JPH0586282B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to hot rolling of metal materials, and in particular, a method for removing linear surface flaws that occur at the edge of a rolled material when rolling the ridges of the material. and regarding equipment. <Prior Art> In recent years, customers' demands regarding the surface properties of hot-rolled steel sheets and cold-rolled steel sheets have become increasingly strict. In particular, surface flaws on the edge of the board, which had been neglected in the past, are now being highlighted as an important issue due to the reduction in the amount of margin due to the improvement of edge drop. The main surface flaws on the edge of the board are:
These are linear flaws that occur parallel to the rolling direction, and are caused by existing flaws on the side surface of the rolled material, flaws or uneven wrinkles that occur at the edge of the plate during the rolling process, etc. rolling (hereinafter referred to as horizontal rolling)
It is known that due to the width expansion of the rolled material at the time, it went around from the side surface to the edge of the surface plate and remained. As a method for preventing the above-mentioned linear flaws, methods described, for example, in Japanese Patent Publication No. 14632/1982 and Japanese Patent Application Laid-Open No. 28542/1982 are known. The former uses caliber rolls for rolling in the width direction of the plate (hereinafter referred to as vertical rolling) to apply a large reduction in the width direction of the rolled material, giving a forging effect to the edge of the plate to prevent the occurrence of defects. It is. The latter uses the collar of the caliber roll of a vertical rolling mill to apply rolling to the ridge of the material to adjust the cross-sectional shape of the end of the material to be rolled, thereby suppressing the width expansion caused by subsequent horizontal rolling. It is something. <Problems to be solved by the invention> The method disclosed in the above-mentioned Japanese Patent Publication No. 14632/1983 requires a powerful vertical rolling mill to apply a sufficient forging effect, and it cannot be used for wide materials or thin slab materials. When rolling a product, such a large reduction tends to cause buckling at the edges of the product, which may even worsen the surface quality of the edges of the product. Further, in the method of JP-A-53-28542, as shown in FIG.
The edger 1 applies pressure to
Since it rotates around the roll axis 4, the inclined part 2
For example, the peripheral speed is different at the 2' point and the 2'' point,
Since the circumferential speed is faster at the 2'' point than at the 2' point,
A speed difference occurs between the inclined portions 2 and 3 and the surface of the rolled material that comes into contact with the inclined portions 2 and 3. Due to the influence of such a speed difference, slips occur near the ridges of the rolled material, which may also deteriorate the surface quality of the product. The present invention has been made in view of the above-mentioned problems, and provides a hot rolling method and apparatus that are effective in preventing surface linear flaws parallel to the rolling direction that occur at the ends of rolled material sheets. The purpose is to <Means for Solving the Problems> The present invention provides a step in hot rolling of metal materials that includes vertical rolling and horizontal rolling of the material to be rolled.
Rolling only the ridge portion of the material to be rolled at a constant circumferential speed using a roll having a rotation axis perpendicular to the traveling direction of the material to be rolled and inclined with respect to the plate surface of the material to be rolled. This is a hot rolling method characterized by the addition of a step. Further, in a hot rolling apparatus for metal materials, a vertical rolling mill that rolls the material to be rolled in the width direction, a horizontal rolling mill that rolls the material in the thickness direction, and a 4 machine that rolls only the ridge portion of the material to be rolled at a constant circumferential speed. This hot rolling apparatus is characterized in that it is comprised of a ridge rolling apparatus that holds individual rolls so that the rolling position, roll angle, and roll spacing in the sheet width direction can be adjusted. <Function> The present inventors conducted a hot rolling experiment using a low carbon steel piece and a stainless steel piece, and as a result, the following findings were obtained. (1) By smoothing out existing flaws (cracks) and uneven wrinkles on the side surface of the rolled material through rolling, it is possible to prevent surface linear flaws at the edge of the plate. (2) To flatten the shape of the ridge by rolling the ridge of the material to be rolled at a constant circumferential speed, at right angles to the direction of movement of the material to be rolled, and at an angle to the plate surface. As a result, the amount of heat dissipated from the ridge can be reduced and the ridge temperature can be maintained at a high temperature, making it possible to suppress cracks caused by rolling in this area, which is effective in preventing the surface linear flaws. . (3) By constant circumferential speed rolling, there is no speed difference between the surface of the material to be rolled and the rolls that roll only the ridges, and defects (cracks) and uneven wrinkles existing on the ridges can be removed. Since the surface can be smoothed, the surface linear flaws can be prevented. These findings led to the present invention. The present invention will be explained in detail below using the figures. FIG. 1 is a schematic diagram showing an example of a ridge rolling device 12 which is a main part of the present invention. In FIG. 1, the ridge rolling rolls 13
The rolled material 10 corresponds to each of the two ridges 11.
Four of them are installed perpendicular to the direction of movement of the board and inclined to the surface of the board. Note that only one holding device 14 for the edge rolling roll 13 is shown as a representative. The edge rolling roll 13 is fixed to a rod 18 of a rolling hydraulic cylinder 17 attached to a housing 16 via a bearing 15. The housing 16 is fixed on a base 23 and has an arcuate rack 22. A gear mechanism 21 that allows the cylinder 17 to move is fitted into the rack 22, and is connected to the angle adjusting hydraulic cylinder 19 via a bar 20. With such a configuration, by adjusting the strokes of the rolling hydraulic cylinder 17 and the angle adjusting hydraulic cylinder 19, the rolled material 1 can be adjusted.
The rolling angle θ and rolling position δ of the edge rolling roll 13 can be determined in accordance with the change in material thickness of 0. In addition, in order to accommodate changes in the width of the rolled material 10, a hydraulic cylinder 24 directly connected to the base 23 is used.
This is possible by adjusting the roll interval in the sheet width direction by moving the rolls along the width direction center line 25 of the rolled material 10. By the way, regarding the rolling load required for ridge rolling, the inventors of the present invention developed the ridge of a SUS430 material with a thickness of 20 mm and a width of 150 mm prior to designing this ridge rolling equipment.
Experimental rolling at a temperature of 1100°C revealed that it was extremely small. Therefore, the ridge mill does not require a rigid mill housing such as that used in conventional horizontal or vertical mills. Therefore, as a method of supporting the ridge rolling roll 13, it is not necessary to stick to supporting the roll neck on both sides as shown in FIG. 1, but for example, as shown in FIG. It may be supported in any state. In addition, if the thickness of the material to be rolled 10 is thin and there is a risk that the upper and lower roll ends or roll bearings may come into contact with each other if the ridge rolling rolls 13 are vertically symmetrically arranged, the material to be rolled 10 may be The upper rolls for rolling the front edge and the lower rolls for rolling the back edge may be arranged in tandem alternately in advance. Further, it is assumed that the ridge rolling roll 13 is driven by a drive device (not shown), but if there is not enough space to incorporate the drive device for the same reason as above, Since a horizontal rolling mill or a vertical rolling mill disposed in front or behind the ridge rolling roll 13 functions as a pinch roll, the ridge rolling roll 13 may be non-driven. Therefore, as for the arrangement of the ridge rolling rolls 13, it is desirable to install them between the horizontal rolling mill and the vertical rolling mill, but they may also be arranged in front or behind the horizontal rolling mill and the vertical rolling mill. , the effects of the present invention remain unchanged. <Example> An example in which the present invention was implemented in hot rough rolling of SUS304 material will be described below with reference to FIG. As shown in FIG. 3, the ridge rolling device 12 according to the present invention is arranged between a vertical rolling mill 27 for rough rolling and a four-high horizontal rolling mill 28. The leading end of the material to be rolled 10 is fed into the ridge rolling roll 13 by the vertical rolling mill 27, while the trailing end is fed into the horizontal rolling mill 2.
It is pulled out by 8. Therefore, the rolled material 10
is sufficiently pinched over its entire length by the vertical rolling mill 27 and the horizontal rolling mill 28, so the driving device for the edge rolling roll 13 is not used. The material to be rolled 10 is a slab made of SUS304 and has dimensions of 180 mm in thickness, 1025 mm in width, and 7500 mm in length. Rough rolling is performed by reverse rolling as shown in Table 1.
Pass rolling was performed, and then rolling was carried out using a 6-stand tandem rolling mill to finish the plate to a thickness of 3 mm.

