Method of preparing ends of pipes with inner polymer coating for welding
FIELD: welding jobs.
SUBSTANCE: invention relates to the methods of preparing the ends of pipes with inner polymer coating for welding, and can be used in repair of pipelines. The proposed method consists in the following. A tip with a rubber seal ring is fitted into the pipe with inner polymer coat, the aforesaid seal ring being place on pre-compressed smaller-diameter tip part, some 150 to 200 mm-long. Then using a mandrel, the aforesaid smaller-diameter part is expanded for the pipes ends sizes and shapes to match.
EFFECT: sealing of welded pipes, simpler procedure.
The invention relates to the field of pipeline transport and can be used in the repair of pipelines with internal polymer coating for welding.
It is known that when welding two pipes end-to-end produce preparatory work to edit them all. Edit ends of the pipes necessary to ensure that matches the size and shape of pipe ends if the ends are dents, deviations from the circular shape of the pipe and the diameter from the nominal value.
There is a method of preparation of pipe ends by deformation of the outer centralizer and other devices of the edges of the connected pipe ends (see guidance document. Statement on the elimination of accidents and damage to oil pipelines RD-39-110-91. Rotaprint PI-TER-1992).
The closest technical solution is welded connection of pipes with internal coating and a method of connecting pipes with internal coating (see patent 2140038), namely, that the inner surface of the pipe ends in place surfacing is made in the form of a bell, and the ends of the deposited layers have an annular groove, followed by the cutting edges of the pipe, and before applying a corrosion-resistant alloy inner surface of the pipe end is subjected to processing under the bell, and when the cutting edges for welding to produce an annular groove, blending into the end naplavlennogo the layer, and welding end sections are overlapping seam in two stages, first fill the root seam homogeneous weld electrode layer, and then filling the seam.
The disadvantage is the occurrence of high stresses in the deformation of the metal pipe at the edges of the distributed application efforts and the complexity of the execution of the method.
The purpose of the invention is improving the efficiency of the method by the features of the software matches the size and shape of pipe ends and simplification of the method.
This objective is achieved in that the inner cavity of the pipe with a polymer coating insert the tip with a rubber o-ring located on the pre-reduced in diameter portion of the tip length of 150-200 mm, and then using a mandrel carrying out radiatia reduced diameter portion of the tip to ensure coincidence of the size and shape of the welded pipe ends.
The drawing shows a General view of the device for implementing the method.
The device includes steel pipe 1, tip 2, a rubber o-ring 3 and the inner polymer coating 4.
The method is implemented as follows.
Into the internal cavity of the steel pipe 1 with a polymer coating 4 insert the tip 2 with sealing ring 3 and open it using a mandrel, osushestvlyaem the preparation of connected pipes for welding.
The use of the present invention will allow for the preparation of the ends of steel pipes with polymeric coating, providing match the size and shape of the welded pipe ends.
The method of preparation of the pipe ends with an inner polymer coating for welding, which consists in the fact that the inner cavity of the pipe with a polymer coating insert the tip with a rubber o-ring located on the pre-reduced in diameter portion of the tip length of 150-200 mm, and then using a mandrel carrying out radiatia reduced diameter portion of the tip to ensure coincidence of the size and shape of the welded pipe ends.
FIELD: technological processes; pipes.
SUBSTANCE: dimensions and shapes of joined pipe ends are compared, distributed straightening force direction and intensity is defined, pipe ends dimensions and shapes are matched by application of distributed straightening force to pipe walls along its whole diameter. At that distributed straightening force is applied to pipe generatrix in section, length of which is established depending on intensity of distributed straightening force. In part of section that starts from pipe end, intensity of distributed force is established with constant value, and in remaining part it is evenly reduced down to zero.
EFFECT: reduction of wall surface curvature and lower stress in it.
FIELD: technological processes.
SUBSTANCE: invention concerns electric arc welding, particularly method of automatic argon arc welding of overlapping joints of steel pipes by non-melting electrode. The method involves preliminary pipe edge preparation and welding by tilted electrode with pipes rotating against electrode to form weld seam. Axial rotation speed of welded pipes is 0.1-0.8 rpm. Electrode is tilted in two planes: by 50-70 degrees against the article axis and by 60-85 degrees against weld seam plane.
EFFECT: improved quality of weld seams in overlapping joints of steel pipes, reduced hopping during rotation of long-length welded article, reduced cost of welded product.
3 cl, 3 dwg, 1 tbl
FIELD: technological processes.
SUBSTANCE: invention is related to the method of arc welding in protective gases of butt-welded joint of solid stock with packet from two sheets of the same thickness made of aluminium alloys and may be used in different machine-building industries. Packet sheets are fixed in relation to each other, packet butt joint is assembled with solid stock with thickness that is equal to packet thickness, and welded. Prior to packet sheets fixation top sheet of packet is shifted in relation to the bottom sheet from the joint at the distance of (0.8-1.2)δ, where δ - thickness of sheets in packet. Welding is performed in the mode of full weld penetration of butt-welded joint of solid stocks with thickness equal to packet thickness.
