DE8007034U1 - CONNECTING PIPE - Google Patents

Description

AND DR. ΒΒ ^ ΟΗ '^ Έ.ύ CJb'BAiU BR NATIONAL. PCT AND

DUCK PATENT LAWYER EUROPEAN PATENTS

ZUCELABfSlSN AT THE EUROPEAN PATENT OFFICE TRADEMARKS

CEHMAN AND KUHOPEAN PATENT ATTORNEY LICENSE AGREEMENTS

August 28, 1981 1G-4O87

description

to the utility model application

NYBY UDDEHOLM AB 64480 Torshälla / Sweden

concerning
Composite pipe

The present invention relates to a composite pipe whose wall has a layered structure with at least two layers lying one behind the other in the radial direction and extending in the circumferential direction made of at least two different materials, in particular at least two different steel qualities, e.g. carbon steel and stainless steel. Furthermore, the present invention relates to a process for the production of such composite pipes by powder metallurgy, in which by atomizing melts of the materials in question, powders mainly consisting of spherical particles in the layered structure are filled with corresponding compartments of a metallic hollow cylindrical shell and by vibration and / or Ultrasound to about 60 to 70 %

BORO: 80C0 K 24337 AND 292561 POST CHECK ACCOUNT MUNICH

ZWEIBROCXEI. ".." .. "." ".". '".' I pat-cj 5519-803 (BL2 70010080)

INPUT MOI. ". I '.'. '..''.'.'.' .. '. HESSE (CABLES) BAYER.VEREINSBANK MUNICH

(NEXT TO ".." · .. '· ..''.' .. '' .. ''. TVONCHEN ACCOUNT 565500 (BLZ 70020270)

and by isostatic cold pressing of the closed casing to at least 80 % of the theoretical density and the pressed body produced in this way is heated and then hot extruded into a tube.

There is already a method for producing composite pipes made of stainless steel and another high-alloy steel, in which two different powders, which were produced by atomizing melt in inert gas from the stainless steel and the high-alloy steel and consist mainly of spherical particles, in one made of ductile metal, hollow cylindrical, thin-walled shell are filled, which has one or more concentric and removable partitions, the powder particles of the different steel grades are filled into the spaces with simultaneous vibration and after removing the partitions and evacuating and closing the shell, these are pressed cold isostatically is said to be further compressed by the vibration already to about 60 to 70 I of the theoretical density compacted powder fills at least 80% of the theoretical density and the compacted body thus obtained is heated and then hot with the shell network

■ · · · · Ji I · ■

• · · · _ (■ Il
3

The outer surface layer is extruded into a tube (DE-AS 24 19 014).

It has now been shown that in the case of the aforementioned
known method produced composite pipes at the
Border between the different steel grades
existing powder fillings transition zones arise, their

Expansion and its material properties fluctuations

1 and their thickness and properties therefore vary | ^;

can ieren. In particular if the composite pipe is not Jj

from two approximately equally thick, in the radial direction behind- | '

layers lying on top of one another and thus the limit ': $

between the powder fillings made of different steel- $

■■ '' ■ -ι

quality is not in the neutral zone of the pipe, i; | can the aforementioned, uncontrollable transition zone
between the layers of the composite pipe made from powder fillings of different steel qualities; ' Uniformity of the quality of the composite pipes produced.: Affect, especially if
a layer of the composite pipe is relatively thin or that
Composite pipe is made from more than two, for example three, layers.

The object of the present invention is to provide
a composite pipe with improved quality, the
can be produced economically and in a simple manner.

According to the invention this object is achieved in that to avoid transition zones either at the borders Metallic intermediate layers are inserted between the powder fillings, which are preferably made of a material such as e.g. nickel, which allows the diffusion of admixtures and / or alloying elements, in particular of carbon, inhibits or prevents, or one of the powder fillings is filled in a second inner shell, which is inside the first-mentioned outer shell is arranged

or one of the powder fillings through a compact inserted into the cavity of the outer shell or made of solid Material existing pipe section is replaced.

The composite pipe according to the invention offers the advantage that the filling of the powder fillings is simplified and these are precisely separated from one another and are indefinite and uncontrollable Transition zones between the layers made of different materials can be avoided and that the physical and chemical properties of the composite pipe over its entire length and over the entire circumference are essentially constant, so that the composite pipe according to the invention in exactly the same Have quality produced industrially. This also applies if the layers differ greatly from one another Have thicknesses and in particular one layer is very thin.

Because of the compartments, according to the invention, at the boundaries between the compartments made up of powders of different materials metallic intermediate layers made of a material such as nickel, inserted into the outer shell that inhibits the diffusion of admixtures and / or alloy elements, in particular of carbon, or prevented, a change or deterioration of material properties in the transition zone between those arranged on both sides of the intermediate layers and made from powders of different steel grades Layers avoided by diffusion of admixtures or alloy elements from one layer into the other.

