JPH0126766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-high rolling mill for rolling plate-shaped materials, which can reduce the rolling pressure and perform rolling with high efficiency.

[Conventional technology]

Recently, steel products for cold regions are required to be rolled at a low temperature of 900°C or lower during the steel manufacturing process so as not to lose their brittleness even at low temperatures of -60 to -80°C. Conventionally, rolling was carried out at a temperature of about 1100°C, so when the above-mentioned low-temperature rolling is performed, the rolling reaction force increases to about twice that of normal rolling, and the components of the rolling mill cannot withstand this rolling pressure. This may lead to damage and accidents.

For this reason, the amount of rolling per roll is limited, and it takes a long time to roll to the required thickness, and the temperature of the material cools due to long rolling times, which further increases the rolling reaction force. It has been difficult to manufacture steel materials with sufficiently improved low-temperature brittleness using conventional rolling mills.

It is known that in order to reduce this rolling reaction force, it is good to reduce the diameter of the rolling work roll. This technique is disclosed in Japanese Patent Publication No. 53-20942, but this device is for a six-high rolling mill, and only the intermediate rolls are driven.

[Problems that the invention attempts to solve]

In view of the above-mentioned problems, an object of the present invention is to enable rolling that reduces rolling reaction force, suppress the occurrence of slip phenomenon between a work roll and its supporting roll, and provide sufficient pressure to the roll. It is an object of the present invention to provide a multi-high rolling mill which can provide rolling power capable of biting plates and which can compactly arrange a power source when driving intermediate rolls and work rolls at the same time.

[Means for solving problems]

The present invention uses a pair of small-diameter work rolls as a slave drive,
An intermediate roll that supports this work roll and has a larger diameter than the work roll is configured to be the main drive, and the arrangement of the rolls is changed to a pair of slave drive small diameter work rolls, a pair of main drive intermediate rolls, and a pair of main drive intermediate rolls. This is a multi-high rolling mill consisting of rolls and a pair of reinforcing rolls that support the rolling load.

[Effect]

A pair of upper and lower intermediate rolls are driven as main drives, and a pair of upper and lower work rolls are also driven as slave drives at the start of rolling to assist in biting the plate into the work rolls.
That is, the occurrence of the slip phenomenon caused by reducing the work roll diameter to reduce the rolling reaction force can be suppressed.

Further, the main drive devices that rotationally drive the upper and lower intermediate rolls are arranged apart from each other along the roll axis direction, and the auxiliary drive devices that rotationally drive the upper and lower work rolls are arranged on both sides of the main drive device. In addition, by providing a gear casing in which gear trains arranged in a substantially horizontal direction are vertically shifted and arranged to transmit the driving force of the auxiliary drive device to the upper and lower work rolls, respectively, the intermediate roll and the work roll can be driven simultaneously. Even in this type of multi-high rolling mill, the power source can be arranged compactly.

〔Example〕

Before describing embodiments of the present invention, the principle of the present invention will be explained below.

It is known that in order to reduce the rolling reaction force, it is better to reduce the diameter of the rolling work roll.

A detailed study of this revealed that the rolling reaction force decreases approximately in proportion to the diameter of the work roll.

Therefore, when rolling low-temperature materials, by reducing the work roll diameter, the rolling reaction force generated thereby is small, and the low-temperature materials can be rolled with high efficiency.

On the other hand, rolling requires applying rolling processing energy to the rolled material from work rolls.

However, the torque that can be applied by driving the work roll diameter by a motor or the like decreases in proportion to the cube of the roll diameter due to the twisting strength of the roll.

Therefore, it is considered that this rolling energy can be provided by driving the rolls that support other work rolls, that is, the reinforcing rolls in a normal four-high rolling mill.

However, when the plate is caught at the beginning of rolling, if only the reinforcing roll is driven and the work roll is not driven, the friction coefficient is small because the roll is made of a hard material, and slippage occurs between the two rolls. This is a problem in that sufficient rolling energy is not transmitted to the work rolls.

