RU1787606C - Method of screw rolling of tubes - Google Patents

Abstract

Usage: in pipe rolling in the manufacture of seamless hot-rolled pipes in screw rolling mills. SUMMARY OF THE INVENTION: in the process of deforming a workpiece in a gauge formed by rulers and rolls, the interaction of the rolls and pipe from the inlet and outlet side is controlled. If the load on one of the rolls is exceeded, the rolls on the input and output sides of the rolls are moved simultaneously and in the same direction separately, independently from each other, stabilizing the deformation zone along the length. 4 ill.

Description

ate

with

The invention relates to pipe rolling and can be used in the manufacture of seamless hot-rolled pipes in screw rolling mills.

There is a known method of screw rolling pipes, including deformation of a workpiece in two work rolls deployed at a feed and rolling angle, in which fixed rulers are used as a guiding tool to ensure that the rolled workpiece is held in a certain position relative to the drive rolls.

A disadvantage of the known method is that when the axis of rolling of the billet deviates from the axis of symmetry of the mill as a result of incorrect installation of the rulers in the deformation zone or their uneven wear, a deterioration in the geometric dimensions of the pipes obtained is observed.

The closest technical solution to the proposed one is a method of screw rolling of pipes, including deformation of the workpiece in a gauge formed by two rulers and two rolls, in which during the rolling process the interaction of the rolls and the pipe is controlled and, when the loads on one of them are exceeded, the rolls are moved in one direction before load balancing. A disadvantage of the known method is that the control of the loads and the movement of the rolls is carried out only parallel to the axis of symmetry of the mill. Under real conditions of screw rolling of pipes, the rulers often skew when the settings are incorrect, in addition, the rulers wear unevenly, not only one relative to the other, but also along the length of each ruler, while the sections of the lines corresponding to the input side of the rolls wear out differently from the sections of the corresponding output side. The rolls on the inlet and outlet sides also wear out differently. Wherein

VI

oo vj

ABOUT

about

about

the rolling axis deviates not parallel to the axis of symmetry of the mill, but at a certain angle, which cannot be compensated for in a known manner. Such (angular) deviation of the rolling axis causes a deterioration in the quality of the pipes, leads to eccentric differences and reduces the productivity of the mill due to the instability of the rolling process on the input side of the rolls.

An object of the invention is to increase process productivity and pipe quality, including geometric accuracy, by stabilizing the rolling process. This goal is achieved by the fact that in the method of screw rolling of pipes, including the deformation of the workpiece in a gauge formed by rulers and rolls, the interaction of the rolls and the pipe and the simultaneous movement of the rolls, in case of excessive loads on one of them, are controlled in one the direction before load balancing, in contrast to the known, control and move separately the input and output sides of the rolls independently of each other, stabilizing the deformation zone along the length.

. Unlike the known method of screw rolling according to the proposed method, when the load is exceeded in the process of pipe deformation on one of the rolls, the input and / or output sides of the rolls are moved separately from each other. This ensures a uniform stress-strain state along the entire length of the deformation zone, compensates for the uneven wear of the rolls and rulers, and helps stabilize the high-speed mode during rolling.

This increases the productivity of the rolling process, improves the quality of the pipes, eliminates the possibility of emergency shutdowns of equipment.

In FIG. 1 shows a diagram of pipe rolling in the work rolls of a screw rolling mill in the presence of a deviation of the axis of symmetry of the mill from the axis of rolling on the input side; in FIG. 2 shows a rolling pattern for a deviation of the axis of symmetry on the output side; in FIG. 3 and 4, a rolling diagram is shown when the axis of symmetry deviates from the axis of rolling at the input and output side simultaneously.

1 - rolled workpiece, 2 and 3 - work rolls, 4 - axis of symmetry of the mill, 5 - axis of rolling, 6 - mandrel, reference rod is not shown conventionally. The arrows indicate the direction of movement of the input or output sides of the work rolls.

The method of screw rolling is as follows.

The workpiece 1 is defined in the work rolls 2 and 3, which give it helical movement due to the inclination of the rolls forming an angle of feed to the axis of the workpiece. When the axis of the workpiece deviates to the side on the inlet side of the mill from the axis of symmetry of the mill (Fig. 1), the load on the rolls in the inlet side st0 is not uneven, the left roll is subjected to greater pressure from the side of the workpiece. To eliminate the deviation from the axis of symmetry, the input side of the work rolls 2 and 3 is moved to the side (indicated by arrows in the diagram 5) of the more loaded roll. When leveling the load on the input side of the work rolls, a symmetrical rolling pattern will be provided along the entire length of the rolls. In a similar way, the output side of the rolls is moved when they are not uniformly loaded (Fig. 2). In the case of an uneven load of the rolls on the input and output sides, simultaneously, the input and output sides are simultaneously moved either to one side (Fig. 4) or different sides (Fig. 3).

The simultaneous movement of the input and output sides of the rolls is independently one

0 from another allows maintaining the geometrical dimensions of the deformation zone when the rolling axis deviates from the axis of symmetry of the mill. This deviation can be detected by measuring the pressures on the necks of each roll on the input and output sides. Stabilization of the deformation zone will allow to increase the productivity of the process, ensuring uniform axial speed of the workpiece and improve the quality

0 pipes, by reducing the difference in alignment of the voltage at the inlet and outlet of the swath.

Example. The process of rolling a thick-walled workpiece into a sleeve on a Kosovolkovoy

5 stan - elongator. During rolling, a thick-walled billet with a diameter of 450 mm and a wall thickness of 105 mm is set from the inlet side to the mill rolls and is deformed on a stationary short rotating mandrel until a sleeve with a diameter of 360 mm with a wall of 70 mm is obtained on the outlet side of the mill.

During the rolling process, the pressure on the compression screws of each roller at the input and output side was monitored. In FIG. Figure 5 shows the oscillograms of pressure changes on the compression screws: line 1 corresponds to the load on the neck of the input side of the left roll (Fig. 1), line 2 corresponds to the load on the neck of the left roll on the output side, line 3 corresponds to the load on the neck of the right roll on the output side , and line 4 corresponds to the load of the right roll from the input side. As can be seen from the load graphs, the pressure on the inlet side of the right roll is 50-70 i.e. exceeds pressure on the inlet side of the left roll. At the same time, the difference between the loads on the output side between the left and right rolls is 23-25, i.e. When rolling with such uneven loads, almost on each billet, metal slipping relative to the roll, on the inlet side, was observed, which significantly reduces the productivity of the rolling process, the lateral difference in the rolled sleeve was 30%.

During the rolling process, the input and output sides were simultaneously displaced according to the circuit shown in FIG. 3, only in the opposite direction. The input side of the rolls was moved toward the highest load, to the right, by 14 mm, and the output side to the left by 6 mm, without changing the distance between the rolls. Wherein

Ј

the pressure difference on the inlet side decreased to 5-10 i.e., on the outlet side, the pressure difference was not fixed after moving. The rolls were displaced independently on the input and output sides.

During rolling, the machine time of the process decreased by 10%, which will give a mill productivity increase of at least 2%, the value of the transverse difference decreased to 15-20%.

Claims (1)

SUMMARY OF THE INVENTION A method for screw rolling of pipes, including deformation of a workpiece in a gauge formed by rulers and rolls, control of the interaction of the rolls and pipe during deformation, and when the load on one of the rolls is exceeded, moving them in one direction at the same time until the loads are balanced, characterized in that . in order to increase productivity, the rolls are moved by acting on their necks from the inlet and outlet sides of the pipe independently of each other, stabilizing the deformation zone along the length.  Phi A 1 Fs / g-z