JP2730711B2 - Cold rolling of metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cold rolling a metal strip, and more particularly to a method for cold rolling a metal strip in which the rolling efficiency is enhanced by adjusting the sheet temperature of the metal strip.

[0002]

2. Description of the Related Art Conventionally, for example, in cold rolling of a stainless steel strip in a reverse rolling mill, supply amounts of roll coolant and strip coolant are determined from an upper limit of a sheet temperature with respect to a maximum value of a rolling speed, and supplied as a constant amount. Had been done. Therefore, in the pass in which the rolling speed does not reach the maximum value, the roll coolant and the strip coolant are excessively supplied, and the sheet temperature is reduced, the deformation resistance of the sheet is increased, and the rolled sheet thickness does not become a predetermined value and the number of passes is increased. And an optimal pass schedule that maximizes the rolling efficiency has not been realized. Particularly in the case of austenitic stainless steel, hardening is severe due to the unique phenomenon that induced martensite is generated when the sheet temperature decreases.According to JP-A-2-220701, the coolant flow rate is changed for each rolling pass. There has been proposed a rolling method in which unnecessary cooling is not performed. JP-A-2-220701
Pass schedule and sheet temperature shown in
Table 1 shows the coolant amount. This is the base plate thickness 4.0
0.8mm austenitic stainless steel (SUS304)
The width is 1023 mm.

[0003]

[Table 1]

According to this rolling method, although rolling is performed while changing the amount of coolant in each pass to a predetermined optimum amount, there is still a variation in the range of 90 to 180 ° C. from the sheet temperature, and It cannot be said that rolling is performed under the conditions. The base plate thickness, base plate deformation resistance, stop time between passes, etc. vary somewhat from coil to coil, and it is considered that such a difference in plate temperature occurs. It must be rather large.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, and maintains the sheet temperature as high as possible as long as there is no quality problem, and always realizes efficient rolling under optimum conditions. The aim is to provide a method.

[0006]

According to the present invention, in a method for cold rolling a metal strip, the temperature of the metal strip being rolled is detected, and the temperature of the metal strip becomes as high as possible within a range not exceeding a target value. Thus, there is provided a method for cold rolling a metal strip, wherein the strip coolant flow rate, the roll coolant flow rate, and the rolling speed are adjusted in this order.

[0007]

According to the present invention, the sheet temperature in the pass is directly detected by a thermometer, and if the sheet temperature is lower than the maximum value of the sheet temperature previously obtained from the deformation resistance, the amount of coolant is limited. If the conditions (whether there is no possibility of occurrence of defective shape or breakage of the sheet) are allowed, the rolling speed is increased. Conversely, when the detected sheet temperature is higher than the previously determined maximum sheet temperature, the coolant amount is increased or the rolling speed is limited. In this way, rolling under optimum conditions at the maximum sheet temperature is always realized, and the rolling reduction per pass can be increased, so that the number of rolling passes is reduced and the rolling efficiency is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the rolling method of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a cold rolling facility according to this embodiment, 1 is a tension reel, 2 is a deflector roll, 3 is a rolling mill, 4 is a strip coolant nozzle,
5 is a roll coolant nozzle, 6 is a thermometer, and S is a steel strip. The steel strip S is rolled to a predetermined size by the rolling mill 3 while reciprocating between the left and right tension reels 1 and 1. The strip coolant nozzle 4 and the roll coolant nozzle 5 are provided in the same manner in the upper, lower, left and right directions.

FIG. 2 is a flow diagram showing an adjustment procedure for implementing the rolling method of the present invention in such a rolling facility. First, a target value of the sheet temperature at which the deformation resistance of the material to be rolled is small and heat scratch does not occur is set. The higher the target value, the more advantageous the rolling efficiency is, which is advantageous, but there is an upper limit because heat scratch occurs.

The minimum amount of the roll coolant is set based on the lubrication performance, the maximum amount is set based on the installed capacity, the minimum amount of strip coolant is set based on the performance of removing the deposits on the plate surface, and the maximum amount is set based on the installed capacity. , The plate temperature is detected, and adjustment is performed according to the flow of FIG. The adjustment is performed in the order of the strip coolant amount, the roll coolant amount, and the rolling speed. As a specific example, a case where austenitic stainless steel (SUS304) having a base plate thickness of 4.0 mm is rolled to 0.8 mm will be described. The board width is 1000 mm. Rolling was performed at a roll diameter of 90 mm and a rolling speed of 400 mpm (constant).

First, the sheet temperature target value is set to 170
° C. The roll coolant amount was set to 5000 to 9000 liters / minute, and the strip coolant amount was set to 3000 to 6000 liters / minute. First, as a comparative example, Table 2 shows the results of rolling by fixing the amount of roll coolant and the amount of strip coolant to the respective maximum amounts.

[0012]

[Table 2]

The sheet temperature was in the range of 90 to 180 ° C., and the rolling load was 700 to 800 t. On the other hand, Table 3 shows the results of rolling while limiting the amount of coolant while detecting the sheet temperature according to the present invention while keeping the same pass schedule.

[0014]

[Table 3]

In particular, it is recognized that the sheet temperature has increased after the last seven passes, and the rolling load is on average about
9% reduction. Therefore, although the same pass schedule was used here for comparison, when the pass schedule was reviewed from this result, it was found that rolling by eight passes was possible with one pass reduction in the case of the method of the present invention.

[0016]

According to the present invention, rolling is performed while maintaining the sheet temperature as high as possible as long as there is no quality problem, so that the rolling load is reduced and the rolling reduction per pass can be set to a large value. An excellent effect of reducing the rolling efficiency is obtained. About 7-9% for SUS 304, SUS
Even with 430, a 3% improvement in rolling efficiency can be seen.

Further, by controlling the sheet temperature to the target value, the thermal crown amount became constant, and the surface shape of the steel strip was stabilized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a cold rolling mill according to the present invention.

FIG. 2 is a flowchart showing an adjustment procedure in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tension reel 2 Deflector roll 3 Rolling machine 4 Strip coolant nozzle 5 Roll coolant nozzle 6 Thermometer S Steel strip

Claims (1)

(57) [Claims] 1. A method for cold rolling a metal strip, comprising detecting a temperature of the metal strip during rolling, and controlling a flow rate of a strip coolant and a roll so as to be as high as possible within a range where the temperature of the metal strip does not exceed a target value. A method for cold rolling a metal strip, comprising adjusting a coolant flow rate and a rolling speed in this order.