SU1424888A1 - Process tool for screw rolling of tubes - Google Patents

Abstract

The invention relates to pipe production and relates to a tool for rolling or three-roll screw rolling mills. The aim of the invention is to improve the accuracy of the diameter of the pipes. The technological tool for helical rolling of tubes includes three drive rolls with inlet, pinching and exit sections, deployed at the feed and rolling angles, and a multi-cone mandrel with protrusions

Description

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Belt view, IME: Ksh1uyu guide section and four main (x: input, calibrating 7, cue working and cylindrical. The height of the protrusions in each cross section of the input and calibrating sections is 0.03-0.08, the radius of curvature in the top of the protrusions is 0.06-0.15 from the diameter of the cylindrical section of the mandrel. On the conical working section of the mandrel, the height of the protrusions smoothly decreases to zero, while the length of the output, calibrating and working conical sections of the mandrel is 0.15-0, 35; 1.02-1.05 and 0.6-0.8 lengths of their respective parts s of the work roll, and the angles of inclination of these sections are different from the angles of inclination of the roll calibration sections, respectively, by + (0.3-1), + (0.1-0.5.) and - (0.8-1.5 The tool allows only local, local compression of the prokamgoemoe pipe along the wall, increase the stability of its cross section profile, significantly reduce the amount of tensile tangential stresses. Using this and (the structure allows to increase the accuracy of external and internal diameters and wall thickness of rolled tubes, improve quality their outer and inner surfaces and reduce the expenditure ratio of the metal. .6 ill.

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The invention relates to pipe production and can be used, in particular, on units with three-roll mills to improve the accuracy of the size of the diameter of pipes, including bearing ones.

The purpose of the invention is to improve the accuracy of the diametrical dimensions of pipes.

FIG. 1 schematically shows the proposed technological tool; in fig. 2 is a section A-A in FIG. one; in fig. 3 shows section EB in FIG. one; Fig, 4 - technological tool for. helical rolling of pipes (products) of large diameter with a roller mandrel; in fig. 5 is a sectional view BB in FIG. four; in fig. 6 is a schematic diagram of a specific tool. I

The technological tool includes three rolls, each with input 1, pinch 2 and output 3 sections and a mandrel with protrusions 4 (rollers), having a guide section 5 and three main sections: input 6, calibrating 7 and working conical 8, respectively, the roller sections , each of the roll portions (and the corresponding mandrel portion) may be cone-shaped. The mandrel is fixed to the rod 9. The diameter of the mandrel is determined on a cylindrical portion.

When rolling tubes of larger diameter, when the continuous mandrel has a large mass, you can use the mandrel with three multi-cone rollers, the longitudinal profile of which corresponds to the longitudinal profile of the splined mandrel, the minimum diameter of the rollers in the section corresponding to the pinch rolls is 0.12 -0.24 equivalent diameter of a solid mandrel in this area or 0.28-0.55 distance between the axis of the rollers and the axis of the mandrel.

To eliminate the likelihood of tensile stresses and defects on the inner surface of pipes, as well as to further improve their accuracy, the mandrel with protrusions (or mandrel with rollers) is set with respect to the rolls before rolling, so that the plane passing through the axis the mandrels and the tip of the protrusion or the axis of the mandrel and the axis of the roller are shifted 4-10 from the plane passing through the vertical diameter of the mandrel or through the axis of the roll and the mandrel at a zero feed angle on the roll, and then expose the desired feed angle, then inayut rolling

Rolling tubes occurs between the three multi-conical rollers and the proposed mandrel so №1 obllchom that

it is possible to touch the protrusion of the mandrel or the rollers of the inner surface of the pipe only in certain places of the cross section. This significantly increases the stability of the cross section of the pipe, allows for an increase in diameter reduction, and reduces the possibility (likelihood) of significant tensile stress on the inner surface of the pipe.

In addition, the influence of fluctuations of the initial dimensions of roughing pipes, for example, from the Assel mill, on the rolling process in the subsequent mill on the proposed technological tool is also eliminated (or reduced); single pipe, and in a batch of pipes.

