2 is in the most convex state. ° is in the state of a convex crown, and the plate shape 21 is in the state of medium elongation.

(2) As shown in FIG. 10(b), when the taper piston 7 in the hydraulic chamber 5 is in the intermediate position, the backup roll profile 19 has a slightly convex profile, and the work roll profile 20 has a flat profile. ,and,
During rolling, the plate shape 21 also becomes flat due to the deflection of the rolls.

(3) As shown in FIG. 10(C), when the taper piston 7 in the hydraulic chamber 5 is pushed in the most direction toward the roll center, the pick-up roll profile 19 becomes a flat profile and the workpiece roll profile 20
becomes a concave crown, and due to the deflection of the rolls during rolling, the plate shape 21 becomes a wave-shaped state.

[Problem to be solved by the invention]

However, the conventional rolling mill equipped with a backup roll having a tapered piston type variable roll crown mechanism has the following problems. That is, Fig. 11 Ga
) to (C), the relationship between the change in the roll profile of the lower work roll 1b due to the change in the roll profile of the lower back-up roll 2b, the low/l/profile of the lower back-up roll 2b is a convex profile. As time progresses, the following phenomena occur: That is, the first
As shown in Fig. 1 (6), when the lower back up roll 2b has a flat profile (the taper piston is pushed in), the lower work roll 1b also has a flat profile, but as shown in Fig. 11 (b). As shown, when the lower back-up profile 2b becomes a slightly convex profile,
The lower work roll 1b also has a slightly convex profile, and the lower back roll 2b and the lower work roll 1b are in close contact over the entire body. Furthermore, when the lower back up roll 2b has a larger convex profile, concave profiles 22 are generated at both ends of the roll, as shown in FIG. 11(C), resulting in the lower back up roll 2b and the lower workpiece The roll 1b is not in close contact with the entire body, but is in close contact only with the center 23 of the body and both ends 2c of the lower back up roll 2b, especially the lower back up roll 2b. Both ends 2c
A concentrated load is applied to the portion where the lower work roll 1b and both ends 1c of the lower work roll 1b are in contact with each other. As a result, roll flaws occur on the steel strip, spalling occurs on the roll, and the problem arises that the shape of the copper strip cannot be smoothly controlled. FIG. 12 is a graph showing the relationship between the pushing amount of the taper piston and the backup roll profile when a concave crown is partially formed at both ends of the backup roll described above.

Backup rolls for steel plate rolling can be used on a 4-layer rolling mill or a 6-layer rolling mill.
It is known that any heavy rolling mill deforms due to rolling load, as shown in FIG. Due to the occurrence of such deformation, the end of the roll barrel of the backup roll has the
Or, in the case of a 6-roll mill, each of the center rolls has 9
It is known that concentrated stress occurs between the metal and the surface of the metal.

In order to prevent the occurrence of such concentrated stress, the diameter of the roll is adjusted to a length x) of 30 to 150 μm from the barrel end 8 of the backup roll 2 toward the center of the roll 2, as shown in FIG. It is known to provide a channel 7a 6 which is formed in a tapered shape so that its central portion also gradually becomes smaller in diameter. D
-D' is y, conventional y is 500 to 1000μ
It is m.

Figures 4(a) and 4(b) show the roll barrel length (body length) of 140 mm in the tapered piston type backup roll.
0 vx, rolling load is 10oO~2000T, and Figure 4 (~ is the above x7bX3011iE, y is 500
In μm1 FIG. 4(b), the above X is 15011. Y is 100
As is clear from FIGS. 4(a) and 4(b), which are graphs showing the relationship between the distance from the backup roll barrel end and the roll barrel linear pressure at 0 Ar/), the backup roll barrel end A peak stress concentration occurs in the area. The occurrence of this stress concentration promotes damage to the backup roll.1. This makes it difficult to use tapered piston type backup rolls.

Furthermore, if damage such as cracks or spalling occurs at the end of the barrel of a tapered piston type backup roll, oil in the hydraulic chamber leaks and falls onto the material to be rolled, causing flaws in the material to be rolled. If the damage is severe, rolling becomes impossible. In addition, cold rolling machines that use rolling oil,
In hot rolling mills that use cooling water, leaked oil in the hydraulic chamber mixes with the rolling oil or cooling water, which has a significant negative effect on the quality of these oils.