[Table] Here, in order to compare the effects of the present invention with conventional examples, (1) ridge free rolling, (2) sheet edge rolling using flat rolls, and (3) ridge rolling using caliber rolls. (4) Rolling of 25 slabs was attempted using the four methods of rolling using the edge rolling roll according to the present invention, and the presence or absence of flaws on the front and back surfaces of the plate edges of each finished product was visually inspected. . The rolling results obtained by the above four methods are shown in FIG.
As is clear from this figure, the linear surface flaws on the edge of the plate, which could not be completely eliminated by edge rolling using caliber rolls, can be completely eliminated by implementing the present invention. It was. In this embodiment, the ridge rolling was performed every odd number of passes, but it is more preferable to perform the ridge rolling on all passes. Also,
One guideline for the period from the first ridge rolling to the next ridge rolling is to keep the plate thickness reduction rate due to horizontal rolling to less than 50% during that period. In particular, according to the prior art, the cross section of the rolled material after rolling by a vertical rolling mill shows a doghorn shape as shown in FIG. Concave and convex wrinkles are difficult to smooth out either by subsequent horizontal rolling or by vertical rolling again, and instead cause collapse, which can lead to internal defects. However, according to the present invention, since the flaws (cracks) and uneven wrinkles on the ridge portion 8 are smoothed out, these problems can be solved all at once, and a remarkable effect is produced. <Effects of the Invention> According to the present invention, by rolling only the ridges of the material to be rolled, it is possible to smooth out flaws (cracks) and uneven wrinkles existing in the ridges. This makes it possible to prevent surface linear flaws that occur on the surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a ridge rolling device for rolled materials used in the present invention, FIG. 2 is a schematic diagram showing another embodiment, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a diagram showing the effect of the present invention, FIG. 5 is a diagram schematically showing ridge rolling of a material to be rolled using a conventional caliber roll, and FIG. It is a schematic diagram which shows a part of cross-sectional shape of a rolled material after rolling. 10... Rolled material, 11... Edge of rolled material,
12... Edge rolling device, 13... Edge rolling roll, 14... Housing, 27... Vertical rolling mill,
28...Horizontal rolling mill.

Claims (1)

[Scope of Claims] 1. In the hot rolling of metal materials, a process consisting of vertical rolling and horizontal rolling of the rolled material is carried out at right angles to the traveling direction of the rolled material and of the rolled material. A hot rolling method comprising the step of rolling only the ridge portion of the material to be rolled at a constant circumferential speed using a roll having a rotation axis inclined with respect to the plate surface. 2. A hot rolling machine for metal materials, including a vertical rolling mill that rolls the material to be rolled in the width direction, a horizontal rolling mill that rolls the material in the thickness direction, and four machines that roll only the ridges of the material to be rolled at a constant circumferential speed. and a ridge rolling device that holds the rolls in such a manner that the rolling positions, roll angles, and roll spacing in the sheet width direction can be adjusted.