That is, if the plate thickness before rolling is H, the plate thickness after rolling is h, and the coefficient of friction between the rolls is μ, the limit at which the plate as a rolled material can be completely bitten by the work rolls is obtained by the following formula.

Δh=μ ² R−P/K ………(1) In the above formula, Δh=H−h, R is the radius of the work roll, P is the rolling load, and K is the spring constant of the rolling mill.

That is, from equation (1), the roll radius is small and the friction coefficient between the rolls is hard as described above, so the amount Δh that can be rolled down without slipping is small.

As can be seen from equation (1), this reduction in the rolling reduction amount Δh is largely influenced by the friction coefficient μ.

In other words, when driving the work rolls in a conventional rolling mill with large work rolls, the friction coefficient μ between the work rolls and the rolled material is μ= because the rolled material is soft.
A large enough reduction amount of about 0.25 can be obtained.

On the other hand, in the reinforcement roll drive, the friction coefficient μ between the rolls is about 0.12 because the roll hardness is large, which is about half that of the work roll drive. Therefore, the allowable biting amount Δh into the work roll is determined by this friction coefficient. Due to the influence of , it becomes about 1/4 of the work roll drive.

However, the slip limit rolling amount Δh' after the rolled material is completely bitten between a pair of work rolls is obtained by the following equation.

Δh′=4μ ² R ………(2) The rolling reduction amount is four times that of when the material is bitten, and even if normal high reduction rolling is performed using the reinforcing roll drive method, the material will not be completely bitten by the rolls. Once done, slips between rolls will not occur and will not be a problem.

As a result, it can be seen that if the work roll is not driven, a slip between the work roll and the reinforcing roll occurs when the plate is caught in the work roll at the start of rolling, resulting in poor biting into the work roll.

From the above points, it can be seen that even if the reinforcing roll is the main drive, it is necessary to at least drive the work roll in a sub-drive manner at the start of rolling to assist in biting the plate into the work roll.

The energy required for this auxiliary biting into the work roll was determined for the rolling mill shown in FIG. 1, and the results are shown in FIG. That is, in FIG. 2, the reinforcing roll 4
1 and 42 as the main drive, the energy that can be given to the work rolls 43 and 44 from this reinforcing roll E ₁
and the energy required to process and roll the rolled material 45
_E2 , and this energy is calculated as the biting angle φ when the rolled material 45 starts biting into the work rolls 43, 44.
is arranged by the angle φ between the perpendicular line passing through the tip of the material and the center of the roll between φ=α and φ=0.

The rolling energy E ₂ decreases the above angle φ and becomes φ = 0.
It is maximum when . Moreover, since the cross-sectional shape of the work roll is circular, the energy E ₂ increases in a square root shape as φ becomes smaller.

On the other hand, the energy that can be transmitted from the reinforcing roll to the work roll increases in proportion to (α-φ).

In FIG. 2, E ₂ >E ₁ at the hatching portion, and a slip occurs between the reinforcing rolls 41, 42 and the work rolls 43, 44 in FIG. 1, and the rolled material 45 cannot be bitten any further.

In Fig. 2, if the rolled material is bitten to φ=0,
It can be seen that although rolling can be performed without slipping, slipping occurs between both rolls at the beginning of biting.

In addition, the insufficient energy at the hatching part indicates the amount of energy insufficient at each position φ during the process in which the rolled material is bitten, but this energy ΔE is expressed as E ₁ > E ₂ at φ = 0. Under normal rolling conditions ΔE/E ₀
=0.15-0.3.

In this way, the insufficient energy during biting is small, so if this is applied in a secondary drive manner using work rolls with a reduced diameter, it is possible to carry out rolling without the above-mentioned slip between the rolls.

However, if the above-mentioned drive were not to be implemented in an actual rolling mill, the following problems would arise because the reinforcing roll diameter is extremely large, 1800 to 2000 mm.

That is, the main drive is usually performed by directly connecting the driving electric motor to the rolling roll, but as mentioned above, if the diameter of the reinforcing roll is used as the main drive, the roll diameter is large.
This is disadvantageous because the rotational speed of the electric motor must be reduced and therefore the torque must be increased, and a large electric motor is required.