EFFECT: high quality of welded joint.
5 dwg, 1 tbl
FIELD: technological processes.
SUBSTANCE: opening with diameter of D0=(1.05-1.2)d is made in plate, where d- diameter of rivet rod. In top electrode insulating bushing is installed with external diameter of D1=(1.7-2.5)d, in which rivet rod is loosely fit. From the side of rivet head electrode is installed with flat working surface. Value of pulse current is set as equal to value of pulse at welding of packet from two sheets with the thickness of every one equal to the thickness of plate, with duration of pulse of 0.18-0.25 from duration of pulse during welding of package from sheets.
EFFECT: as a result, high quality joint is produced with high strength characteristics.
1 tbl, 7 dwg
FIELD: technological processes.
SUBSTANCE: invention is related to method of electron-emitting welding of thin-walled pipe with wall thickness of less than 1.5 mm with thin-walled bimetallic connector and may be applied for production of crucial items for nuclear reactor core from zirconium alloys and stainless steel of grade X18H10T. Prior to welding welded end of thin-walled pipe is rolled as cone of not more than 14°, and aligning ring bulge is arranged in its end. Welded end of bimetallic connector is shaped as cone in a similar manner and aligning ring groove is arranged in its butt-end for ring bulge at pipe butt-end. After that split retaining rings are installed on welded ends of pipe and connector at the distance from butt-ends of not more than 5 mm. Welding is made with heating spot of electron beam with diameter of not more than 0.5 of thickness of pipe welded wall with welding speed of not more than 20 m/hour. Heat spot of electron beam is oscillated with frequency of not more than 50 oscillations per second symmetrically to line of joint by trajectory of semi-ellipse with length of small axis not more than thickness of pipe welded wall thickness.
EFFECT: high quality welded joints.
3 cl, 5 dwg, 1 ex
FIELD: instrument making.
SUBSTANCE: invention relates to techniques associated with preparation for assembly and assembly proper for welding thin-wall pipes and a bimetal adapter used in the reactor fuel core. The pipe and the adapter are fitted in split ring shrouds allowing the pipe and shroud ends to extend beyond the shroud boundaries. The thin-wall pipe end gets flared from inside to make a taper with an angle not exceeding 15°. The adapter to be jointed is shaped similarly. On the adapter end face a circular inner groove is made, its depth not exceeding the wall thickness, while, on the pipe end face, a circular flange is made with its outer diameter equal to inner diameter of the adapter circular groove. The pipe and adapter end faces to be welded together are fixed as-assembled using an internal tightening device.
EFFECT: accurate alignment in assembly for welding is ensured along with preservation of cylindrical form of jointed parts after welding.
2 cl, 8 dwg
SUBSTANCE: body of the product is formed. The area surrounding the defect is removed, including the defect that occurred on the processed product body surface during forming, making a recess in the processed surface. Deposits from the depositing tool (electrode) formed by pressing powder consisting of essentially of the product body metal are settled filling the recessed area. Processing is performed in an electrospark discharge machine.
EFFECT: eliminates thermal deformation at periphery of recessed area; increases metallic product manufacture quality.
17 cl, 21 dwg
FIELD: mechanical engineering; welding of rails.
SUBSTANCE: cross cut along vertical plane from head of rail to beginning of rail foot is made on edges of rails 1 and 2 or on edge of one of rails. Horizontal cut is made along end face surface of rails or rail square to previously made cut, and chamber at angle of 45° is made on end face surface of foot to form root face 3 at base of foot. Rails are installed at require technological clearance 4. Welding wire is fitted into clearance together with insulated end tip of electrode holder of semiautomatic welder. Electric arc welding is carried out continuously over entire height of rail with use of side forming crystallizers-straps in zone of welding out welding current providing formation of liquid bath over entire space of technological clearance. Liquid bath in root of weld is obtained owing to melting of edges of rail main metal.
EFFECT: improved mechanical properties of weld and increased welding rate, facilitated welding.
FIELD: mechanical engineering; argon-arc welding.
SUBSTANCE: invention relates to methods of automatic argon-arc welding of austenitic steel pipes in manufacture of important constructions, such as high-pressure pipes used at nuclear power stations. Proposed method includes mechanical preparation of welding surface zone, veeing edges to miter of 3.0-3.5 mm and subsequent multiple-pass welding with nonconsumable negative electrode using filler wire. Welding edges are veed to miter of 2.7-3.0 mm. Welding at first pass is carried out with heat input of 0.35-0.55 MJ/m by impulse current. Welding at second pass is done with heat input of 0.6-0.86 MJ/m by impulse current at cross oscillations of electrode. Welding at third and subsequent passes is carried out with heat input of 0.62-1.16 MJ/m by steady current with cross oscillations of electrode.
EFFECT: increased capacity art welding and quality of weld joint owing to reduction of intercrystalline cracking of weld joint.
FIELD: welding processes and equipment, namely methods for protecting inner surface of welded seam of parts having inner multi-layer protection coating with fragile layers against corrosion action of aggressive medium.
