The method of formation of permanent joints on pipes

 

The invention relates to the field of metal forming, namely the processes of formation of permanent joints on pipes using the effect of local deformation of the intermediate element in the form of a sleeve of plastic material. The distribution of end tubes have a split in the matrix. In the resulting cavity install a sleeve of plastic material and produce axial compression. Install the mating pipe end is free of the sleeve volume of the cavity before the formation of its contact with the end face of the sleeve. Before orbital welding load connected elements of the axial compressive force with the formation density at the contact surfaces. This allows to obtain improved strength characteristics of permanent connections and ensure high corrosion resistance. 4 Il.

The invention relates to the field of metal forming, and in particular to the processes of formation of permanent joints on pipes using the effect of local deformation of the intermediate element in the form of a sleeve of plastic material.

A known method of forming permanent connections on the pipes, including the preparation of the pipe for welding,the pipe from movement and subsequent orbital welding of connected elements (see Orlov P. I. design principles. Engineering, M. p. 175, Fig.195-1).

To the disadvantage of the known method include the reduction of the cross-section at the location of the weld due to hit grata in the cavity formed by the connected pipes. By reducing the flow area changes the nature of the flow of the working fluid passing through the pipes, the formation of stagnant zones, which intensify corrosion, in conditions when the permanent connection is experiencing tensile tangential stress. Reference to technical documentation for refineries received the permanent connection is controlled by x-ray analysis, and the passage of the ball of the appropriate diameter. It also requires high qualification of the welder, which, however, does not guarantee the absence of defects.

There is also known a method of forming permanent connection of pipes, including the preparation of pipe ends to the Assembly, the hand of one of them up to a diameter exceeding the outer diameter of the coupling end of the pipe, the installation of the latest in oral, received by the hand, and the subsequent orbital welding of connected elements at the end of distributed pipe end (see Orva is the presence of a cavity, formed by a conical transition area of one of the pipes and the end of the return pipe. The working fluid supplied to the pipeline, is also located in the stagnant zone with known effects on the character of its course and effects of corrosion on the performance characteristics of permanent connection.

Object of the invention is to provide such a method of education permanent connection, which would not change the nature of the flow of the working fluid would meet the requirements of a minimum cost, and would provide enhanced performance characteristics.

The technical result is achieved in that in the method of forming permanent connection of pipes, including the preparation of pipe ends to the Assembly, the hand of one of them up to a diameter exceeding the outer diameter of the coupling end of the pipe, the installation of the latest in oral, received by the hand, and the subsequent orbital welding of connected elements at the end of distributed pipe end, according to the invention the distribution of the end tubes have a split in the matrix, then, without releasing the last received in the cavity installing a sleeve of plastic material and produce axial compression, squeezing materialelor the end of the pipe in the cavity of the pipe to the education of his contact with the end face of the sleeve, and before orbital welding load connected elements of the axial compressive force with the formation density at the contact surfaces.

The proposed method allows to obtain high-quality detachable connection, which does not change the nature of the working fluid in the pipeline, meet the requirements of minimum cost and provide increased performance characteristics.

This is because using an intermediate element in the form of a sleeve of plastic material, eliminate the profiling of the inner surface of one of the adjacent pipes and the possibility of formation of stagnant zones. The implementation of orbital welding of connected elements in terms of their axial compression allows you to create compressive residual stresses in the weld. The latter is controlled by cheaper means, such as eddy sensors.

The invention is illustrated by drawings, where Fig.1 shows the initial position of the profiled end of the pipe segment split matrix (in working position), sleeve of plastic material and a stepped punch before elimination of profilesthe inner surface of the pipe; Fig.2 - stage end of videoslove axial loading of connected elements; in Fig.4 - permanent connection to the pipes.

Variant implementation of the invention consists in the following.

Heat transfer pipe 1 (Fig.1) perform operations with the aim of preparing the outer surface of its ends to the profile: edit pipe, cut it length and scraping the surface of the ends to the metal layer.

Next, perform the profiling of the end of the pipe for which it is fixed from possible movements and through hard punch to produce the distribution end to the outer diameter exceeding the outer diameter of the end of the mating pipe.

Then the pipe is fixed from possible movements and through radial movement of the segments 3, matrices with step working cavity cover the external surface of the pipe section is subjected to the hand.

Then in the cavity of the tube end is placed a sleeve 2 of plastic material. At the final stage of Assembly tooling, pipe and sleeve into the hole of the latter with a minimum gap set speed punch 4 (Fig.1)

Applying axial force to the end face of the stepped punch, cause its movement and, as a consequence, the extrusion of the material of the sleeve in the axial direction with fill wavetoy of the pipe to the education of his contact with the end face of the sleeve.

