JPH05277533A - Method for controlling surface roughness of steel plate in temper rolling - Google Patents

Abstract

PURPOSE:To uniformize the surface roughness of a steel plate after temper rolling over all the length by automatically controlling a rolling load in accordance with a detected signal of roughness measurement so as to confine a measured value of roughness of a surface roughness measuring device provided on the outlet side of a roll mill within a prescribed area. CONSTITUTION:A detected signal of the measuring device 2 for steel plate surface roughness is outputted to a comparison arithmetic unit 3 to calculate a deviation from the target value of a preset steel plate surface roughness here. After this arithmetic output is transformed by a rolling reduction force controller 4 to a load varying value of each stand, prescribed rolling reduction forces are instructed to rolling down devices 5a, 5b. As a result, the surface roughness of the steel plate changing with wear of the work roll and with time can be measured on-line and simultaneously with it, the rolling load of each stand can be automatically controlled so that the surface roughness of the steel plate is confined within a prescribed tolerance and consequently, the uniform surface roughness can be kept under control all over the length of the steel plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the surface roughness of a steel sheet during temper rolling, and is particularly advantageously applied to obtain a temper sheet having a uniform surface roughness over the entire length in the rolling direction. It is a proposal for technology.

[0002]

2. Description of the Related Art Generally, it is important to control the surface roughness of cold-rolled steel sheet from the viewpoints of die galling resistance during pressing, paintability, and solder rise during canning. The pressure control roll is controlled by means such as roughness control. For example, it is a technique for controlling the roughness of the work roll of each stand of the temper rolling mill. This conventional technique is because the surface roughness of the steel sheet is proportional to the wear of the work rolls and gradually decreases as the rolling distance increases, as shown in FIG. On the other hand, in the conventional general method, in consideration of the above-described change with time of the surface roughness of the steel sheet,
The surface roughness of the steel sheet is regularly measured using a stylus type roughness meter offline, and the rolling load of each stand is adjusted by the manual intervention of the operator based on the measurement result. It was controlled so that it was within the allowable range.

[0003]

However, in the above-mentioned prior art, a sample is taken from a part of the steel sheet to measure the plate surface roughness, and the rolling force is controlled based on the measurement result to change with time (generally). However, it did not guarantee the surface roughness over the entire length of the steel sheet.

In recent years, it has become more common to perform annealing (continuous annealing equipment or hot dip galvanizing equipment) -temper rolling-continuous post-treatment. By the way, in such an equipment row, since the steel sheet is continuously temper-rolled at a high speed, if the surface roughness deviates from the reference value, in the above-mentioned conventional technique, the sampling is performed. It takes time to measure roughness (usually about 10 minutes). As a result, there is a problem in that the steel strip that has been temper-rolled before the failure indication is given becomes a defective product and the yield decreases. Further, the work of sampling-measurement of roughness is a relatively troublesome work, which has been a factor of increasing the operator load.

An object of the present invention is to solve the above-mentioned problems of the above-mentioned prior art, and to provide an automatic control technique for making the surface roughness of the steel sheet after temper rolling uniform over the entire length.

[0006]

[Means for Solving the Problems] The above object is to control the surface roughness of the steel sheet during temper rolling, and install a surface roughness measuring device on the exit side of the temper rolling mill to change the steel sheet momentarily. This can be realized by a method of continuously measuring the surface roughness and automatically controlling the load of each rolling stand based on the surface roughness detection signal so that the steel plate surface roughness becomes a target value.

[0007]

FIG. 2 shows an example of a temper rolling equipment train used for carrying out the method of the present invention, which is a two-stage quadruple temper rolling mill. In the figure, reference numeral 1 is a steel sheet passing plate, 2 is a steel plate surface roughness measuring device, and this device is disposed, for example, so as to face the passing plate material on the delivery side of the final stand. With this measuring device 2, the surface roughness of the steel sheet after temper rolling can be measured online.

The detection signal of the steel plate surface roughness measuring device 2 is output to the comparison calculation device 3 to calculate a deviation from a preset target value of the steel plate surface roughness. The calculated output is further converted into a load change value of each stand by the rolling force control device 4, and then a predetermined rolling force is instructed to the rolling devices 5a and 5b of each stand (note that the roughness is relative to the roughness). The influence coefficient of each stand rolling load is experimentally measured in advance because it varies depending on work roll roughness and steel plate surface hardness).

