JPS6152915A - Plate rolling method by work roll shifting mill - Google Patents

Abstract

PURPOSE:To prevent the worsening of a plate crown by forecasting a roll crown profile from the arithmetic values of the abrasion profile of a work roll and the heat crown profile and by selecting the change and stoppage of a roll shifting based thereupon. CONSTITUTION:A rolling load and rolling length are measured by a load cell L and roll revolution meter R and further the temp. of the material to be rolled by a thermometer T. The abrasion of a work roll 1 is calculated by the prescribed equation with inputting these detecting signals into a computer C. The heat crown of the roll 1 is calculated by the computer C from the temp. detected value and rolling and pitching times then. The profile of a roll crown is forecasted on each rolling from the calculated both profiles and at the time when this forecasted profile is made a recessed crown the selection of the shifting change and stoppage is performed. The worsening of a plate crown is prevented simply and effectively with said method.

Description

Detailed Description of the Invention (Industrial Field of Application) The technical content described in this specification regarding a plate rolling method in a work roll shift mill is to prevent deterioration of plate crown resulting from continued rolling under work roll shift. This is where we propose the results of development research on how to avoid this.

(Prior Art) A work roll shift mill is aimed at flattening roll wear Frt and alleviating roll chance during plate rolling.

However, if the work roll shift continues throughout one cycle, that is, from a roll change to the next roll change, the plate crown will increase in the latter half of the cycle. In other words, although the absolute value of roll wear is large in the latter half of the cycle, it is smoothed out, so roll wear is the most important factor! Transfer to the cutting board crown is the cause of the increase in the board crown, but no reports have been found regarding this point.

PROBLEM TO BE SOLVED BY THE INVENTION It is a problem in rolling plates in work roll shift mills to advantageously avoid an increase in the plate crown in the latter half of the cycle.

(Means for solving the problem) By appropriately predicting the changes in the roll profile of the upper and lower work rolls for each rolling, taking into account the causes of the increase in the plate crown described above, and by appropriately predicting the changes in the roll profile of the upper and lower work rolls, It is an object of the present invention to prevent the plate crown from increasing by continuing or stopping the work roll shift depending on the properties of the subsequent rolled material at the time when the work roll shift is changed.

This objective is advantageously achieved by a configuration based on the following points.

When rolling a plate while shifting work rolls using a work roll shift mill, the wear profile and heat crown profile of the upper and lower work rolls are calculated for each rolling, the roll crown profile is predicted from both profiles, and this predicted profile is calculated. When the plate becomes a concave crown, the work whirl is further shifted or stopped depending on whether or not it is compatible with the shift change of the work roll, in which the subsequent rolled plate can be rolled only in the part immediately following the concave crown. This is a plate rolling method in a work roll shift mill, which is characterized by:

Here, as shown in Fig. 1, a pair of work rolls 1 are placed #
l. Using a work roll shift 3 with a backup roll 2 so as to shift along the axial direction perpendicular to the plane, the rolling load, rolling length 2, and temperature are measured by the load cell L and roll tachometer R. The temperature of each rolling object is measured by the meter T, and these detection signals are manually input to the computer C to determine the wear amount of the work roll 1, for example, the following formula (1) % formula % We: Radius wear per rolling roll Quantity P: Rolling load B: Plate width L: Plate thickness after rolling.

td: Contact arc length D: Roll diameter f: Advanced rate Ab double weight function plate end we (eage+=a-We 1--- (2) a
: Calculated by computer C according to the weighting function, and based on the above temperature detection value, rolling time and pitch time, work roll 1
The heat crown of is calculated using, for example, an axially symmetric difference equation or by Get Recomputer C.

In this way, the wear profile and heat crown profile of the upper and lower work rolls are calculated for each rolling, the roll crown profile is predicted from both profiles, and when this profile becomes a concave crown, the properties of the subsequent rolled rolls are predicted. In particular, depending on the width, a shift change or a stop of the work roll is selected.

(Function) Fig. 2 shows an example of the relationship between the number of sheets rolled, the amount of shift, and the plate crown when rolling is performed by shifting the work rolls using a conventional work roll shift mill. As is clear from the figure, from the latter half of the cycle, as the roll shift continues, the plate crown becomes larger, and the plate width also becomes larger.

