RU2259244C2 - Reversible mill for production of thin not rolled strip - Google Patents

Abstract

FIELD: metal working.

SUBSTANCE: invention relates to reversible strip hot rolling mills. Proposed mill contains rolling group consisting of one or more rolling stands, two furnace coilers located before and after rolling group, two cutoff shears, transporting and working roll tables, and hot strip coiler. According to invention, one cutoff shears are arranged after first coiler in furnace before rolling group and other shears are located after rolling group before second coiler in furnace. Cutoff shears arranged after first coiler in furnace are of combination design to provided both stationary and flying cutting.

EFFECT: possibility of use of blanks manufactured at big mill aline with continuous cast blanks without cooling down.

2 ex, 3 dwg

Description

The invention relates to the field of metallurgical engineering, and in particular to reversible hot strip rolling mills that are installed in rolling shops of metallurgical plants for the production of thin hot rolled strips from slabs.

Known reversible mill according to US patent No. 5647236, MKI B21B 1/34, containing:

- one or two reversible rolling stands;

- two winders in furnaces located in front of and behind the reversing rolling stands;

- a coiler for winding a hot strip.

Obtaining a thin hot-rolled strip from a slab is carried out by reverse rolling in finishing stands as follows.

1. First, a slab with a thickness of 75 to 100 mm, obtained on a continuous casting machine and having straight ends after cutting on dividing scissors, is crimped to an intermediate thickness that can be wound onto one of the coilers in the furnace.

2. A strip of a given thickness is obtained as a result of finish rolling with winding of tackle on winders in furnaces.

The rolling technology in the mill does not provide for the cutting of strip ends, and accordingly there are no scissors for cutting the strip ends in the mill line.

Finishing rolling of the strip has the following features:

- on all passages except the penultimate, the strip is completely passed through the stands, and its rear end stops before entering the furnace winders;

- on the penultimate finishing pass, the rolling stops when the rear end exits the winder and before it enters the finishing stands;

- the last finishing pass is carried out when the strip is reversed and is accompanied by a dynamic adjustment of the stand to a given strip thickness;

- a strip with a thickened front end, after the last finishing pass, is wound onto a roll on a coiler of a hot strip.

The disadvantages of the described mill are as follows:

- limitation of technological capabilities due to the predominant use for rolling slabs obtained in thin slab continuous casting machines, and having straight ends after cutting on dividing scissors;

- decrease in yield due to the occurrence of a shortage in the penultimate finishing pass and a portion of the strip rolled in transition in the last finishing pass.

As a prototype, a reversing mill of the company Tippins, USA, drawing No. 92-0182-B was selected.

The mill contains the following equipment:

- one reversible rolling stand;

- two winders in furnaces located in front of and behind the reversible rolling stand;

- two detachable stationary scissors, one of which is located behind the first winder in the furnace in front of the reversing rolling stand, and the second behind the stand in front of the second winder in the furnace.

The finished product on the mill is formed into a roll on a coiler for winding a hot strip (not shown).

The rolling technology at this mill includes:

- rough reversible rolling of a slab obtained both in a continuous casting machine and in a crimping mill to obtain a rolling of intermediate thickness, which can be wound on one of the coilers in the furnace;

- fair reverse rolling with winding on coilers in furnaces;

- winding the strip after the last finishing pass to the coiler for winding the hot strip.

The rolling strip in the described mill has the following features:

- with reversible finishing passes, the back coiled and uneven end of the strip wound on the coiler in the furnace is cut off with stationary scissors when the strip stops before the coiler reverse.

Cutting off the non-standard end of the strip allows you to increase the yield of the roll in comparison with the analogue. At the same time, the presence of stationary scissors in the mill line, in addition to billets with smooth ends obtained from a continuous casting machine, can also supply billets with substandard uncut ends, which are expanded from slabs in rough stands, which expands the technological capabilities of the rolling mill in comparison with the analogue.

However, before rolling the workpieces transported from the roughing stands, it is possible to cut off the non-standard ends on stationary scissors only when these workpieces stop, for the time necessary to perform the cut, which increases the pause between roughing and finishing rolling, leads to additional cooling of the workpiece, and this worsens strip quality.

The basis of the invention is the task of improving the quality of the strip.

This problem is solved due to the technical result, which consists in ensuring the non-stop operation of the rolling mill when cutting on the go substandard workpieces obtained from thick slabs in roughing stands.