Therefore, in the present invention, a pair of intermediate rolls having the roll diameter necessary for the main drive are newly introduced, a pair of reinforcing rolls that directly support the rolling load are not driven, and a pair of work rolls are driven as a auxiliary drive. ,
A 6-high rolling mill is provided.

In other words, in the rolling mill of the present invention, the work roll diameter can be reduced from the conventional φ1000 to 1200 mm to φ600 to φ750 mm, and the rolling reaction force for rolling a material with a width of 5000 mm can be reduced by 30 mm.
This is possible because it facilitates the design of the rolling mill, as it can be significantly reduced by ~40%.

That is, the above-mentioned work roll is made a slave drive and is used as an auxiliary drive for biting the rolled material mentioned above, and the main drive roll is provided as an intermediate roll.

If the diameter of the intermediate roll is φ1000mm, which is the same as the diameter of conventional work rolls, the drive system will have sufficient margin.

That is, if the diameter of the work roll is reduced, the rolling torque is reduced approximately in proportion to the 1.5th power of the diameter of the work roll, so that sufficient driving strength can be obtained.

In addition, the diameter of the reinforcing roll that supports the entire rolling reaction force is set to φ1800 to 2000, which is the same as the diameter of conventional rolls. As mentioned above, since the reaction force is reduced by 30 to 40%, sufficient strength can be obtained.

As described above, since the rolling load is reduced by reducing the diameter of the work rolls, a sufficient strength margin is obtained even if all the components of the rolling mill are of the conventional level, and safe operation is possible.

Next, an example 6 of the present invention will be explained using the drawings.
A corrugated rolling mill will be explained.

In FIG. 3, the stand 2 has three pairs of rolls, namely work rolls 43 and 44, intermediate rolls 46 and 47 movable in the roll axis direction, and reinforcing rolls 41 and 42.
is built-in. This middle upper roll group is raised and lowered by a rolling down device 1.

The work rolls 43 and 44 are auxiliary driven by the spindle 10. This drive is performed by gears 11 and 19 provided after the spindle 10. That is, as shown in FIGS. 3 to 5, the spindle 10
The upper spindle is connected to the gears 11, 20, 21 and the coupling 22 by gear groups provided on both the left and right sides of the upper spindle.
It is driven by a slave drive electric motor 23 via.

Similarly, the lower work roll 44 is driven by a slave drive electric motor 27 via the universal coupling 10, the gears 19, 24, 25, and the coupling 26.

The aforementioned gear group is installed within the gear casing 12. Further, the intermediate rolls 46 and 47 are driven by main drive motors 17 and 18 connected via a universal coupling 8 and a slide coupling 9. The approximate dimensions of each roll are: work rolls 43 and 44 have a diameter of 500 to 800 mm, body length 5200 mm, intermediate rolls 46 and 47 have a diameter of 1000 mm,
Body length 5200mm, reinforcing rolls 41 and 42 diameter 2000mm
mm, body length of approximately 5200 mm is used. A hydraulic bending device 35 is installed to apply bends to the upper and lower work rolls 43 and 44, and a hydraulic bending device 34 is also installed to apply bends to the upper and lower intermediate rolls 46 and 47. The configuration is such that a shift device 40 for movement is engaged.

In addition, when the work roll diameter is reduced by about 30 to 40% compared to the conventional 4-high rolling machine, such as the small-diameter work roll of the present invention and the 4-roll drive 6-high rolling mill, the deflection of the work roll is proportional to the 4th power of the roll diameter. As a result, the deformation curve of the work roll changes significantly in response to a change in rolling load or sheet width, causing a problem in that the cross-sectional profile of the rolled sheet changes.

Therefore, the main drive intermediate rolls 46 and 47 newly added in the present invention can be moved left and right in the roll axis direction symmetrically with respect to the center of the rolled material 45, as shown by the arrows in FIG. , the shape and plate crown control function of the known 6-high rolling mill can be exhibited, sufficient control of the plate cross-sectional shape can be achieved, and the performance of the rolling mill of the present invention can be further improved.

