JPS62214803A - Stable rolling method for irregular section steel sheet - Google Patents

Abstract

PURPOSE:To prevent sheet biasing and to produce a product having a good shape by providing excess metal parts to both sides of a material to be rolled from which one or plural lengths of irregular section steel sheets are simultaneously rolled and providing pressing parts consisting of slopes to rolling rolls. CONSTITUTION:The irregular section steel sheet in generation is rolled of plural lengths and in the case of, for example, two lengths, the excess metal parts 8, 8' and the pressing parts 9, 9' by roll calibers are provided to the material 4 to be rolled. Since the roll surfaces are inclined, the material 4 to be rolled receives reactions F, F' in the central direction respectively at the surface edges in the stage when the excess metal parts are pressed to the pressing parts 9, 9' and are rolled. The excess metal part 8' fills tthe pressing part 9' but the excess metal part 8 does not fill the pressing part 9 if the material 4 biases to, for example, a right direction. The rolling width of the pressing parts increases from the right side and decreases from the left side. The balance between the rolling reactions f, f' of the pressing parts and the reactions F, F' is, therefore, broken, and the right side becomes larger. The self-aligning effect by which the escape of the material 4 toward the outside direction by the edge part is prevented is thus induced.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to caliber rolling of one or more stands in a continuous hot rolling mill (hot strip mill), in which a difference in plate thickness is provided in the width direction. The present invention relates to a rolling method for stably threading a steel plate with an irregular cross section.

(Prior art) Conventionally, as a method of giving a strip thickness difference in the width direction, there are known methods such as adding a crown to the roll used for rolling or carving a groove-like caliber on the roll. It's cool.

For the former, in order to give a large difference in thickness within the working range of general strips, a large round is given to the roll from the front stage of the hot strip mill, and a crown is applied according to the thickness of the rolled material. The crown of the strip is formed by reducing the number of strips without disturbing the shape, and the cross-sectional shape in the width direction is limited to the crown shape.

The latter (setting #I# in qo-ru will prevent local protrusions) 1
It is a rolling method for imparting a 7-ply shape to the grain.For example, it is described in U.S. Pat.
No. 22, Japanese Unexamined Patent Publication No. 55-88943, etc.

Although this rolling method is effective in rolling irregular cross-section steel plates with repeated thickness differences in the width direction at relatively small pitches, the pitch P shown in Fig. 1 is large. If the overall thickness is relatively small, that is, the thickness tl of the thick part and the thickness t2 of the thin part, that is, in the case of an irregular cross-section steel plate whose entire shape is a thin steel plate, the shape deteriorates,
This sometimes resulted in product defects or rolling defects. FIG. 5 is an explanatory diagram showing an example of two-strip rolling in order to make effective use of the roll barrel of the rolling mill when rolling a steel plate with an irregular cross section as shown in FIG. 1. . In the figure, 1 and 3 are operating rolls involved in rolling the deformed steel plate, 1 is an upper roll, 2 is a lower roll 2, a caliber carved on the upper roll 1, and 4 is a pressurized abrasive material.

In order to efficiently roll the above-mentioned irregular cross-section steel plates, the present applicant has developed a rolling method using a continuous hot rolling mill! !
! J Application No. 59-128880 (Japanese Unexamined Patent Application Publication No. 1987-1283) was previously filed. This invention has solved the forming problems with continuous hot rolling mills.

(Problem that @Ming tries to solve) Although the invention of the above-mentioned patent application No. 12888/1983 established a technology for expressing the shape of a steel plate with an irregular cross section having a wide range of thickness differences, there is no means to prevent the sheet deviation that sometimes occurs. There was no effective method for this, and further improvements were desired.

In other words, in the case of strike IJ tube rolling, there is no lateral holding mechanism, so sheet deviation occurs, but in the case of flat plates, there is no particular problem even if sheet deviation occurs to some extent as long as the roll barrel is not stiff. In the case of rolling a deformed steel plate with a difference, the biting position of the stand is not close to the plate, and the rolling reduction ratio in the widthwise direction of the biting position is different, resulting in a difference in elongation and poor shape. leading to, in extreme cases, perforation,
This causes the drawing area 9 to become unable to be rolled. FIG. 6 is an explanatory view showing the main part of the situation in which sheet deviation occurs when such rolling is performed. In particular, when this needs to be formed by multi-stage rolling, the effect is significant. In FIG. 5, 5 represents the center of the roll convex portion, 6 represents the center of the rolled material recess, and 7 represents the size of the plate side. Here 1
B indicates the part that is subjected to excessive reduction, and B indicates the area that is under-reduced. In this way, there is a difference in the reduction ratio between parts A and 8, and this causes a difference in elongation in the longitudinal direction, resulting in a local shape. Defects occur and in extreme cases, rolling becomes impossible.

Therefore, in the case of multi-stage rolling of such a deformed steel plate, it is essential to ensure the shape of the rolled material to be passed through all the stands continuously and stably in the center under an optimal rolling schedule.

The present invention was developed in view of the current situation, and provides a stable threading technique during multi-stage stand caliber rolling, which is necessary for manufacturing irregular cross-section steel sheets with a wide range of thickness differences in the strip width direction. This is to prevent shape defects.

(Means for Solving the Problems) The present invention provides extra thickness on both sides of a material to be rolled in which one or more strips of irregular cross-section steel plates are rolled at the same time, and the roll for 10,000 rolling has an inclined surface formed by a roll caliber. It has a presser foot with a self-aligning type. FIG. 2 is an explanatory diagram showing an embodiment in which a misfire occurs.

Generally, a steel plate with an irregular cross section is rolled in multiple strips, but in FIG. 2, all 12 strips of Tr are shown.