According to the invention, it can be advantageous to use the metallic To produce intermediate layers of the same or substantially the same material from which one of the adjacent powder fillings is made by atomization.

When using an inner shell to fill one of the powder fillings, according to the invention preferably at least the outer and / or the inner jacket of the inner shell made of a material such as nickel, which is the Diffusion of admixtures and / or alloy elements, in particular of carbon, inhibits or prevents.

In an analogous manner according to the invention when using of a compact introduced into the outer shell, preferably at least the outer and / or inner jacket of the compact made of a material such as nickel, which inhibits or prevents the diffusion of admixtures and / or alloy elements, in particular of carbon.

The outer shell and optionally the outer and inner shell or the inner compact are preferably used provided on its front face with an insert made of a ductile material, preferably ductile Metal, such as soft iron, low-carbon steel or cast iron, is made, the yield point of which is in the container the extrusion press is noticeably below the flow limit of the powder filling of the compact, in such a way that that the extrusion process begins at the pressure required for the ductile material of the insert and through the tunnel effect encroaches on the powder filling.

This front insert of the outer shell is preferably generally conical, with its conical Outer surface an approximately circular arc-shaped cross-sectional profile has, the centers of which lie on a circle which is roughly on the flat face of the insert of the outer

• · * I

Sheath concentric, but with a gap around the inner jacket of the outer shell runs in such a way that this circle, on J

which are the centers of their cross-sectional profile, j when the compact formed from the outer shell | in the Con-!

tainer of the extruder is introduced, approximately in the middle Ϊ] of the annular gap of the extrusion tool. '4

When using an outer and an inner shell or when an inner compact is arranged in the cavity of the outer shell, the inner shell or the inner compact can be closed by means of an insert which is shaped so that it is approximately a partial section of the front insert described in the previous paragraph corresponds to the outer shell, so that it in cooperation with a modified front insert having a corresponding recess of the outer Shell results in a combined insert that is generally conical and one in a first approximation has conical lateral surface with an approximately circular arc-shaped Cross-sectional profile, the centers of which lie on a circle that is roughly on the flat face of the modified insert of the outer shell runs concentrically, but at a distance around the inner shell the outer shell, in such a way that this circle on which the

Centers of the cross-sectional profile, which is circular in the form of a first approximation of the combined insert, if the by cold isostatic pressing of the outer shell formed compact is introduced into the container of the extrusion press, which has a flat front end face, comes to lie approximately in the middle of the annular gap of the extrusion tool.

This shape and arrangement of the approximately circular arc-shaped cross-sectional profile that the front insert of the outer shell or the combination of the front inserts of inner and outer shell or inner compact and outer Shell, it is achieved that during the extrusion of the compact formed by cold isostatic pressing of the outer shell the soft iron or similar metal front insert or combined insert with the welds and the adjacent parts of the outer jacket and the inner jacket of the outer and optionally the inner shell forms a waste first part of the extruded tube, which is through a substantially sharply formed and essentially perpendicular to the pipe longitudinal axis extending separation surface of the subsequent one, which forms the actual composite pipe and is at least partially made of high-quality material Part is delimited. Because of this sharp

At the separation surface, the first scrap part can easily be cut off or falls off after extrusion even by itself when the connection to the subsequent actual composite pipe, which is at least partially off high-quality material, in particular stainless steel, has no or no noticeable strength. Preferably, those on the front face of the outer shell and optionally those on the front face the inner shell or the inner compact provided on their adjoining the powder fillings Surfaces with a layer or a coating of glass or another preventing a metallic bond Provided material to create a predetermined breaking point at this point, which is approximately perpendicular to the longitudinal axis of the extruded composite pipe extends. Such a predetermined breaking point facilitates the separation between the aforementioned first part of the extruded pipe and the subsequent one, the real one Composite pipe representing part.

Preferably an outer and optionally an inner one Sheath used in which at least the outer jacket, preferably Outer and inner jacket, with the shrinkage during isostatic pressing facing outwards and in the opposite direction Bulges are provided, which are dimensioned so that they

•> It

are essentially eliminated again by the shrinkage occurring during isostatic pressing, and which are manufactured in accordance with DE-AS 28 46 660 in particular. This design of the casing offers the advantage that the compact obtained after the cold isostatic pressing of the outer casing does not have an "hourglass shape" with a constricted central area. This so-called "hourglass shape" often arises from the fact that the ends of the casing, which are closed by means of a lid or the like, show less shrinkage when subjected to cold isostatic pressing than the middle area of the casing. Since a compact is required for the extrusion process, the outer jacket of which is designed as precisely as possible cylindrical, it is necessary to trim the ends of an "hourglass shape" of the compact, which is very expensive processing, with the risk of cracks occurring. The bulge of the shell according to the invention offers the advantage that machining or trimming of the compact to achieve a cylindrical shape is unnecessary, since the outward bulges of the outer shell enable the production of compacts whose diameters correspond very precisely to the desired diameter dimensions of the compact . Accuracies of + 0.2 % , in particular + 0.1 % , and the diameter dimensions of the compact can be achieved

• · t • ι

can be produced with an absolute accuracy of +0.2 mm, in particular + 0.1 mm.

