RU2329110C2 - Method of manufacturing spiral-profile pipes - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method of flutes formation on pipe by rollers installed around the pipe, the axes of which are installed at the angle to pipe axis and rotate around own axes, by means of their contact with pipe with application of holder and simultaneous effect of torque moment and axial force on the pipe, applied from the side of pipe portion distanced from the rollers. Holder is used with through channels, which are cut for the rollers for their contact with tubular billet in the process of flutes formation. Holder is installed outside the pipe, providing possibility of contact in the process of flutes formation of its internal surface with tubular billet by fitting with gap for provision of fixation and alignment of pipe, and with profile part of pipe - by transitional fitting for limitation of flutes swelling. At that torque moment is applied in the point of rollers contact with pipe.

EFFECT: technological resources are expanded and quality of manufactured item is increased.

2 cl, 1 dwg

Description

The invention relates to the processing of metals by pressure and can be used to obtain shaped pipes.

A device for the manufacture of pipes with multiple helical corrugations, including a mandrel with protrusions and depressions according to the number of runs of the corrugations, the formation of corrugations on the original pipe, located around it and at an angle to its longitudinal axis with rollers, endowed with the possibility of free rotation

(see patent RU No. 2050213, class C1, B21D, 15 / 04,20.12.1995).

The closest adopted for the prototype is a method of manufacturing pipes with screw corrugations, based on shaping on the original pipe mounted on the mandrel of the corrugations by means of rollers located around the longitudinal axis of the pipe and in contact with its outer surface under the action of the axial force applied to the pipe section that is removed from the rollers and torque coinciding with the direction of rotation of the pipe

(see patent RU No. 2152838, CL B21D 15/04, 1995).

A common disadvantage of these methods are limited technological capabilities: low quality of manufactured pipes due to distortion of the geometric shape of the corrugations with significant heights and elevation angles of the helix. On the one hand, there is a shortage of metal in the corrugation of a part of the pipe, on the other hand, an excess of metal - a splash of the corrugation profile beyond the described circumference of the contour of the profile of the pipe billet, which leads to jamming of the rollers, pinching and distortion of the shape of the pipe surface.

These shortcomings limit the ranges of angles of elevation of the helical line of the corrugations and their height.

The objective of the invention is the expansion of technological capabilities and improving the quality of shaped pipes.

The proposed method for the manufacture of spiral-shaped pipes, based on the formation of corrugations on the pipe, rollers installed around the pipe, the axes of which are located at an angle to the pipe axis, rotating around their own axes due to their contact with the pipe using a mandrel and the simultaneous impact of torque on the pipe and axial force exerted from the side of the pipe section that is removed from the rollers, according to the invention, a mandrel with through channels cut under the rollers is used to form corrugations their contact with the pipe billet during corrugation, the mandrel is installed outside the pipe with the possibility of contact during the corrugation of its inner surface with the tube billet to fit with a gap to ensure fixation and centering of the pipe, and with the profile part of the pipe for transitional fit to limit " corrugations "of the corrugations, while the torque is applied at the place of contact of the rollers with the pipe and additionally run the pipe by rotating rollers around the pipe axis by means of Nia torque to be deleted from the roller portion of the mandrel and fixing the axes of the rollers, wherein the roller axis at an angle of 0 to 90 ° to the tube axis.

The described method allows you to expand the technological capabilities of the process: increase the length of the corrugated pipes, the height of the corrugations, the angle of elevation of the helical line of the corrugations and reduce the thickness of the pipe wall. Thus, to improve the quality of manufactured pipes.

The drawing shows a manufacturing diagram of a spiral profile pipe and a device for its implementation.

The method is as follows.

A mandrel 2 having through channels through which the rollers 3 are in contact with the generatrix of the cylindrical surface of the tubular billet is mounted on the tube stock 1. The mandrel 2 can be made of several sections that differ in inner diameter (d ₁ , d ₂ ) depending on the selected diameter of the original pipe billet 1 and the required parameters of the described circumference of the profiled spiral profile pipe 4.

At the beginning of the work, the rollers 3 are simultaneously (synchronously) moved in the radial direction until they are inserted into the tube stock by a predetermined amount, and the front end of the tube stock is clamped in a gripper (not shown in the drawing).

In the process, an axial traction force P is applied to the gripper, and at the point of contact of the rollers with the tube billet, a torque M with an angular velocity ω.

The axial velocity of the pipe V is consistent with the angular velocity of its rotation ω and the angle of elevation of the corrugations based on the ratio

V = R · tgθ · ω,

where V is the axial velocity of the pipe, R is the radius of the circumference of the pipe, tg is the trigonometric function, θ is the angle of elevation of the corrugations on the profile of the pipe, ω is the angular velocity.

In the above expression, we substitute the known relationship between the angular velocity and the number of revolutions of the pipe per unit time

ω = 2 · π · n,

where π = 3.1416, n is the number of pipe revolutions per unit time.

As a result, we have an expression relating the number of pipe revolutions around its axis and the angle of elevation of the corrugations with the linear velocity of the axial movement of the pipe:

V = 2 · π · R · tgθ · n.

The mandrel can have kinematic connections with the rollers, in the particular case, when the devices for fixing the axes of the rollers are located on its outer surface. In this case, a torque can be applied to the mandrel portion that is remote from the rollers, which will rotate the rollers around the axis of the pipe and thereby run the pipe in addition to the rolling process, which leads to a decrease in the rolling force and an increase in the quality of the finished product.

Depending on the tasks, the mandrel can be made with several sections that differ in inner diameter. The initial part of the mandrel is made with a diameter of d ₁ , contacts the pipe by landing with a gap, and is designed to fix and center the pipe relative to the traction device. At the outlet of the mandrel, the inner diameter of the mandrel d _{2 is} in contact with the profile of the pipe through transition fit. The inner diameters d ₁ and d ₂ may differ from each other or may be equal

d ₁ ≠ d ₂ , d ₁ = d ₂ .

Thus, the mandrel performs two functions: firstly, it fixes and centers the axis of symmetry of the pipe relative to the axis of the traction device, and secondly, it limits the "inflation" of the corrugations of the profile part of the pipe during an imperfect rolling process.

The described method allows to expand the technological capabilities of the process: increase the height of the corrugations, the angle of elevation of the helical line of the corrugations and reduce the thickness of the pipe wall. Thus, to increase the range and quality of products.

Claims (2)

1. A method of manufacturing spiral-shaped pipes, including forming on the corrugation pipe with rollers installed around the pipe, the axes of which are located at an angle to the pipe axis, rotating around their own axes due to their contact with the pipe using a mandrel and simultaneous impact of torque and axial on the pipe the force exerted from the side of the pipe section that is removed from the rollers, characterized in that a mandrel with through channels cut under the rollers for their contact with the pipe billet is used in percent in the course of forming corrugations, set the mandrel on the outside of the pipe with the possibility of contact in the process of forming corrugations of its inner surface with the pipe billet to fit with a gap to ensure fixation and centering of the pipe, and with the profile part of the pipe - on the transitional fit to limit the "bloat" of the corrugations, while torque is applied at the point of contact of the rollers with the pipe. 2. The method according to claim 1, characterized in that the pipe is further run in by rollers rotating around the pipe axis by applying torque to the mandrel portion remote from the rollers and fixing the roller axes, while the roller axes are positioned at an angle from 0 to 90 ° to the axis pipes.