JP3241556B2 - Supply method of skin pass liquid in skin pass mill of metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying a skin pass liquid in a skin pass rolling mill installed in a continuous processing line for a metal strip such as a steel strip.

[0002]

2. Description of the Related Art In many cases, a skin pass rolling mill is installed in a continuous processing line for metal strip (hereinafter, described as an example of a steel strip), for example, a continuous annealing facility. The skin pass rolling in such a case is generally a so-called wet skin pass performed by supplying a skin pass solution.

When an automatic surface inspection device is arranged directly connected to such a skin pass rolling mill or via a device such as a side trimmer, a skin pass solution during skin pass rolling remains on the surface of the steel strip. Since this is recognized as a flaw and is erroneously detected, which is an inconvenience due to an error in automatic surface inspection, it is necessary to carefully drain the skin pass rolling mill and to minimize the supply of skin pass liquid. Has been oriented.

[0004] Incidentally, when the supply amount of the skin pass liquid is small, there is no problem if the rolling speed is low. However, at the high speed, a local oil film breakage occurs, and the lubricating state is different from other parts, so that the rolling state is low. In other words, there is a problem that quality defects such as shape defects are caused. Since the throughput of the steel strip, for example, the total surface area that passes, is proportional to the passing speed,
For example, in a continuous lubrication system for steel strips, it is naturally conceivable to control the amount of lubrication according to the line speed.
Japanese Patent No. 3322 discloses an oiler motor speed controller that controls the speed of an oiler motor using an output signal of a line speed detector as an input signal.

Japanese Patent Application Laid-Open No. 60-240331 discloses that the required amount of rolling oil per unit surface area of a steel strip is determined by the reduction ratio, the deformation resistance of the steel strip, and the passing length of the steel strip after replacing the rolling roll. It is described to calculate and determine, and to supply the steel strip with an amount of the rolling oil emulsion liquid according to the calculated value of the required amount of the rolling oil per unit area, and the amount of the emulsion liquid proportional to the rolling speed is described. Supplied.

However, according to the experiments conducted by the present inventors, in the skin pass rolling, if the supply amount of the skin pass liquid is directly proportional to the rolling speed, the skin quality is slightly insufficient at a high speed and the surface quality is poor as described above. Is easy to occur.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and realizes a method for supplying an appropriate amount of skin pass liquid without causing an excessive supply and without running out of an oil film due to an insufficient supply. With the goal.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method of supplying a skin pass liquid in a metal strip skin pass rolling mill. Power between rolls proportional to the power
A skin pass solution having a supply amount corresponding to the calculated value of the thickness of the Kinpass solution is sprayed onto the roll of the skin pass rolling mill, the metal strip near the roll inlet, or both.

A second aspect of the present invention is a method for supplying a skin pass solution in a metal strip skin pass rolling mill, comprising detecting a rolling speed and a rolling load, and setting the rolling speed to the 0.7th power and a rolling load of -0.13. Proportional to the power
It is characterized in that a supply amount of the skin pass liquid corresponding to the calculated value of the thickness of the skin pass liquid between the rolls is sprayed onto the roll of the skin pass rolling mill, the metal strip near the roll entrance, or both.

Further, according to a third aspect of the present invention, there is provided a method for supplying a skin pass liquid in a metal strip skin pass rolling mill, comprising detecting a rolling speed, and spraying the metal strip surface in front of the skin pass rolling mill. The skin pass solution is squeezed to a film thickness of the skin pass solution between the rolls, which is proportional to the 0.7th power of the detected rolling speed, by rolling down the solution on a ringer roll installed near the roll entrance of the skin pass mill. It is characterized by the following.

