RU2544728C2 - Treatment method of metal strap and device for its implementation - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to rolling of a metal strap. According to the method of treatment of a metal strap by plastic deformation, which involves rolling with coverage of a drive roll with the front end of the strap and with coverage of a driven roll with the rear end of the strap with angle of contact within π≤φ₁ and φ₀ < 2π radian respectively with mismatch of circumferential speeds of rolls and provision of reduction of tension of the strap ends, there reduced are forces of front and rear tensions on free ends of the strap by supplying a lubricant-cooling liquid to a gap between the drive and driven rolls and the strap at the entry of the strap to the rolls. In the device containing a frame of a working stand, drive and driven rolls, pressure rollers located centrally and symmetrically relative to the deformation zone, upper and lower curved guards fixed on the frame of the working stand, at the inlet of the upper and lower guards there installed are atomisers for supply of lubricant-cooling liquid to the gap between drive and driven rolls and the strap.

EFFECT: reduction of longitudinal and transverse variation in thickness of a strap.

2 cl, 1 dwg

Description

The invention relates to techniques for rolling production and can be used in the production of metal strips, which can be used in mechanical engineering, energy, agricultural and transport engineering, food industry, as well as in the production of greenhouses, light removable frame structures, etc.

A known method of rolling or processing a metal strip by plastic deformation, in which the rolling is carried out with one rotating and one braked roll (SU 249330 A1, IPC B21B 1/00, publ. 07.17.1967).

The disadvantage of this method is the change in rolling pressure along the length of the roll with the appearance of disturbances (jerking winders, palpation of rolls), leading to the formation of longitudinal and transverse thickness variations of the strip.

A known method of rolling strips and sheets, in which the driven roll informs the peripheral speed opposite to the speed of the strip, rolling is carried out with front tension (SU 1490777 A2, IPC B21B 1/22, publ. 11/16/1987).

The disadvantage of this method is the change in rolling pressure along the length of the roll when disturbances occur, leading to the appearance of longitudinal and transverse thickness variations of the strip, reducing its quality.

A known method of rolling strips, adopted as a prototype, in which the process is carried out by sequential plastic deformation in two groups of rolls, and in the second group of rolls, the process is conducted with the rolls covered by a strip and with a mismatch of their peripheral speeds (SU 1600871 A1, IPC B21B 1/28, published on October 23, 1990).

The disadvantage of this method is the reduced quality of the strip, the appearance of longitudinal and transverse thickness variations on the strip due to changes in rolling pressure.

A device is known for covering a strip of rolls of a rolling stand containing tension rollers and a mechanism for moving them (SU 1098599 A2, IPC B21B 39/16, publ. 06.23.1984).

The disadvantage of this device is the insufficient coverage of the roll barrels with a strip, which reduces the quality of the rolled strips due to the appearance of an increased longitudinal thickness difference of the strip.

A device is known which is adopted as a prototype for covering a strip of rolls in a rolling stand, comprising drive shafts of levers located on a parallel axis of the roll and carrying pressure rollers at the free ends mounted centrally symmetrically with respect to the deformation zone (AC 579050, IPC B21B 39/16, publ. 05.11.1977).

The disadvantage of this device is the insufficient (up to 180 degrees) coverage of the roll barrels with a strip, which reduces the quality of the rolled strips due to the increased longitudinal thickness variation of the strip during rolling.

The objective of the proposed method and device for processing a metal strip by plastic deformation is to improve the quality of the strip by reducing the longitudinal and transverse thickness variations.

The technical result is achieved due to the fact that the method of processing a metal strip by plastic deformation, in which the process is carried out with the leading and driven rolls covered by a strip providing tension to the ends of the strip, and with a mismatch in the peripheral speeds of the rolls, in contrast to the prototype for reducing front and rear forces of tension at the free ends of the strip, the angles of coverage of the leading φ ₁ and the driven φ ₀ rolls by the strip are set within π≤φ ₁ , φ ₀ ≤2π radians.

The device for implementing the method comprises a bed of the working stand, driving and driven rolls, pinch rollers located centrally symmetrical with respect to the deformation zone, in contrast to the prototype, in order to increase the angle of coverage of the rolls with a strip up to 2π (radian), the upper and lower are fixed on the stand bed curved wiring, guide and bypass rollers are placed at the cage entrance, inclined wiring is rigidly fixed between the bypass and pressure rollers, pulling rollers are installed at the exit of the cage, and pressure rollers are mounted abzheny hydraulic drives.

