RU2397033C1 - Pipe cold-rolling mill - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to the field of pipe-rolling production, more specifically, to cold-rolling mills for pipes of large dimension type. Pipe cold-rolling mill comprises frame with guides, working stand installed on them, movable power bed plate with support rails and geared racks, movable cassette, working rolls installed in it with master pinions, and also drive for reciprocal motion of stand. Movable cassette comprises replaceable calibres with alternating rolling diametres. To synchronise motion of movable power bed plate and cassette there is a double-arm lever connected by means of connecting rod and additional connecting rod with movable power bed plate and connecting rods of permanent length with movable cassette. To connect connecting rods with stand bed plate, there are replaceable pairs of double-support frames. Upper support is arranged in the form of cylindrical stem fixed on bed plate, where stand is fixed. Lower support is arranged in the form of slot in cassette guide, in which stand is fixed. Each pair of replaceable double-support stands is arranged with holes for axes of connecting rod fixation, arranged away from axis of rolling at height, which corresponds to interval of rolled pipes with mismatch of rolling diametre of replaceable caliber and rolling diametre of working stand within the limits of ±5% from diametre of rolled pipes.

EFFECT: invention makes it possible to expand functionality due to wider range of rolled pipes with simultaneous improvement of finished pipes quality, increased efficiency, improved reliability and durability, and also reduced wear of tool.

6 dwg

Description

The invention relates to the field of pipe production, and more specifically to mills for cold rolling large-sized pipes.

Known working stand of the cold rolling pipe mill (see US Pat. RF No. 2061565, B21B 21/00, declared. 19.03.1992, publ. 06/10/1996). The working stand of the cold pipe rolling mill comprises a movable power bed with support rails and gear racks, a movable cassette with work rolls, pinion gears, and a two-arm lever connected by a variable-length connecting rod with a movable power bed and two constant-length connecting rods with a movable cassette. Moreover, at the connecting points of the connecting rod with the lever and the bed there are mechanisms for moving the connecting rod axes.

Due to the small size of the tool, the known stand can only be used in roller mills. The implementation of this stand for rolling large-sized pipes will lead to an increase in its dimensions and the size of the connecting rods connecting the movable power bed and the movable cassette with a two-arm lever. In addition, on large mills, it is difficult to use mechanisms for moving the axes of attachment of the connecting rod of the bed. It becomes difficult to adjust the mill to a rolling diameter due to two settings, since each connecting rod joint has a powerful manual adjustment mechanism.

The rolling diameter is the diameter on which there is no sliding friction of the caliber against the pipe, that is, the instantaneous speed of the caliber relative to the pipe is zero.

The closest in technical essence is a cold pipe rolling mill containing a frame with guides, a working stand installed on them, including a movable power bed with support rails and gear racks, a movable cassette with work rolls, pinion gears and interchangeable gauges with streams of variable cross-section around the circumference , as well as a drive for moving the power bed, a two-arm lever connected by a connecting rod with a movable power bed and connecting rods of constant length to a movable cassette (see Pat. RF No. 2220795, B21B 21/00, declared June 4, 2002, published on January 10, 2004).

A disadvantage of the known design of the mill is limited technological capabilities, namely, a narrow range of rolled pipes, low quality of rolled pipes, increased wear of the rolling tool, due to the fact that when changing from one diameter of the rolled pipe to another, the shoulder of the connecting rod of the bed two shoulders lever due to the need to adjust to a new rolling diameter, as a result of which the angle between the connecting rods of the bed and the cartridge changes. This leads to an increase in the difference in the values of the rolling diameters of the working stand and the calibration of the tool along the cassette.

The mismatch of the rolling diameters of the working stand and the calibration of the tool along the cassette leads to a decrease in the quality of rolled pipes. With a large discrepancy of rolling diameters exceeding 10-15% of the pipe diameter, normal cold rolling of pipes is impossible.

A mill of a similar design, designed for rolling pipes of large sizes from ⌀200 to ⌀450 mm, will require the installation of a bulky connecting rod of the bed, a powerful mechanism for moving the axis of attachment of this connecting rod to the two-arm lever, which is difficult to manually move the axis with the connecting rod when setting to a rolling diameter during transshipment and provide reliable fixation of the performed adjustment of the position of the axis during rolling. In this regard, the time of transshipment of the mill increases, which leads to a decrease in productivity, and the unreliable fixation of the connecting rod mounting axis reduces the reliability and durability of the mill equipment.

The objective of the present invention is to create a cold pipe rolling mill, which allows to expand technological capabilities by expanding the range of rolled pipes while improving the quality of finished pipes, increasing productivity, increasing reliability and durability, as well as reducing tool wear.

The task is achieved in that the cold pipe rolling mill, comprising a frame with guides, a working stand installed on them, including a movable power bed with support rails and gear racks, a movable cassette with work rolls, pinion gears and interchangeable gauges with variable rolling diameters, and also a drive for moving the power bed, a two-arm lever connected by a connecting rod to a movable power bed and connecting rods of constant length with a movable cassette, according to the invention is provided with an additional step a unit connecting a two-arm lever with a movable power frame and interchangeable pairs of double-support racks for connecting rods to the stand frame, the upper support being made in the form of a cylindrical rod fixed to the frame, on which the rack is fixed, and the lower bearing is made in the form of a groove in the cassette guide in which the stand is fixed, in addition, each pair of interchangeable double-post racks is made with holes for connecting rods located from the rolling axis at a height corresponding to the interval of rolled pipes with a mismatch of cat the changing diameter of the interchangeable gauge to the rolling diameter of the working stand within ± 5% of the diameter of the rolled pipes.

