RU2331492C2 - Method of manufacturing screw and section pipes with hollow screw crimps - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method includes forming crimps on the pipe, installed onto workholder with screw surface, using rollers, located around the longitudinal axis of the pipe, under action of axial force, applied to workholder section, remote from the rollers, and of torque, created by interaction of workholder and rollers.The torque is also applied to the section of workholder, which is adjacent to rollers, using a fairlead bush. Inner screw surface of the latter corresponds to screw surface of the workholder, and works in combination with it.

EFFECT: technological features increase, so does the quality of the product manufactured.

2 cl, 1 dwg

Description

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

A known method of manufacturing pipes with multiple helical corrugations, including the formation of corrugations on the original pipe, located around it and at an angle to its longitudinal axis by rollers, endowed with the possibility of free rotation (see Patent RU No. 2050213, class C1, B21D, 15/04, 12/20/1995).

The closest technical solution to the present invention is a method of manufacturing pipes with screw corrugations, including forming on the original pipe mounted on a mandrel, corrugations located around the pipe and at an angle to its longitudinal axis by rollers when moving the pipe along its longitudinal axis under the action of axial force, in the process of forming corrugations, a torque is applied to the pipe section approaching the rollers, and the axial force exerted on the pipe is applied to the part that is removed from the rollers the mandrel weft and by means of the mandrel to the pipe section approaching the rollers (see Patent RU No. 2152838, class 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. The reason for this lies in the large power loads perceived by the surface of the rollers, which leads to jamming of the rollers, pinch and distort the shape of the profile surface of the pipe. Pinching the corrugated part of the pipe makes it difficult to remove it from the mandrel, due to the fact that the removal process from the mandrel of the profile pipe is limited by the technological capabilities of equipment that implements the “turning” of the mandrel from the profile pipe. 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, including the formation of corrugations on a pipe mounted on a mandrel with a screw surface by means of rollers located around the longitudinal axis of the pipe under the action of the axial force and torque arising from the interaction of the mandrel with the rollers that is removed from the rollers, differs from the known method in that a torque is applied to a portion of the mandrel approaching the rollers by means of a guide sleeve, an internal screw th surface relief which corresponds to the spiral surface of the mandrel and running it in tandem, and a receding portion of mandrel rollers torque is applied by creating a rigid contact between the tube and the mandrel.

In addition to the mandrel portion that extends away from the rollers, torque is applied by creating rigid contact between the tube and the mandrel.

Application to the mandrel of the torque directed in the direction of rotation of the pipe allows you to: remove the load of the forced rotation from the rollers; reduce axial force applied to the pipe; to reduce the influence of adverse factors arising from the changing distance between the point of application of axial force to the pipe and the point of contact of the rollers with the pipe; increase axial stability of the pipe-mandrel system, as the mandrel is subjected to axial tension, and the pipe is compressed.

All of the above creates a favorable scheme of pipe deformation and, as a result, allows to increase the L / D, h / D, s / D ratios i.e. expand technological capabilities and improve quality, where L is the length of the original pipe, h is the height of the corrugation, s is the thickness of the pipe wall, D is the diameter of the original pipe.

The drawing shows a diagram of the manufacture of spiral-profile pipes with hollow screw corrugations.

The method is as follows. The source pipe 1 is introduced into the mandrel 2, their front ends are clamped by a gripper 3 to create a hard contact between them. The rear end of the mandrel 2 is screwed into the guide sleeve 4, the rollers 5 are placed around the pipe 1 at a predetermined angle to its longitudinal axis. The rollers 5 are moved to the pipe axis in the radial direction, the initial pipe is compressed and corrugations 6, depressions 7 form on its surface with a helix angle of rotation α °. When the rollers 5 are closed, an axial force P _{1 is} applied to the gripper 3. The force P ₁ is transmitted with a linear speed V _{1 to the} guide sleeve 4 and due to the addition of forces on the screw surface of the sleeve creates a torque M ₁ that rotates the mandrel in the direction of the helix with a peripheral speed ω ₁ . When turning the mandrel through the deformable part of the pipe (6, 7) transmits torque to the rollers. As a result of the interaction of the rollers 5 with the pipe 1, the deformed section of the pipe (6, 7) rotates around the longitudinal axis of the pipe at a peripheral speed (from an equal peripheral speed ω ₂ and moves with a linear speed V ₂ equal to the speed of the mandrel V _1. Thus, in the proposed technical solution there is no speed difference, which ensures the stability of the process of running the source pipe.

In the proposed method, the role of the rollers is reduced only to the run-in of the pipe billet, the role of the mandrel is to remove the profiled part of the pipe (6, 7) from the deformation zone.

Angular ω _1,2 and linear V _1,2 speeds depend on power (Р _1,2 ; М _1,2 ), geometric (L / D; h / D; s / D; α °) and some other factors (for example , cross-sectional shape, number of corrugations).

When V ₁ = V _{2 the} shape of the corrugation corresponds to the profile of the cavity of the helical channel formed by the walls of the mandrel and rollers.

If the velocities V ₁ = V _{2 are} equal, the axial force P ₁ is transmitted to the pipe with a linear velocity V ₁ through the pipe 1 and, due to the addition of forces on the screw surface of the mandrel, creates a torque M ₁ that rotates the pipe 1 by an angle φ together with the mandrel 2 in the direction helix with an angular velocity ω ₁ . When turning, the deformable part of the pipe 6 transfers the torque M _{1 to the} rollers 3. As a result of the interaction of the rollers 3 with the pipe 1, the deformed section of the pipe 6 rotates around its axis with an angular velocity ω ₁ equal to the angular velocity of the mandrel ω ₂ and, subject to the rule of the right screw, moves with a linear velocity V ₁ equal to the linear velocity of the mandrel V ₂ . The stability of the process of rolling the pipe is ensured by copying the mandrel, a die formed by the relief of the mandrel and the profile of the rollers.

When V ₁ > V _{2 the} step of the profile part of the pipe increases, the shape of the corrugations in the axial direction stretches, in the transverse narrows. The movement of the pipe profile part outstrips the movement of the pipe material at the exit of the pinch zone and stretches it, which affects the size of the path traveled by the pipe profile part L ₁ and the mandrel L ₂ , and leads to a decrease in the angle of elevation of the pipe profile part 7, i.e. leads to stretching of the corrugation profile.

When V ₁ <V _{2 the} step of the profile of the pipe decreases, the shape of the corrugations in the axial direction is compressed, elongated in the transverse. The movement of the profile of the pipe lags behind the movement of the material of the pipe at the outlet of the pinch zone and compresses it, which leads to an increase in the angle of elevation of the profile of the pipe 6 and the compression of the corrugation profile.

Reducing the rolling power of profile pipes by N _i allows you to expand the technological capabilities of the process: increase the length of the corrugated pipes being manufactured, the height of the corrugations, the angle of elevation of the corrugation helix and reducing the pipe wall thickness, thereby improving the quality of the pipes being manufactured.

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

Claims (2)

1. A method of manufacturing a spiral profile pipe, comprising forming corrugations on a pipe mounted on a mandrel with a helical surface by means of rollers located around the longitudinal axis of the pipe under the action of axial force and torque arising from the interaction of the mandrel with the rollers removed from the rollers, characterized in that a torque is applied to the mandrel portion approaching the rollers by means of a guide sleeve, the inner screw surface of which corresponds to relief screw mandrel surface and work with it as a couple. 2. The method according to claim 1, characterized in that a torque is applied to the mandrel portion remote from the rollers by creating a hard contact between the pipe and the mandrel.