SU874236A1 - Method of sheet rolling - Google Patents

Description

(54) METHOD FOR ROLLING THE UNITS

I

The invention relates to rolling production and can be used in the manufacture of cold rolled sheets for offset printing.

A known method for the production of sheets for offset printing, consisting in cold rolling, annealing and dressing, and the training is carried out repeatedly with fine values of the roughness of the rolls. With this method of production, due to different distribution of stretches across the strip width, the required flatness of the sheets is not provided, and repeated training reduces the productivity of the equipment and requires the preparation of a large fleet of rolls with different surface roughness 1.

A known method of producing cold-rolled sheets, including rolling a hot-rolled strip in a continuous four-stand mill with tension and supplying a coolant to the strip, annealing the coils and training G2.

The closest in technical essence to the proposed offer is a method of cold rolling strips in roll stands with rotating at different adjustable speeds and at different specific front and rear tension of the strip. Used in this method of rolling, the magnitude of misalignment of the circumferential speeds of the rolls is 1.04-1.10 and the ratio of specific tensions (J ,, (-frQ + V They are designed to align the rolling moments between 15 and 3 rolls,

However, such parameter ratios do not reduce the rolling force and produce sheets with

20 high flatness. Furthermore, the known method is not applicable when rolling on a continuous mill, since at the indicated ratios the tension values in the last cages will exceed the strength of the strip.

These methods do not provide a given level of quality to the surface and flatness of the sheets. .

The purpose of the invention is to improve the surface quality and improve the flatness of the sheets.

This goal is achieved by the fact that, according to the method of rolling sheets for offset printing, in the line of a continuous cold rolling mill with interstitial tensions, rolling is carried out with a mismatch of the speeds of the work rolls in a part of the line, and the number of these stands is accepted by sequential alternation through the cage , starting with the last one in the course of rolling, and the mismatch of the speeds of the work rolls and the value of the interstand tensions are determined by the following relationship:

B

1+ (0, 24) X

but

and. to the ratio

l

 1.2-2.8,

GO

where V / I, Mg) the circumferential speeds of the upper and lower work rolls in the stand; L - vel1-1china relative strip stretch; front and back specific nat strip lines in the cage.

With V-1 / VQ 1 + 0.24 X, friction is frustrated and the rollers slip, and with V -, / Vr 1 + 0, 1 X, there is no noticeable decrease in the rolling force and an increase in the roughness of one side of the strip. If & / ((ed 7 2.8, then the front end of the strip may break, and with b /; / (e Ij2, the rolling force varies little.

The drawing shows a diagram of a continuous four-stand mill with an indication of the ratio of the speeds of the work rolls (V and VQ) and the front and rear specific attacks (s and cage when implementing the proposed method.

The mismatch of the speeds of the work rolls and the presence of relatively large melt-tension tensions leads to a decrease in the rolling forces and an improvement in the flatness of the sheets. A roller rotating at a higher speed (leading; s) ensures that more lubricant enters the deformation zone and, consequently, the roughness of the side of the strip that faces the deformation zone to the drive roll, Bbmie, than on the other front side of the strip. The smooth front sides of the coils of the strip, coiled into a roll, will be pressed against the roughness, which prevents the welding of the coils during annealing. Cages, rolling in which leads without a mismatch of speeds, isolate KJ from each other (Ieti, whose work rolls rotate at different speeds.

The production of large stretches in the cage during tensioned rolling is limited by the strength of the strip. Therefore, if two adjacent stands of a continuous group operate with a velocity mismatch, in order to effectively reduce the rolling force, the front tension of the first stand T should be greater than the rear TQ, i.e.

GO 61, 1.2-2.8 (FIG. 1) AND)

and close to the tensile strength of the strip. Tension Tx | is ass, 2

on the second stand TQ,

and the forward tension of the second stand

X ;;: take in accordance with the relation (1).

