WO2013163972A1 - Method for applying a corrosion and/or wear-inhibiting metallic coating onto the inner lateral surface of a metallic tubular body by means of magnetic impulse welding; and a welding jig comprising a blade-type coil - Google Patents

Description

METHOD FOR APPLYING A CORROSION AND / OR WEAKNESSHOLDING

METALLIC COATING ON THE INTERNAL COATING AREA OF A METALLIC,

TUBULAR BODY BY MAGNETIC PULSE WELDING; WELDING DEVICE WITH A SPOOL OF A SWITCHED TYPE OF SWORD

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The invention relates both to a method for applying a

 Corrosion and / or wear-inhibiting, metallic coating on the inner circumferential surface of a metallic, tubular body, using a corrugated sheet of the corrosion and / or

 anti-wear metallic material, wherein the domed metal sheet is impacted by high kinetic energy

 Inner shell surface of the tubular body is connected to the tubular body, as well as a welding device for welding a curved plate, in particular an inner sleeve on the

 Inner circumferential surface of a tubular body.

From DE 18 04 55 A is a device for

 Magnetic impulse pressure deformation for the connection of two components known, in which case the outer component to the inner member by way of

 Magnetic pulse welding technique is applied. DE 69634343 T2 describes a method for connecting components by means of

 Magnetic pulse welding z. B. in the production of frames for

 Motor vehicles. That is, here, for example, the ends of two frame beams are welded together by means of magnetic pulse welding.

From DE 10 2006 050 292 A1, the fixing of a sleeve in a bore 3o by means of a press-fitting of the sleeve in the bore is known. In this case, the sleeve is pressed by magnetic pulses against the inner wall of the bore. In this press-fitting process, the edge layer of the bore is plastically deformed, which leads to the development of residual compressive stresses in the edge region, whereby the sleeve is finally held. The sleeve itself, from z. As steel, the safe recording of a screw against the background, that the material of the bore, z. B. aluminum is very soft, and therefore for the transmission of large forces, eg. B. by means of a screw, is unsuitable. A material connection through a

 Welding of the two components does not take place here, since the Wandungo the sleeve is not accelerated, since the sleeve is in the initial state substantially already applied to the bore wall. However, a high kinetic energy impact of the sleeve on the edge region of the bore would be a prerequisite for a weld, so a material connection.

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 For the transport of corrosive or abrasive media in a pipeline already plated steel pipes, so-called CLAD pipes are used, the inside of a metallic coating of a corrosion and / or wear-inhibiting metallic material, eg. B. Edelstahlo and consist of standard steels outside. The advantage of

 Use of such CLAD tubes is that the

 Coating material as a "white material" relatively thin on the

Inner circumferential surface of a tube made of a conventional C-steel (black material) can be applied. The bearing pipe portion 5 can therefore be made of a relatively cheaper material, as the coating. In this context, from DE 582 387 A a method for the production of CLAD tubes is known in which initially two sheets are joined together, namely on one side a sheet of black material and on the other side a sheet of white material as stainless material. The two sheets are spot welded together, then in the following Operation to roll the sheet to a tube. Such a clad material combines the cost advantages of conventional steel with the performance of e.g. As stainless steel in relation to the

 Corrosion resistance and wear resistance. Such CLAD

For example, 5 pipes are used as pipelines on large oil and gas fields for the connection of offshore platforms to the mainland or as

 Connecting pipes in refinery and plant construction. Such pipes must, especially if they are no longer or only very difficult to access after installation, the highest quality requirements

i o correspond. In particular, the permanent connection of the inner coating to the inner circumferential surface of the outer tube must be ensured in this respect. In particular, the adhesive forces must continue to be such that they are able to withstand the effects of force, such as those laying such pipes z. B. occur on the seabed.

 15 In fact, in such pipes, when laying in the sea due to the S-shaped formation of the pipes in the transition from the ship to the seabed, often the inner lining or the inner shell due to the resulting stresses of the outer tube dissolves because the welded surface for receiving the resulting thrust and

20 tensile forces between the two material layers is too low.

Another well-known method for coating the inner wall of a pipe is so-called powder build-up welding, which, however, is also very expensive, among other things, since there is a mechanical post-treatment of the welded-on inner layer

 required. However, such a coating is high

 corrosion-resistant, partly because stainless steels and nickel-based alloys can be used.

Conceivable in this context is the production of

corrosion resistant coatings on the inner surface of a tubular body by explosive plating. By explosive plating or explosion welding, the coating material is accelerated to the material to be coated by means of an exothermically reacting explosive and thereby joined. The quality of the connection is in

5 Substantially dependent on the speed of impact of the accelerated material on the inner surface of the outer (black) material.

Explosive plating is not very practicable as a manufacturing process, because it has to be handled with explosives.

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 The object underlying the invention is therefore to provide a method for coating the inner circumferential surface of a tubular body with a sheet that reproducible

 Welding joints of the same quality and quality between the sheet and the tubular body allows.