[0011]

[Action] Recent elastohydrodynamic lubrication (Elastohydrodynamic l)
ubrication, EHL) theory (for example, edited by Tribology Research Group, "Basic and Applied I", 196.9.30)
According to the Dowson-Higgingson film thickness calculation formula based on the above, the dimensionless parameter of the film thickness of the lubrication surface in line contact is expressed as H
[−] , Assuming that the minimum film thickness is h _min [m] , H = 2.65 G ^0.54 × U ^0.7 × W ^-0.13 (1) h _min = H · R (2) Where G is viscosity, U is speed, W is load ,
The dimensionless parameters [-] and R are the roll radius [m] in this case.

That is, if skin pass rolling is considered to be a problem of a high-pressure viscous elastic body due to rolling contact of a cylinder having a radius R, the dimensionless parameter of the film thickness between rolls or its minimum value is set to the 0.7th power of the line speed. It turns out that it is proportional.
For example, <br/> thickness between the rolls when the min 40 0 m is the line speed is four Baikyo when the 5 0 m. Therefore, if the supply amount is controlled irrespective of the line speed, the supply becomes insufficient at the time of high-speed rolling, and the supply becomes excessive at the time of high-speed rolling if it is simply proportioned as in the prior art. Further, as can be seen from the above equation (1), although the effect is small as compared with the speed, the oil film thickness changes even with the load. Therefore, in the present invention, the skin pass rolling with an appropriate supply amount is realized by calculating the film thickness from the rolling speed, or both the rolling speed and the rolling load, and supplying the skin pass liquid corresponding to the calculated film thickness.

In the above equations (1) and (2), (2.65 G
If ^0.54) and deforming the R is constant, the metal string
Supply quantity Q [m ³ of Tsu skin pass liquid per unit area of up
/ M ² ] can be expressed as follows. Metal strip with both rolling speed and rolling load as variables
The supply amount per unit area Q ₁ [m ³ / m ² ] is: Q ₁ = a × U ^0.7 × W ^-0.13 (3) In addition, the metal strip in the case of the simple type in which the rolling load is constant
The supply amount Q ₂ [m ³ / m ² ] per unit area of the tip is as follows: Q ₂ = b × U ^0.7 (4) In the normal skin pass rolling, the value of the rolling load is almost constant, unlike the general rolling.
An expression is sufficient.

[0014]

EXAMPLE 1 FIG. 1 shows a first example of a skin pass rolling mill according to the present invention. S is a steel strip, 1 is a work roll, 2 is a backup roll, 3 is a skin pass liquid nozzle, 4 is a skin pass liquid pipe, 5 is a flow control valve, 6 is a skin pass liquid supply tank, 7 is a speedometer, 8 is a load meter, 9 is an arithmetic unit.

[0015] This skin pass rolling mill has a work roll 1
4 composed of a, 1b and backup rolls 2a, 2b
In a heavy rolling mill, skin pass liquid nozzles are provided on the upper and lower surfaces of the work rolls 1a and 1b and on both front and back surfaces of the steel strip S between them.
The skin pass liquid is ejected from 3a and 3b. Work roll 1a
The rolling speed signal is input to the computing unit 9 from the speedometer 7 connected to the, and the rolling load is input to the computing unit 9 from the load meter 8. The arithmetic unit 9 performs the calculation according to the equation (3), and the flow control valve 5 is adjusted based on the result, and the supply amount of the skin pass solution supplied from the skin pass solution supply tank 6 to the skin pass solution nozzles 3a and 3b is adjusted. You.

In the case where the variation of the rolling load is small,
The calculation may be performed according to the above equation (4) using only the rolling speed signal. Constants a and b in equations (3) and (4)
May be obtained by theoretical calculation, but a certain rolling speed,
Alternatively, the drainage state is observed while adjusting the flow rate at a certain rolling speed and rolling load, and the constant a or b can be determined by determining an appropriate flow rate.

