JPH0545321B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to reducing the vertical curvature that occurs when the width of a metal slab is reduced during rolling by a rolling mill row that includes a width reduction mill that has vertical rolls with calibers and a horizontal reduction mill that has horizontal rolls. The present invention relates to a hot width rolling method for preventing roll surface roughening. [Prior Art] Conventionally, in order to fully utilize the low-cost mass production capability that is a feature of continuous casting machines, efforts have been made to establish energy-saving processes by consolidating slab sizes and directly connecting them to rolling lines. Of these, the aggregate width of the slab is
To achieve this by width rolling the slab, as proposed in the publication, width reduction rolling is necessary. The characteristics of this width reduction rolling method, compared to conventional rolling methods, are (a) the ratio of the roll contact arc length during rolling to the average sheet width, that is, the roll gap shape ratio, is small at 0.3 or less, and (b) the slab The plate width ratio, which is the ratio of width to thickness, is small at 15 or less, and (c) the amount of repeated reduction per roll is small.
It is large at 300mm. In addition, the rolling deformation during width reduction rolling is characterized by the fact that the rolling force in the width direction by the vertical rolls during width reduction does not propagate to the center of the strip width, resulting in local thickened areas called dog bones at both ends of the strip width. That's true. Therefore, at an appropriate stage of the rolling process,
It is necessary to roll the locally deformed part by horizontal rolling. In this width reduction rolling process, the locally increased thickness increases by 50 to 100 mm compared to the original thickness, and as a result, the surface inside the caliber of the vertical roll becomes rough, and
Roll life is extremely shortened. In order to prevent roughening of the roll surface and roughening of the rolled material due to the roughening, many so-called hydraulic rolling methods have been employed in the past, in which hot rolling oil is supplied to the roll surface during rolling. In order to supply lubricating oil to the roll surface during this hydraulic rolling, as introduced in Japanese Patent Application Laid-Open No. 122661/1984, a water jet is applied to the biting side of the caliber roll to drain the caliber roll cooling water. There is a device in which a rolling oil injection nozzle is arranged to inject and supply lubricating oil to the rolling surface of a caliber-equipped roll that has been drained by the water injection nozzle, which is a so-called water injection type oil supply device with a wiper. [Problems to be Solved by the Invention] By the way, in order to prevent such rough skin on the roll surface, roughening cannot be completely prevented by only hydraulic rolling in which hot rolling oil is supplied during rolling.
Although the rate of promotion of rough skin decreases, it is not possible to prevent the promotion of rough skin due to the increase in the amount of width reduction rolling, and streamline roughness occurs on the roll surface, and once this occurs, it is transferred to the rolled material. This creates linear flaws and deteriorates the quality of the rolled material. Therefore, there has been a strong demand for a complete preventive measure against surface roughness during width reduction rolling. The present invention was made in order to solve the above-mentioned problems in the conventional hot width rolling method, and provides a hot width rolling method that achieves an excellent roll surface roughening prevention effect by combining hydraulic rolling with a grinding means. It is something to do. [Means for Solving the Problems] The technical means of the present invention for solving the above problems is to arrange vertical rolls with calibers for rolling in the driven width direction on the input and exit sides of the driven horizontal rolls. , in a hot width rolling method in which, when width rolling a metal slab with a vertical roll with a caliber, the local plate thickness increase part caused by the width direction rolling is horizontally reduced and the width direction rolling is repeated again. , when a localized thickness increase part that occurs when a metal slab is width rolled with a vertical roll is further increased by width rolling in the reverse direction of the vertical roll, the vertical roll in contact with the increased local thickness increase part; The method is characterized in that hot rolling oil is applied to the rough surface area of the roll inside the caliber side wall of the incoming caliber on the side wall of the caliber, and the rough surface area of the roll inside the caliber on the exit side caliber side wall is ground with a roll grinding wheel. . [Operation] The operation of the present invention will be explained below with reference to the drawings. Second
Figures a and b show an apparatus for implementing the hot width rolling method of the present invention, and in Figure 2a, 1a and 1b are vertical rolls with calibers that perform rolling in the width direction of the sheet;
Two stages 1a and 1b are disposed at the front and rear of the horizontal roll 2 that performs rolling in the thickness direction. This 2
A metal slab 3, which is a material to be rolled, is reciprocated between seed rolling rolls 1a, 1b and 2 and rolled into a predetermined shape. In this rolling process, when the metal slab 3 is rolled down by the vertical rolls 1a and 1b, as shown in Fig. 2b.
