SU1443993A1 - Roll for tube rolling mill - Google Patents

Abstract

The invention relates to pipe production and can be used for cold rolling of pipes in HPT mills. The purpose of the invention is to increase productivity due to repeated reductions, and feed rates and simplified manufacturing technology. The roller contains a barrel with a stream, which has an entrance blank section along the length ki with an arc forming a ridge of constant radius, a working section with a variable ridge radius increasing and an output blank section. The comb at the beginning of the working area at the central angle of 0.10-0.15 rad is made with a straight line generatrix, adjacent tangentially to the end of the arc generatrix of the inlet idle section. 2 silt, 1 tab. with S (L

Description

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The invention relates to pipe production and can be used during cold rolling of pipes.

The purpose of the invention is to increase productivity by increasing crimps and feed rates and simplifying manufacturing technology.

Fig, represented roll, cut along the ridge of the stream; figure 2 - node 1 in Fig, on an enlarged scale, at the time of the beginning of the supply pipe.

The roll of the cold rolling mill consists of a barrel 1 with a replaceable caliber 2 in a stream. The stream has, along the barrel length, an inlet idle section ab with an arc forming a ridge uof, standing radius, a worker with a variable crest radius at bd and an output idle portion de, with the ridge at the beginning of the working region b at the central angle of 0.10-0, 15 rad is made with a straight line generator (in with a continuous line and), with number 1 tangent to the end of the arc forming part of the inlet section. The radius of the ridge: .- the input blank section is equal to the smallest radius of the worker / segment.

To construct the profile of the ridge in the working area, one or another known calibration method is used. Regardless of the method of calibration in the proposed design, the profile of the ridge-stream of calibers in the initial part of the working section is performed along a straight line perpendicular to the initial radius of the roll in the working section and, therefore, adjacent to the end of the arc forming the idler section. In this case, the roll radius increases from the initial, according to the cosecant law, the central angle, i.e. with increasing intensity. ness. This rectilinear part continues until the intensity of the increase in the radius of the roll ridge reaches the limiting one, always known in practice and set by the maximum allowable axial loads on the work feed cartridge or by some other means.

The limiting intensity of the increase in the roll radius at the beginning of the working section is expressed in terms of the taper angle of the sweep of the ridge of the calibers J- and 0.11 rad. Practically this

the angle does not exceed 0.15 rad. Then, for the central angle C, which characterizes the extension of the rectilinear segment (an approximation is obtained with an accuracy of up to 3 digits after the decimal point), the inequality Cf - j j from this follows that it is practically sufficient for cf: 0.10-0.15 rad.

If the limiting intensity of the roll radius increase is already achieved, and according to the calibration method chosen, the same intensity of tube reduction should be continued, then the curve of the roll radius change along the ridge of the gauge stream smoothly changes to the Archimedes spiral curve, at which the intensity of the roll radius increase remains constant and which is commonly used in the formation of the reduction region.

If, however, the intensity of the increase in the roll radius on the straight line section has reached the limit, and according to the calibration conditions, less intense pipe pressings are needed, then the straight line section is reduced to the technical pressure until the roll increase intensity reaches the required value; and, starting from the obtained point, an increase in par of the roll dus is performed along the Archimedes' mating spiral until the pipe is compressed to the required value.

The broach cross-sections in the straight section have an oval shape with a constant major axis and decreasing in accordance with the roll radius. crest small axis.

Pr linear section of the profile. } The ridge of the gauge creek enters as an integral part of the working section, as it necessarily shrinks the outer diameter of the rolled pipe. In its location, it corresponds in the existing structures to the transition section between the supply shed and the actual start of pipe squeezing. Approximately the same correspondence exists between the lengths of these areas. Equal equality is not here because both the linear form of the proposed area and its length can be obtained from the optimality condition, which determines the achievement of the maximum permissible by boundary conditions

the intensity of the initial compression-pipe.

Consider the process of rolling pipes along the route, 5 - 32x5 mm at the mill XIIT-55 PNTZ in the rolls of the proposed design. The radius of the roll on the barrel is equal to the mill HPT-55 182 mm. Take the estimated radius of the workpiece RQJ equal to 31.75 mm The pipe of radius R, passes unhindered when fed through the inlet section (feed shed), a constant radius of 150.25 mm, the depth of which is correspondingly 31.75 mm. Further, it is moved by the feeding mechanism within the rectilinear part of the working section, and this movement is not hampered by the working surface of the roll (ordinate Y (Fig. 2), which determines the depth of roll penetration into the pipe surface, which is equal throughout the straight section 32 mm). At the same time, this area is not idle, since within it limits the deformation of pipe diameters by changing the roll radius along the ridge from 150.25 to 153.22 mm. The table shows the roll radii and the corresponding ordinates Y depending on the angle of rotation for proposed and known forms of comb. As the calculations show, the maximum angle by which you need to turn the swath when feeding.

for the known form of the ridge on the considered rolling route is 11.3 °. As can be seen from the table, in

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In this angle, a roll of a known shape prevents the pipe from moving. The radius of the supply shed at the same time on the known roll is 140 mm.

Comparison of the proposed and known designs of the roll are shown in the table.

Performing the ridge radius of the inlet idling equal to the smallest radius of the working section allows to exclude from the manufacturing technology of the replacement part of the roll the operation of manual polishing of a diameter drop of a stream,

Claims (1)

Invention Formula . The roll of the cold rolling mill is coarse, containing a barrel with a stream having an input idle section along the barrel length with an arc forming a ridge of constant radius, a working section with a variable crest radius increasing area and an output idle section, which is increase in productivity due to increased crimping. ; and the supply and simplification of manufacturing technology, the ridge at the beginning of the working section at the central angle of 0.10-0.15 rad is made with a straight line forming, tangentially to the end of the arc forming the input idle section, while the radius of the input idle section is made equal to the smallest radius of the ridge of the work area. 32.00 32.00 32.00 32.00 32.00 32.00 32.00 .one . I ifoda -a Osva ka