The height of the protrusions on the mandrel and the radius of curvature of the protrusions were determined experimentally on a laboratory rolling mill and based on theoretical studies of the stress-strain state when rolling thin-walled pipes.

The lengths of the swath sites, respectively

Cavities are equal to 1d, IgHlg, and the main parts of the zoo large wall reductions on most mandrels are respectively 1d (,, Igo

The length of the front guide section is 1 dz, the length of the section with linearly decreasing protrusion height located behind the calibrating section of the mandrel is Q, (0.4-0.6) 16.0 (this section is part of the conical working section). The height of the protrusions 4 h. Equals 0.03–0.08 of the diameter of the cylindrical cup 35

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important roll areas, which is unacceptable, especially when rolling thin-walled tubes (d / S 9),

If the protrusion height is less than 0.03 of the mandrel diameter df, n and the radius of curvature is less than 0.06 of the mandrel diameter, very careful adjustment of the mill is necessary, besides, with small protrusions and their wear during operation, the effect of local contact with the pipe disappears, which leads to a violation of the process, poor calibration of the internal diameter of the pipes, an increase in their different diameters. At small radii of curvature of the protrusion, there may be a violation of the smooth contact of the metal with the mandrel, the appearance of cuts, scuffing on the inner surface of the pipes, difficulties in setting up the mill.

; 0.1 - 0.5 and 0.8 for plots

STI mandrels Bn (0.03 - 0.08) don.

It has been established that the differences in the taper angles in the corresponding sections of the mandrel with roll protrusions should be 0.3 - 1 1.5, respectively, 6-8 mandrels.

With a difference in the corners of the roll and the protrusion (roller) is higher than 0.5 and 1.5, in these areas the calibration of pipes by the inner diameter is practically not carried out, besides, the appearance of internal defects is possible.

With a difference in the angles of inclination of the inlet section of the roll ei, e and the first one behind the guide during rolling of the conical portion of the protrusion (roller) ot less than 0.3 the gap between the roller and

projection (roller) is almost parallel. Taking into account the occurrence of thickening of the wall in the inter-roll gaps from plastic bending of a certain actual transverse and longitudinal differentiation of pipes, the arrival is quiet at the calibration mill from the Assel mill (rolled), other irregularities on the outer and inner surfaces (for example, the diameter along the length of the pipes, etc.) this leads to a significant reduction in the wall thickness of individual sections of the pipe, which is unacceptable in this process.

With a difference of Ы, and ci, more than 1 contact of the pipe in its inner diameter with the mandrel is practically not carried out, especially at the end of the section.

Execution in sections 6 and 7 of the angle of inclination of the protrusion (roller) to the rolling axis is 0.1-0.5 ° more and 0.8-1.5 less than the angle of inclination of the forming roll on the calibrating and exit sections, due to similar considerations mi

If the difference in angles is less than 1 ° and 0.8 °, the occurrence of

large wall reductions on the most

important roll areas, which is unacceptable, especially when rolling thin-walled tubes (d / S 9),

If the protrusion height is less than 0.03 of the mandrel diameter df, n and the radius of curvature is less than 0.06 of the mandrel diameter, very careful adjustment of the mill is necessary, besides, with small protrusions and their wear during operation, the effect of local contact with the pipe disappears, which leads to a violation of the process, poor calibration of the internal diameter of the pipes, an increase in their different diameters. At small radii of curvature of the protrusion, there may be a violation of the smooth contact of the metal with the mandrel, the appearance of cuts, scuffing on the inner surface of the pipes, difficulties in setting up the mill.

With a height of protrusions of 0.08 and a radius of curvature of the protrusions of more than 0.15 don, the local (in certain places of the pipe cross-section) deformation disappears or deteriorates, since the mandrel of the inner surface of the pipe can be significantly covered and the process can be difficult.

5 Research conducted at the laboratory showed that the best combination of speed, deformation performance and accuracy in outer and inner diameters occurs at the following ratios between the lengths of the respective sections of the mandrel and the roll: 1 to (O, 15 - 0.35) 1

-In

(0.6 -

  (1.02 - 1.05) 1. 0.8) 1.

