SU1470370A1 - Method of rolling plate metal - Google Patents

Abstract

The invention relates to rolling production, namely to the rolling of sheets and strips. The purpose of the invention is to improve the quality and prevent bending of rolled products. The method is carried out as follows. When rolling sheet metal, protrusions and valleys are formed on the roll out, followed by stripping of the protrusions by rolling in smooth rolls with a mismatch of peripheral speeds determined by empirical dependence. The method makes it possible to improve the flatness of the strips, increase the stability of the rolling process, prevent the strip from bending, improve the working conditions of the fixture and capture the front end of the strip with the rolls of the next stand during sequential and continuous rolling. Breaks and surface defects of the strip are prevented. The advantage of this method is that it does not require special devices for its implementation.

Description

one

The invention relates to rolling production, namely to the rolling of sheets and strips.

The purpose of the invention is to improve the quality and prevent bending of rolled products.

The method is carried out as follows.

When rolling sheet metal, protrusions and valleys are formed on the roll out, followed by stripping of the protrusions by rolling in smooth rolls with a mismatch of peripheral speeds determined from the ratio

 -fL-z (-. ()

VH-2 {-n) 8

where b, 6 - the height of the protrusions on the upper and lower wide edges of the strip, respectively, mm;

and, y - linear velocity of the upper and lower rolls, respectively, m / s;

“, N is the ratio of the total area of the protrusions on the upper and lower edges x, respectively, to the area of the face;

H is the thickness of the strip before rolling in smooth rolls, taking into account the height of the projections, mm.

The method provides an increase in the stability of the stripes to the loss of flatness, and the relief relief with the mismatch of the speeds of the rolls contributes to the fragmentation of deformations along the length, width and thickness of the strip. After rolling, the metal in the place of the projections (the sizes of the projections are commensurate with the size of the deformation zone) will experience compressive stresses, and in the place of the depressions - tensile, which compensate each other in the whole volume of the metal and prevent accumulation of uneven stretching along the strip length. The loss of a flat shape on the section where the compressive stresses coincide in direction, sum 4 O CO O

They are also excluded, since the area of this area, determined by the linear dimensions of the protrusions, is small, and the critical stresses of flatness losses are correspondingly large.

The vertical speed of movement of the metal particles when approaching the horizontal plane along the rolling axis tends to zero. Therefore, to prevent the bending of the strip, it is necessary that the volumes of metal leaving the upper and lower rolls are equal, i.e. the condition is met (considering the entire deformation zone is the sticking zone)

() - (LB-a b k W, (2)

where L, B, H - the initial dimensions of the strip, taking into account the applied relief; a, b, f are the length, width and height of the form (4000), on the bottom edge, respectively, mm,, 8 mm, the distance between the protrusions along the width and 25 mm length (). Having determined the dependence of (3) the ratio of the areas of the surfaces of the protrusions to the areas of the faces, 0625; , 1024, set the magnitude of the velocity mismatch, which is

V I-2b (1-p). about (4%

and 7Г-28 () ° Then, 04w, i.e., at the speed of the lower roll of 10 m / s, the speed of the upper roll must be maintained at 10.4 m / s. In the process of rolling with the specified mismatch, gniem crushing deformations along the length, width and height of the strip. Different voltages in different parts of the strip compensate each other, preventing accumulation of uneven stretching along the length of the strip. Decrease size, L, 6 L, 1s -

Brooking the protrusions on the respective plots contributes to the growth of the upper and lower edges of the critical; the number of protrusions on the 1st along the length of the strip, respectively, the upper and lower edges

These flatness loss voltages increase the stability of the process. The conditions of the metal flow at the upper and lower rolls are leveled, which contributes to the prevention of 11 M / Tvn .1.4 ...-- - -,

In the case of this equality, the rotation of the bend and strip breaks

. „,. , h-t, l TTGT.O- .ili - v1 -1 11O. QPPIRP Y NPG TII 1 PO.GK

compensation of the lack of metal on the face with less massive protrusions increased rolling speed. This prevents strip bending and discontinuity, improves metal flow conditions and

surface quality improvement. After rolling, the sheet has a flat shape without breaks, local flatness and surface defects.

The proposed method allows improved surface quality of the strips. To reduce the flatness of the strips due to the equivalent ratio of the areas of the surfaces of the protrusions to the areas of the faces as n and l, i.e.

hanging compressive stresses with tensile stresses in places of hollows, increasing the stresses that are critical in flatness by crushing deformations and stresses. The method allows, preventing bending polobak

b a k LB

(3)

get the expression (1) to determine the mismatch of the linear speeds of the rolls.