SUBSTANCE: method comprises steps of forming beads 3 on portions of surface of parts 1, 2 without coating; assembling parts according to beads and welding with use of single heating source; applying multi-layer coating; before applying coating forming protrusions 4 on shaped beads and forming cavity 7 under them; at assembling providing touching along surfaces 8 of said protrusions for further welding; forming portion of bead surface under protrusions without inner layer of coating; filling part of cavity between protrusions and end of inner layer of coating with material of outer layer or layers 6; providing thickness of protrusion no less than total thickness of inner and outer layers of coating; using as outer layer or layers of coating material thermally softening at high temperatures during welding process.
EFFECT: improved operational reliability, enhanced protection of parts having inner protection coating with fragile layers.
FIELD: plastic working of metals, namely processes for forming butt welded seams on tubes at making tube studs of U-shaped tube bundles using effect of localized hot plastic deforming of welded seam and near-seam zones.
SUBSTANCE: method comprises steps of preliminarily working tube ends by expanding them from cylinder to cylinder; assembling tubes with use of mandrel and placing intermediate member of additive material between joined end surfaces of end portions of tubes sized by expansion and end surfaces of step ring. Welded seams are formed by argon-arc welding due to melting material of intermediate member at its both sides adjacent to tube ends. The intermediate member is heated up and it is subjected to hot radial squeezing while concentrating its initial deformation in surface layers according to position of ring steps, welded seams and near-seam zones on mandrel for providing size of their outer diameter equal to initial outer diameter of tubes.
EFFECT: improved quality of welded seams.
FIELD: plastic metal working, possibly in crimping machines.
SUBSTANCE: crimping die set and coupling are used for holding worked part in crimping machine. Coupling is placed onto worked part with possibility of unclamping and it has fist clamping portion and second clamping portion mutually joined through hinge. Crimping die set may be inserted to crimping machine. Said die set has groove for worked part and recess for coupling on its working surface. Recess for coupling has configuration necessary for holding coupling in it. In order to crimp part in crimping machine, coupling is arranged around part in predetermined position and then it is tightened around part. Coupling and article are inserted into recess for coupling and groove for article respectively in crimping die set. Then die set with coupling and article is placed into crimping machine.
EFFECT: enhanced efficiency and reliability of crimping process.
13 cl, 6 dwg
FIELD: ventilation and air conditioning.
SUBSTANCE: connection by tight folded seam of two flexible metal pipes, sections of pipelines, segments or elbows of pipes used to transmit flows of gas is provided with double fold in form of flange at end of first pipe enclosed by second double fold made on end of second pipe at least with partial adjoining to shape and provision of enclosing solid metal sealing. Connection is formed by outward flanging universal bending or edging machine provided with forming rolls installed for rotation and feed rolls installed fro displacement in one plane. Said rolls are set into motion by motor and project from machine table. At first stage of operation double in form of flange is made on end of first pipe, and at second stage, step member is formed on end of other connected pipe. Width of step member exceeds size of double bend in form of flange. At third stage member is driven over double bend and projecting part of step member is pressed tightly to double bend with enclosing of bent and provision of sealing. Shifted lower roll of device is made in form of hollow shaft accommodating drive shaft carrying axially secured forming roll. Feed roll is made in form of hollow shaft which accommodates drive shaft carrying upper shifted forming roll. Feed roll and lower are mounted in slides to provide synchronous displacement. Rolls are also installed in slides for displacement in direction of axially secured forming roll and shifted lower roll.
EFFECT: provision of high tightness of connection.
4 cl, 11 dwg
FIELD: machine engineering, namely joining of constructional members of articles, for example flexible members and tips.
SUBSTANCE: method comprises steps of changing shape and size at least of one of joined members at using forces of interaction of electromagnetic fields of electric currents to be passed through electric current lead. Shape and size of joined members are changed due to moving movable members of shaping tool by action of forces caused at direct interaction of electromagnetic fields of electric currents. On portions of electric current lead turned to movable members of shaping tool electric current are passed in one direction while moving said portions together with movable members of tool. On portions of electric current lead remote from movable members electric currents are passed in opposite direction and motion of said portions is limited by means of restriction members.
EFFECT: enhanced efficiency of process, lowered energy consumption of used equipment.
FIELD: plastic working of metal.
SUBSTANCE: clamping-tool device 29 in the form of tongs for placing mechanic fixing organs includes first member for placing, limiting and (or) measuring path portion, length or distance at arranging fixing organ; second member for placing, limiting and (or) measuring at least one component of effort created at moving or overcoming path portion in fixing organ or by means of fixing organ.
EFFECT: enhanced quality of assembling process.
9 cl, 9 dwg
SUBSTANCE: proposed stand comprises a carcass, driven roller and pay-out rollers. It features an optimum kinematic arrangement. One of the driving roller shaft supports is movable. The mandrel with the disk to be straightened attached thereon is mounted in two supports arranged on the guides to move along the direction of the driving roller, fixed by a locking device.
EFFECT: simpler design, ease of operation plus lower metal input.
2 cl, 1 dwg