To solve the problem, it is proposed by a method of the type mentioned that the sheet with the inner circumferential surface of the tubular body in sections circumferentially by

o Magnetic pulse welding is connected. The connection is made

 cohesive, but not necessarily over the entire surface. In magnetic pulse welding, the effect of a pressure wave to

 Welding of overlapping workpieces used. The pressure wave is generated by pulsed electromagnetic induction and force5. Specifically, in magnetic pulse welding by means of a capacitor discharge, a high current pulse is generated, which is conducted into a stable magnetic coil. The coil creates a strong magnetic field. The magnetic field induces current into the electrically conductive sheet which generates a magnetic field which is opposite to the magnetic field generated by the coil. The sudden construction of two

opposite magnetic fields provides in the present case for the explosive acceleration of the sheet on the inner shell of the tubular body. The connection mechanisms are comparable to those of explosion welding or explosive plating.

5 Advantageous features and embodiments of the invention will become apparent from the dependent claims.

Thus, it is provided in particular that the sheet is tubular

 Inner sleeve is formed, wherein advantageously the tubular inner sleeve i o has a longitudinally extending slot. By the

 Using a slotted sleeve is achieved at every

 Magnetic pulse welding process, the distance of the white material to the black material is just as adjustable that the

 Acceleration values and thus the impact speed just so

15 is great that it comes to a joining process. Would be the distance

 between the white material and the black material too large, then the acceleration distance would be too large, with the result that the forming work is too large, hence the

 Impact speed for a joining process between the white and

20 the black material is too low. That is, a certain kinetic energy is needed to ensure welding of the white and black material.

According to a further advantageous feature of the invention it is provided 25 that the tubular body is slotted in the direction of the longitudinal axis. In conjunction with the slotting of the inner sleeve and the overlapping of the slots is thereby achieved that the leadership of the cable can be done to the coil through the two slots. The welding of the slotted inner sleeve on the inner circumferential surface of the tubular body 30 is now carried out such that the sleeve-shaped sheet has an extension in the direction of the longitudinal axis of the tube, which is at least smaller than the length of the coil used to generate the magnetic pulse.

 Circumferentially circulating is now the coil on the

 Inside the slotted sleeve guided along, in which case also sections, the inner sleeve in the manner of a point or

 5 Strichverschweißung is connected to the tubular body. In this case, the sheet of an electrically conductive material is advantageous

 educated. The magnetic pressure is dependent on the

 Conductivity of the coating material, ie the sheet. Is the

 Conductivity too low, so the use of so-called i o driver materials in question. By a driver material is meant a material of high electrical conductivity, ie z. As aluminum. This driver material rests directly on the white material, wherein the current induced by the magnetic field in the driver material of the inner sleeve then provides the required strong magnetic field, which is the

 15 magnetic field in the coil is opposite. By doing that

 Driver material rests directly on the coating material, the two materials are not accelerated relative to each other. That is, the driver material can be removed from the sheet after the actual coating process. After coating the

 20 inner lateral surface of the tubular body, which may also be slotted, as already stated, with the material of the inner sleeve, the individual segments of the inner sleeve are welded together. Also, the outer tube and the inner tube are welded in the region of the respective slots, wherein it should be ensured that a mixing of the

25 both materials is avoided if possible.

The segmental welding of sheet metal segments or inner sleeves of small axial extent has the further advantage that due to the explosive acceleration of the sheet on the inner circumferential surface 30 of the tubular body to scale layers. On the surfaces flake off and thus a uniform intensive welding

is guaranteed.

The invention is also a welding device for

Welding an inner sleeve to the inner circumferential surface of a

tubular body as described above, wherein the

Welding device according to the invention characterized in that the coil is formed in the manner of a sword. The trained in the manner of a sword coil has a height which corresponds to the diameter of the tubular body to be coated or the diameter of the

Inner sleeve corresponds. In any case, make sure that the height of the coil formed as a sword is chosen so that the distance of the coil to the curved plate, in particular the inner sleeve can be set to the optimum value. The coil itself has only a single turn, and is formed in the manner of a plate, in particular in the manner of a rectangular plate. In the region of the plate, in particular the rectangular plate, an L-shaped slot is arranged, wherein the long leg of the L in the plate-shaped coil (flat coil) parallel to the longitudinal axis of the plate-shaped,

in particular rectangular coil extends.

It is essential in the magnetic impulse welding with the spool formed as a sword that the sword during the

Welding process is held rigid. Otherwise, the impulse to the white material may be too low to cause a mating between the two materials.

With reference to the drawings, the invention will be explained in more detail below by way of example. Fig. 1 shows schematically a slotted tubular body of black material, wherein in the tubular body is a slotted sleeve of white material;

FIG. 1 a shows an enlarged detail of FIG. 1; FIG.

Fig. 2 shows a representation according to FIG. 1 a, wherein the white

 Material of the inner sleeve with a driver material, eg. B.

