RU1809786C - Method of metal strip hot rolling - Google Patents

Abstract

Usage: in a reversing stand of a mill equipped with primary and secondary furnace winders connected by a heating tape. SUMMARY OF THE INVENTION: in each successive heating cycle, the place of contact of the strip with the tape heater is changed at the moment of their joint winding on the main winder by pre-winding part of the heating tape on the winder and capturing the strip with its coils; at least in part: heating cycle ° joint coiling of the strips is carried out on an additional coiler. 1 s, p. f-ly, 1 ill.

Description

 The invention relates to methods for processing a metal sheet, namely, heating a sheet during rolling on mills equipped with furnace winders and can be used for hot rolling of metal strips; The aim of the invention is to increase the intensity and uniformity of heating of the processed strip.

, The drawing schematically shows a mill on which the proposed rolling method is implemented. It is similar to that described in the prototype, but, as can be seen from the figure, here the rotation directions of the coilers (indicated by arrows) are changed. In the furnaces 1 of the sheet reversing stand 2, the main and additional winders 3 and 4 are arranged in pairs, on which there is a heating belt 5 and a processing one. lbsa 6. The ends of the heater ribbon are fixed on adjacent winders, the rotation of which is synchronized with each other. This tape, which is constantly in the furnace, having a temperature higher than the required heating temperature of the strip being treated, when co-winding with the latter, carries out its rapid heating. The tape is made of heat resisting material. AT . During the rolling process, the processed.-elongated strip is usually no less than 3-4 times, therefore, the heating strip should be an appropriate number of times longer than the rolling tackle being rolled. Its length is performed not less than the length of the processed strip before the last | bypass (the finished strip into the oven is no longer routed) to ensure full, consistent winding of the strips. Its width can be taken equal to the width of the finished strip; thickness equal to 0.003-0.005 m depending on. the initial and final thickness of the rolled metal. i The proposed rolling method is as follows: the processed strip entering the furnace for heating for the first time is wound in the furnace in the same way as in the prototype method. The end of her capture

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one main winder and begin to lie in the last, completely reeling off a pole with a heating tape. Then, the heated olos with the opposite end is fed for rolling, while returning the tape heater to an additional winder. All is repeated in the opposite oven. In the same furnace, as soon as the processed strip leaves it, the part of the heating tape that came into contact with the processed strip is rolled onto a freed coiler. After that, when the last second time begins to enter the furnace, then it

the end is fed over the unwound part to the same winder between the upper turn and the unwound part of the tape. Immediately by rotation of this coiler, it is captured between adjacent turns of tape, two strips are rewound together and then the heated metal is again fed for rolling. The same steps are repeated in the opposite furnace. In subsequent heating cycles in

depending on the ratio of the lengths of the rolled and heating strips, you can use either the same technique, unwinding another chilled section, or rewind the heating tape on your coiler and rewind the strips on an empty main coiler if the previously used parts of the tape have already warmed up again . . . Part of the heating cycles by completely similar actions can be carried out on an additional winder, including by grabbing the end of the strip to be processed with an empty additional winder. To do this, at the time of a pause in heating, the heating tape is pre-rewound completely to the main winder. The drawing in the left furnace shows such a moment of winding two strips on an additional winder. N. not the opposite side — the strip being processed leaves the furnace after; heating on the main winder and at the same time the heating tape is wound onto an additional winder.

The use of joint winding of strips on an additional winder provides new opportunities for increasing the intensity and uniformity of heating. Here, the surface coils of the coil from the heating tape on the main winder go deeper when winding on the additional and vice versa. This provides the best conditions for warming up the strip as soon as possible and aligning the temperature along its length.

The proposed method also provides a significant increase in the heating intensity of the heater ribbon due to the fact that, when there is no processed strip, the heater coil is divided into two smaller rolls by rewinding, which heat up faster than when they are a whole (as at

prototype).

On the technical side, it is not difficult to ensure that the strip arrives at an additional coiler. For this purpose, movable adjustable guides of known designs can be used. The capture of the end of the strip by turns of a roll of heating tape is also quite reliable and simple. For this purpose, it is desirable that the angle between the winding

the strip and the unfolded part of the heater tape was sharp, which is also easy to ensure, for example, by installing a support non-drive roller between the winders, which would bend around the heater tape when rewinding (not shown).

It may happen that part of the strip to be processed has to be wound with a portion of the heater belt that has lost its heat in the previous heating cycle.

In this case, there will be no noticeable difference in heating if the section is small, Constant heat transfer will quickly equalize temperatures in relatively close sections of the roll (several adjacent turns).

GT r and m - e r. The proposed method can be rolled hot rolling with a temperature of 1000-1100 ° C from transformer steel with an initial thickness of 0.006 m, a width of 1.2 m and a length of 40 m into a strip of thickness

0.0015 m, the same width (after trimming) and a length of approximately 150 m in 5 passes, i.e. using 4 cycles of heating in the furnace, since hot tackle is fed per 1 pass, bypass the furnace. Rolling rate at

this will not be lower than in the known method (the same rolling speeds and pauses between passes). For each heating cycle, it is possible to ensure that the strip is heated by no less than 100-110 ° С, i.e. to produce rolling in the temperature range close to the temperature of the initial billet.

The heater tape is used with the following linear dimensions: 0.003 x 1, +150) m;

in the first and second heating cycles in both furnaces wind strips on free main winders. In the third heating cycle, the coils are coiled together on the main coiler with a preliminary

winding more during the absence of the heated metal of that part of the heating strip that gave off heat the previous time. Heating before the last pass is carried out by winding two strips on

free additional winder1.e, for

during heating pause, the heating tape is pre-wound on the main winder.

When processing the next billet coming in again for rolling, it is possible to change the indicated heating scheme, taking into account the heating scheme of the previous rolling

The proposed method is especially effective when rolling strips of metals and alloys requiring both a high rolling temperature and a relatively narrow temperature range in which it is carried out. For example, when rolling transformer and other hardly deformed steels and alloys. By intensifying the heating of the strips and increasing its uniformity, it will increase the rolling productivity and the quality of the finished product.

Claims (2)

1. The method of hot rolling a metal strip, including reversible 0 5 rolling in a pair of rolls and alternately unwinding and unwinding the strip with the main furnace winders, when the strip is rewound together with a heater tape pre-wound on an additional furnace winder, characterized in that, in order to increase the intensity and uniformity of heating of the processed strip, each successive heating cycle, the place of contact of the strip with the heater tape is changed at the moment of their joint winding by preliminary winding on the main winder from an additional winder part of the heater tape and grabbing the strip with its turns. 2. The method according to claim 1, with the fact that at least in part of the heating cycles the joint winding of the strips is performed on an additional winder.