In combination with one described in the previous section Shell, a front insert is advantageously used for the outer shell, which has a flat end face, which merges into a beveled or rounded edge along the outer circumference, whereby to achieve a good Lubrication during the extrusion process is the glass used for lubrication, which is in the form of a glass washer on the face of the compact in a container or recipient of the extrusion press which has a flat front end face is placed by the beveled front edge of the front insert of the outer shell and the very precise fit the essentially exactly cylindrical outer diameter of the compact to the essentially cylindrical Inner diameter of the container or recipient of the extrusion press during the entire extrusion process is supplied distributed approximately evenly in the circumferential direction between the tool and the extruded object.

· »» ■ »· * 111 I,

In the following the invention is explained in more detail with reference to a schematic drawing of exemplary embodiments.

Show it:

Fig. 1 is a longitudinal section through an embodiment of the inventive casing in part filled state;

FIG. 2 shows a longitudinal section through the casing according to FIG. 1 in the filled and closed state; and

3 to 6 are longitudinal sections similar to FIG. 2 of modified embodiments.

In the exemplary embodiment according to FIGS. 1 and 2, the outer casing is generally designated 21 and its outer casing 22 is provided with a bulge 23 opposite to the shrinkage during cold isostatic pressing. The outer jacket 22 preferably consists of a pipe section of a spiral-welded pipe, the pitch angle o (of the spiral weld seam, not shown, being dimensioned so that the spiral forms approximately one or more complete turns over the length of the outer jacket 22 , the ends of the pipe section forming the outer jacket 24 are drawn in, as will essentially be described later.

If the inner jacket has a larger diameter, it can be advantageous to manufacture it from a spiral-welded pipe. The insert 1, which is arranged in the area of the casing base, has a central bore 2 and a flat one outer end face 4, the outer edge of the insert 1 being rounded or beveled at 5. On his The insert 1 has a cylindrical outer circumferential surface Section 7 on.

The surface 6 of the insert 1 on the bottom, which is directed towards the interior of the shell 21, is essentially flat and has an annular recess 8, which the lower end of a into the cavity of the outer shell 21 inserted inner sheath 10 receives. This inner shell 10 is tapered at 11 and has at its lower At the end of a cylindrical section 12 which rests against the cylindrical outer wall of the recess 8. The inner one Cover 10 is fastened to insert 1 on the bottom by means of spot welds 13. Furthermore, are on the bottom insert 1 the outer jacket 22 by means of a circumferential weld seam 14 and the inner jacket 24 by means of a circumferential weld seam Weld seam 15 firmly connected, the weld seams 14 and 15 must result in a tight connection, while this need not be the case with weld 13. Through the inner shell 10, the interior of the outer shell 21 is in

two departments 16 and 76 divided. The inner shell 10 is preferably made of a thin sheet of nickel, preferably in a thickness between 0.1 and about 0.5 mm.

In order to avoid wrinkling and to achieve a compacted compact that is centered as precisely as possible, it is according to the invention advantageous, at least the outer jacket 22 of the outer shell 21 in the area between the inserts 1 and 30 with to provide one of the shrinkage during isostatic pressing opposite and outwardly directed bulge 23, the is dimensioned so that it is essentially eliminated again by the shrinkage during isostatic pressing. Between the inserts 1 and 30, the outer jacket 22 has an essentially constant one in the area indicated at 50 Outside diameter. The outer jacket 22 has a cylindrical one at its front and rear end Section 56 and 66, respectively, from which the bulge is seen in the axial direction, in each case towards the middle of the capsule initially increases gradually and steadily in an area 57 or 67 having a concave cross-sectional profile, wherein the inclination of the outer jacket 22 relative to the envelope axis also increases gradually and steadily, then the slope of the outer jacket remains in a conical shape Intermediate area 58 and 68 essentially constant and adjoined by an area 59 and 69, in which

the outer jacket 22 has an outwardly convex cross-sectional profile and gradually and steadily merges into the axially parallel central region 50. The areas 57, 58 and 59 with changing cross-section of the outer jacket 22 form a transition area 55, which is arranged approximately in the area of the insert 30, the cross-sectional contour of the insert 30 approximately representing a mirror image of the contour of the transition area 55, which is located on the line 70 , which corresponds to the shrunk compact obtained by cold isostatic pressing of the outer shell, is mirrored, but is enlarged in the ratio of the diameter of the compact to the radial diameter shrinkage of the shell 21. It is essential that the outwardly concave area 57, 58 is approximately mirror-inverted to the cross-sectional profile 36 of the insert 30, the line 70 representing the mirror symmetry axis and the angle of curvature of the outer jacket 22 indicated at β approximately in the ratio of the percentage shrinkage to the angle of curvature S des adjacent insert is reduced.