 Aluminum is occupied;

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 Fig. 3 shows the type of connection between the tubular

 Body on the one hand and the inner sleeve on the other;

Fig. 4 shows schematically the trained as a sword coil.

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 According to the figures, the tubular body is denoted by 1. The tubular body has a slot 2, wherein in the slotted tubular body 1, a slotted inner sleeve 10 is inserted, which is formed from the coating material. The inner sleeve is as

Formed sleeve segment and has a length corresponding to the length of the formed as a sword coil. The slot of the inner sleeve is denoted by 12. The tubular body may have a length of up to 12 m. The diameters of such CLAD tubes can be up to 500 mm. In the drawings according to FIG. 1 or FIGS. 1 a and 5 2 a, the coil represented schematically by 20 can also be seen. The coil is located immediately above the white material, due to the slotted inner sleeve, the distance X (Figure 1 a) between the inner circumferential surface of the tubular body on the one hand and the outer lateral surface of the slotted sleeve on the other hand is adjustable.o The distance X is here the acceleration distance, which is required for the sheet metal of the inner sleeve with the required Impact speed on the tubular body of black material impinges, so ultimately can develop the required kinetic energy. The connection of the inner sleeve or a curved plate with the tubular body takes place in sections on the inner wall of the tubular body circumferentially.

If the conductivity of the white material is too low, then comes

Driver material with a better electrical conductivity is used. This means that, for example, the inner sleeve or the curved plate is provided on the inside with an aluminum layer. These

 Aluminum layer is directly on the white material, that is, the coating material, wherein the positive force acting on the driver material is transferred directly to the white material by the positive connection between the white material and the driver material. A

cohesive connection between the driver material on the one hand and the white material on the other hand is not to be feared, since there may be no relative movement between the white material and the driver material. The driver material, for example a coating of aluminum is designated 15.

From Fig. 3 it can be seen in the development that the welding of the white material with the black material is linear or line-shaped, wherein the width of the stroke corresponds approximately to the width and the length of the stroke approximately the length of the formed as a sword coil , It can thus be seen that the magnetic impulse welding method does not make a full-surface connection of the white material to the black material, but, similar to spot welding, only the two materials are locally connected. The distances between the individual welds, ie the joint distances and the shape of the joint can be freely selected by the shape of the sword. Once the white material is circumferentially bonded to the black material, the coating material is firmly on the inner circumferential surface of the black material of the tube 1. After the coating is completed, first the individual sleeve segments of the inner tube are welded together. Thereafter, the welding 5 of the slot 12 takes place on the inside to then weld the slot 21 of the tubular body, so the outer tube.

From Fig. 4, the shape of the formed as a sword coil can be seen. The sword 20 has a in a rectangular plate of i o electrically conductive material, for. As copper, arranged L-shaped slot 21, wherein the long leg 21 a of the slot is parallel to the longitudinal axis of the sword. This creates a coil with one turn. The length of the sword can be about 1, 0 m to 1, 5 m; the thickness of the sword amounts to max. about 10 mm.

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LIST OF REFERENCE NUMBERS

1 tubular body

2 slot

 10 inner sleeve

 12 slot

 15 shift

 20 coil

 21 L-shaped slot

21 a thigh

Claims

Claims: 1. A method for applying a corrosion and / or  wear-resistant, metallic coating on the  Inner circumferential surface of a metallic, tubular body (1) by means of a sheet (10) of the corrosion and / or  anti-wear, metallic material, wherein the sheet (10) by striking with a high kinetic energy on the  Inner circumferential surface of the tubular body (1) is connected to the tubular body,  characterized,  that the sheet (10) is curved and with the  Inner circumferential surface of the tubular body (1) is partially connected circumferentially by magnetic pulse welding. 2. The method according to claim 1,  characterized,  that the sheet (0) is designed as a tubular inner sleeve. 3. The method according to claim 2,  characterized,  the inner sleeve has a slot (12) extending in the longitudinal direction of the sleeve. 4. Method according to one of the preceding claims,  characterized, that the sheet (10) is electrically conductive. 5. The method according to any one of the preceding claims,  characterized,  the sheet (10) has a layer (15) of an electrically conductive material. 6. The method according to claim 5,  characterized,  in that aluminum is used as the layer (15) of electrically conductive material. 7. The method according to any one of the preceding claims,  characterized,  in that the tubular body (1) has a slot in the direction of the longitudinal axis. 8. Welding device for welding a curved plate, in particular an inner sleeve on the inner circumferential surface of a tubular body according to one or more of the preceding claims,  marked  by a coil (20) designed like a sword. 9. Welding device according to claim 8,  characterized,  that the coil has a one-sided winding. 10. Welding device according to one of claims 8 or 9,  characterized, that the coil is formed in the manner of a plate. 11. Welding device according to one of claims 8 to 10,  characterized,  that the coil is formed in the manner of a rectangular plate having an L-shaped slot (21).