By adopting such a control method, it is possible to measure on-line the steel plate surface roughness that changes (decreases) with time as the work rolls 6 and 8 wear, and at the same time, the steel plate surface roughness is predetermined. The rolling load of each stand can be automatically controlled so that it falls within the target value of, that is, the allowable range, and as a result, it becomes possible to control and guarantee the uniform surface roughness over the entire length of the steel sheet.

[0010]

EXAMPLE An example in which the method of the present invention is applied to a stand quadruple type temper rolling mill shown in FIG. 2 will be described below.
In FIG. 2, the threaded steel plate 1 includes a first stand and a second stand.
Each sheet is temper-rolled by a stand and then wound up. At this time, the steel plate surface roughness measuring device 2 is installed on the exit side of the second stand. A specific example of this device is a surface texture measuring device using laser light disclosed in Japanese Patent Application Laid-Open No. 60-201204, which is a prior application of the same applicant.

Although the rolling load of each of the first and second stands can be controlled as the operation end of the roll rolling force, in this embodiment, the rolling load of the second stand is simplified in order to simplify the control system. Only changed.

An example in which the surface roughness of the steel sheet was controlled according to the method of the present invention was compared with the case where the conventional control method (manual intervention method by the operator) was used. The results are shown in FIG. 3 as the relationship between rolling distance and roughness variation. As the steel strip used for the temper rolling at this time, the steel plate for tinting shown in Table 1 was used, and the temper rolling was performed under the conditions shown in Table 2. In addition, the unit width load W (ton / mm) of the second stand
[= Load / plate width] change amount ΔW and steel plate surface roughness σ (μm
When the relationship of the change amount ΔRa of Ra) was previously obtained by an experiment, the relationship shown in FIG. 4 was obtained. (Δσ / ΔWT≈0.3 (μRa · mm / ton) Furthermore, in an actual operation, if the rolling load of the second stand is changed without any limitation, drawing or breakage is caused. Calculation is performed inside the rolling force control device 4 so as not to control over the range of 100 tons,
When it exceeds the limit, the control is stopped and the work roll replacement is displayed to the operator.

Considering the results of this embodiment, the control method of the present invention, as shown in FIG. 3, has a smaller change in the surface roughness of the steel sheet due to the rolling distance than the conventional method. It turns out that the method works. Also,
In order to change the surface roughness by the method of the present invention, even if the second stand load is changed, if it is changed within the range of ± 100 tons from the initial load, poor elongation and breakage reduction do not occur, and good results are obtained. It was also confirmed that temper rolling can be performed.

This embodiment is applied to the tin plate material steel sheet shown in Table 1, but not only that, the variation amount ΔW of the unit width load and the variation amount Δσ of the surface roughness of the steel sheet are determined for each steel type. If it is investigated in advance, it can be applied to other steel plates. Further, the load operation end may be a combination of a plurality of stands other than the two stands.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

As described above, according to the present invention, it is possible to reduce the change with time of the surface roughness of the steel sheet.
It is possible to guarantee surface roughness over the entire length of the steel sheet. Moreover, unlike the prior art, the operator does not need to perform the roughness measurement by sampling, and the operator load can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a rolling distance and a steel sheet surface roughness during temper rolling.

FIG. 2 is a schematic diagram of a temper rolling mill.

FIG. 3 is a diagram showing changes in plate surface roughness according to the control method of the present invention and the prior art.

FIG. 4 is a diagram showing a relationship between a change ΔW in width load and a change Δσ in steel plate surface roughness.

[Explanation of symbols]

 1 Steel plate 2 Steel plate surface roughness measuring device 3 Comparative arithmetic device 4 Rolling force control device 5a, 5b Rolling device

Claims (1)

[Claims] 1. A surface roughness measuring device is installed on the exit side of a temper rolling mill to measure a steel plate surface roughness, and the roughness is adjusted so that the measured value of the steel plate surface roughness falls within a predetermined range. A method for controlling the surface roughness of a steel sheet in temper rolling, which comprises automatically controlling a rolling load based on a detection signal of measurement.