The bulge 23 is dimensioned so that the inner surface of the outer shell 22 after the cold isostatic pressing to shrinks to line 70, which corresponds to the ideal cylindrical shape. The cylindrical ones are accordingly Sections 56 and 66 of the outer jacket 22 up to the alignment

with the line 70 drawn in, preferably by rolling, the transition regions 55 and 65 being formed at the same time will. It has been shown that the bulging of the outer jacket is advantageous for exact centering of the compact is. The bulging of the outer jacket can be combined with a spiral-welded outer and / or inner tube be applied according to the invention.

An insert 30 provided for closing the front end face of the outer casing 21 essentially has a circular arc-shaped cross-sectional profile 36 and a flat end face 34 and a central bore 32. The centers of the circular arc-shaped cross-sectional profile lie on a circle that is approximately in the area of the line of intersection between the flat end face 34 and the wall of the bore 32, i.e. in the region of the front boundary line of the bore 32, and is marked by two crosses 38 in Fig. 2 is indicated. The roughly circular cross-sectional profile 36 offers the advantage that when the compact is extruded from soft iron or a similar metal existing insert 30 together with the welds 26, and the adjacent parts of the outer jacket 22 and the Inner jacket 24 form the first part of the tube, which is cut off after extrusion or even by itself drops off when the connection to the preferably fails

high-quality material made from the powder filling of the capsule subsequent composite tube or does not have sufficient strength. Due to the approximately circular arc-shaped design of the boundary line of the insert 30 is achieved that the dividing line between the front, as waste portion of the extruded tube and the actual, preferably at least partially made of high quality material The composite pipe is sharp and designed as a separating surface extending essentially perpendicular to the pipe's longitudinal axis is.

On the circumference of the front face 34, the front insert 30 has a beveled or rounded outer Edge 35, which merges into a cylindrical section 37 to which the already mentioned circular arc-shaped Cross-sectional profile 36 connects.

• I III ·

- 18 -.

• · · ι

The invention is explained below using an example: Around a compact with an outside diameter of 144 mm for the extrusion of a composite pipe with an outside diameter of 50 mm and a wall thickness of 5 mm, a spiral-welded pipe 600 mm long and having an outer diameter was used as the outer jacket for the outer shell 21 of 154 mm and a wall thickness of 1.5 mm constricted at both ends by rollers, in such a way that at the ends cylindrical sections with an outer diameter of 144 mm, corresponding to sections 56 and 66 of FIG. 2 were present, followed by transition areas that correspond to the transition areas 55 and 65 of Fig. 2 were shaped. Then the ends of the outer jacket were ground flat. Moving in the ends of the outer jacket 22 can also be made according to the invention by means of pressing tools. The pressing tool for the drawing in of the front end of the outer jacket 22 has an annular gap which is exactly the shape desired The shape of the transition section 55 and the cylindrical section 56 of the outer shell 22 corresponds to and its The gap width roughly corresponds to the material thickness of the outer jacket 22. This press tool is axially over the top Outer jacket end advanced, whereby this receives the desired change in shape. Corresponding to the drawing in of the upper one TüJcS of the outer jacket can retract its lower

End done in an analogous manner by means of a correspondingly designed second pressing tool. Furthermore, was an annular bottom plate 1 made of low-alloy carbon steel with about 0.004 l of carbon and a thickness of 20 mm, the outer diameter of which is the inner diameter of the outer shell 22 and the inner bore 2 of the outer diameter of the inner shell 24 corresponded Base plate 1 was provided with an annular, 3 mm deep recess 8, the outer edge 9 of which had a diameter of 80 mm. In this depression or recess 8 was made of a 0.3 mm thick nickel sheet inner

Sheath 10 with its lower tapered end 12, which is also j | if it had an outside diameter of 80 mm, inserted ψ and fastened by means of spot welds 13. The non-tapered upper section of the inner casing 10 had an outer diameter of 88 mm. The drawing-in or tapering at the lower end of the inner casing 10 were also produced by means of a pressing tool in a manner similar to that described in connection with the drawing-in of the ends of the outer casing 22. Then the inner jacket 24 was welded tightly to the base 1 by means of a circumferential weld seam 15 and then the outer jacket 24 was also welded tightly to the base by means of a circumferential weld seam 14.

Two powder grades A and B were provided. Powder A consisted of preferably spherical or predominantly spherical powder of stainless steel with a diameter of less than about 1 mm which had been produced by sputtering in an argon atmosphere from the desired stainless starting material. The powder B was produced in an analogous manner from a common steel material as a starting material, namely a carbon steel. The shell 21, which was open at the top, was placed upright on a plate and vibrated at 80 Hz. First, powder B was filled into the inner casing 10 by means of a funnel 40, this powder being compressed by the vibrations to a density of approximately 68 % of the theoretical density. The powder B was poured into the compartment 16 of the cavity of the shell 21, which is divided off by the inner shell 10, until its surface was at a distance c from the upper edge 18 of the inner shell 10. Up to this distance c, the lower cylindrical section 42 of the funnel also extended from the upper edge 18 into the casing 10, whereby the upper end of the casing 10 was fixed in a concentric position to the longitudinal axis of the outer casing 21. The centering of the upper end of the casing 10 achieved in this way is achieved in that the upper edge of the funnel 40 has a downwardly extending cylindrical section