A buffer stand, operating without speed mismatch, makes it possible to isolate from each other the stands that work with the mismatch of the speeds of the work rolls. In such a stand, rolling will be the most stable if

bo 0.46, b 0.02-0.3,

0 — specific rear and pegde and less than tension; . 6f- - yield strength of the strip.

those. if the rear tension is higher (almost twice) than the front. In this case, the higher the value of the front tension, the first stand by declaring speeds will be the rear TQ for the stand behind it, operating normally. The front tension T of this stand may be small (2) and it

but

will not be back t. for another stand operating with speed mismatch. Slight rear tension. TO of this stand allows 587 rolling in it with a large stretch without danger of breaking the strip. Example. Hot rolled strip made of steel 08 kp 2.0 mm thick. A width of 1115 mm, wound into a roll, weighing 6 tons is transported to a four-stand quarto-mill 1700 cold rolling. The roll is fixed on the softener, set the strip at the filling speed of 0.5 m / s in all the stands of the continuous group. The front end is secured to the winder, and set the compression modes. Include.

The proposed mode 1 -yr--1 + 0.1

1,02,01,50,51,330,5

1,161,500,94.0,561,61,2.

1,00,940,700,24i, 350.45

1,140,700,500,201,41,2 The proposed mode 2-g-1 + 0,24 X 1,02,0 1,50,5 1,33 0,5

1.384 1.50 0.94 0.56 1.6 1.2 1.00.94 0.70 0.24 1.33 0.45

1.34 0.70 0.50 0.20 1.4 1.2 Proposed mode 3-1 + 0.17X

.1,02,01,50,51,350,5

1,271,500,940,561,61,2

1,00,940,700,241,330,45

1,240,700,500,201,41,2

H

Nosh1os.kostnos.t 2-g8 mm / 1000 MMj

longitudinal thickness variation

0,010-0,014 mm;

yield of sheets 73%

UL

one

Non-flatness 2g8 mm / 1000 mm;

irodolno thickness difference 0,0090, 011 mm;

yield of sheets 75%

V / i

1120 Non-flatness 1005 2-g8 mm / 1000 MMj

1250 longitudinal thickness difference 120 0,, 012 MM-,

74% yield of sheets to the strip and rolls, set the tension and misalignment of the peripheral speeds of the upper and lower work rolls through the cage in the second and fourth cages of the mill, set according to the indicated ratios of circumferences: 1X roll speeds and tension. The table shows the modes of rolling and quality indicators strip, obtained by the proposed and known methods.

The proposed mode is 8-p + 0.24 x

2.0

1.0

1.5 1.33 0.5 0.5

1.5 1.384 0.94 0.56 1.6 2.0

longitudinal thickness 0,01-0,013 MMi yield of sheets 72%

1 120 Non-flatness 950 mm / 1000 MMi

1,00,94 0,70 0,24 1,33 0,45

3 4

1.34 0.70 0.50. 0.20 1.4 2.0 mode 9

0.5 1.350.5

0.56 1.62.0

0.24 1,330.45

0.20 1.42.0

Known mode

As can be seen from the table, rolling on the proposed method can significantly improve the surface quality and flatness of the sheets.

The roughness of the reverse (non-impacted side of the strip is obtained by 2 classes lower than the front.

Laminated strip, wound into a roll, transported to the bell-type furnaces. The alternation of the rough and smooth sides of the strip in the roll prevents welding of the coils during annealing.

The annealed strip is then subjected to training.

Claims (3)

Invention Formula Method of sheet rolling, mainly for offset printing, in a line of continuous cold rolling mill with adjustable speed 87A236 ten Continuation of the table lengthy face 0.01-0.012 mm-, yield of sheets 73% Vi  . The flatness is 2-7 mm / 1000 mm-, longitudinal thickness variation 0.01-0.012 mm, yield of sheets 72% The work rolls and interstand tensions, differing so that, in order to improve the surface quality and improve the flatness of the sheets, rolling is carried out with a mismatch of the speeds of the work rolls in a part of the line stands, the number of these stands alternation through the cage, starting with the last one in the course of rolling, and the mismatch of the speeds of the work rolls and the magnitude of the interstand tensions are determined by the following relationship: V + 0.1-0.24 x Vn And the ratio |., ..- 2.8, where v and lrj. -. the outer speeds of the upper and lower work rolls in the cage; L is the value of the relative stretching of the strip in the cage G and bo — the front and rear specific tensions of the strip in the cage.5 Sources of information taken into account during the examination 1. USSR author's certificate No. 59002l, cl. B 21 B 1/38, 1978. 2. Ksenzuk F.A. and others. Baltsov1 IR cold rolling mills. M., Metallurgists, 1969, p. 238-244. 3. USSR author's certificate No. 619227, cl. B 21 B 1/06, 1979. .M V, i4 X and , -i / "d,