Locally increased thickness portions 4 are formed at both ends of the width. When this local deformation becomes large, it causes surface flaws on the material and an increase in the rolling power during rolling in the width direction. For this purpose, the thickened part 4 is first reduced to the same thickness as the other central part by the horizontal rolls 2, and then rolled again in the width direction by the vertical rolls 1a and 1b to reduce the width. Take. In Fig. 3, the roll rotation of the vertical rolls 1a and 1b with calibers in Fig. 2a is defined as normal rotation a, the direction in which the metal slab 3, which is the material to be rolled, moves in the A direction, and reverse rotation b, in which the direction in which it moves in the B direction. In this case, for each of the vertical rolls 1a and 1b on the left side with respect to the rolling direction A, the locally increased thickness portion 4 is shown in contact with the side wall of the vertical roll caliber. Third
Figure a shows the rolling state of the caliber side wall of the vertical roll 1a and the metal slab 3 which is the material to be rolled.
When the metal slab 3 formed into a substantially rectangular shape by the horizontal rolls 2 is rolled in the width direction by the vertical rolls 1a by reverse rotation, a locally increased thickness part 5 is generated and contacts at the caliber side wall 5b. When the next repeated rolling, that is, further rolling in the width direction by normal rotation of the vertical rolls 1a, an enlarged local thickened portion 6 is generated and comes into contact with the caliber side walls 5b and 6a. FIG. 3b shows the rolling state of the caliber side wall of the vertical roll 1b and the metal slab 3. When the metal slab 3 formed into a rectangular shape by the horizontal roll 2 is rolled in the width direction by the vertical roll 1b by normal rotation. ,
A local thickening portion 7 occurs, and the caliber side wall 7a
Contact with Next, when repeated rolling, that is, further rolling in the width direction by reversing the vertical rolls 1b, an enlarged local thickness increase portion 8 is generated, and the caliber side wall 7
It touches at a and 8b. That is, the caliber side walls 5 of the vertical rolls 1a, 1b
b, 7a are in contact with the locally increased thickness portions 5, 7 of the metal slab 3 regardless of whether the roll rotates in the forward or reverse direction, and the caliber side walls 6a, 8b are always in contact with the increased local portions of the metal slab 3 only when rotating in one direction. Increased thickness of target plate 6, 8
touches. The caliber side walls 6a, 8b are formed by rolling because the locally increased thickness parts 6, 8 produced by rolling in the width direction increase in only one direction, and the difference in the inner circumferential speed of the caliber is large. Friction occurs between the metal slab 3 and streamlined rough skin at the area. This rough surface is transferred to the rolled material and becomes linear flaws, which extremely shortens the life of the roll. In addition, the caliber side walls 5b, 7a
Since the caliber inner circumferential speed difference is small, roll surface roughness is slight, and since it contacts the rolled material during reciprocating rotation in both directions, the surface roughness disappears and appears as slight roll wear. Hereinafter, the caliber side walls 6a and 8b will be referred to as rough areas of the internal roll of the caliber, and the caliber side walls 5b and 7a will be referred to as the worn area of the internal roll of the caliber. Based on these findings, the present inventors researched various hot rolling oils and roll grinding methods for the rough surface area of the rolls in the caliber, and as a result, vertical rolls 1a, 1
