JP2000218304A - Steel mill equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel mill equipment which can prevent cooling of a slab without using a complicated coil furnace and can perform rough rolling to finish rolling with a smaller number of mills. SOLUTION: On the upstream side of a hot rolling line with a finish rolling mill 30 of 4 or more continuous stands, a normal/reverse mill 10 which can roll the end of a plate into a tapered shape is installed, and the end of a rolled steel is rolled into a tapered shape through a reverse operation of the normal/ reverse mill. Then, the plate is continuously rolled in one direction by means of the normal/reverse mill and the finish mill.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact rolling plant capable of performing from rough rolling to finish rolling with a small number of mills.

[0002]

2. Description of the Related Art In a conventional continuous steel sheet manufacturing facility comprising a continuous casting apparatus and a hot rolling line, a slab discharged from the continuous casting apparatus is reheated in a reheating furnace, and then a bar (thickness of 30 to 30 mm) is coarsely milled.
50mm) and strip (thickness 1) with a finishing mill.
〜16 mm) and rolled up with a down coiler.

However, such a conventional continuous steel plate manufacturing facility requires a large number of mills (rolling mills) and rolls from a thick plate (slab) to a thin plate (strip) by the same facility, so that the entire rolling line length is reduced. There is a problem that becomes very long.
Therefore, in order to shorten the total length of the continuous steel plate manufacturing equipment, for example, Japanese Patent Application Laid-Open Nos. 7-80505 and 7-30
No. 8701, JP-A-7-16609 and the like have been proposed.

[0004] Japanese Patent Application Laid-Open No. 7-80505 discloses a "continuous hot-rolling equipment", as schematically shown in FIG. 6A, a rough mill 1 (rough rolling mill) and a finishing mill 2 (finish rolling mill). The winding and rewinding device 3 is arranged in the middle, and the slab (slab) obtained by continuous casting is roughly rolled and wound, then unwound and finish-rolled, thereby achieving compactness of the equipment and energy saving. Things. Japanese Unexamined Patent Publication No. Hei 7-308701, entitled "Continuous Casting Direct Hot Rolling Equipment and Rolling Method", directly connects a continuous casting machine 4 and a hot rolling mill 1 as schematically shown in FIG. By rolling a slab having a thickness of 80 mm or less with the above-mentioned equipment, low-speed rolling can be performed while suppressing a decrease in temperature of a rolled material and generation of scale. In this figure, 5, 6 and 7 are an induction heater, a soaking furnace and a coiler, respectively. Further, JP-A-7-166
No. 09, “Hot rolling equipment and hot rolling method”, FIG.
As schematically shown in (C), at least a first stand of a tandem rolling mill group 1 capable of reverse rolling is provided with a rolling mill for rolling only the first rolling pass.

However, the above-mentioned Japanese Patent Application Laid-Open No. 7-185605
No. (Fig. 6A), rough mill 1
In addition, the number of finishing mills 2 required is the same as that of the conventional mill, and the number of mills cannot be reduced substantially. Further, in the equipment of Japanese Patent Application Laid-Open No. 7-308701 (FIG. 6B), it is assumed that reverse rolling is not performed in the rough mill 1, so that the number of the rough mills 1 increases,
In addition, since it is assumed that reverse rolling is not performed in the rough mill 1, the number of passes of the rough rolling 1 is limited, and thus there is a problem that the thickness of the CC slab cannot be increased. It is known that the higher the CC thickness, the better the quality. Furthermore, in the equipment disclosed in Japanese Patent Application Laid-Open No. Hei 7-16609 (FIG. 6C), when the intermediate winding is performed by the winding and rewinding device 3, there is a problem that the longitudinal end rear end and the width end are cooled, and the finishing mill 2 It is a stand and has a problem that the number of one-way rolling passes at 1000 ° C. or less is too small.

In order to solve the above-mentioned problems, the inventor of the present invention first described "Continuous steel plate manufacturing equipment" (Japanese Patent Application No. 8-2).
No. 70764).

On the other hand, in the rolling of the ordinary rolling mill 1, the allowable reduction amount for biting the leading end of the rolled material 9 between the two rolling rolls 8 is as shown in the schematic diagram of FIG. A bite angle greater than the friction angle cannot be obtained. Therefore, the bite reduction amount is limited to a small value. In FIG. 7A and FIG. 7B, the thickness of the steady portion of the rolled material 9 conveyed in FIG.
The thickness after rolling is h1, the bite angle is θ1, and the friction coefficient is μ.
And the reduction amount Δh1 at this time. This bite angle θ1
However, if it is smaller than the friction angle of the coefficient of friction, it can be engaged, and if it is larger, it slips and cannot be engaged. This is t
Under the condition of anθ1 <μ, the amount of reduction is determined by the calculation formula of Δh1 = H0−h1 and the bite angle. In other words, all the conditions are determined by the frictional condition of the roll, and it is impossible to reduce the amount of reduction any more. For this reason, reverse rolling in which the rolled material is reciprocated and rolled is performed, but there is a problem that the rolling line becomes long.

