JP2553186B2 - Cold rolling method for austenitic stainless steel strip - Google Patents

Description

The present invention relates to a cold rolling method for austenitic stainless steel strip, and more particularly to a cold rolling method for reducing rolling passes.

<Prior Art> Conventionally, in the cold rolling of an austenitic stainless steel strip, the coolant amount was a constant amount regardless of the pass as shown in Table 1 (for example, 5000 / min).

Therefore, there are passes that cool more than necessary among passes that do not increase the plate temperature, and it is difficult to reduce the number of passes. This situation is shown in FIGS. 2 (a) and 2 (b) as a conventional example for SUS304. As can be seen from FIG. 2 (b), the third, fourth,
The surface temperature of the steel strip in the 5th or 7th pass is low
As shown in the figure, induced martensite occurs as a phenomenon unique to austenitic stainless steel. That is, when the surface temperature of the steel strip is too low or the rolling reduction is high, the amount of martensite is increased and the steel is hardened. Therefore, it is difficult to reduce the number of passes because the reduction rate is restricted from increasing.

<Problems to be Solved by the Invention> The present invention solves the problems of the prior art and provides a rolling method for an austenitic stainless steel strip which reduces the number of rolling passes and improves productivity. To aim.

<Means for Solving the Problems> In the present invention, when cold rolling an austenitic stainless steel strip, the flow rate of the coolant is changed for each rolling pass.

<Operation> In the present invention, the coolant supply amount during rolling is set to an amount suitable for the rolling pass, the surface temperature of the steel strip is not overcooled more than necessary, and the rolling reduction is maximized to reduce the number of passes. This is intended to improve productivity.

That is, the productivity is improved by the following procedure. Optimize the amount of coolant for each pass by controlling the coolant valve opening for each pass → Optimize the surface temperature of the steel strip for each pass → Improve the reduction rate for each pass → Finally reduce the number of passes To improve productivity.

<Example> FIG. 1 shows an outline of an example in which the present invention is applied to reverse rolling. In the case of reverse rolling, the stainless steel strip 1 is rolled by the work roll 4 and reels 2, 3
Are alternately wound up and cold-rolled to a predetermined thickness. During rolling, the coolant is supplied to the bite portion of the work roll 4 through the supply pipe 5 to prevent an excessive temperature rise.

In order to specifically implement the method of the present invention, the surface temperature of the steel strip is measured by the plate temperature measuring device 11 as shown in FIG. 1, and the number of passes and the appropriate plate temperature stored in the control device 10 are measured by the signal. Output the opening signal of the valve 6 defined by the range,
The amount of coolant can be controlled. In addition, 7 is a receiving tank, 8 is a filter, and 9 is a coolant recovery pump.

To improve the rolling productivity, that is, reduce the number of passes,
It is necessary to improve the reduction rate in each rolling pass.
For that purpose, generation of induced martensite during rolling of austenitic stainless steel strip must be avoided.
In order to increase the rolling reduction and prevent the generation of martensite, the surface temperature of the steel strip should be as high as possible, as can be seen from FIG. However, if the surface temperature of the steel strip becomes too high, problems such as coolant deterioration and steel plate shape defects will occur.
Is the rise.

Table 2 shows an example in which the present invention is carried out by changing the supply amount of the coolant amount in each pass. A graph of this data is an example of the present invention shown in FIGS. 2 (a) and 2 (b). Here, SUS304 with a thickness of 4 mm was inter-rolled to a final plate thickness of 0.8 mm using a coolant of mineral oil. In the conventional example, since the amount of coolant is 5000 / mim regardless of the path, it can be seen that the surface temperature of the steel strip is cooled more than necessary, as shown in FIG. 2 (b). The required number of passes was 9 passes.

However, in the present invention, Table 2 or FIG.
As shown in (b), the temperature of the steel strip surface is not unnecessarily cooled by changing the amount of coolant for each pass, so that it becomes possible to finally roll to a predetermined thickness in 8 passes, It is clear that productivity can be improved by reducing the number of passes, which is the object of the present invention.

<Effects of the Invention> As described above, according to the present invention, the coolant amount is changed for each pass so as not to cool the surface temperature of the steel strip unnecessarily in each pass. It is possible to secure a high reduction ratio in the steel sheet, reduce the number of rolling passes, and improve productivity.

[Brief description of drawings]

FIG. 1 shows an outline of an embodiment in which the present invention is applied to reverse rolling. FIGS. 2 (a) and 2 (b) are graphs showing a situation in which the number of rolling passes is reduced by controlling the amount of coolant for each pass in the case of applying the present invention to SUS304 in comparison with the conventional case. . FIG. 3 is a graph showing the relationship between the plate temperature and the amount of martensite in the rolling reduction. 1 ... Stainless steel strip, 2 ... Reel, 3 ... Reel, 4 ... Work roll, 5 ... Coolant supply piping, 6 ... Coolant amount control valve, 7 ... Receiving tank, 8 ... Filter, 9 …… Coolant recovery pump, 10 …… Coolant control device, 11 …… Plate temperature measuring instrument.

Claims (1)

(57) [Claims] 1. A method for cold rolling an austenitic stainless steel strip, characterized in that, when cold rolling an austenitic stainless steel strip, rolling is performed by changing a coolant flow rate for each rolling pass.