The essence of the proposed method is as follows.

When rolling on a sheet mill on wide edges of a strip, projections with a height of 0.1–0.5 of the required crowd of the finished strip are formed in one of the pre-finishing gaps while maintaining the ratio. At the same time, you can increase the stability of the npOKaTj process, improve the working conditions of the fixture and capture the front end of the strip with the rollers of the next stand during sequential and continuous rolling. Rupture and surface defects are prevented.

40 lanes.

The advantage of this method is that it does not require special devices for its implementation. The economic effect is obtained by increasing -lCv rViin: 7SH11D-G.1llVyi / J J-ltllWi U, h L

The honeycomb of the protrusions should not exceed the value of the production of strips of increased catechine of strip reduction to obtain the required dimensions. In the next pass, the relief is removed on broad flatness gragorias.

Claims (1)

Invention Formula n x strip with the mismatch of the speeds of the rolls in the expression (1). Example. At the 2000 hot rolling mill strip, to obtain a sheet of 5x1600 from OB steel, the class B 250x1650 mm heated to 1250 ° C is used. At the same time, in the penultimate stand of the mill 50 A method of rolling sheet metal, including forming, on a roll, protrusions and depressions with subsequent removal of protrusions by rolling in smooth rolls, characterized in that, in order to improve the quality and prevent bending of the rolled metal. The edges of the strip form the protrusions: on the top- 55, the removal of the protrusions is carried out when rolling. r f-partrinr -ovrirtO / r rriO / r r OlJrJO l. there are faces with a width and length of mm, height, 8 mm, the distance between which in length and width is 20 mm ke in rolls with mismatch of peripheral speeds determined from the ratio (4000), on the bottom face, respectively, mm,, 8 mm, the distance between the protrusions along the width and 25 mm length (). Having determined the dependence of (3) the ratio of the areas of the surfaces of the protrusions to the areas of the faces, 0625; , 1024, set the magnitude of the velocity mismatch, which is V I-2b (1-p). about (4% and 7Г-28 () ° Then, 04w, i.e., at the speed of the lower roll of 10 m / s, the speed of the upper roll must be maintained at 10.4 m / s. In the process of rolling with the specified mismatch, crushing of deformations occurs along the length, width and height of the strip. Different voltages in different parts of the strip compensate each other, preventing accumulation of uneven stretching along the length of the strip. Reducing the size of the plots contributes to the growth of critical plots contributes to the growth of critical stress flatness loss, increases the stability of the process. The metal flow conditions at the upper and lower rolls are leveled, which contributes to the prevention. 1.4 ...-- - -, rotation of bending and strip breaks rotation of bending and strip breaks  .ili - v1 -1 11О. QPPIRP Y NPG TII 1 PO.GK surface quality improvement. After rolling, the sheet has a flat shape without breaks, local flatness and surface defects. The proposed method makes it possible to improve the flatness of the bands by equalizing the compressive stresses with tensile in depressions, increasing the stresses critical in flatness by crushing the deformations and stresses. The method allows, by preventing the bending of the strip, to increase the stability of the npOKaTj process, to improve the working conditions of the core reinforcement and to grip the front end of the strip with the rollers of the next stand with sequential and continuous rolling. Rupture and surface defects are prevented. 40 lanes. The advantage of this method is that it does not require special devices for its implementation. The economic effect is obtained by increasing -lCv rViin: 7SH11D-G.1llVyi / J J-ltllWi U, h L  nor the production of strips increased no production of bands increased gory of flatness. Invention Formula 50 A method of rolling sheet metal, including forming, on a roll, protrusions and depressions with subsequent removal of protrusions by rolling in smooth rolls, characterized in that, in order to improve the quality and prevent bending of the rolled metal. carried out with rolled art O / r rriO / r r OlJrJO l. by the disagreement of the circumscribed 1470370 56 y (1-n) 6n and n - the ratio of the total area c (t- / t je protrusions on the top and bottom where b and b - the height of the protrusions on the top of the game x, respectively, to the flat wide faces of the band of the face; respectively, mm, y and y are the linear velocities of the upper ion and the thickness of the strip before rolling into lower rolls, respectively, smooth rolls, taking into account the height m / s; protrusions ,. mm;