is provided, the inner diameter of which corresponds to the outer diameter of the cylindrical section 56 of the outer jacket 22. This cylindrical section 44 of the funnel 40 can be pushed onto the upper end of the outer jacket 22 by a distance e until it hits a stop surface 46 of the funnel. In order to facilitate the introduction of the lower cylindrical section 42 of the funnel 40 into the upper end of the casing 10, the length of the cylindrical section 42 and its penetration depth c into the upper end of the casing 10 are selected to be somewhat greater than that
Distance e by which the edge 44 of the funnel 40 over the
upper end of the outer jacket 22 is slidable. Through this
Construction of the funnel 40 a precise and stable fixation of the upper end of the shell 10 is achieved. After the powder B has been filled in approximately to the lower edge of the extension 42 of the funnel 40, the latter is removed and that
Powder filled into compartment 16 and compacted by vibration is closed off by means of a pressed-on washer 17 which is fastened to inner jacket 24 and to casing 10 by welds 19. This annular disc is preferably made of one about 0.5 to 1 mm thick
Nickel layer. Subsequently, the section 76 of the cavity of the shell 21 located between the shell and the outer shell 22 was filled with powder of steel quality A up to one
Filled piece above the upper edge 18 of the envelope 10,

with simultaneous vibration of the shell by means of 80 Hz, the powder A was also compressed to about 68% of the theoretical density. So much powder A was poured in that after the front insert 30 had been pressed in, the powder A was in full contact with the lower outer surface of the insert 30 and the lower part of the insert 30 was at a distance a from the annular disk 17. When the front insert 30 was inserted, the shell 21 was also further vibrated at 80 Hz. After inserting the front insert 30, it was welded tightly to the outer and inner sheaths by means of the welds 26 and 38.

The casing was cold isostatically pressed at 4700 bar in water to a density of 88 % of the theoretical density. In the process, the outer diameter of the compact shrank to 144 mm, that is to say to the same dimension as the drawn-in cylindrical sections 56, 66 at the ends. The dimension of 144 mm also corresponded to the inner diameter of the container of the extrusion press. This ensured good centering. The compact was completely in the rest straight and was able to inductive heating to 1200 ⁰ C extruded directly to the desired composite pipe without further processing were necessary. The front section of the tube, made only of low-alloy carbon steel, was cut off, with

nothing has been cut off from the actual composite pipe

i de. Because of the aforementioned vertical separation area f

between the extruded front insert 30 and the jj The composite pipe itself had flawless surfaces. The loss of material was thereby reduced to a minimum restricted. The composite pipe obtained had an approx. 3 mm thick outer layer made of steel quality A and an approx. 2 mm thick inner layer made of steel quality B. The quality of the stainless steel inner layer was in no way due to diffusion of impurities and / or alloying elements from the carbon steel Because the interposed nickel layer, the outer layer impairs the diffusion of such additions and / or alloy elements, in particular the diffusion of carbon to a large extent. Furthermore the nickel layer created a good and permanent connection between the outer and inner layers created, which had a beneficial effect on the strength properties of the composite pipe.

FIG. 3 shows an embodiment similar to FIG. 2, with the same parts having the same reference numerals as are designated in FIG. The inner shell 10 'extends a bit further up in FIG. 3 than in FIG Fig. 2 and is at its upper end with a conically to-

\ i - 24 -

provided running section 88, which corresponds to the conical section 11 provided at the lower end. After this The compartment 16 'divided by the inner casing 10' is filled with powder quality B at the top an annular insert 80 is pressed onto the casing 10 '. This annular insert 80 is shaped so that it in combination with a modified insert 30 'of the outer shell 21' in a first approximation the shape of the insert 30 of FIG Fig. 2 results. Here correspond to the arc-shaped Cross-sectional profile 36 of FIG. 2, the profile 36 'of the insert 30 'and the profile 86 of the insert 80. The insert 80 is attached by means of a circumferential weld 89 attached to the inner shell 10 '. The insert 80 can also be connected to the inner jacket 24 by welding. It is not necessary, however, that these welds be completely tight. After inserting the insert The compartment 76 'of the outer casing 21' is filled into the inner casing 10 'by means of powder of steel quality A so far that the powder also the end face 84 of the insert 80 covers a piece, such that when Pressing in the insert 30 ', the powder is in full contact with its lower delimiting surface and in particular also the gap between the upper face 84 of the insert 80 and the lower face 39 'of the insert 30 'is completely filled with powder.

