RU2677808C1 - Shaped blank of the “dog bone” form from continuously cast slab manufacturing method - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to the rolling. From the continuously cast slab forming the beam blank in the rolling mill calibers by making the longitudinal incision in the slab lateral longitudinal faces center with the triangular split ridge with the sharp generative angle in the box-shaped caliber, which width at the ridge top is equal to the original slab width, increasing the roll notch depths in the I-beam flanges formation points until the specified value reaching, the roll cut parts unbending with the I-beam flanges formation, at that, the roll cutting depth increasing is produced using calibers consisting of split crests with variable values of the angle at the apex and heights from one caliber to another, at that, the roll shape formation in these calibers is produced without lateral constraint by the calibers releases, formed for the I-beam flanges roll pre-cut parts unbending is produced due to the ridge with forming at the apex obtuse angle penetration, then performing increase in the notch width in the caliber with a flat bottom, and the shaped blank final formation in the shaped caliber of a given shape. Ridges height in the first three calibers is taken in the amount of 10, 20 and 30 % of the shaped blank flanges width, respectively, and the angle at the split ridges apex, starting with the acute angle of 50 degrees in the first caliber, changing with increase of 10 degrees in the subsequent second and third calibers.EFFECT: reduction of consumption ratio, increased productivity and the product quality improvement.3 cl, 7 dwg, 1 tbl

Description

The invention relates to rolling production, and in particular to the production of shaped beams such as “dog bone” from a flat slab on a crimping mill.

A known method of rolling a slab in width in the vertical direction on a crimping mill having several box gauges with a gradually increasing width of the bottom of the gauge. When rolling slabs in width in the vertical direction according to this method, at the place of contact of the metal with the rollers, the metal broadens to form the so-called “dog bone” shape. Flange inspection takes place in alternating box calibers. After that, metal in the shape of a “dog bone” is rolled into a preform of a preform with a shaped gauge (1).

There is a known method of rolling a slab in which a protrusion is located in the center of the first box gauge for forming a concave stream in the center in the direction of the thickness of the slab, while the metal is rolled through the next gauge to reduce the width, holding it with a similar protrusion to prevent falling and get the workpiece in the form of dog bone. " After that, the concavity of the metal is eliminated using a flat-bottom box caliber and the metal takes the form of a beam blank of a given shape in a shaped gauge (2).

A known method of rolling a slab, in which the parts corresponding to the shelves of the beam, are broadened, passing through many box calibers, each of which has protrusions in the center of the bottom of the caliber with different angles of the protrusions at the apex (3).

The disadvantages of the above methods are:

- the use of a slab with a width much greater than the width of the finished beam blank;

- it is difficult to manufacture a beam blank for a large I-profile, using only a crimping mill due to the limited length of the roll barrel;

- uneven broadening of shelves in two directions;

- it is impossible to further produce the I-beam profile from one heating, due to the large number of passes and, as a result, a drop in the temperature of the roll;

- additional end trim, due to improperly formed ends of the roll due to the large difference in the coefficients of the hoods on the elements of the profile.

In each of the known methods listed, deformation is applied with the formation of a “dog bone” shape, in which the slab is substantially squeezed in the width direction so that the compression force does not affect the central part of the slab, the slab expands only at the ends and forms a “dog” shape bone".

A known method of manufacturing a beam billet for the production of a universal I-beam profile, comprising making a longitudinal cut in a hot flat billet on each side using a plurality of pairs of sliced calibers, each of which has a triangular protrusion in the center of the bottom of the caliber, while the triangular protrusions have the same predetermined angles at the apex and gradually increasing heights, moreover, a gradual increase in the depth of the notch and a gradual increase in the width of the notch after reaching two times the set depth at which the ends of the rolled metal on both sides of the notch are not subject to compression from the bottom of the caliber during the manufacture of the notch and the increase in its depth. During at least one pass of the step of increasing the depth of the incision, the ends of the metal on both sides are bounded by the walls of the gauge to prevent the metal from spreading across the width. The step of increasing the notch width is carried out using a flat-bottom box caliber in a crimping mill. The step of increasing the notch width is performed using vertical rollers in a universal mill (4). This method is closest in technical essence and the achieved result to the proposed invention and adopted as a prototype.

The disadvantages of this known method are: - increasing the width of the notch in a flat-bottom box gauge has low efficiency, due to the fact that the angle between the cut flanges is 60 degrees, and compression in a flat-bottom gauge will go mainly to their deformation, and not to bend. Also, taking into account the deformation of the flanges, there will be a decrease in the element of the profile of the roll intended for the formation of the wall of the shaped workpiece;

- the statement about the distribution of the material as a result of cutting when the side walls of the gauge are limited on both sides in the direction of the bottom of the gauge, in other words the width of the incised slab is larger than the width of the original slab after 350 mm of cutting in the center of the slab, is doubtful. To carry out verification calculations of this method, sufficient initial data are not shown.