In addition, in the device for implementing the method, nozzles for supplying a cutting fluid are installed at the entrance to the upper and lower wiring.

During cold rolling of rolled steel as a result of disturbances (jerking of coilers, beating of rolls), the rolling pressure changes along the length of the strip, which leads to the appearance of longitudinal and transverse thickness variations on the strip.

The known process of asymmetric rolling and its kind of rolling-drawing (DF), which is carried out with the coverage of the rolls strip, as well as the mismatch of their peripheral speeds (RL Shatalov, EA Maximov. Asymmetric rolling of sheet metal, M .: MGOU, 2011 .-- S.80).

In order to weaken the influence of these perturbations on the rolling process during the rolling process during the appearance of winder jerks, beatings of rolls and other disturbances, it is necessary to reduce and stabilize the front and rear tension forces at the free ends of the strip. To stabilize the tension forces of the front and rear free ends of the strip, the process is carried out with the rolls covered by a strip, while the front end of the strip covers the drive roller, and the rear end of the strip covers the driven roller.

The forces of the rear and front tension T ₀ ∗∗ and T ₁ ∗∗ at the free ends of the rolled strip are determined by the formula of L. Euler (RL Shatalov, EA Maximov. Asymmetric rolling of sheet metal. - M .: MGOU, 2011 . - p. 85).

The tension of the front end of the strip T ₁ is determined within T ₁ ∗∗ ≤T ₁ ≤T ₁ ∗, the tension of the rear end of the strip T ₀ is determined respectively within T ₀ ∗∗ ≤T ₀ ≤T ₀ ∗.

Here T ₁ ∗∗ is the tension force of the front end of the strip in the free section,

T ₁ ∗ is the tension force of the front end of the strip in the plane of the strip exit from the rolls,

T ₀ ∗∗ is the tension force of the rear end of the strip on a free section,

T ₀ ∗ is the tension force of the rear end of the strip in the plane of the strip entry into the rolls

$$T_0\ast \ast =T_0\ast /e{f}^{\varphi 0}{T}_{\mathrm{one}}\ast \ast =T_{\mathrm{one}}/e{f}^{\varphi \mathrm{one}},(\mathrm{one})$$

where f is the coefficient of friction on the arcs of coverage between the driven, leading rolls and the strip,

φ ₀ , φ ₁ - respectively, the angle of coverage of the driven roll strip, the angle of coverage of the leading roll strip.

As can be seen from the formula, to reduce the forces of the front T ₁ ∗∗ and rear T ₀ ∗∗ tension on the free ends of the strip, it is necessary to reduce the friction forces, for which purpose lubricant is supplied to the surface of the barrel of the drive and driven rolls. Moreover, in accordance with formula (1), the friction coefficient on the arc of coverage between the driven, driving rolls and the strip decreases, causing a decrease in the forces of the front T ₁ ∗∗ and rear T ₀ ∗∗ tension on the free ends of the strip.

In addition, in the formula (1), the angle of coverage of the leading roll with a strip of φ ₁ varies from zero to 2π (radian), the angle of coverage of the driven roll with a strip of φ ₁ varies from zero to 2π (radian). The value of 2π (radian) is the maximum, which corresponds to the magnitude of the coverage of the roll strip 360 degrees. Expression (1) for calculating the tension forces at the free ends of the rolled strip shows that with an increase in the angle of coverage on the driving roll φ ₁ from zero to 2π (radian), the force T ₁ ∗∗ the tension of the front end of the strip in the free section decreases to a minimum value.

Similarly, with an increase in the angle of coverage on the driven roll φ ₀ from zero to 2π (radian), the force T ₀ ∗∗ the tension of the rear end of the strip in the free section decreases to a minimum value.

A decrease in T ₀ ∗∗ and T ₁ ∗∗ leads to stabilization of the rolling pressure along the length of the strip when disturbances appear (jerking of coilers, runout of rolls) and to an improvement in the quality of the rolled surface.

The greatest decrease in the force of the front tension at the free end of the rolled strip is observed if the coverage angle of the drive roll is 2π (radian) or 360 degrees. Similarly, the greatest decrease in the force of the rear tension at the free end of the rolled strip is observed if the coverage angle of the driven roll is 2π (radian).

Since the drive roll transfers more power to the deformation zone _{, the} coverage angle is set to π≤φ _1, and the driven roll transfers less power, in this case the coverage angle must be set to φ ₀ ≤2π.