Further, as a rolling facility having a rolling reduction larger than a normal maximum rolling reduction, a pune ratari mill is conventionally known (for example, “Overview of 600 mmφ Hot Single Punella Tari Mill”, Ishikawajima Harima Technical Report) , Showa 4
August 4th, ^ UTHS system-atechnology to produce ho
t strip in thin gauges ”, Metallurgical Plant Tech
nology International 1994, Japanese Patent Publication 46-2960
No. 5, "Planetary rolling mill", and JP-B-55-37324, "Complete rolling auxiliary corrugation device for rear end of material in planetary rolling mill," etc.).

[0009] However, in the pune ratari mill, the rolling equipment itself has a special and complicated structure, the impact is large because the small-diameter roll is applied to the plate at high speed, and the life of the components (particularly, the bearing of the small-diameter roll) is short, and mass production is difficult. There was a problem that was not suitable for die rolling equipment.

[0010] In order to solve the above-mentioned problems, the inventor of the present invention first described "high-pressure rolling method and rolling equipment thereof".
(Japanese Patent Application No. 9-147458, unpublished).

[0011]

Problems to be Solved by the Invention Japanese Patent Application No. Hei 8-27076
No. 4 is a rolling equipment for reducing the rolling line length by performing winding and rewinding during rolling. In addition, Japanese Patent Application No. 9-
No. 147458 has a taper shape at the tip end by reverse rolling to increase the bite reduction amount in the stationary part and increase the reduction amount per stand of the rolling mill. However, in the rolling equipment disclosed in Japanese Patent Application No. 8-270664, there is a problem that a complicated coil furnace is required because intermediate winding and rewinding are performed in the middle of a rolling pass.

The present invention has been made to solve these various problems. That is, an object of the present invention is to provide a rolling facility capable of preventing slab cooling without using a complicated coil furnace and capable of performing from rough rolling to finish rolling with a small number of mills.

[0013]

According to the present invention, in a hot rolling line in which four or more continuous finishing mills (30) are arranged, a plate tip can be rolled in a tapered shape upstream of the hot rolling line. A forward / reverse rolling mill (10) is installed, and the forward end of the rolled material is rolled into a tapered shape by the reverse operation of the forward / reverse rolling mill, and then continuously rolled in one direction by the forward / reverse rolling mill and the finish rolling mill. A rolling facility is provided.

According to the configuration of the present invention, by rolling the leading end of the rolled material into a tapered shape by the forward / reverse rolling mill (10), it is possible to perform rolling with a high bite reduction amount, which is larger than the normal maximum reduction amount. A large rolling reduction is obtained. Accordingly, the thickness of the plate supplied to the downstream finishing mill (30) can be reduced, and the amount of reduction per stand increases, so that the number of stands installed on the entire line can be reduced.

According to a preferred embodiment of the present invention, a forward / reverse type preheating / heating furnace (32) is provided upstream of the forward / reverse rolling mill. Further, a tip heating furnace (34a, 34a) for heating the tip of the rolled material is provided upstream or downstream of the forward / reverse rolling mill.
b). With this configuration, it is possible to prevent a decrease in temperature that tends to occur at the time of taper rolling at the tip where the tip is rolled into a tapered shape.

Further, in the one-way continuous rolling, when the thickness reduction amount of the tapered portion increases, the motor speed relationship of each stand increases the roll speed ratio between the upstream side and the downstream side. Device (36). In addition, a reduction control device (38) for instructing reduction reduction to reduce the roll gap of the tapered portion in the one-way continuous rolling in accordance with the increase in the taper reduction amount is provided. With this configuration, tension fluctuation when the tip taper portion passes,
Variations in plate thickness can be prevented.

[0017]

Preferred embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, common parts are denoted by the same reference numerals, and redundant description will be omitted.
FIG. 1 is an overall configuration diagram of the rolling equipment of the present invention. FIG.
As shown in (A), the rolling equipment of the present invention has a continuous 4
This is a hot rolling line in which finishing mills 30 or more are arranged, and a forward / reverse rolling mill 10 capable of rolling the tip of the plate into a tapered shape is installed upstream of the finishing rolling mill 30.

According to this configuration, as shown in FIG. 2B, the leading end of the rolled material 13 is rolled into a tapered shape by the reverse operation of the forward / reverse rolling mill 10, and then the forward / reverse rolling mill 10 and the finish rolling mill 30 Continuous rolling in one direction.

