JPS6011565B2 - Method for preventing plate width fluctuation of rough rolled material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing strip width variation of a raw material during rough rolling.

In a hot rolling line, a slab heated in a heating furnace is first roughly rolled and then sent to the finishing rolling process.In the rough rolling process, vertical width cutting (treading) rolling is performed at the same time as horizontal rolling. The board width is determined.

To set the plate width, a hard roll set at a predetermined width position is engaged with both the left and right twill parts of the material, and the material is rolled in the width direction with a uniform reduction amount to make the material width uniform. ing. However, the heating slab has low-temperature skid marks added in the heating furnace at regular intervals,
Only this skid mark portion is harder than other non-skid portions, and therefore has greater deformation resistance. Therefore, when width reduction rolling is performed with a constant reduction amount, strip width fluctuations occur between the skid part and the non-skid part of the material. Although rolling progresses to the center, in the cold and hard skid section, rolling does not progress effectively to the center of the sheet width, resulting in a dog-bone shape at both edges. For this reason, when the material after width reduction is rolled with horizontal rolls, dog
Only the skid portion with large bones was rolled to a wide width, increasing the difference in overall sheet width variation, which was a factor leading to a decline in the production rate of the finished product. An object of the present invention is to provide a means for preventing the occurrence of such sheet width fluctuations, thereby improving sheet width accuracy and improving product quality.

The main aim of the present invention is to change the rolling amount of the vertical rolls between the skid part and the non-skid part of the rough rolled material, to engage the skid part with a large rolling force and to engage the non-skid part with a small rolling force. The width reduction amount is made uniform by engaging the rollers at 1, and the reduction amount is adjusted without changing the position of the hard roll.

In the method of the present invention, the apparent width of the non-skid portion where rolling resistance is small is formed in advance to a small width, and the shoring force of the hard roll for width reduction acts particularly effectively on the skid portion. Configure it as follows.

That is, in a rough rolled material 1 having a skid part 11 and a non-skid part 12 as shown in FIG. 1, the apparent width of the non-skid part 12 is reduced to a predetermined width W in advance. . The reduction of the plate width added to the non-squipped portion 12 is as follows:
It does not further reduce the actual board width dimension Wo,
As shown in FIG. 2, by curving the material itself in the board width direction, the apparent board width is narrowed and the board width is kept close to the width reduction setting dimension.

As a means for bending the rough rolled material 1, for example, as shown in FIG. 3, a set of three rolls, one on the upper side and two on the lower side, are combined in a staggered position, and either the upper or lower roll is assembled. By rolling down the roll or both rolls simultaneously, the material 1 sandwiched between the rolls is curved in the width direction. In principle, this bending roll mechanism 2 is installed on the inlet side of the hard roll for width reduction in the stand at the latter stage of the rough rolling line, but in the case of reverse rolling, as shown in FIG. It may be provided on both sides. The process of performing width reduction rolling based on the method of the present invention will be described next.

The rough rolled material 1 is engaged with the bending roll mechanism 2 on the entry side of the hard roll 3, and the bending reduction is uniformly applied only to the non-skid portions 12, excluding the skid portions 11. Therefore, as shown by the imaginary line in FIG. 1, only the portion excluding the skid portion 11 is curved, and the apparent width of this portion is reduced. The material formed in this way is immediately introduced into a hard roll and rolled down in the board width direction.

At this time, the vertical rolls are set to have a rolling force suitable for rolling down the skid part 11 to a predetermined board width, and roll down the skid part 11, which is a relatively hard part, to a predetermined board width dimension. At this time, the non-skidded part 12, which is a softer part than the skidded part 11, has already been curved, reducing the apparent board width and escaping inward from the engagement surface of the hard roll. It is in a state where it is not greatly affected by width reduction rolling by rolls, and therefore the metal flow phenomenon caused by rolling is kept to a minimum. In the material whose width has been reduced through such a width reduction process, there is a skid part 11 where metal flow problems are less likely to occur, and a non-skid part 12 where metal flow is minimized by curving. Since width reduction is performed while the excess thickness remaining in the plate remains almost uniform, there is no unbalanced flow of excess thickness in the subsequent horizontal rolling process using horizontal rolls, and the plate is rolled to a uniform width. .

As described above, according to the method of the present invention, it was possible to effectively prevent variations in the strip width in a roughly rolled material having a skid portion, improve the strip width accuracy, and improve the walking distance.

In addition, in the process of bending the material in the width direction of the plate, scale generated on the material can be peeled off, so it also has a secondary effect as a descaler. By the method of the present invention, it is possible to prevent the decrease in the width killing effect due to buckling when the par thickness is small, which is a drawback of conventional AWC (width dimension control/opening/closing of hard rolls).

That is, the conventional AWC cannot be used in the latter stage of rough rolling, but the method of the present invention can be used.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a roughly rolled material before width reduction in which only the non-skid portion is deformed based on the method of the present invention. FIG. 2 is a sectional view taken along the line 0--RO in FIG. 1. FIG. 3 is an explanatory diagram of a curved rolling process based on the method of the present invention. Figure 4 is the third
FIG. 3 is a side view showing the curving roll shown in the figure in a state where it is incorporated into a width cutting process. 1: Assembled rolled material, 2: Curving roll mechanism, 3:
Ken〇1're. Figure ′ and Figure J Figure 4

Claims (1)

[Claims] 1. A roll mechanism for bending the rough-rolled material in the strip width direction is provided at the entrance position of the hard rolls in the rough-rolling line, and in the process immediately before width rolling using the hard rolls, a roll mechanism is provided for only the non-skid portion of the rough-rolled material. A method for preventing plate width fluctuations in roughly rolled material, which comprises reducing the apparent width of the plate by imparting a certain amount of curvature in the width direction of the plate, and setting the amount of reduction of hard rolls targeting the skid portion.