If the coverage angles of the driving and driven rolls with a strip of φ ₁ and φ _{0 are} less than π (radians), then the values of the front and rear tension forces at the free ends are not enough to reduce the influence of disturbances (winder jerks, roll eccentricity) and changes (fluctuations) in rolling pressure and, accordingly, reducing the longitudinal thickness variation of the rolled strip.

Given all of the above, the coverage angles φ ₁ and φ _{0 are} set within π≤φ _1, φ ₀ ≤2π radians.

In FIG. shows a diagram of a device for implementing the method.

The device (see Fig.) Contains the leading 1 and driven 2 rolls, the first 3, second 4, third 5, fourth 6 pressure rollers, the upper 7 and lower 8 wires, covering the rolls 360 degrees and fixedly mounted on the stand frame 9, axis 10 pressure rollers are located in the pillows 11 in contact with the rods 12, first 13, second 14, third 15, fourth 16 hydraulic cylinders, fixedly mounted on the frame. Rollers 17 and bypass 18 are located at the cage entrance, inclined wire 19 is fixed between the bypass roller and the first pinch roller, pulling rollers 20 are installed at the cage exit. Lubricant-coolant (coolant) from the reservoir 21 is pumped into nozzles 23 ( in Fig. shows one nozzle from the side of the drive roll) located at the entrance to the upper 7 and lower 8 of the wiring, and is sprayed into the gap between the driven, driving rolls and the strip.

The method is carried out using the device (Fig.) As follows. From the unwinder (not shown in FIG.), The strip is fed from left to right onto the guide 17 and the bypass 18 rollers installed at the entrance to the cage. Then, through the inclined wiring 19, the strip is fed to the first pressure roller 3 of the driven roll 2. The first hydraulic cylinder 13 is turned on, the rod of which moves the pillow. Through the pillow and axis 10, pressure from the hydraulic cylinder is transmitted to the first pinch roller 3, which presses the strip to the barrel of the driven roll 2. The main drive of the rolls 1 (not shown) is turned on and the strip sandwiched between the first pinch roller and the driven roller is sent to the gap between the upper curved wiring 7 and the driven roll, covers the driven roll 360 degrees. At the exit of the upper wiring, the strip enters the second pinch roller 4. The second hydraulic cylinder 14 is turned on, which presses the strip to the barrel of the driven roll, directing it into the gap between the driven and drive rolls.

Further, due to the operation of the main drive rotating both rolls, the strip moves into the gap between the third pinch roller 5 and the drive roll. The third hydraulic cylinder 6 is turned on, which presses the strip to the barrel of the drive roll. Further, sandwiched between the third pressure roller and the drive roller, the strip moves into the gap between the lower curved wiring 8 and the drive roller 1, covers the drive roller 360 degrees.

At the exit of the lower wiring, the strip falls onto the fourth pinch roller 6. The fourth hydraulic cylinder 16 is turned on, which presses the strip to the barrel of the drive roll. Further, after the bending of the fourth pinch roller, the strip is guided to the pulling rollers 20 and moves to a winder (not shown). Thus, the conducted and leading rolls are covered by a strip, respectively, at an angle of 360 degrees.

Cutting fluid (coolant) is supplied from the reservoir 21 by the pump 22 and is sprayed into the gap between the rolls and curved wiring using nozzles 23.

When using the front end of the strip of the drive roll and the rear end of the strip of the driven roller by 2π (radian), the rear tension at the free end of the strip is reduced by 10%, the front tension at the free end of the strip is 10.1%. This, in turn, leads to stabilization of the rolling pressure along the strip in the range of 12.9-18.7%. In this case, the longitudinal thickness of the strip decreases by 10-12%, and the quality of the rolled strip increases.

Claims (2)

1. A method of processing a metal strip by plastic deformation, including rolling with the front end of the strip of the leading roll reaching the rear end of the strip of the driven roll with a coverage angle of π≤φ ₁ and φ ₀ <2π radians, respectively, with a mismatch of the peripheral speeds of the rolls and providing reducing the tension of the ends of the strip, characterized in that they reduce the forces of front and rear tension at the free ends of the strip by supplying a cutting fluid into the gap between the drive and driven rolls and the strip at the strip inlet rolls. 2. The device for processing a metal strip by plastic deformation according to claim 1, comprising a bed of the working stand, driving and driven rolls, pressure rollers arranged centrally symmetrically with respect to the deformation zone, upper and lower curvilinear wires mounted on the bed of the working stand, At the entrance to the upper and lower wiring, nozzles are installed to supply the cutting fluid into the gap between the drive and driven rolls and the strip.