Conventionally, for example, even if the film thickness is appropriate when the line speed is 50 m / min, the oil film breaks when the line speed is 400 m. However, the present invention always provides an appropriate oil film regardless of the rolling conditions. And the trouble of the automatic surface inspection device due to oil residue is solved, and the EHL
The validity of the theory was also demonstrated. Embodiment 2 FIG. 2 shows a second example of a skin pass rolling mill according to the present invention. 1 are denoted by the same reference numerals, and reference numeral 10 denotes a ringer roll, and 11 denotes a ringer roll lowering mechanism.

This skin pass rolling mill has a work roll 1
4 composed of a, 1b and backup rolls 2a, 2b
In the heavy rolling mill, the skin pass liquid is sprayed from the skin pass liquid nozzles 3a and 3b on the front and back surfaces of the steel strip S in front of the rolling mill, and the skin pass liquid nozzles 3a and 3b and the work rolls 1a and 1b.
The rolling is performed after the liquid is squeezed by the ringer rolls 10a and 10b provided in the middle of the rolling mill, that is, near the roll mill inlet.

In this embodiment, upper and lower ringer rolls 10a,
The film thickness existing in the middle between 10b and steel strip S
Applying the HL theory and the formula ( 1 ), the arithmetic unit is set as follows: H ′ = a ′ · U ^0.7 · W ^−0.13 (1 ′) Calculate the rolling force W of the ringer roll 10 at 9;
The value of W is changed by the rolling mechanism 11 of the ringer roll 10. Therefore, the injection amount of the skin pass liquid in the skin pass liquid nozzles 3a and 3b in the preceding stage is set to be somewhat large, and is made appropriate in the linger rolls 10a and 10b.

In the ringer rolls 10a and 10b, excessive skin pass solution is squeezed out, and at the same time, unevenness in the width direction is eliminated, and an appropriate amount is uniformly distributed and good rolling is performed. Is resolved,
The problem that excessive skin pass solution adheres to a roll or a rolling mill and drops on a steel strip is also solved.

[0021]

According to the present invention, an appropriate amount of skin pass liquid is supplied without oil residue due to excessive supply and without oil film shortage due to insufficient supply, and there is an excellent effect that productivity and quality are improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work roll 2 Backup roll 3 Skin pass liquid nozzle 4 Skin pass liquid pipe 5 Flow control valve 6 Skin pass liquid supply tank 7 Speedometer 8 Load meter 9 Computing unit 10 Ringer roll 11 Rolling-down mechanism

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiharu Fujiwara 1-chome, Kawasaki-dori, Mizushima, Kurashiki-shi, Okayama Pref. Kawasaki Steel Corporation Mizushima Works (56) References JP-A-60-240331 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 27/10 B21B 45/02 310

Claims (3)

(57) [Claims] 1. A method for supplying a skin pass liquid in a metal strip skin pass rolling mill, comprising detecting a rolling speed, and determining a roll-to-roll distance proportional to the 0.7th power of the detected rolling speed .
A skin pass solution in the skin pass rolling of a metal strip characterized by injecting a skin pass solution of a supply amount corresponding to the calculated value of the thickness of the Kinpass solution onto the roll of the skin pass rolling mill, the metal strip near the roll entrance or both of them. Supply method. 2. A method for supplying a skin pass liquid in a metal strip skin pass rolling mill, comprising detecting a rolling speed and a rolling load, and determining a rolling speed and a rolling load in proportion to the 0.7th power and the −0.13th power of the rolling load. the thickness of the
And supplying a skin pass solution having a supply amount corresponding to the calculated value to the roll of the skin pass mill, the metal strip near the roll entrance, or both of them. 3. A method for supplying a skin pass liquid in a metal strip skin pass rolling mill, comprising detecting a rolling speed, and applying a skin pass liquid sprayed onto a surface of the metal strip in front of the skin pass rolling mill. By rolling down the linger roll installed near the entrance, a roll proportional to the 0.7th power of the detected rolling speed is reduced.
A method for supplying a skin pass solution in skin pass rolling of a metal strip, wherein the skin pass solution is squeezed to a thickness of the skin pass solution between the metal strips.