The hot width rolling of the metal slab was carried out by applying solid or liquid hot rolling oil to the side wall of the inlet caliber and grinding the side wall of the outlet caliber. That is, hot rolling oil is applied to the entrance side caliber side walls of the vertical rolls 1a and 1b, and the roughening that occurs during rolling is extremely suppressed by the oil lubrication effect. This slight roughening of the roll surface is immediately ground by a grinding wheel that presses against the side wall of the outlet caliber to ensure that it is eliminated. This is done continuously during width rolling rotation of the vertical rolls, and a Kyver side wall surface with no roll surface roughness is always supplied to the biting side, eliminating the occurrence of surface flaws during width rolling caused by roll surface roughness. It is something to do. In particular, since the oil film on the exit side caliber side wall is eliminated by contact between the rolled material and the roll surface, it is easy to grind, and roll cooling water can be used as a grinding medium. In this way, even if hot rolling oil was applied to the exit side caliber side wall, it would flow out due to the roll cooling water, so no effective measures could be taken, but by installing a grinding wheel device instead, the roll surface could become rough. We were able to achieve great results in prevention. Note that the hot rolling oil used in the present invention may be any commonly used and well-known oil, and by grinding on the exit side caliber side wall, the roughness of the roll surface is significantly reduced compared to when only hot rolling oil is used. Can be reduced. As for this equipment configuration, from the mechanism of roll surface roughness occurring during reversible rolling, the local thickness increase part that occurs during vertical roll rolling is further increased by the reversal direction width rolling of the vertical roll. A hot rolling oil application device may be provided on the side wall of the inlet caliber of the vertical roll in contact with the roll, and a roll grinding wheel device may be provided on the side wall of the outlet caliber. [Example] Hereinafter, an example of the hot width rolling method of the present invention will be described. FIG. 1a is a schematic plan view of the width rolling device, and FIG. 1b is a detailed view of the rolling oil application device and the roll grinding wheel device of FIG. 1a. The metal slab 3, which is a material to be rolled, is first conveyed and rolled in the direction of arrow A, and then rolled in the width direction by a vertical roll 1a with a caliber. The locally increased thickness portion 4 generated by this width reduction is rolled in the thickness direction by the horizontal rolls 2 to the original thickness of the material to be rolled. Then, after being rolled down in width by a vertical roll 1b, it is reversely conveyed in the direction of arrow B and rolled. By repeating this several times, the desired dimensions can be achieved. Reference numerals 9a and 9b are roll choking devices for holding the vertical rolls 1a and 1b, which are linked to a drive device, set at predetermined positions, and are always located at both ends of the material to be rolled during rolling. The local thickness increase portion 4 that occurs during vertical roll rolling is caused by the vertical rolls 1a,
The vertical rolls 1a, 1 are increased in width by the reverse direction width rolling of 1b, and this increased local thickness increase portion contacts.
A roll chock device 9 is installed on the side wall of the inlet caliber of b.
A solid lubricant applicator 10 is provided via a and 9b, and a roll grinding wheel device 11 is provided on the outlet side wall of the caliber. When the metal slab 3, which is the material to be rolled, is conveyed and rolled in the direction of arrow A, the rough surface area 6a of the roll caused by the locally increased thickness is caused by the hot rolling oil provided in the roll chock device 9a of the vertical roll 1a. The coating device 10 and the roll grinding wheel device 11 prevent roll roughening. The hot rolling oil applicator 10 and roll grinding wheel device 11 have a solid lubricant 10a or a roll grinding wheel 11a slidably attached to a holder box 12 as shown in FIG. It is pressed against the parts 6a and 8b. This air pressure is controlled by the pressure regulating valve 13 and the on/off solenoid valve 14.