After the front insert stack 30 'has been pressed in, the powder filling A lies snugly against the lower boundary surfaces 39' and 36 'of the insert 30' and the inner cavity of the outer capsule 21 'is completely compressed by vibration to about 68% of the theoretical density Powder filled. After the capsule 21 'has been closed by means of circumferential, tight welds 26 and 28, it is cold isostatically pressed at about 4500 to 5000 bar, the bulge 23 of the outer shell 22 of the outer shell 21' being eliminated as a result of the shrinkage that occurs during cold isostatic pressing, so that the outer shell 22 shrinks approximately up to the dashed line. At the same time, the bulging of the inner shell 10 'also shrinks approximately to the dashed line 90, so that the powder filling of steel quality B compressed by the isostatic pressing forms a cylindrical layer of essentially the same thickness over the entire length of the capsule. When cold isostntic pressing, the density of the powder fillings in both compartments 76 'and 16' is increased to about 88 % of the theoretical density.

In Fig. 4 there is a further modification of that according to the invention formed shell similar to FIG. 3, wherein the same parts are provided with the same reference numerals. An essential difference between the embodiment according to FIG. 4 and that according to FIG. 3 is that that in the embodiment of FIG. 4, a complete inner capsule or shell 100 is provided, with Outer jacket 102 and inner jacket 104, a bottom piece 110 and a top insert 180. In this embodiment the interior 116 of the inner capsule 100 can be filled with powder the steel grade B are already filled before the capsule 100 is introduced into the outer capsule 21 '. For this the bottom piece 110 of the capsule is connected to the outer jacket 102 in the usual way by means of welds 114 and 115 and the inner jacket 104 are connected, then the powder filling B is poured into the space 116 while vibrating at about 80 Hz and the front insert 180 pressed in and by means of circumferential weld seams 189 and 189 'with the Outer jacket 102 and the inner jacket 104 connected. The thus filled capsule 100 can in the interior of the outer Sheath 21 'can be introduced by sliding it over the inner jacket 24. Then it becomes steel grade powder A is filled into the compartment 76 'with vibration until the surface of this powder completely covers the capsule 100 covered so that the powder of steel grade A

when pressing in the front insert piece 30 'fed up whose lower boundary surfaces 39 'and 36' rests, so that the inner cavity of the outer capsule 21 'is completely filled. After closing the capsule using a circulating denser welds 26 and 28, this can be cold isostatically pressed, the bulge 23 of the Outer jacket 22 of the outer shell is removed as a result of the shrinkage that occurs during cold isostatic pressing, so that the outer jacket shrinks approximately up to the line 70 shown in dashed lines. At the same time, it is also shrinking Bulge of the outer shell 102 of the capsule 100 approximately up to the dashed line 190, so that the a powder filling of steel quality B compressed by isostatic pressing over the entire length of the capsule forms substantially the same thickness cylindrical layer.

Instead of a capsule 100 filled with powder, according to the invention a correspondingly trained compact can also be used. In this case the inner capsule 100 by means of the welds 114, 115, 189 and 189 'are tightly closed, and outer jacket 102 and inner jacket 104 must be completely tight in order to to be able to carry out a separate cold isostatic pressing of the inner capsule 100. This cold isostatic

I · I ·

Pressing is preferably carried out with a pressure between 1500 and 5000 bar, but in particular approximately with the same pressure with which the outer shell 21 'also follows Introduction of the compact is cold isostatically pressed.

Since the compact, unlike a non-pre-pressed capsule 100, is already introduced into the cavity of the outer Shell 21 'has also been given a shrinkage in the axial direction, it is expedient to take this shrinkage into account when designing the length of the capsule 100.

In the embodiment according to FIG. 5, a shell 220 designed similarly to the shell 21 of FIG. 2 is provided, the outer shell 202 of which has a cylindrical section 250 and tapered end sections 255 and 265 as well as cylindrical end sections 256 and 266 The base plate 221, which is welded to the outer jacket 202 and the inner jacket 224, is tightly closed. To produce the composite pipe, a pipe section 226 made of stainless steel of steel quality B is pushed over the inner jacket 224. The front insert 230 is pressed in as soon as the cavity 240 of the casing 220 is completely filled with powder of steel quality A , in such a way that this powder is fully applied to the lower boundary surface 236 of the insert 230.

This lower boundary surface 236 has an arcuate cross-section profile similar to the cross-sectional profile 36 of FIG. Since the tube section 226 shows essentially no shrinkage during cold isostatic pressing, the angles / 3 and cP ″ are reduced compared to the angle / 3 and ο in FIG. 2 in a ratio that corresponds to the reduction in the entire cavity 16 plus 76 of the capsule 21 corresponds to the introduction of the solid material 226 into a space 240 to be filled with powder.

