JPS62183903A - Rolling method for thick plate - Google Patents

Abstract

PURPOSE:To smooth roll profiles and to improve rolling efficiency by stepwise shifting a pair of upper and lower work rolls in the axial parting direction thereof at every pass of a material to be rolled. CONSTITUTION:The upper and lower work rolls 2, 2' backed up by a pair of upper and lower back up rolls 1, 1' are axially shifted at every pass in the direction where the rolls part from each other. The wear loss of the rolls 2, 2' in this stage is max. at the down stream end in the shift direction and max. at the upper stream end and the wear of the rolls is axially dispersed between said ends. The profiles of the rolls 2, 2' are, therefore, smoothed and the schedule for rolling sequence can be made regardless of sheet widths. The profiles of the work rolls 2, 2' are smoothed and the rolling efficiency is improved by the above-mentioned method.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a method for rolling thick plates.

[Prior art and its problems]

Conventionally, when rolling a steel plate, the work roll is shifted in its axial direction to prevent local wear of the work roll and thus to smooth the work roll profile, which has already been put to practical use in hot strip mills and the like. ing.

That is, in a hot strip mill, the edge of the work roll and the edge of the strip are aligned, and the work roll is shifted slightly along the axial direction around the edge of the work roll to reduce local wear and tear on the edge of the IJ tube. The aim was to prevent strip edge drop.

Further, as another method for preventing local wear of the strip, there is a method of periodically changing the passing position of the strip on the work roll for each strip.

However, when the above-mentioned method is applied to rolling a thick plate, there are the following problems. That is, in plate mills, it is necessary to perform reverse rolling and roll multi-rolled plates with significantly different widths. As a result of the increased shift amount of the work roll, a long work roll is required. Therefore, the above-mentioned method cannot be directly applied to rolling thick plates. For this reason, when rolling thick plates, it is necessary to establish a schedule in which rolling is performed in order from wide to narrow plates, resulting in a decrease in rolling efficiency.

[Purpose of the invention]

The purpose of this invention is to distribute the wear of the work rolls of a plate mill along the axial direction of all the rolls, thereby smoothing the work roll profile, and thus making it possible to schedule the rolling order without depending on the width of the plate. An object of the present invention is to provide a method for rolling thick plates.

[Summary of the invention]

In the present invention, when a material to be rolled is reverse rolled by a plate mill, a pair of upper and lower work rolls of the plate mill are shifted stepwise in a direction away from each other in the axial direction for each pass of the material to be rolled. In this way, the wear of the work roll is distributed over the roll axis direction, and the profile of the work roll is smoothed.

[Structure of the invention]

The rolling method of the present invention will be further explained with reference to the drawings.

FIG. 1 is a sectional view showing a state in which a material to be rolled is being rolled by the method of the present invention.

As shown in Figure 1, a pair of upper and lower backup rolls 1
, 1', a pair of upper and lower work rolls 2.
2' are shifted stepwise in the direction away from each other in the axial direction for each pass of the rolled material 3.

By shifting the pair of upper and lower work rolls 2+z' in this way, the amount of wear on the work rolls 2 and 2' is
The downstream end of the shift direction is the maximum, and the upstream end is the minimum, but
During this period, the wear of the roll is distributed in the roll axis direction. Therefore, the profile of work roll 2.2' is:
It is smoothed as shown in FIG. FIG. 2 shows an example in which the work rolls 2 and 2' are shifted in three stages, and the diagonal lines indicate the worn parts of the rolls.

The profile of the work roll 2.2' is smoothed as shown in Figure 2, so even if a narrow strip is completely rolled, a wide strip is rolled, or even the same strip is rolled. After concentrating and rolling a wide material to be rolled, a steel plate with a smooth profile can be obtained even if a wide material to be rolled is rolled.

Next, the plate thickness is 150m, the plate width is 3000m, and the length is 3400r.
When a rolled material of RA was rolled by the method of the present invention, the profile was smooth, the thickness was 15 cm, and the width was 3000 mm.
．． , length 34000. A steel plate was obtained. The relationship between the rolling load at this time, the shift amount of the work roll, the bending force of the work roll, and the return thickness of the rolled material is shown in FIG.

As shown in Fig. 3, the reason why the bending force of the work roll is increased near the final pass is to completely smooth the profile of the steel plate by controlling the crown of the work roll. According to the method, since the edge of the rolled material coincides with the edge of the work roll near the final pass, crown control by the work roll can be easily performed.

〔Effect of the invention〕

As explained above, according to the present invention, the wear of the work roll is dispersed along the roll axis direction and the roll profile is smoothed, so that the roll profile is smoothed from the widest to the narrowest, unlike the conventional method. There is no need for rolling, and the rolling order can be scheduled regardless of the strip width.Moreover, as the edge of the material to be rolled approaches the edge of the work roll as it approaches the final pass, crown control by the work roll is possible. This brings about the Ishikawa effect of making it easier to perform.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a state in which the pressed daughter material is rolled by the method of the present invention, FIG. 2 is a cross-sectional view showing a state in which work roll gold is shifted by the rolling method of the present invention, and FIG. The figure is a graph showing the relationship between the rolling load, the shift amount of the work roll, the bending force of the work roll, and the plate thickness of the material to be rolled. In the drawings, 1, 1'... Backup roll, 2.2'... Work roll, 3... Rolled material.

Claims (1)

[Claims] When reverse rolling a material to be rolled by a plate mill, a pair of upper and lower work rolls of the plate mill are shifted stepwise in the axial direction away from each other for each pass of the material to be rolled, and thus, A method for rolling a thick plate, characterized in that wear of the work roll is distributed along the axial direction of the work roll to smooth the profile of the work roll.