The purpose of the present invention is to solve the above-mentioned conventional problems, and to provide a tapered piston variable type that can smoothly control the shape of the copper strip without causing roll flaws or spalling on the copper strip. An object of the present invention is to provide a rolling mill equipped with a backup roll that covers a roll crown mechanism.

[Means to solve the problem]

The present inventors have conducted extensive research in order to achieve the above-mentioned object. As a result, we obtained the following knowledge.

As shown in FIG. 8, in the backup roll 2 having a tapered piston type variable roll crown mechanism,
An end plate 18 connects the sleeve 4 and the arbor 3, and the tapered piston 7 moves at the end plate 18. Even if the diameters of the sleeve 4 in the width direction change, the end plate 18 does not change its diameter or deforms only within the range of elastic deformation.

The end portion of the sleeve 4 fixed to the end plate 18 cannot be made thicker, and is the weakest portion of the sleeve 4 in the width direction. like this,
Keeping the weak part near the end of the sleeve 4 from coming into contact with the work rolls in the quadruple rolling mill or the intermediate rolls in the grand prize rolling mill allows the backup roll 2 to withstand high rolling loads for a long period of time. required for continuous use.

The stress concentration shown in FIGS. 4(a) and 4(b) does not occur when the tapered piston type puncture roll is kept in a flat shape, and the tapered piston 7 is moved toward the end plate 18 and the backup This occurs when the roll 2 has a convex roll crown.

For this reason, in a tapered piston type puncture-up roll, if such stress is transferred from the inside of the barrel, that is, the barrel end of the backup roll, to the center of the roll by more than 16C) +z, the linear pressure of a is made uniform, and damage to the rolls can be prevented.

The present invention has been made based on the above-mentioned knowledge, and provides a four-layer or six-layer rolling mill equipped with a backup roll having a tapered piston variable roll crown mechanism, from the barrel end of the backup roll. The roll diameter is between 160 and 250H towards the center of the roll.
The diameter of the roll barrel end is 500 mm larger than the diameter of the center of the roll.
It is characterized in that it is formed in a tapered shape that gradually decreases in diameter within a range of 2,000 μm.

Next, the present invention will be explained with reference to the drawings. In this invention, from the barrel end 8 of the backup roll 2 to the center of the roll 2 shown in FIG. ), the diameter (D') of the barrel end 8 is 5.
A chamfer 6 is provided which is formed into a tapered shape that gradually reduces in diameter so that it has a small diameter within a range of 2000 μm from oO.

The chamfer 6 may have a straight line, a gentle six-curve shape, or a pre-curved shape.The point where the flat part of the roll 2 transitions to the tapered shape of the chamfer 6 is, for example, a diameter of 500 to 15001 m. It is preferable to have a rounded shape.

By configuring the backup roll 2 as described above, the rolling load is 500-2000T, the roll barrel width is 1
Non-contact of the barrel end can be achieved during rolling within the range of 300 to 22001111.

FIGS. 5(a) and 5(b) show a tapered piston type backup roll in a rolling mill of the present invention, with a barrel length (body length) of 1400111 and a rolling load of 1000 to 2.
000T, and in FIG. 5(a), the above X is 160mx
, when y is 500 μm, FIG. 5(b) shows that the above X is 25
011I, is a graph showing the relationship between the distance from the end of the pack-up roll noggle and the troll barrel linear pressure when y is 2000 μml. As can be seen from FIGS. 5(a) and 5(b), the roll barrel linear pressure is small and uniform, and no peak stress concentration occurs.

As is clear from a comparison between FIGS. 5(a) and 5(b) and FIG. 4←), Φ), this invention allows the above
250, and if the above y is set to 500 to 2000 μm, the roll barrel linear pressure within 150111 from the barrel end 8 will be small and uniform, and a non-contact state can be maintained at the barrel end 8, This prevents damage to the ends of the backup roll.