The air is supplied from an air piping system 16 which is connected to an air header 15 via an air line. Further, the holder box 12 is connected to a fixed frame 18 via a reciprocating drive mechanism equipped with a hydraulic cylinder 17, and is capable of reciprocating swinging along the caliber side wall. Further, the fixed frame 18 is attached to a mounting frame 19 using adjustment screws, and the mounting frame 19 is fixed to the roll choking devices 9a, 9b. When this metal slab 3 is transported in the direction of arrow A, the solid lubricant 10a and the roll grinding wheel 11a provided in the roll choking device 9b of the vertical roll 1b control the on-off valve 14 by the position control device 20, In this case, the air pressure is cut off and the pressure is controlled so as not to press. When the metal slab 3 is conveyed and rolled in the direction of arrow B, the solid lubricant 10a and the roll grinding wheel 11a disposed in the roll chocking device 9b of the vertical roll 1b are pressed by air pressure, and the roll choking device 9b of the vertical roll 1a is pressed. Air pressure is cut off from the solid lubricant 10a and the roll grinding wheel 11a, which are disposed at 9a, and are controlled so as not to be pressed. The above explanation has been made regarding the hot rolling oil application device 10 and the roll grinding wheel device 11 installed on the lower side of the caliber side wall.
A device with the same mechanism is installed on the top side of the caliber side wall. Table 1 shows an example of the rolling conditions under which the present invention was carried out, and shows the results of an investigation into the presence or absence of a grinding wheel under the production conditions of a continuous cast slab of 280 mm thickness and 1800 mm width to a target slab size of 250 mm thickness and 750 to 900 mm width. When only solid hot rolling oil was used, roll surface roughness of 0.6 to 1.0 mm occurred at width reduction rolling of 200,000 tons, but when a grinding wheel was pressed, no roll surface roughness occurred.

〔Effect of the invention〕

As explained above, the present invention minimizes the roughness of the roll surface that occurs on the side wall of the vertical roll caliber during width rolling by applying hot rolling oil immediately before width rolling, and further suppresses the roughness of the roll surface that occurs slightly on the side wall of the exit side caliber. This makes it possible to smooth and erase by immediately grinding with a whetstone each time. Therefore, surface flaws such as linear flaws on the rolled material caused by roll roughness are prevented from occurring, improving quality.In addition, since the promotion of roll roughness is eliminated each time, roll life is extended compared to conventional methods. This has great effects on hot rolling, such as doubling the amount of steel.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, in which FIG. 1a is a schematic plan view of a width reduction rolling device, FIG.
Figure a is a perspective view of a width reduction rolling apparatus for explaining the operation of the present invention, Figure 2 b is a perspective view of a metal slab subjected to width reduction rolling, and Figures 3 a and b are metal rolled by vertical rolls. It is a sectional view explaining the state of a slab. 1a, 1b...Vertical roll with caliber, 2...Horizontal roll, 3...Metal slab, 4-8...Local thickness increase portion, 5b, 6a, 7a, 8b...Caliber side wall, 9a, 9b... ...Roll check device, 1
0... Rolling oil application device, 11... Roll grinding wheel device, 10a... Lubricating body, 11a... Grinding wheel.

Claims (1)

[Claims] 1. When a vertical roll with a caliber for rolling in the driven width direction is arranged on the input and exit sides of a driven horizontal roll and width rolling of a metal slab is performed with the vertical roll with a caliber, the amount of damage caused by the rolling in the width direction In a hot width rolling method in which a locally increased thickness part is horizontally reduced and rolled again in the width direction, the localized thickness increased part generated when a metal slab is width rolled with vertical rolls is further rolled in the vertical direction. When the width is increased by rolling in the reverse direction of the rolls, hot rolling oil is applied to the rough part of the inner roll of the caliber on the entrance side caliber side wall of the vertical roll that is in contact with the locally increased thickness part of the roll, and A method for hot width rolling of a metal slab, characterized in that a rough surface area of a roll in a caliber on a side wall of a side caliber is ground with a roll grinding wheel.