In FIG. 2, numerals 8 and 8' are extra thickness parts provided on the material to be rolled, and 9.9' is a holding part by the roll caliber. Extra flesh part 8, 8'l'! Since the roll surface is inclined when it comes into contact with the holding parts 9 and 9' and is rolled, the rolled material 4 receives the same reaction force F toward the center of the rolled material at both edges, respectively.
Receive F' from the roll. Here, if we consider the case where the material to be rolled 4 shifts in one direction, for example, to the right in the figure, there is sufficient extra thickness 8' in the presser part 9' on the side where it shifts, but the shifted section 9 on the opposite side The excess thickness 8 no longer adds light to the roll, and the rolling element of the presser part becomes larger from the closer side and becomes smaller on the opposite side. Therefore, the balance between the rolling reaction forces r, r' of the presser part and the reaction forces F, F' in the center direction applied to the rolled material becomes larger on the closer side.

This means that the rolled material 4 is prevented from escaping outward at the edge portion, that is, a self-aligning action occurs.

Next, we will give a thorough explanation of the inclination angle of the holding parts 9 and 9'. From the point of view of the self-aligning function, the effect is small when the inclination angle is less than a certain value within the cross-sectional shape of the rolled material 4.

In addition, if that part is not to be used as a product, from the viewpoint of yield, it is better to have as little extra flesh as possible, so it is desirable to narrow the hole and make the angle as steep as possible.

On the other hand, in terms of sheet threadability, the steeper the angle, the greater the change in the rolling reduction of the biting part for the same amount of sheet yomi.In other words, the difference in elongation increases, the deterioration of the shape becomes severe, and the sheet slanting becomes extremely large. In some cases, the excess wall portion may not be caught in the holding portion.

Therefore, in consideration of one or more points, the angle f of the holding portion is set to be greater than Iff or greater than the inclination angle of the cross-sectional shape of the material to be rolled.

Regarding the relationship between the width of the presser foot and the excess thickness, 1.
Either make them coincide with each other, or make the width of the excess portion slightly narrower than that of the sub-section of the presser part 9. This frame is necessary in order to prevent the extra thickness protruding outward from the presser portion from being rolled and reduced in the narrow roll gap of the flat roll portion. Otherwise, local elongation will occur at the edge portion, resulting in ear waves, which is inappropriate.

However, if the width of the presser part is significantly narrower than the width of the excess thickness, the excess thickness will not fill part of the caliber, and the reaction forces F and F' to the cross-sectional shape of the rolled material during rolling will become smaller. .

In other words, the self-aligning effect is weakened.

Therefore, it is desirable to make the excess thickness match the length of the holding part, or to set the excess thickness to be slightly shorter. It is necessary.

As described above, according to the present invention, the presser part 9゜9' consisting of an inclined surface is provided on the roll involved in rolling a steel plate of irregular cross section, and this mechanism causes the self-aligning function of the rolled material itself. This prevents the sheet from shifting and enables stable sheet threading. This effect is particularly noticeable when the rolled material is stably passed at high speed in a rolling method in which a multi-stand roll is equipped with a caliber and continuous rolling is carried out to roll a steel plate with an irregular cross section. Figure 3 shows the cutting situation of the two-strip irregular cross-section steel plate illustrated in Figure 2.
Reference numeral 10 indicates a section cut by a slitter or the like.

Regarding the cross-sectional shape, in addition to the shape shown in Figure 1, a modified cross-section steel with thinner sides and a thicker center as shown in Figure 4, and other similar modified cross-section steel plates are assumed. It is also applicable to the present invention.

(Example) In the finishing stand of a continuous hot rolling mill, 5 stands of rolls with calibers engraved on the upper roll were installed, and the finished shape had a plate width, that is, a pitch P of 2UUm and a thickness lt: 3.
．． The irregular cross-section steel plate shown in FIG. 1 was rolled at OW t2=2.0 wm.

At this time, in order to make maximum use of the roll barrel, three stripes were used. As a result, the product plate size was 600 square meters, and rolling was carried out by adding extra thickness of 30 w on each edge of this mill. As a result, a modified cross-section steel plate with a good shape could be manufactured.

The rolling speed was the same as that of ordinary flat plate rolling, and high-speed threading was possible.

(Effects of the Invention) The present invention makes it possible to roll a steel plate with a different cross section of each stock, which conventionally could only be caliber rolled in one stand, even when calibers are carved in multiple stands in a continuous hot rolling mill. This is an industrially extremely significant invention that enables the mass production of steel plates with particularly wide pitches and thickness differences.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing an example of a steel plate with a modified cross section according to the present invention. Figure 2 is an explanatory diagram showing an embodiment of the present invention. An explanatory diagram showing the mode of obtaining the desired irregular cross-section steel plate from the rolled material, @ Figure 4 is an explanatory diagram showing another embodiment, Figure 5 is an explanatory diagram showing the conventional rolling situation, and Figure 6 FIG. 3 is an explanatory diagram showing a shift phenomenon. Agent Patent Attorney Masaaki Aki Sawa Mitsugai 1 person + 1 figure, +5e Naka 611ri

Claims (1)

[Claims] (1) When rolling a steel plate with an irregular cross section using a continuous hot rolling mill for thin plates, extra thickness is provided on both sides of the rolled material that is rolled one or more strips at the same time, and the rolls involved in the rolling are provided with extra thickness on both sides. A method for stable rolling of a steel plate with an irregular cross section, characterized in that a holding part consisting of an inclined surface is provided at a position where the extra thickness part is abutted and rolled, and rolling is performed while causing a self-aligning action in the material to be rolled.