Figure 6 is a graph showing the relationship between the width of the chamfer and the adjustment range of the work roll crown when the work rolls do not shift in a four-layer rolling mill. The difference between the chamfer amount (
ΔR) is shown for each case of 500 μm, 11000 μm, 1509 μm, and 2000 μm. In addition, the part where the roll transitions from the flat part to the chamfer has a diameter of 50t.
A radius of ttx is formed. As is clear from Fig. 6, when " is 500 μm, the chamfer width is 160 μm.
1+m or more, when ΔR is 1000 μm, the chamfer width is 17!5111 or more, when ΔR is 1500 μm, the chamfer width is 210 mn or more, and when ΔR is 20.
When O08m, a chamfer width of 25011 is a stable control range.

FIG. 7 is a graph showing the relationship between the surface stress of the chamfer shoulder where the work roll and the backup roll contact and the chamfer amount (ΔR) under the following conditions of the above-mentioned rolling mill. mark), 150
111 (○ mark), 200 m (X mark) and 250 m
mC mouth seal).

a. Roll width: 142011E b. Roll diameter 2 backup roll 1420r+
m Work roll 600111I C0 reduction blade: 1O00Tf d, Work roll bend: Max 65 Tf No. 7
As is clear from the figure, the amount of chamfer (ΔR) was set to 500.
Surface stress cannot be reduced unless the thickness is μm or more.

If the allowable surface stress is 200 or less than f/-, when the chamfer width is 250111, the chamfer amount (Δ
R) is required to be 2000 μm or less.

From Figures 6 and 7 above, in order to obtain effective shape control ability, the chamfer width must be 160 m or more, the chamfer amount (ΔR) must be 500 μm or more, and the roll surface pressure must be In order to keep the stress below the allowable stress,
When the chamfer width is 250 m or less, the chamfer amount (Δ
R) is required to be 2000 μm or less.

Furthermore, when the amount of chamfer (ΔR) exceeds 2000 μm, the rate of change in the roll diameter at the transition from the flat part of the roll to the chamfer increases, resulting in a change in the work roll in a 4-fold or 6-fold rolling mill, or A linear pattern is transferred from the intermediate roll to the work roll, causing roll flaws. This is especially common during cold rolling or cold temper rolling. Furthermore, if the chamfer width exceeds 250 mm, the surface pressure at the chamfer shoulder increases to exceed the allowable stress, causing defects such as spalling and roll scratches.

From the above, in this invention, the width of the chamfer from the end of the roll barrel of the bank-up roll to the center of the roll is limited to within the range of 160 to 25 On,
Then, in the chamfer, the difference between the diameter of the center part of the roll and the diameter of the end part of the roll 9 rails, that is, the chamfer amount ΔR, is set to 5.
It was limited to a range of 00 to 2000 μm.

The rolling mill of the present invention includes a normal 4-layer rolling mill, a 4-layer rolling mill with shiftable work rolls, a normal 6-layer rolling mill,
The present invention can be applied to any six-layer rolling mill in which the work roll and/or the intermediate backup roll can be shifted.

Next, embodiments of the invention will be described with reference to the drawings.

〔Example〕

FIG. 1 is a schematic front view showing a roll portion of a four-layer rolling mill equipped with a backup roll having a tapered piston type variable roll crown mechanism according to the present invention. As shown in FIG. 1, the rolling mill includes an upper back-up roll 2a and a lower work roll 1 disposed above an upper work roll 1a.
The lower back-up roll 2b disposed below b is composed of a taper 3 and a sleeve 4 shrink-fitted to the arc 3.

Work roles la and lb are backup roles 2a.

The barrel is 251K longer than the 2b, and the work roll is
Both rolls a and lb and backup rolls 2a and 2b have a structure that does not shift. A hydraulic chamber 5 is formed at both ends of the taper 3 by the taper 3 and a recess provided in the sleeve 4, and a taper piston 7 is disposed within the hydraulic chamber 5. The wall surface of the hydraulic chamber 5 is tapered, and when hydraulic pressure is applied to the hydraulic chamber 5 and the taper piston 7 is pushed toward the center of the roll, the outer diameter of the sleeve 4 on the side where the taper piston 7 is arranged becomes The outer diameter is about 1500 μm larger at the outermost end than the outer diameter before pressing, that is, the amount of change in the roll profile is 1500 μm.