(C) shows another example of the configuration. In this configuration example, a forward / reverse rotation type heating / heating furnace 32 (for example, a burner heating furnace) is provided on the upstream side of the forward / reverse rolling mill 10 so that the rolled material 13 is maintained or heated to a temperature suitable for rolling during the reverse operation. Has become.

(D) and (E) show still another configuration example. In this configuration example, a leading end heating furnace 34 for heating the leading end of the rolled material 13 is provided upstream or downstream of the forward / reverse rolling mill 10.
a and 34b (for example, an induction heating furnace) to heat the tip portion during the reverse operation.

FIG. 2 is a partial configuration diagram of the forward / reverse rolling mill of FIG. In FIG. 1, a forward / reverse rolling mill 10 includes two upper and lower rolling rolls 11 and two upper and lower backup rolls 12.
3 is an ordinary four-high rolling mill. In the present invention, the forward / reverse rolling mill is not limited to the four-high rolling mill, but may be another type of rolling mill. An axle box 15 is provided at both shaft ends of the backup roll 12. Rolling roll 11 between housing 16 and the lower side of both axle boxes 15 of upper or lower (in this embodiment, lower) backup roll 12
Is provided with a hydraulic pressure reduction device 17 for applying a rolling force to the rolling device. One end of the shaft of the rolling roll 11 is
An electric motor 18 is mounted for driving the motor 18 to rotate forward and reverse.

In FIG. 2, a hydraulic pressure lowering device 17 is a hydraulic cylinder, and a cylinder body 20 fixed to a housing 16 and an axle box 15 of a backup roll 12 can be moved up and down (opening and closing a gap between two rolling rolls 11). 21 for applying a rolling force to the rolled material 13 while maintaining the rolling force
And a hydraulic source (not shown) via a pipe 24,
3 and a hydraulic chamber 22 for supplying and discharging pressure oil. The piston 2 is attached to the cylinder body 20 and the piston 21.
1 is provided with a position detector 25 (for example, a magnescale or the like) for detecting the position. The detection value detected by the position detector 25 is input to a calculation device 26 that converts the value into a rolling force. Further, the motor 18 is provided with a detector 27 (for example, a tachogenerator or the like) for detecting the number of revolutions of the rolling roll 11, and the detected value is input to an arithmetic unit 26 which converts the detected value into a rolling force. Although not shown, the tilt rolling information P1 and P2 for each of the first and second passes are also input to the arithmetic unit 26 in the same manner. A command device 28 is provided which outputs the pressure reduction command calculated by calculating these input data by the calculation device 26. Further, a hydraulic (hydraulic) servo valve 29 is provided between the above-mentioned hydraulic pressure source and the hydraulic pressure reduction device 17,
The hydraulic servo valve 29 supplies or discharges pressure oil for controlling the rolling force of the hydraulic pressure reduction device 17 to or from the hydraulic chamber 22 in response to an operation signal output from the command device 28.

FIG. 3 is a schematic diagram of taper rolling by a forward / reverse rolling mill, and shows that a reduction amount larger than a normal maximum reduction amount can be obtained. In (a),
The thickness of the steady portion of the conveyed rolled material 13 is H0, the length of the inclined tip portion formed by the two forward and reverse inclined rollings of the present invention is L2, the thickness of the inclined tip portion is h2, Angle to θ
2. The coefficient of friction is μ, and the amount of reduction in the third forward rolling is △.
h2, and the roll gap of the rolling roll is G0. h2
Is made thinner than the above-mentioned h1 by inclined rolling. Also, H0
If>G0> h2, rolling is possible even when tan .theta.2> .mu .. Therefore, H0−h2 = △ h2> △ h1.
As a result, if the leading end of the rolled material 13 is inclined and the outlet thickness h2 is made smaller than the roll gap G0 of the rolling roll, the biting angle can be made smaller than the friction angle of the friction coefficient and slipping can be prevented. Rolling with a high rolling reduction can be performed, and a rolling reduction larger than a normal maximum rolling reduction can be obtained. Therefore, the rolling line can be shortened.

FIG. 4 is a partial configuration diagram of the finishing mill shown in FIG. 1, and FIG. 5 is another partial configuration diagram of the finishing mill shown in FIG. As shown in FIG. 4, each finishing mill 30 includes upper and lower rolling rolls 30a, a hydraulic pressure reduction device 31 that applies a rolling force to the rolling rolls 11, and an electric motor 30b that rotationally drives the rolling rolls 30a. Roll 30
The configurations of a, the hydraulic pressure reduction device 31, and the electric motor 30b are the same as those of the above-described rolling roll 11, the hydraulic pressure reduction device 17, and the electric motor 18. Further, the rolling equipment of the present invention includes a roll speed control device 36 for controlling each electric motor 30b. When the thickness reduction amount of the tapered portion increases in the one-way continuous rolling after the above-described rolled material tip portion is rolled into a tapered shape, the roll speed control device 36 changes the motor speed relationship of each stand to the upstream side and the downstream side. The speed command is given so that the roll speed ratio becomes large, thereby preventing the tension fluctuation when the tapered portion passes.