With lfl (j 0.15 1, the supporting effect of the mandrel is lost, which makes it possible to increase the stability of the pipe profile with a significant reduction in diameter to pinch the rolls (i.e., in the inlet cone of the deformation zone)

At IAO 0.35 1D, an unstable secondary capture is observed.

At 1 gp c: 1.02 1, very careful adjustment of the mill is required; any displacement of the mandrel in the axial direction can lead to a significant distortion of the gap between the roller and the mandrel.

At 1.05 Ig it is also difficult to establish the required gaps between the roller and the mandrel, especially when the rolls are worn,

With IgQ: 0.6 1c, the profile of the pipe n has time to acquire a round shape (with significant reductions in diameter in the area of pinching the rolls).

At IBO - 0.8 1, cases of obstructed collapse of the pipe from the mandrel are observed due to the large axial resistance on its side with a slight departure of the internal surface of the pipe from the mandrel.

The choice of the length of the conical working section of the mandrel with a decreasing lug of projections equal to 0.4-0.6 of its total. length (1,), due to the following.

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0.4 1

in

bad is possible

pipe runoff from the mandrel due to the small departure from it of the inner surface of the pipe

At Хр - 0,6 1 (zo, the calibration of the pipe with an internal diameter deteriorates due to its insufficient contact over the entire surface with the conical and cylindrical sections of the mandrel.

When choosing the diameter of the rollers, proceed from the same considerations as when justifying the choice of the radius of curvature 1Ш at the apex of the protrusions of the solid mandrel, and then recalculate this value

on

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the distance between the axis of the mandrel and the axis of the rollers N.

The distances from the axes of the rollers to the axis of the mandrel N are determined for each particular case of rolling, i.e. A mandrel is made for each pipe size, as when rolling on other mills of any unit.

Before rolling, the mandrel with the protrusions 4 (rigidly fixed on the rod 9 and fixed together with the rod against rotation) is set with respect to the rolls so that the plane passing through the axis of the mandrel and the top of the protrusions from the plane passing through the vertical diameter of the mandrel ( or through the axis of the frame

ki and axes of work rolls), at 4-1U. At the same time, during adjustment, the feed angles on the rolls are reduced to zero, the mandrel is shifted (turned), and then the desired feed angles are again set.

The rod on which the mandrel or mandrel assembly with three rollers is rigidly fixed is kept from rotating on the output side of the mill (the rollers rotate around their axes).

The need to shift the protrusions of the fixed mandrel or rollers on

 1 n °

The angle 4-10 from the plane passing through the axis of the gauge and the axis of the work roll is caused by the following considerations.

When the displacement is less than 4, the stability of the protrusions (rollers) in the center decreases, since the magnitude of the pressure on the protrusions (rollers) causes their displacement to the roll axis in the radial and tangential directions: in this case even a small displacement of the protrusions during rotation Rolls and rollers may cause additional longitudinal and transverse fracturing. In addition, it is not possible to reach large reductions in diameter, a defect may appear on the inner surface of the pipes, as there is a large reduction in diameter in the transverse direction, which reduces the stability of the pipe profile.

The offset of the projections (rollers) on

ABOUT

A ZTol higher than 10 causes a damping ovalization or loss of stability of a pro. L, which is unacceptable, since it can cause an increase in the oval

nosti finished pipes (especially thin-walled) or their different diameters. In addition, the danger of tangential tensile stresses and the possibility of defects on the inner surface of pipes in the areas under the work rolls where contact with the protrusions of the mandrel or rollers is absent is not eliminated. This is especially important when rolling (calibrating, in particular) thick-walled pipes.

Example. Rolling on the proposed (technological) tool.

Pipes 168x18 mm in size made of steel ШХ-15 or ЗОХГСА are set in multi-tapered rolls with a barrel length of 285 mm, with a diameter of 400 mm over clamped section. The angles of feeding and rolling of the rolls are respectively 5 and 4. The slopes of the individual sections on the roll are 2, respectively.

Mr. Cone 5 30, 2 and 1; in a pinch of rolls 0 °, at the output - astka 1 and 2 °. The length of the inlet section of the rolls is 1d 150 mm, the clamped IR is 20 mm, the output cone is 1 115 mm (Fig. 6).