To achieve the technical result, a reversing mill containing a rolling group consisting of one or more rolling stands, two winders in furnaces located in front of and behind the rolling group, two cutting shears, and one cutting shear located behind the first winder in the furnace in front of the rolling group, the second - for the rolling group in front of the second winder in the furnace, transport and working roller tables, the winder for winding the hot strip, according to the invention, the cutting shears located behind the first winder in the furnace are made to combined with the possibility of both stationary cutting and flying cutting.

The rolling group, introduced into the formula, can include either one or several rolling stands depending on the final strip thickness and mill productivity, which does not affect the achievement of the technical result.

As a result of a comparative analysis of the proposed solution with the prototype, it was found that they have the following common features:

- rolling group consisting of one or more rolling stands,

- two winders in furnaces located in front of and behind the rolling group,

- two detachable scissors, with one scissors located behind the first winder in the furnace in front of the rolling group, the second - behind the rolling group in front of the second winder in the furnace,

- transport and working roller tables,

- a coiler for winding a hot strip;

as well as distinguishing features:

- detachable scissors located behind the first winder in the furnace are made combined with the possibility of both stationary and volatile cutting.

Thus, the proposed reverse rolling mill has new components, a new form of execution of these parts.

Between the distinguishing features and the achieved technical result, there is a causal relationship.

Due to the fact that the cutting scissors located behind the first winder in the furnace are made combined with the possibility of both stationary and flying cutting, it became possible in the mill to cut the workpiece both when it is stopped and to cut off-the-shelf ends of workpieces obtained from thick slabs in roughing stands and transported non-stop to the rolling group, which will prevent cooling of the workpiece and will lead to an increase in the quality of the finished strip.

At the same time, thanks to the implementation of combined scissors with the possibility of stationary cutting, the possibility of stationary cutting of the ends, which must be removed during reverse rolling of the strip with winding on coilers in furnaces, has remained.

The exclusion from the above set of distinctive features of at least one does not ensure the achievement of a technical result.

The claimed technical solution is not known from the prior art, therefore, it is new.

The claimed technical solution has an inventive step, since the proposed design of the reversing mill for a specialist does not explicitly follow from the prior art.

The claimed solution is industrially applicable, since its technological and technical use is not difficult. Using this technical solution, a preliminary design of the reverse mill of 1700 was completed. for the Enakievo Metallurgical Plant.

Thus, the claimed decision can be granted legal protection, since it is new, has an inventive step and is industrially applicable, i.e. meets all the criteria of the invention.

The claimed solution is illustrated by drawings, which depict the following:

figure 1 - the location of the equipment of the reversing rolling mill with a single stand rolling group, side view;

figure 2 - location of the equipment of a reversing rolling mill with a double stand rolling group, side view;

figure 3 - place I figure 1, 2.

The reversing mill consists of a rolling group containing one (Fig. 1) or two (Fig. 2) rolling stands 1, 1a, two coilers 2, 3 located in furnaces 4, 5; two detachable scissors, one of which combined scissors 6, are located behind the coiler 2 in front of the rolling group, and the second - stationary scissors 7, are located behind the rolling group in front of the coiler 3. Near the scissors 6, 7 are boxes 8 for trimming. Between the combined scissors 6 and the coiler 2, as well as between the stationary scissors 7 and the coiler 3, the master rollers 9, 10 are located.

The reversing mill also contains transport and working roller tables 11, a winder for winding the hot strip (not shown in Figs. 1, 2, 3). Combined scissors 6, which are part of the reversing mill, can be, for example, a pendulum type or a swinging type. Preferred in the inventive materials combined scissors swinging type, as more acceptable in overall dimensions. Combined scissors 6 consist of a bed 12, in which a swinging frame 13 is mounted, supported by a drive shaft 14 located in the bed 12. In the swinging frame 13, the upper knife support 15 and the lower knife support 16 are mounted for movement. The upper knife support 15 is connected with the rods of two hydraulic cylinders 17, the bodies of which are mounted on a swinging frame 13. The lower knife support 16 is connected through connecting rods 18 to the eccentrics 19 mounted on the drive shaft 14.