The joined items before welding load axial force. Produce their orbital welding. The heat of connected elements through the heat also causes heating of the bushing material. Since the coefficient of linear expansion of the last several times higher than the coefficient of pipe materials and the connecting elements experience a compressive force, a further loading of the sleeve with the formation density at the contact surfaces (Fig.3).

The release pipe from axial loads, taking into account the tensile axial residual stresses in the material of the sleeve causes the formation of compressive stresses in the weld, increasing its strength characteristics.

Thus, by controlling the residual stress in the weld is possible to evaluate the quality of permanent connection.

Pilot validation of the developed method was the formation of permanent joints on pipes of steel 20. Initial geometrical dimensions of the tube were: outer diameter - 25 mm, wall thickness - 2.5 mm External profiling the ends of the pipes was carried out in industrial equipment horizontal hydraulic press, double action, alum who, avnue 0,6 MN. The cylindrical section after the distribution of end-of-pipe had a length of 20 mm with an inner diameter equal to the 25+0,05mm

The sleeve was made of aluminum alloy brand AMG-6 with a length of 18 mm, an external diameter of 24,9 mm and hole diameter and 19.4 mm, equal to the diameter of the holes in the pipes.

Orbital welding was performed in accordance with the recommendations for welding of steels.

Tooling for extrusion of the material of the sleeve was made of tool steel WA with hardness after quenching is not less than 56 units and precision of the Executive sizes 9-th degree.

The formation of a permanent connection with the use of intermediate elements guarantees the high performance characteristics of compounds; removes any defects that affect the operation of the products, for example, U-shaped tube bundles.

The tensile tests confirmed the improved strength characteristics of the permanent connection.

The density of permanent connections in combination with high corrosion resistance provided 100% of their suitability to the requirements of production.

The invention is applicable in the manufacture of U-shaped troublesome.

Claims

The method of forming permanent connection of pipes, including the preparation of pipe ends to the Assembly, the hand of one of them up to a diameter exceeding the outer diameter of the coupling end of the pipe, the installation of the latest in the cavity, the obtained distribution, and subsequent orbital welding of connected elements at the end of distributed pipe end, wherein the distributing end of the tubes have a split in the matrix, then, without releasing the last received in the cavity installing a sleeve of plastic material and produce axial compression, squeezing the material of the sleeve in the axial direction with filling the available free volume, then carry out the installation of the mating end of the tube in the cavity of the pipe to the education of his contact with the end face of the sleeve, and before orbital welding load connected elements of the axial compressive force with the formation density at the contact surfaces.

 

Same patents:

The invention relates to the processing of metals by pressure and can be used when attaching the tubes of heat exchangers using the effect of localized directional plastic deformation of the pipe material

The invention relates to the processing of metals by pressure and can be used when attaching the tubes of heat exchangers using the effect of localized directional plastic deformation of the pipe material

The invention relates to the field of metal forming and can be used when attaching the tubes of heat exchangers using the effect of localized directional plastic deformation of the pipe material

The invention relates to the field of metal forming and can be used in the combined fixation of the tubes by mechanical rolling and welding

The invention relates to the field of metal forming, in particular to the processes of the combined fastening of the tubes by mechanical rolling and welding

The invention relates to the processing of metals by pressure and can be used when fixing the pipe with bimetallic profiled ends in tube sheets of heat exchangers

The invention relates to the processing of metals by pressure, in particular to the process of fixing the pipes in the pipe hole heat exchangers using the effect of localized directional plastic flow of the material pipe

The invention relates to the field of metal forming and can be used when attaching the tubes of heat exchangers

The invention relates to the field of metal forming

The invention relates to the field of metal forming

The invention relates to the processing of metals by pressure, and in particular to methods of producing flare on the pipe ends, and means for forming, and can be used in the aviation industry in the manufacture of hydraulic gas pipeline systems

The invention relates to the field of metal forming, namely to set tip carnerosana in steel pipe, lined with PE sheath

The invention relates to mechanical engineering and can be used to produce membranes consisting of patches of different shapes, for example, cone and cylinder

The invention relates to the processing of metals by pressure, in particular to the distribution pipe in a rigid matrix

The invention relates to a stamping parts from billets and can be used for distribution pipe ends

The invention relates to the processing of metals by pressure and can be used in aviation, shipbuilding and related industries

The invention relates to the field of metal forming and can be used in aviation, shipbuilding and related industries

The invention relates to the processing of metals by pressure, namely the parts are manufactured from billets

The invention relates to the field of metal forming, namely, stamping parts from billets, and can be used in aviation, shipbuilding and related industries

The invention relates to the processing of metals by pressure and can be used when attaching the tubes of heat exchangers using the effect of localized directional plastic deformation of the pipe material
Up!