The mandrel has a length of 170 mm, with 1do 0.3 1d 45 mm, 1 1.02 Ig 20.4 mm, IBO

equal to 9 ° 30, 6% 5 °, 4 °, 3 ° in the deformation zone: at the entrance-ОО ОО lO

  Bo 0.7.

 80.5 mm (of which 1 go 35 mm 10.5 mm), If 1 racks in over1.1 e d 126 mm, 7 mm 18 mm. (0.14 dpn).

four

in - JJ mm, Tnj 5 mm. Diameter opt - 1 24 mm, d on. (0.06 d) R

The mandrel has the following main tilt angles: on the caliber of the lean section (section 7) 6 °, 230, 2 on the entrance cone (multi-cone section 6) O 30, on the conical working section (multi-cone section 8), respectively, 0 ° 10 and 1 ° 10, those. Location on

The 6 angles of inclination of the forming working areas of the protrusions (rollers) are 0.5–1 times larger than the angles of inclination of the forming sections of the roll inlet cone; on the gauge lean area

7- by 0.5 °, and on the conic working section 8 - by 0.8 - less than the corners of the corresponding sections 2 and 3 of the roll.

The fluctuation of the diameter along the length of the pipes in the lot was reduced from Q, 16 - 0.12%

Technological tool for helical rolling of tubes, including three pinch-driven rolls, p set in a circle after 120, pa return to the feed and rolling angles and a multi-cone mandrel having: sections: anterior guide, a conical working, a cylindrical and a back cone, and installed with a guide section up to the press rolls, characterized in that, in order to increase the diameter of the pipes, the mandrel is made with an additional input and calibrating sections of tapering tapering the input cone and roll front directly with each other and between the guide and the horse working areas, and three longitudinal protrusions at the entrance and working working areas perimeter through 120, the height of which is equal to the length of the curvature at the top of the input and calibrating plots is with

according to the current technology (without justified, 0.03 - 0.08 and 0.06 ki) to 0.08 - 0.1% and from (± 0.58) - (± 0.74)% to 0, 4 - 0.5%, respectively.

0.15 of the diameter of the cylindrical section of the mandrel, and the length of the input, calibrating and working

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Compression in diameter increases to 5-6 mm instead of 3.6-3.8 mm for a known tool, (i.e. 2.5 - 3.5% versus 1.5 - 2%), the cross-sectional profile in the hearth does not acquire the shape of a square with rounded edges or a pentagon, since local contact of the protrusions of the mandrel (rollers) with the inner surface of the pipe sharply reduces the likelihood of plastic hinges in the cross section of the pipe, increases the stability of the profile. Local contact with the mandrel leads to local deformation of the different pipe sections. The heterodiametry is significantly reduced.

The proposed tool can be used not only for calibrating pipes with an internal diameter, but also for other processes of helical and cross-rolling, where the reduction along the wall should be practically absent, and the product (material) should be given either exact geometrical dimensions or mechanical properties.

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Claims (1)

Invention Formula Technological tool for helical rolling of tubes, which includes three drive rolls with a pinch, arranged in a circle after 120, turn back to the feed and rolling angles, and a multi-cone mandrel having: sections: forward guide, tapered work, cylindrical, and backward tapered , and set the guide section to clamp the rolls, characterized in that, in order to improve the accuracy of the diametrical dimensions of the pipes, the mandrel is made with additional input and calibrating sections of reverse taper, respectively, the input cone and pinch of the rolls directly behind each other and between the guide and the conical working sections, and three longitudinal projections on the input calibrating and working sections along the perimeter through 120, whose height and radius of curvature at the top of the input and calibration sections em co55 responsibly 0.03 - 0.08 and 0.06 0, 15 the magnitude of the diameter of the cylindrical section of the mandrel, and the length of the input, calibration and working 91A24888Y the conical sections of the flap are 0.8 lengths, respectively, they are 0.15–0.35; 1,02 - I, 05 and 0,6 - roll sites. 4Z 8 7 FIG. 3 8 78 FIG. If entrance B- B Howl