FIG. 6 shows a very similar embodiment of the invention to FIG. 5, with a solid pipe section 326 having a significantly greater wall thickness than the pipe section of the embodiment according to FIG Fig. 5 has. Correspondingly, the angles / 3 ″ ″ and cT ^{y /} in FIG. 6 are selected to be significantly smaller, since the remaining cavity 340 to be filled with powder is also significantly smaller than the cavity 240 in FIG has a recess 338 on its end face facing the insert 330, the contour of which corresponds to the contour of the lower outer surface 336 of the insert 330, which has an arcuate cross-sectional profile as a first approximation

of the chamber 340 with powder of quality A, so much powder is introduced with vibration that this is the upper end face 338 of the pipe section 326 covers a piece in such a way that the powder of steel quality A after being pressed in of the insert 330 close to the lower boundary surface this insert rests and also fills the space between this boundary surface 336 and the end surface 338. The tapered ends of the outer jacket 332 formed from a pipe section, which form the conical sections 355 and 365 as well as the cylindrical sections 356 and 366 comprise, are preferably by rolling or by means of a suitable pressing tool, as described in the description of the exemplary embodiments according to FIGS. 2 and 3 was explained.

According to the invention, it is particularly advantageous in the case of the Embodiments the front insert 30, 30 ', 230 or 330 initially with the inner jacket and the outer jacket to weld the outer shell tightly and then the cavity of the outer shell from the bottom end of the To fill the envelope and only at the end to insert the bottom insert 1, 221 or 321 and weld it tightly. This procedure offers the advantage that the position of the inclined section 55, 255 or 355 is accurate opposite to the mirror image of its inclination.

• I Il

formed portion of the curved boundary surface of the front insert 30, 30 ', 230 and 330 are fixed by means of the welds 26 and 28 during welding can, while this precise fixation when pressing the front insert into the filled with a powder filling Cavity of the outer shell 21 is not possible as exactly. When filling the powder types from the rear At the end of the outer shell, in the embodiment according to FIGS. 1 and 2, the inner shell 10 can be attached directly to the lower one Boundary surface 36 of the front insert 30 are welded and in this case it is not necessary to provide the bottom insert 1 with a recess. However, the casing 10 is expediently Also in this case covered by an annular disc when the grade B powder filling is introduced is so that when the powder of quality A is subsequently poured in, the powder filling of quality B is somewhat covered can be and the powder of quality A is full on the bottom insert. That is advantageous Filling in the powder from the rear end of the outer shell, in particular also in the embodiments according to FIG 4, 5 and 6, since in these cases the inner capsule 100 or a corresponding compact or the tubular Sections 226 and 326 with their front end faces 184, 238 and 338 directly to the lower one

• · · j

• · · ι • ■ · ·

Can connect the boundary surface of the front insert.

According to the invention, the departments 16, 76; 16 ', 76 '; 116, 76 '; 240; 340 can be divided into two or more sections in the axial direction and into these sections Powders of different steel grades are filled in each time in order to produce composite pipes, their outer layer and / or the inner layer consists in sections of different steel grades. This training of the Composite pipe can be advantageous if parts made of different steel grades, e.g. On different parts its scope should be welded. It is known that unfavorable influences occur in the area of the weld seam the properties of the steels on which they are manufactured of sections made of the same material can be avoided. At least some of the sections mentioned can also be used of the departments by preformed compacts and / or pipe sections made of solid material made of the same material as the parts to be welded. The boundaries between the sections mentioned can be conical or funnel-shaped with a preferably approximately circular arc-shaped cross-sectional profile, with the midpoints this circular arc-shaped cross-sectional profile form a circle that is approximately concentric around the inner surface of the

· »· * Ti *« »Il 1

outer shell extends, preferably at a distance that is approximately half the width of the annular gap of the extrusion tool corresponds, in such a way that after the extrusion of the composite pipe the boundaries between the said sections extend approximately perpendicular to the pipe's longitudinal axis, preferably the corresponding ones at the stated limits Parts of intermediate layers are inserted according to the patent application filed by the applicant at the same time entitled "Tubular composite parts as well as method and compact for their production" and the attorney's mark 1A-4092 are designed. To the revelation express reference is made to this patent application and a copy of the same is attached. The applicant keeps reserve the right to combine both registrations if this should prove expedient. Examples of the above Parts of intermediate layers are shown in Figs. 2, 4 and 5 at C- | Cp C,, C., C. and Cr shown in dashed lines.

In FIGS. 2 and 5, the two intermediate layers can serve to provide the composite pipe with end pieces which have the same steel quality B as the inner layer formed from the powder filling 16 or the pipe section 226. For this purpose, in FIG. 2 the sections below C, and above C, ¹ of division "6 are filled with powder B and only the remaining middle part of 76 is filled with powder A. In an analogous manner in FIG. 5 powder B is below C. and filled in _{above C 5.}

• * · ■ ■ · · ■

• · · a

- 34 -

In Fig. 4, for example, between C "and C, powder the Steel grade C can be filled if in this

Area where the composite pipe is to be welded to grade C steel.