The lower part of the swinging frame 13 is connected with a crank mechanism consisting of connecting rods 20 and a crank shaft 21. The crank shaft 21 is connected by a gear (not shown in Fig. 3) with a gear ratio 1: 2 with a drive shaft 14, which, in its the turn is connected with the drive of scissors (not shown in Fig. 3).

Reversing mill operates as follows.

Depending on the billet strip used for rolling, two technological operating modes are possible.

Mode I. (Example 1). The workpiece is obtained from a blank casting machine, has a thickness of 50-100 mm, even ends after cutting a slab on dividing scissors. In this case, the billet is fed into the rolling group of the mill without cutting off its ends with flying combined scissors 6. In several reverse passages through stand 1 (FIG. 1) or stand 1, 1a (FIG. 2), the slab is compressed to an intermediate thickness (usually 20 25 mm), which allows you to wind the strip onto winders 2 or 3. Reverse rolling of the strip to a final thickness is carried out by winding the strip of intermediate thickness onto winders 2, 3 located in furnaces 4, 5. When winding the strip onto winder 2, the back end of the strip stops at combined 6. Before the scissors ratchet strip carried substandard segment of its end. To carry out the cut, the lower support 16 is lifted by the eccentrics 19 to the upper position, and the swinging frame 13 is installed in a vertical position by the crank shaft 21. The fixing of these nodes in a predetermined position is carried out by the scissors drive. The strip is cut when lowering the upper caliper 15 from the hydraulic cylinders 17. After cutting the strip, the combined scissors 6 return to their original position in which the lower caliper 16 is lowered and the upper caliper 15 is raised. The cut end of the strip falls into the box for cleaning the trim 8. When winding the strip on the coiler 3, the rear end of the strip stops at stationary scissors 7. Cutting the non-standard end is carried out by lowering the upper support of the scissors 7. The strip is reversed and fed to the rolling stand. After the last pass, the strip is transported to a coiler for winding a hot strip, where a roll is formed from it.

Mode II. (Example 2). The workpiece is obtained in a roughing stand from a thick slab, has a thickness of ~ 40 mm, uneven ends (during rolling in the roughing stand they are not cut off). The workpiece is fed into the rolling group of the mill when cutting along its front end with combined scissors 6. The scissors 6 work in the start mode for cutting. In this case, the drive shaft 14 receives rotation from the drive in a clockwise direction (see FIG. 3), the crank shaft 21 receives rotation counterclockwise (see FIG. 3) through a gear transmission with an angular speed two times smaller than the angular drive shaft speed 14. Eccentrics 19 in the acceleration phase rotate from a vertical to a horizontal position, i.e. rotate through an angle of 90 °, lifting the lower knife support 16 through the connecting rods 18, at the same time the crank shaft 21 rotates upward from the horizontal initial position by 45 °, communicating through the connecting rods 20 and the swinging frame 13 a horizontal speed equal to the speed of the strip to the upper knife the caliper 15 and the lower knife caliper 16. Before cutting the strip, the upper knife caliper 15 is lowered to the lower position by hydraulic cylinders 17, which hold it in this position by an force exceeding the cutting force. The strip is cut by moving up the lower knife support 16, while the eccentrics 19 rotate from horizontal to vertical position 90 ° clockwise, and the crank shaft 21 is rotated to the vertical position of the cranks with the direction up. After the cut, the knife calipers are retracted to their original position. The strip is crimped in rolling stands 1 (Fig. 1) or 1a (Fig. 2) and wound onto a coiler 3. The rear end of the strip stops at stationary scissors 7 and is cut off before reversing the strip. The strip is rolled in reverse passages through the rolling stands 1, 2 with a segment of the non-standard ends of the strip on scissors 7, 8 before its reverse.

Given the above, it can be concluded that when working on the inventive reversing mill, it is possible to use, along with the workpieces obtained in the continuous casting machine, workpieces obtained in the crimping mill, performing cuts on the fly, which eliminates the reinforcement of blanks and obtaining low-quality rolled strip.

Claims (1)

A reversing mill for the production of a thin hot-rolled strip containing a rolling group consisting of one or more rolling stands, two winders in furnaces located in front of and behind the rolling group, two cutting shears, and one cutting shear located behind the first winder in the furnace in front of the rolling group, the second - for the rolling group in front of the second winder in the furnace, transport and working roller tables, a winder for winding the hot strip, characterized in that the cutting scissors located behind the first winder in the furnace are made of combi th e, with both fixed and volatile cut.

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