Further, the method of driving the slave drive work rolls 43, 44 and the main drive intermediate rolls 46, 47 will be described below.

That is, from the start to the end of the biting of the rolled material 45 into the roll, at least the circumferential speeds of both the work roll and the intermediate roll are driven to be synchronized. However, the drive torque of the slave drive work roll is kept within a transmittable range due to its strength. Therefore, the diameter of the work rolls 43 and 44 was changed from the conventional 70 mm.
% (from φ1000 to φ700), the allowable torque of the smaller diameter work roll is approximately proportional to the cube of 0.7 of the roll diameter reduction ratio, so the allowable transmitted torque is 34% of the conventional torque per roll. If the rolling speed is the same, a motor with a small capacity of about 2450KW (49%) can be installed, which is the square of the roll diameter, compared to the conventional 5000KW, and when combined with the slip limit power of the intermediate roll drive, Sufficient plate biting rolling power can be generated (as mentioned above, the biting insufficient energy, that is, the power is 15 to 30%).

Of course, if the drive of the work rolls is continued even after the plate has been sufficiently bitten by the work rolls, the main driving power of the intermediate rolls can be added up, and sufficient rolling power can be applied to the rolled material. High pressure rolling becomes possible. In this case, the drive of the work rolls may be changed to constant torque control instead of speed control.

That is, in the past, when rolling a material with a deformation resistance of close to 30 kg/mm ² at a rolling temperature of about 750°C, the permissible reduction amount per roll was about 2 to 3 mm, but with the rolling mill of the present invention, In particular, due to the effect of reducing the rolling reaction force, it is now possible to perform reduction rolling that is approximately twice as much as conventional methods, making it possible to significantly shorten the rolling time, and making it possible to manufacture rolled steel materials with sufficiently improved low-temperature brittleness through low-temperature rolling. It becomes possible.

〔Effect of the invention〕

According to the present invention, it is possible not only to perform rolling in which the rolling reaction force is reduced, but also to prevent the slip phenomenon between the work roll and its support roll, so that the biting of the roll provides sufficient rolling power. In addition, it is possible to realize a multi-high rolling mill in which the power source for simultaneously driving the intermediate roll and the work roll can be arranged in a compact manner.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram illustrating the situation in which it is necessary to bite the rolled material into the work rolls, Fig. 2 is an explanatory diagram illustrating the energy necessary for plate biting in the rolling mill shown in Fig. 1, and Fig. 3 4 is a schematic configuration diagram showing a 6-high rolling mill with a 4-roll drive system, which is an embodiment of the present invention.
This figure is a partial view of the top view of FIG. 3, and FIG. 5 is a sectional view taken along the line AA in FIG. 3. 2... Housing, 43, 44... Work roll, 4
6, 47... Intermediate roll, 41, 42... Reinforcement roll, 8, 10... Universal coupling, 9...
Slide coupling ring, 14, 16...shaft, 17,
18... Main drive motor, 11, 19, 20, 21,
24, 25... Gear, 22, 26... Coupling,
23, 27... Slave drive motor, 40, 50... Shift device.

Claims (1)

[Scope of Claims] 1 Consists of a pair of upper and lower small-diameter work rolls, upper and lower intermediate rolls that support the work rolls and have a larger diameter than the work rolls, and upper and lower reinforcing rolls that support the intermediate rolls; In a multi-stage rolling mill equipped with a main drive device that rotationally drives the intermediate rolls, the main drive devices that rotationally drive the upper and lower intermediate rolls are arranged spaced apart from each other along the roll axis direction, and the upper and lower work rolls are respectively driven. The auxiliary drive device is provided with an auxiliary drive device that rotates and is arranged on both sides of the main drive device, and further arranged in a substantially horizontal direction to transmit the driving force of the auxiliary drive device to the upper and lower work rolls, respectively. A multi-high rolling mill characterized in that it is equipped with a gear casing in which gear trains are arranged vertically offset from each other.