All information and features disclosed in the documents, in particular the disclosed spatial design, are used claimed as essential to the invention insofar as they are new individually or in combination compared to the prior art

Claims (9)

national, pcT- and D R. WH 1, C * H ', N TS.tJ Gf E * BA.UER national, pct and EUROPEAN PATENTS PATENTANWALT EUROPEAN PATENTS TRADEMARKS APPROVED BY THE EUROPEAN PATENT OFFICE TRADEMARKS LICENSE AGREEMENTS GERMAN AND EUROPEAN PATENT ATTORNEY LICENSE 28 .August 1981 1G-4O87 protection claims 1. Composite pipe, the wall of which has a layered <| Structure with at least two in the radial direction behind-S ' lying, extending in the circumferential direction || Layers of at least two different materials, particularly at least two different ij Stahlqualitä- th f, for example, carbon steel and stainless steel, wherein ; Powders consisting predominantly of spherical particles i corresponding departments in the layered structure i ": a metallic hollow cylindrical shell filled and I by vibration and / or ultrasound to about 60 to 70 % and by isostatic cold pressing of the closed shell to at least 80 % of the theoretical density ): are sealed and the pressed body produced in this way is / warms and then hot-extruded into a tube K is characterized in that to avoid j ^; establishment of transition zones either at the boundaries between the !: Powder fillings arranged metallic intermediate layers ! , which are preferably made of a material such as nickel, ; exist that the diffusion of impurities and / or POSTAL ADDRESS: OFFICE: 8000 K / S4337 AND 292561 POST CHECK ACCOUNT MUNICH DR. E. NEUGEBAUER ZWEIBROCKEI. ".."'.."."' I. **, "¹;; pat-d 5519-803 (BLZ 70010080) POST BOX 260101 INPUT MOI. ". JIJt. * :: '. 1.IiRESSE (CABLES): BAYER. VEREINSBANK MÖNCHEN D-8000 MÜNCHEN 26 (NEBENDEM * .. · * .. ** .. ·: * .. '* .. ·: IT MÖNCHEN ACCOUNT 565500 (BLZ 70020270) Il · «■ · Il Il , III · I I Il lit III Il I 1 I · It, 11 · I ι · »II. I * i.ll Il I · _ · 19 _ · ■ Alloy elements, in particular of carbon, inhibits or prevents or one of the powder fillings into one second inner shell is filled, which is arranged within the first-mentioned outer shell or a the powder fillings by a compact inserted into the cavity of the outer shell or made of solid material existing pipe section is replaced. 2. Composite pipe according to claim 1, characterized in that the metallic intermediate layers consist of essentially the same material from which an adjacent powder filling is made 3. Composite pipe according to claim 1, characterized in that at least the outer and / or the The inner cladding of the inner shell is made of a material such as nickel, which allows the diffusion of impurities and / or alloy elements, in particular of carbon, inhibits or prevents. 4. composite pipe according to claim 1, characterized in that at least the outer and / or The inner shell of the compact inserted into the outer shell is made of a material such as nickel, which is the Diffusion of admixtures and / or alloy elements, in particular of carbon, inhibits or prevents. SI I
r. 5. composite pipe according to one or more of claims 1 to 4, characterized by an outer and / or inner shell or inner capsule, in which at least the outer shell, preferably Outer and inner jacket, with the shrinkage during isostatic pressing against and outwardly directed bulges are provided, which are dimensioned so that they are due to the shrinkage occurring during isostatic pressing can essentially be eliminated again. 6. composite pipe according to one or more of claims 1 to 5, characterized by an outer and / or inner shell or inner capsule, which has a conical, Has hemispherical or funnel-shaped insert, which is made in one or more parts from solid material and / or from powder is and preferably the rear end of the shell or capsule with a plate or cone-shaped Insert is provided, which is preferably made in one piece from solid material and / or powder is produced, the front and rear inserts preferably at least in the case of the outer shell are tightly connected by welding to the outer and inner jacket of the shell. 7. composite pipe according to one or more of claims 1 to 6, characterized by an outer and / or inner shell, in which at least the outer jacket has approximately the same strength properties along its circumference having in the axial direction and preferably at least the outer jacket made of a spiral-welded or a extruded pipe. 8. composite pipe according to one or more of claims 1 to 7, characterized by a front insert for the outer shell with a flat end face, which along the outer circumference in a beveled Edge passes. 9. composite pipe according to one or more of claims 1 to 8, characterized in that at least a division (16, 76; 16 ', 76'; 116, 76 '; 240; 340) divided into two or more sections in the axial direction and that these sections are made of powders of different steel grades, or at least one Part of these sections of the above-mentioned departments from preformed compacts and / or from solid pipe sections Material, which preferably consist of different materials, is made, with the limits between the said Sections are conical or funnel-shaped with a preferably approximately circular arc-shaped cross-section profile, wherein the centers of this circular arc-shaped cross-sectional profile form a circle that is approximately extends concentrically around the inner jacket of the outer shell, preferably at a distance which is approximately half the width of the annular gap of the extrusion tool, in such a way that the limits after the extrusion of the composite pipe between the said sections a plane extending in a first approximation perpendicular to the pipe's longitudinal axis form, intermediate layers preferably being inserted at the stated limits.