From the roll barrel end of the backup rolls 2a and 2b toward the center of the roll, the roll diameter is between 160 and 250 μm, and the diameter of the roll barrel end is in the range of 500 to 2000 μm than the diameter of the center of the roll. A chamfer 6 having a small diameter is formed inside.

1I31in, the roll barrel length of the backup roll is 1370m, the width of the chamfer 6 is zoom depth, and the chamfer 6 is formed in two stages, a 50m part from the end of the roll barrel and a 15011 part after that. It is a graph showing the relationship between the pushing amount of the taper piston 7 and the backup roll profile when a radius with a diameter of 30 x m is formed in the transition part from the flat part to the chamfer.

However, the taper piston 7 is not in a completely pushed-in state as shown in FIG. 10(c).

As a result, the taper piston 7 is moved toward both ends of the body, and the backup rolls 2a, 2b (D o -Even if the luer profile is a convex crown, both ends of the backup rolls 2a, 2b are connected to both ends of the work rolls la, lb. There is no strong roar, and backup roll 2a
, 2b and the work rolls la, lb were in close contact over the entire length of the trunk. Therefore, roll flaws did not occur on the steel strip, spalling did not occur on the roll, and the shape of the copper strip could not be controlled smoothly.

〔Effect of the invention〕

As explained above, according to the rolling mill equipped with a backup roll having a tapered piston type variable roll crown mechanism of the present invention, roll flaws occur in the copper strip.
There is no occurrence of spalling on the rolls, and the industrially useful effect of smoothly controlling the shape of the copper strip is brought about.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing the roll portion of a four-layer rolling mill equipped with a backup roll having a tapered piston variable roll crown mechanism of the present invention, FIG. 2 is a front view of the backup roll, and FIG. FIG. 4(a) is a graph showing the relationship between the pushing amount of the tapered piston of the backup roll of the present invention and the backup roll profile.
, (b) is a graph showing the relationship between the distance from the barrel end of the conventional backup roll and the roll barrel linear pressure.
Figures (a) and (b) are graphs showing the relationship between the distance from the barrel end of the backup roll of the present invention and the roll barrel linear pressure, and Figure 6 shows the relationship between the chamfer width and work roll crown preparation range. Graph, FIG. 7 is a graph showing the relationship between surface stress and chassofer amount, FIG. 8 is a vertical cross-sectional view of a backup roll having a conventional tapered piston type variable roll crown mechanism, and FIG. 9 is a graph of the conventional backup roll described above. FIG. 10 is an explanatory diagram illustrating shape control rolling using a conventional four-layer rolling mill equipped with the above-mentioned backup roll. FIG. FIG. 12 is an explanatory diagram showing changes in the contact situation between the backup roll and the work roll, FIG. 12 is a graph showing the relationship between the pushing amount of the taper piston and the backup roll profile, and
FIG. 3 is an explanatory diagram showing a modification of the backup roll of a four-layer rolling mill. In the drawing: 1... Work roll. 2...Backup roll, 3...Arper. 4... Sleeve, 5... Hydraulic chamber, 6... Chamfer t, 7... Taper piston. 8... Barrel end, 9... Thin steel strip. 10... Hydraulic oil supply passage, 11... Rotary joint. 12... Hydraulic unit, 13... Slip ring. 14... Piston position sensor. 15...Position sensor signal line. 16...Taper piston control panel. 17...Operation switch, 18...End plate. 19...Backup role profile. 20... Work role profile. 21...Plate shape, 22...Profile. 23...Center of the torso.

Claims (1)

[Scope of Claims] 1. In a four-layer or six-layer rolling mill equipped with a backup roll having a tapered piston variable roll crown mechanism, the distance from the roll barrel end of the backup roll to the center of the roll is 160 to 250 mm. The roll diameter is formed into a tapered shape that gradually decreases during the length of the roll so that the diameter at the end of the roll barrel is smaller than the diameter at the center of the roll within a range of 500 to 2000 μm. rolling machine.