Such a constructive implementation allows us to expand technological capabilities by expanding the range of rolled pipes and to improve the quality of pipes due to the minimum mismatch (up to ± 5%) of the rolling diameters of the working stand and tool calibration. This is achieved by the fact that the range of rolled pipes is divided into two or more intervals, and for each interval, its own mounting point of the connecting rods on two-pillar racks is determined in height so that when the cartridge moves forward, that is, from the workpiece to the finished pipe, the rolling diameter increases and accordingly, it decreased when moving backward - from the finished pipe to the workpiece, achieving minimal mismatch in the rolling diameters of the working stand and tool calibration. The mismatch of the rolling diameters of the working stand and calibration will be within ± 5% of the pipe diameter over the corresponding section. This circumstance ensures the minimum axial rolling force from the sliding friction forces of the caliber against the pipe and guarantees high surface quality of the finished pipe.

The height of the connecting point of the connecting rods to the replaceable stand is selected from the condition of the minimum allowable mismatch of the rolling diameters of the working stand and the tool calibration in a certain interval of rolled pipes, and the number of replaceable stands with their connecting rod heights corresponds to the number of intervals of rolled pipes.

In addition, productivity, reliability and durability are increased and tool wear is reduced due to minimal mismatch of the rolling diameter of the working stand to the rolling diameter of the tool calibration.

To explain the invention, a specific embodiment of the invention is provided below with reference to the accompanying drawings, in which:

figure 1 shows a General view of the cold rolling mill;

figure 2 is the same, a top view;

figure 3 is a section aa in figure 1;

figure 4 is a section bB in figure 3;

figure 5 is a section bB in figure 3, the cassette is conditionally not shown;

Fig.6 is a diagram of the provisions of the rolling diameters of the caliber and stand in the working area.

The cold pipe rolling mill comprises a frame 1 with guides 2, a working stand 3 mounted on them, a movable power bed 4 with support rails 5 and gear racks 6, a movable cassette 7, work rolls 8 with driving gears 9 located therein, and a drive 10 reciprocating movement of the stand 3. The movable cassette 7 contains interchangeable gauges 11 with variable rolling diameters.

To synchronize the movement of the movable power frame 4 and the cassette 7 there is a two-arm lever 12 connected by a connecting rod 13 and an additional connecting rod 14 with a movable power frame 4 and a connecting rod 15 of constant length with a movable cassette 7.

To connect the connecting rods 13, 14 to the bed 4 of the stand 3, there are interchangeable pairs of double support racks 16. The upper support is made in the form of a cylindrical rod 17 fixed to the frame 4, on which the rack 16 is fixed. The lower support is made in the form of a groove and in the guide 18 of the cassette 7, in which the rack is fixed 16. Each pair of interchangeable double-post racks 16 is made with holes under the connecting rod axis 19 of the connecting rods 13, 14 located on the rolling axis at a height h corresponding to the interval of rolled pipes with mismatch in the rolling diameter of the interchangeable gauge 11 rolling the diameter of the working stand 3 within ± 5% of the diameter of the rolled pipes.

The mill works as follows.

When rolling pipes, the working stand 3 performs a reciprocating movement, and in stand 3, the power bed 4 along the guides 2 moves at its own speed and at its own stroke length, and the cassette 7 moves along the guides 18 at its own speed at its own stroke length. Moreover, their movements are synchronous. The bed 4 and the cassette 7 are moved by means of connecting rods 13, 14, 15, connected by a two-arm lever 12 with the drive 10. Accordingly, in the cassette 7 the rollers 8 perform a swinging movement and calibrate 11 to roll the pipe 20 on the mandrel 21.

Rolling of the pipe 20 in the working area is carried out on a variable rolling diameter. The variable stream in caliber 11 has a variable rolling diameter corresponding to the rolling route. The connecting rods 13, 14 of the bed are fixed on the uprights 16 with 19 axes in the holes, which are located at a height h corresponding to the interval of rolled pipes with mismatch of the rolling diameter of the replaceable gauge to the rolling diameter of the working stand within ± 5% of the diameter of the rolled pipes.

When rolling pipes along a route that does not fall into the interval of routes defined by struts 16 with holes at a height h, the struts 16 are dismantled and another pair of struts with their height h is installed for the mounting holes of the connecting rods 13, 14 of the bed 4, corresponding to the new rolling route.

For each rolling route, a technological tool changes: calibers, mandrel, wiring and more. Replaceable two-post racks are only dismantled during the transition from one interval of rolled pipes to another, which significantly reduces the complexity and time of transshipment.

The proposed cold pipe rolling mill in comparison with the known ones allows expanding technological capabilities by increasing the range of rolled pipes to ⌀450 mm while improving the quality of finished pipes and productivity, increasing reliability and durability, as well as reducing tool wear.

Claims (1)

A cold tube rolling mill comprising a frame with guides, a working stand installed on them, including a movable power bed with support rails and gear racks, a movable cassette with work rolls, pinion gears and interchangeable gauges with variable rolling diameters, as well as a drive for moving the power bed, two-arm lever connected by a connecting rod with a movable power bed and rods of constant length with a movable cassette, characterized in that it is equipped with an additional connecting rod connecting the two-arm lever with a movable power bed, and interchangeable pairs of double support racks for connecting the connecting rods to the stand frame, the upper support being made in the form of a cylindrical rod fixed to the frame, on which the rack is fixed, and the lower support is made in the form of a groove in the cassette guide in which the rack is fixed, at in this case, each pair of interchangeable double-support racks is made with holes for connecting rods, which are located from the rolling axis at a height corresponding to the interval of diameters of the rolled pipes with a mismatch of the rolling diameter of the interchangeable cable a libra with a rolling diameter of the working stand within ± 5% of the diameter of the rolled pipe.

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