The problem to which the invention is directed is to provide a method for manufacturing a dog bone-shaped billet from a continuously cast slab for the production of several types and sizes of I-profiles, capable of reducing the cost coefficient, increasing productivity and rolling efficiency, and also improving product quality by use continuously cast slabs.

The problem is achieved due to the proposed method for manufacturing a shaped billet of the “dog bone” shape, which includes forming a beam billet from a continuously cast slab in the gauges of a crimping mill by performing a longitudinal incision in the center on the lateral longitudinal faces of the slab with a triangular split crest with an acute forming angle in the box caliber , the width of which at the top of the ridge is equal to the width of the initial slab, an increase in the depth of incision of the roll in the places of formation of the flanges of the I-beam until reaching of this value, the extension of the cut parts of the roll with the formation of the flanges of the I-beam, while increasing the depth of cut of the roll is carried out using calibers consisting of split ridges with variable values of the angle at the apex and variable height of the ridges from one caliber to another, while forming the roll in the data calibers are made without lateral constraint by the releases of calibers, the extension of the previously cut parts of the roll forming for the shelves of the I-beam is performed by penetrating Ram ridge forming an obtuse angle at the vertex, whereupon the increase in notch width in the caliber with a flat bottom and the final formation of the shaped shaped workpiece in a predetermined shape caliber. Moreover, the height of the ridges in the first three calibers is taken in the amount of 10, 20 and 30% of the width of the shelves of the shaped workpiece, respectively, and the angle at the top of the split ridges, starting from an acute angle of 50 degrees in the first gauge, is changed with an increase of 10 degrees in subsequent second and third calibers.

The implementation of the proposed method for the manufacture of shaped blanks of the form "dog bone" is illustrated by the figures:

FIG. 1 - continuously cast slab, positioned before the first pass.

FIG. 2 is a front view of a first split gauge.

FIG. 3 is a front view of a second split gauge.

FIG. 4 is a front view of a third split gauge.

FIG. 5 is a front view of a fourth caliber for expanding previously cut shelves.

FIG. 6 - metal deformation in the experiment using a cutting gauge.

FIG. 7 is a front view of a box caliber with a split ridge.

The proposed method for the manufacture of shaped blanks of the form of "dog bone" from continuously cast slabs is as follows.

Heated to a temperature of 1250 ° C, the molded slab 1 is fed to the rolls of the crimping stand and, using a tilter, is turned 90 degrees to the side face 2 (Fig. 1). Next, the slab is rolled in the first split gauge K1 (Fig. 2). The first gauge is a box gauge with a split ridge 3, which is located in the center of the bottom of the gauge, which perform a longitudinal incision 4 of height h and an acute angle α. In the first gauge, the acute angle is 50 degrees. The width of the caliber a along the top of the ridge for uniform cutting of the slab along the side face is equal to the thickness of the heated slab c. Uniform cutting of the slab 1 along the side face 2 occurs due to centering (pinching) of the side walls of gauge 5. After rolling in the first gauge, the roll is fed and rolled in the second gauge K2 (Fig. 3). The width of the second caliber a is taken equal to the width of the roll, taking into account the broadening in the second. caliber. In this case, the contact of the metal with the side walls of caliber 5 occurs at the final stage of the change in caliber. Forming the angle of the crest of the second caliber a. it is also an acute angle with a magnitude of 10 degrees greater than the ridge angle in the previous gauge and is 60 degrees, an increase in the depth of the roll occurs. This design of the caliber is due to the fact that in the first caliber there was only a preliminary cutting of the slab, which is not enough to keep the roll from stalling only with a split crest. Cutting in the second gauge, as in the first, occurs only until the metal contacts the bottom of the box caliber, that is, there is a slight study on the tops of the shelves. Next, the roll is rolled in the third caliber K3 (Fig. 4). This caliber is designed in such a way that to keep the roll from stalling during the final cutting, a split ridge with an increased generatrix of the split ridge is sufficient to a value of 70 degrees, while the side walls of gauge 5 are absent. By increasing the angle by 10 degrees in calibers, the metal “ridge” of the ridge surface is guaranteed to “fit”. From aisle to aisle, the angle is increased to approach the unfolded corner - the smooth barrel, that is, not a sharp increase from an acute angle to the unfolded, but gradual, so that the metal formed by cutting for the flanges does not decrease in height when rolling on a smooth barrel, but almost completely transforms into the flanges. With this shaping, free broadening occurs in the caliber and all the strain energy is directed only to comb 3, that is, to cut. With such a deformation scheme, there is a minimal decrease in the roll along the element intended for forming the wall of the shaped workpiece. The final cutting in the caliber occurs as in previous calibers only until the metal contacts the bottom of the caliber, that is, there is also a slight lack of processing of the profile elements designed to form the shelves of the shaped workpiece, which does not allow a decrease in height of the shelves and the roll wall . The height of the ridges h in the first three calibers take 10, 20 and 30%, respectively, of the width of the shelves of the shaped workpiece. The crest of the first caliber is intended for the initial cutting of the slab along the side face, its task is to cut as accurately as possible in the center of the slab with pinching in the caliber. If the caliber is made higher, then it needs to be inserted more into the rolls, and since the side walls of the caliber have a slope and the width of the caliber along the height of the ridge h is equal to the width of the heated slab in, then the metal going to form the flanges will also be crimped more, which is not necessary. It is necessary that the metal "fall apart" as much as possible at the cutting site without any constraint. The height of the ridge of the third caliber is calculated based on the width of the flanges in the final profile, it is equal (along the perimeter of the ridge) to the width of the flanges in the final profile. The crest of the second caliber is taken as intermediate between the first and second calibers. Next, the roll is rolled in the fourth caliber K4 (Fig. 5). This caliber is designed for extension of the cut part of the roll, the roll angle is developed. The forming angle of the ridge is taken to 100 degrees and the perimeter of the ridge is approximately equal to the perimeter of the ridge of the third caliber. Therefore, the shape change in this caliber occurs until it touches the central part of the crest and peals. The transition from the part of the caliber ridge to the bottom of caliber 6 occurs along an arc of a circle, to obtain the prerequisites for the hem and the extreme element of the shelves. That is, preparations are underway for further rolling of the roll on a smooth barrel with a minimum decrease in the width of the wall (central part) of the profile.

Further shaping of the roll after the fourth pass is carried out according to the scheme with the alternation of calibers smooth barrel - shaped caliber. In this case, the main and sufficient control (processing) on the tops of the shelves occurs only in the shaped (finishing) beam caliber.

Specific examples of the proposed method.

To obtain a beam blank of size 610 × 350 × 90 mm, a flat continuously cast slab with a thickness of 250 mm and a width of 1100 mm was heated to a temperature of 1250 ° C and rolled on a crimping mill in calibers K1, K2, K3, K4, as well as on a smooth barrel and in shaped (finishing) beam caliber according to the 17-way diagram shown in the table.

Next, the shaped workpiece is transported to the crimping stand of the beam mill, where, depending on the final profile, it is further rolled according to the developed schemes. This shaped billet obtained by the proposed method can be used for the production of three sizes 17 profile sizes.

Using the proposed method for the manufacture of dog-shaped beam billets from continuously cast slabs, it is possible to produce several types and sizes of I-beams, reduce the consumption coefficient, increase productivity and rolling efficiency, and improve product quality through the use of continuously cast slabs.

Sources of information taken into account:

1. Japan patent No. 55-70402, 4/1980, Mcl. B21B;

2. Japanese Patent No. 56-41002, 3/1981, Mcl. B21B;

3. US patent No. 4086801, etc. March 31, 1976, publ. 05/02/1978, B21B 1/08, B21B 1/088, B21B 1/10.

4. US patent No. 4420961, priority 07/10/1981, publ. 12.20.1983, Mcl. B21B 1/08, B21B 1/10.

Claims (3)

1. A method of manufacturing a shaped billet in the form of a “dog bone” from a continuously cast slab, comprising forming a beam billet in the gauges of a crimping mill by making a longitudinal incision in the center on the lateral longitudinal faces of the slab in a box gauge using a triangular split crest with an acute forming angle, the width of which at the top of the ridge, it is equal to the width of the initial slab, increasing the depth of the notch of the roll in the sections of the formation of the flanges of the I-beam to achieve the specified value, the extension of the cut of the parts of the roll with the formation of the flanges of the I-beam, characterized in that the depth of the incision is made in calibers containing split ridges with variable angles at the apex and a variable height of the ridges from one caliber to another, while forming the roll in these calibrations is performed without lateral obstruction by the outlets of calibers, the extension of the previously cut parts of the roll in the sections of the formation of the flanges of the I-beam is unbent by means of a ridge, forming an obtuse angle at the apex, after produces an increase in the caliber width of the notch with a flat bottom and the final formation of the shaped shaped workpiece in a predetermined shape caliber. 2. The method according to p. 1, characterized in that the height of the ridges in the first three calibers is, respectively, 10, 20 and 30% of the width of the shelves of the shaped workpiece. 3. The method according to p. 1, characterized in that the angle at the apex of the split ridges is 50 degrees in the first gauge and increases by 10 degrees in the subsequent second and third calibers.

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