If the work roll shift is performed here, the roll wear is smoothed out, and as a result, the wear profile changes greatly as shown in Figures a and b, compared to the case where the work roll shift is not performed.

When rolling is carried out using a roll with a worn profile as shown in Fig. 2 (a), when the work roll is not shifted as shown in Fig. 4 (Fig. 4 (b)) and when it is carried out. (The crown transferred to the plate is different from the one shown in FIG. 2(a)).

At this time, the relationship between the plate width Wo and the roll flat portion WR after the shift is W. It is clear that WR will not deteriorate the crown of the board.

By the way, regarding the area shown in Fig. 2, the dependence relationship between the amount of roll wear and the number of rolling sheets of the plate crown 5: As a result of the investigation, the result is as shown in Fig. 5. A is heat crown and low/I/IM
It turns out that this means that the wear k is equal.

Next, an example of a similar dependency relationship when the roll has an initial crown (as shown in FIG. 6), where a convex crown is shown as positive and a concave crown is shown as negative.

From FIG. 6, it was found that point A is the point where the roll crown changes to a negative C convex) crown.

Roughly speaking, the relationship between rolling pitch and roll crown is as shown in Figure 7, and it is clear that the growth rate of heat crown differs depending on the rolling pitch, so when the rolling pitch is fast, point A shifts to the rear of the cycle. Ta.

In this way, it is possible to calculate the rolling load, rolling length, low/L/abrasion, and heat crown according to the instructions of the thermometer online on the computer O, and calculate the roll profile for each rolling. From the point when the work roll-shift amount exceeds Wc shown in Fig. 4,
If the relationship of WR is controlled so that Wc<WR, plate crown can be prevented.

(Example) Referring again to FIG. 1, the rolling load and rolling length are calculated from the load cell L and roll tachometer R, and the work reel 1 is
The amount of wear is calculated by the calculator 5 using equation (1).

Further, the temperature of the rolled material is measured with a thermometer 8, and the heat crown of the work roll 1 is calculated from this, the rolling time, and the pitch time by the calculator 5 using, for example, an axisymmetric difference equation.

Figure 8 does not show the calculation results of the roll wear amount and heat crown profile for the 10th and 25th rolling rolls, but the roll crown profile is shown in Figures 6 and 7 based on the calculated roll wear amount and heat crown profile. In A
If it exceeds the point, either stop performing the roll shift or change the shift amount of the roll shift device 6 to WG <
By controlling to achieve WR, the increase in the plate crown can be suppressed. (Effects of the Invention) According to the present invention, deterioration of the plate crown can be easily and effectively prevented.

[Brief explanation of drawings]

Fig. 1 is a skeleton diagram of the actual IM rabbit of this invention, Fig. 2 is a graph of the relationship between the number of rolls and plate crown in work roll shift rolling, and Fig. 8 is a graph showing the relationship between the number of rolls and plate crown in work roll shift rolling. An example of roll wear caused by a puro file? Fig. 4 is an explanatory diagram of the rolled portion when the work roll shift amount is 0 and maximum; Fig. 5 is a graph of the relationship between plate crown, roll wear, and heat crown; Fig. 6 Figure 7 shows the relationship graph between heat crown, roll wear, initial crown and roll crown, and Figure 7 shows the change in roll crown due to rolling pitch. ...Work roll 2...Load cell 3...
・Radiation thermometer 4... Integrating tachometer 5... Total n
m e... Work roll shift device. Patent Applicant: Kawasaki Steel Co., Ltd. Fig. 2 Fig. 3 (a) (b)' 1-N Fig. 6 Fig. 7 Fig. 8; ↑ Rolled coil width I225 Three-speed coil width off the shoulder // 72 m ~ side

Claims (1)

[Claims] 1. When rolling a plate while shifting the work rolls using a work roll shift mill, calculate the wear profile and heat crown profile of the upper and lower work rolls for each rolling, and calculate the roll profile from both profiles. The profile of the work roll is determined by predicting the profile of the crown, and determining whether or not the predicted profile is compatible with the shift change of the work roll that allows the subsequent rolled plate to be rolled only on the straight portion of the concave crown when the predicted profile becomes a concave crown. A plate rolling method in a work roll shift mill, characterized by selecting shift changes and stops.