RU2307008C1 - Strip steel lengthwise uncoiling method - Google Patents

Abstract

FIELD: finish working of rolled sheets, possibly lengthwise uncoiling coiled strips for producing narrow strips.

SUBSTANCE: method comprises steps of drawing metal through disc shears at preliminarily notching it; notching strip in shears by depth A due to shifting portions of strip adjacent along strip width in vertical plane in mutually opposite directions; then additionally passing strip through pair of horizontal cylindrical rollers while shifting each of said portions in the same plane but in direction opposite to shifting direction of said portion drawn through shears in order to produce narrow strips. Depth value

where h - strip thickness, mm; σ_y -limit yield of steel, Mpa.

EFFECT: improved quality of ready strip blank for shaping.

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Description

The invention relates to the decoration of sheet (strip) rolled products and can be used for the longitudinal dissolution of rolled strips to obtain narrow strips.

Such strips of a given width can be used as a blank for subsequent profiling, i.e. manufacturing cold-rolled profiles.

Longitudinal dissolution is carried out on the units of longitudinal cutting (APR) using disc scissors. The technology of longitudinal dissolution of hot and cold rolled strip steel is described in sufficient detail, for example, in the book by A. A. Korolev, “Design and Calculation of Machines and Mechanisms of Rolling Mills,” M., Metallurgy, 1985, pp. 238-241.

There is a method of producing strip material, in which, while cutting the edges of the strips, they are pressed against the cylindrical surface of a knife of circular shears using a conical roller (see AS USSR No. 1368112, class B23D 19/04, publ. In BI No. 3, 1983). However, this method is unsuitable for cutting roll strips into narrow strips of a given width.

The closest analogue to the claimed technology is a method of trimming the edges of the rolled disc scissors on.with. USSR No. 517414, cl. B23D 19/04, publ. 07/15/76

This method involves drawing metal through disc scissors with preliminary notching and is characterized in that the notched edges are crushed without complete trimming, and then they are finally trimmed.

The known method is also unacceptable for obtaining narrow strips of wide strip steel, since it will not provide their required quality.

Indeed, if you previously cut the metal to a certain depth with disc scissors and then finish cutting it with knives, then inevitably the appearance of burrs on the lateral edges of the finished strips, which will be all the more, the softer the metal, i.e. the lower its strength characteristics and, in particular, the value of yield strength b _t The appearance of a burr is explained by the influence of counter-directed vertical forces from circular knives, which, in the presence of an axial (lateral) gap between adjacent knives, leads to the drawing of metal into this gap.

The technical task of the invention is to improve the quality of the strip billet for profiling due to the prevention of the appearance of burrs on the lateral edges of narrow strips after dissolution.

где h - толщина полосы, мм, б_т - предел текучести стали, МПа, путем смещения соседних по ширине полосы участков в вертикальной плоскости в противоположных направлениях, а затем полосу дополнительно пропускают через пару горизонтальных цилиндрических роликов, смещая каждый из упомянутых участков в той же плоскости, но в направлении, обратном смещению участка при протяжке через ножницы, с получением узких полос.To solve this problem in a method of longitudinal dissolution of strip steel, including pulling metal through circular shears with its preliminary notching,

where h - the strip thickness, mm, b _m - yield strength steel MPa by displacing neighboring on portions bandwidth in a vertical plane in opposite directions and then the strip is further passed through a pair of horizontal cylindrical rollers by shifting each of said portions in the same plane, but in the direction opposite to the displacement of the site when pulling through scissors, with obtaining narrow strips.

The above mathematical dependence is obtained by processing experimental data (see below) and is empirical.

The essence of the proposed technical solution is to prevent the appearance of burrs on the lateral edges of the resulting narrow strips (the presence of a burr on the billet for profiling significantly accelerates the wear of roll forming rolls), since when the strip is cut to a certain depth through horizontal rollers, the jumpers break between individual sections along it the width and separation of metal into narrow strips.

The inventive method is implemented as follows.

Before the longitudinal dissolution of the strip, the knives of the disk scissors are installed in such a way that there is a vertical gap between the upper and lower knives, which ensures the cutting of the metal by the desired value Δ. After the strip passes through the disk shears, it enters the gap between the additional horizontal drive rollers, the value of which is equal to the actual thickness "h" of the strip. As a result of this, the notched metal is separated.

An experimental verification of the proposed method was carried out at the APR sheet rolling shop No. 7 of OJSC "Magnitogorsk Iron and Steel Works" upon receipt of the workpiece for profiling on units of the same workshop.

For this purpose, the longitudinal dissolution roll hot and cold rolled strips of different thickness (h = 2 ... 8 mm) of steel with _t b = 350 ... 540 MPa performed preliminary metal nadrezku to different depths, and then it was passed through a pair of horizontal cylindrical rollers installed behind the disc scissors APR. The billets obtained in this way were profiled on roll forming section mills, fixing the degree of wear of the work rolls of these mills.

The best results (no burrs on the profiled strips and minimal wear on the rolls) were obtained with the implementation of the proposed methods. When the deviations of the metal notch from the optimal values (corresponding to the Δ values according to the above dependence) the quality of the cut deteriorated.

в отдельных случаях не происходило разделение металла на узкие полосы, что приводило к необходимости остановки АПР, вырезке дефектных участков полосы и перенастройке дисковых ножниц. При величинах

часть металла разделялась на узкие полосы с заусенцем на боковых кромках, профилирование которых увеличивало износ валков (в 1,1...1,6 раза больший, чем при рекомендуемых величинах "Δ").So, with

in some cases, the metal was not divided into narrow strips, which led to the necessity of stopping the APR, cutting out defective sections of the strip and reconfiguring the disk shears. At values

part of the metal was divided into narrow strips with a burr on the side edges, the profiling of which increased the wear of the rolls (1.1 ... 1.6 times more than with the recommended values of "Δ").

The method chosen as the closest analogue was not tested in the experiments because of its unacceptability for the preparation of the workpiece used in profiling.

Thus, a pilot test confirmed the acceptability of the technical solution found to achieve the task and its advantages over the known technology.

According to technical and economic studies conducted at the Central Control Laboratory of OJSC MMK, the use of the developed technology for longitudinal dissolution of coiled steel in order to obtain a strip billet designed for profiling reduces the wear of roll bending rolls by an average of 1.4 times due to the use of blanks with no burrs on its lateral edges.

Concrete example

The preform profiler prepared by the claimed technology of coiled steel strip thickness h = 5 mm, with b _m = 450 MPa.

The value of the preliminary incision of metal in the disc shears APR:

After the notched strip passes through a pair of horizontal rollers, the narrow stripes do not have any burrs on the edges.

Claims (1)

The method of longitudinal dissolution of strip steel, mainly a billet for profiling, including pulling the strip through disk shears with preliminary cutting and obtaining narrow strips, characterized in that the strip is cut into scissors to a depth

, where h is the strip thickness, mm, σ _t is the yield strength of steel, MPa, with the displacement of adjacent sections along the width of the strip in a vertical plane in opposite directions, and then additionally passed through a pair of horizontal cylindrical rollers with the displacement of each of these sections in the same plane and in the direction opposite to the displacement of the section when pulled through scissors.