Further, as shown in FIG. 5, the rolling equipment of the present invention is provided with a draft control device 38. This rolling-down control device 38 has at least several units on the most upstream side (in FIG.
Control of the hydraulic pressure reduction device 31 to reduce the roll gap of the tapered portion in the one-way continuous rolling after the above-described rolled material is rolled into a tapered shape in accordance with the increase in the taper reduction amount. A command is issued to prevent the thickness from fluctuating when the tapered portion passes.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously changed without departing from the gist of the present invention.

[0027]

According to the configuration of the present invention described above, by rolling the leading end of the rolled material into a tapered shape by the forward / reverse rolling mill 10, it is possible to perform a high rolling reduction with a biting reduction, which is higher than the normal maximum rolling reduction. A large reduction amount can be obtained. Accordingly, the thickness of the plate supplied to the downstream finishing mill 30 can be reduced, and the amount of reduction per stand increases, so that the number of stands installed on the entire line can be reduced.

Further, by providing the tip heating furnaces 34a and 34b, it is possible to prevent a decrease in temperature that tends to occur at the time of tip taper rolling in which the tip is rolled into a tapered shape. Further, by providing the roll speed control device 36 and the pressure reduction control device 38, it is possible to prevent a variation in tension and a variation in plate thickness when the tip taper portion passes.

Therefore, the rolling equipment of the present invention can prevent the cooling of the slab without using a complicated coil furnace,
It has excellent effects such as the ability to perform from rough rolling to finish rolling with a small number of mills.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a rolling facility of the present invention.

FIG. 2 is a partial configuration diagram of the forward / reverse rolling mill of FIG.

FIG. 3 is a schematic diagram of taper rolling by a forward / reverse rolling mill.

FIG. 4 is a partial configuration diagram of the finishing mill of FIG. 1;

FIG. 5 is another partial configuration diagram of the finishing mill of FIG. 1;

FIG. 6 is a configuration diagram of a conventional rolling facility.

FIG. 7 is a schematic diagram showing a relationship between a tip friction angle of a conventional rolled material and a rolling roll.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling mill (rough rolling mill) 2 Finishing rolling mill 3 Winding and rewinding device 4 Continuous casting machine 5 Induction heater 6 Soaking furnace 7 Coiler 8 Work roll (rolling roll) 9 Rolled material 10 Forward / reverse rolling mill 11 Rolling roll 12 Backup roll 13 Rolled material 15 Shaft box 16 Housing 17 Hydraulic pressure reduction device 18 Electric motor 20 Cylinder main body 21 Piston 22 Hydraulic chamber 23 Piping port 24 Piping 25 Position detector 26 Arithmetic unit 27 Detector 28 Commander 29 Hydraulic (hydraulic) servo valve Reference Signs List 30 finishing rolling mill 30a rolling roll 30b electric motor 31 hydraulic pressure reduction device 32 preheating furnace 34a, 34b tip heating furnace 36 roll speed control device 38 pressure reduction control device

Claims (5)

[Claims] In a hot rolling line in which four or more continuous finishing mills (30) are arranged, a forward / reverse rolling mill (1) capable of rolling a tapered end of a plate upstream thereof is provided.
0) is installed, and the leading end of the rolled material is rolled into a tapered shape by the reverse operation of the forward / reverse rolling mill, and then continuously rolled in one direction by the forward / reverse rolling mill and the finish rolling mill. Facility. 2. A forward / reverse type preheating / heating furnace (32) is provided upstream of the forward / reverse rolling mill.
Rolling equipment according to the above. 3. A tip heating furnace (34a, 34) for heating the tip of a rolled material upstream or downstream of the forward / reverse rolling mill.
2. The rolling plant according to claim 1, comprising b). 4. A roll speed control for giving a speed command such that a motor speed relationship of each stand increases a roll speed ratio between an upstream side and a downstream side when the thickness reduction of the tapered portion increases in the one-way continuous rolling. The rolling plant according to claim 1, characterized in that it comprises a device (36). 5. A reduction control device (38) for instructing a reduction compensation for reducing a roll gap of a taper portion in accordance with an increase in a taper reduction amount in the one-way continuous rolling.
The rolling equipment according to claim 1, wherein: