EP0020536A1 - Boitiers annulaires et procédé pour la production de tubes par métallurgie des poudres et procédé de production de ces boitiers. - Google Patents

Boitiers annulaires et procédé pour la production de tubes par métallurgie des poudres et procédé de production de ces boitiers.

Info

Publication number
EP0020536A1
EP0020536A1 EP79901411A EP79901411A EP0020536A1 EP 0020536 A1 EP0020536 A1 EP 0020536A1 EP 79901411 A EP79901411 A EP 79901411A EP 79901411 A EP79901411 A EP 79901411A EP 0020536 A1 EP0020536 A1 EP 0020536A1
Authority
EP
European Patent Office
Prior art keywords
capsule
insert
compact
powder
jacket
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP79901411A
Other languages
German (de)
English (en)
Other versions
EP0020536B1 (fr
Inventor
Christer Aslund
Ake Akerman
Hans Eriksson
Benny Flodin
Claes Tornberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Granges Nyby AB
Original Assignee
Granges Nyby AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE19782846658 external-priority patent/DE2846658C2/de
Priority claimed from DE2846660A external-priority patent/DE2846660C2/de
Priority claimed from DE19782846659 external-priority patent/DE2846659A1/de
Application filed by Granges Nyby AB filed Critical Granges Nyby AB
Publication of EP0020536A1 publication Critical patent/EP0020536A1/fr
Application granted granted Critical
Publication of EP0020536B1 publication Critical patent/EP0020536B1/fr
Expired legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/1208—Containers or coating used therefor
    • B22F3/1258—Container manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding

Definitions

  • the present invention relates to a further development of the method for the production of rustproof pipes according to the 'DE-AS 24 19 014 (German specification No. 24 19 014).
  • DE-AS 24 19 014 describes a process for the manufacture of stainless steel tubes which have a uniform structure, physical and chemical properties and good processability, powder from such steel being filled into metallic capsules and the sealed capsules by means of all ⁇ active pressure are compressed and the compact thus obtained is extruded into tubes, and wherein steel powder made of predominantly spherical particles is used by atomizing melt in inert gas, thin-walled capsules made of a ductile metal are used, the wall of which The maximum thickness is about 5% of the outer diameter of the capsule, the density of the steel powder filled into the capsule is increased to about 60 to 70% of the theoretical density by vibration and / or ultrasound, and the density of the steel powder is cold isostatic pressing of the capsule by means of a Pressure is increased from at least 1500 bar to at least 80%, preferably 80% to 93% of the theoretical
  • the metallic capsules which are filled with the steel powder, can be evacuated before closing and / or with a gas, in particular an inert gas, e.g. Argo fill.
  • a gas in particular an inert gas, e.g. Argo fill.
  • metallic capsules are preferably used, the wall thickness of which is less than 3%, in particular less than 1%, of the outer diameter of the capsule and in particular metallic capsules are used, the wall thickness of which is between about 0.1 to 5 mm , preferably between about 0.2 and 3 mm.
  • composite pipes can also be produced, using thin-walled metallic capsules which are divided into two by one or more concentric partitions or more areas are separated and the predominantly spherical powder particles of the different steel qualities are poured into one of these three areas with simultaneous vibration, then the partitions are removed and the capsules are closed, - after which the cold isostatic pressing and the extrusion take place at elevated temperature « Glass is normally used as a lubricant when extruding the compacts into tubes.
  • the object of the present invention is to increase the yield, ie to reduce the percentage of defective extruded products and to increase the quality and dimensional accuracy of the extruded products.
  • This object is achieved in that at least the outer shell of the capsule with a shrinkage in the isostatic pressing and directed outwards. Bulge is provided, which is dimensioned so that it is essentially eliminated by the shrinkage.
  • the embodiment of the capsule according to the invention has the advantage that the compact does not show an "hourglass shape" with a constricted central area after the capsule has been cold-isostatically pressed.
  • This so-called "hourglass shape” often arises from the fact that the ends of the capsule, which are closed by means of a lid or the like, show less shrinkage when subjected to cold isostatic pressing than the central region of the capsule. Since a compact is required for the extrusion process, the outer jacket of which is formed as precisely as possible in a cylindrical manner, it is necessary to trim the ends of an "hourglass shape" of the compact, which is a very expensive machining operation, with the risk that that cracks appear.
  • the design of the capsule according to the invention has the advantage that there is no processing or trimming of the compact to achieve a cylindrical shape.
  • the invention makes it possible to produce compacts whose diameters correspond very precisely to the desired diameter dimensions. Accuracies of + 0.2%, in particular + 0.1%, can be achieved according to the invention.
  • the diameter dimensions of the compact can be produced with absolute accuracy of + 0.2 mm, in particular + 0.1 mm.
  • the outer shell and / or the inner shell are preferably produced in the region of the capsule ends as essentially cylindrical sections, the diameter dimensions of which correspond exactly to those of the desired compact and which continuously merge into a bulged central capsule region.
  • the shape of the outer and / or inner shell of the capsule is designed according to the invention in such a way that the bulging from each of the cylindrical sections at the capsule ends in the axial direction, as seen in each case towards the center of the capsule, initially in a concave cross-sectional profile gradual area and.
  • the inclination of the outer and / or inner casing against the capsule axis also gradually and steadily increasing, followed preferably by a conical intermediate region in which the inclination of the outer and / or inner casing remains substantially constant, a region adjoining this conical intermediate region in which the outer and / or inner jacket has a convex cross-sectional profile to the outside and gradually and continuously merges into an axially parallel central section which preferably has essentially a constant diameter.
  • an improvement in the dimensional accuracy of the compact and a reduction in the reject rate can also be achieved in that a plate, cone, hemisphere or funnel-shaped insert made of solid material is arranged on the front and / or rear face of the capsule.
  • the inserts in the region of the front and / or rear end face of the capsule which are preferably made of an electrically conductive metal, make heating of the compact before extrusion by means of inductive heat considerably easier, since. the metallic inserts can be easily heated inductively and give off their heat to the other parts of the compact, in particular to the powder-filled interior and thus contribute to the rapid heating of the entire compact.
  • OMPI is essentially eliminated again.
  • the dimensions of the compact can be maintained much more precisely according to the invention.
  • the inserts can be designed as a lid closing the end face of the capsule, wherein the inserts can be welded tightly to the outer shell of the capsule and the inner shell of the capsule.
  • sheet metal inserts can also be arranged between the inserts and the interior of the capsule, which are designed as lids and are tightly connected to the outer jacket and the inner jacket by welding.
  • capsules for the production of compacts for the extrusion of tubes can be used for the front face of the capsule, which are funnel-shaped and provided with a central bore, the angle o between the wall of the central bore for the inner jacket of the Capsule and the conical outer surface of the funnel-shaped insert is about 40 ° to 60, preferably about .40 ° to 50 °, in particular about 45 °.
  • annular insert provided with a central bore, which has an essentially flat end face, and its boundary surface between the wall of the central one Bore and its largest outer diameter has an approximately circular cross-sectional profile, the center of the circular profile lying approximately in the area of the intersection between the flat end face and the central bore.
  • a further substantial improvement of the capsules and the compacts produced therefrom and the extruded objects, in particular the extruded tubes, can be achieved in combination with the inserts designed according to the invention or independently of these inserts according to the invention in that at least the jacket of the Capsule has approximately the same strength properties in the axial direction over the entire circumference.
  • At least the outer casing of the capsule according to the invention is preferably formed by a thin-walled, spiral-welded or extruded tube.
  • the slope of the spiral formed by the weld seam in relation to the length of the capsule is preferably dimensioned such that the weld seam forms approximately a complete turn.
  • An outer jacket provided with such a weld seam has only one weld seam at each point along its circumference in the axial direction and approximately the same strength properties in the axial direction.
  • the weld seam can form two, three or more complete turns.
  • the present invention is applicable to capsules and compacts for extruding objects, in particular pipes, rods or similarly profiled, elongated, dense, metallic objects, in particular made of stainless steel or high-alloyed nickel steels, in particular heat-resistant steels for heat exchangers, e.g. high-alloy nickel steels with 80% nickel and 20% chromium, powders made of metal or metal alloys or mixtures thereof or mixtures of powders made of metals and / or metal alloys being filled with ceramic powders into the capsule according to the invention.
  • Spherical or predominantly spherical powder is preferably used as the powder, with an average diameter preferably below about 1 mm.
  • spherical powder is used which is in a protective gas, pre-
  • WIPO « preferably argon atmosphere, has been produced from the desired starting material, ie the desired metal and / or metal alloy, by atomization.
  • Powder grains with a diameter greater than 1 mm, at least for the most part, are preferably sieved, since there is a risk that argon will be trapped in powder grains with a diameter greater than 1 mm.
  • Such an inclusion of argon can occur during atomization, for example due to turbulence. Inclusion of argon would produce unfavorable properties of the extruded objects during extrusion and lead to inclusion lines.
  • the capsule for producing the compacts for the tubes to be extruded is filled with the powder, the density of the powder filled in the capsule being increased by vibration to about 60 to 71% of the theoretical density, and the frequency the vibration is preferably chosen to be at least about 70 Hz, advantageously 80 to 100 Hz.
  • a density of approximately 68 to 71% of the theoretical density can be obtained by vibration at 80 to 100 Hz.
  • the capsule is closed, preferably after evacuation and / or filling with inert gas.
  • capsules which are generally made of thin sheet metal, preferably sheet metal approximately 1 to 2 mm thick, in particular sheet metal approximately 1.5 mm thick, are particularly advantageous.
  • the material for this capsule is preferably kohlenstoff ⁇ poor soft steel, esp. Having a carbon content of less than 0.015%, esp. Less than 0.004 I used to prevent carburization of the powder during the heating 'and during extrusion.
  • the capsule Due to the all-round pressure during cold isostatic pressing, the capsule is compressed uniformly both in the longitudinal direction and in the radial direction and then forms a compact. As far as possible, this compact should not have any irregularities, since these lead to difficulties during extrusion, especially when extruding pipes.
  • a capsule which is designed as an annular body, the outer jacket of this annular body being formed by a spirally welded tube section which is produced, for example, from an approximately 1.5 mm thick sheet metal.
  • an inner jacket is used, for example in the form of a longitudinally welded tube section, which has a smaller diameter but the same wall thickness as the outer jacket.
  • An annular cover is fastened on one side between the outer and inner jacket and the annular space between the two tubes is closed on one side. Then spherical powder is poured into the annular space and compacted to about 68 _ of the theoretical density by vibration with, for example, 80 Hz.
  • the aim of the capsule according to the invention is that the spiral weld seam is as smooth as possible and that the properties of the sheet do not change significantly. Therefore, the weld seam is preferably smoothed by means of rollers and / or by means of grinding. The smoothing of the weld seam by means of rollers can take place immediately after the welding process.
  • the inner jacket can either consist of a spiral welded tube or an extruded tube.
  • the use of an extruded or spiral-welded tube for the inner jacket is particularly expedient in the case of large dimensions. In the case of smaller dimensions, it is generally sufficient if the outer casing of the capsule is produced according to the invention from a tube section which has approximately the same strength properties in the axial direction along its circumference.
  • Fig. 1 shows a top open capsule in view
  • the capsule is generally designated 1 in FIG. 1.
  • the capsule has an outer casing 2 and an inner casing 4.
  • the outer jacket 2 consists of a spiral-welded pipe section with the length L.
  • the weld seam 5 runs spirally over the circumference of the outer jacket 2, the spiral having a pitch angle o which is dimensioned such that the spiral forms approximately a complete turn.
  • n 1
  • n 2
  • the outer jacket 2 and also the inner jacket 4 of the capsule 1 consisted of 1.5 mm thick soft steel sheet with a carbon content of less than 0.004.
  • the lid not shown in FIG. 1, was welded along the weld 16. Powder, which was predominantly spherical, was used to produce the compact
  • OMP Grains with an average diameter of less than 1 mm and which had been produced by sputtering in an argon atmosphere from the desired starting material, for example from stainless steel, were filled into the capsule. After filling, the powder was compacted by vibration with a frequency of 80 Hz to a density of about 68% of the theoretical density. It was then evacuated and the capsule closed with a lid. The lid was connected to the outer wall 2 of the capsule by welding approximately along line 16 in FIG. 1. In the exemplary embodiment mentioned, the capsule had a length of 600 mm and an outer diameter of 150 mm. The inner diameter of the inner jacket 4 was about 55 mm. The inner jacket 4 consisted of a longitudinally welded tube section with a longitudinal weld seam 6. The density of the powder was then increased to about 85% of the theoretical density by isostatic cold pressing at a pressure of 4700 bar. The compact thus obtained was extruded to the tube ' as described in DE-AS 24 19 014.
  • an insert 30 or 40 is arranged both in the area of the lid 10 and the bottom 20, which form the front or rear end face of the capsule.
  • the front insert 30 is generally conical and has a central bore 32 for receiving the inner casing 4 of the capsule.
  • OMPI ⁇ , WIPO « Surface 36 of conical or funnel-shaped insert 30 forms an angle j? with the wall 'of bore 32? , which is preferably in the range between approximately 40 ° and 60 °, advantageously in the range between approximately 40 and approximately 50 ° and in particular approximately 45.
  • the insert 30 has an essentially flat end face 34. However, it is chamfered or rounded at its outer edge at 35 and then initially has a cylindrical section 37 which merges into the conical outer surface 36. At 39, the transition from the conical surface 36 to the wall of the central bore 32 is rounded.
  • the contour of the cover 10, which is designed as a sheet metal insert, corresponds exactly to that of the adjacent parts of the insert 30.
  • the cover 10 has a cylindrical section 17 on the outer edge, which ensures that the cover 10 is in good contact with the Ensures outer casing 2, the outer edge of this cylindrical section 17 being connected to the outer casing 2 by means of a weld seam 16. Also in the inner area, the cover 10 has a short, essentially cylindrical section 19, which bears against the inner casing 4 of the capsule and is tightly welded to the inner casing 4 by means of a weld seam. The cover 10 also has a rounding corresponding to the rounding 39 of the insert 30.
  • a approximately flat plate-forming insert 40 is arranged, which has a central bore 42 and an outwardly facing end face 44- This plate-shaped insert 40 is also chamfered or rounded at the edge at 45 and has an outer cylindrical section 47.
  • the shape of the capsule bottom 20 corresponds to the shape of the insert 40 and also has an outer cylindrical section 27 and an inner cylindrical section 29.
  • the bottom 20 is tightly welded to the outer jacket 2 and the inner jacket 4 by means of weld seams 26 and 28.
  • the inserts 30 and 40 are preferably made of soft iron or low-carbon soft steel.
  • FIG. 3 shows a modified embodiment of the capsule, an insert 130 provided on the front end of the capsule having an essentially circular cross-sectional profile 136 as well as a flat end face 134 and a central bore 132.
  • the centers of the circular arc Cross-sectional profile 136 lie on a circle which lies approximately in the area of the intersection line between the flat end face 134 and the wall of the bore 132, ie in the area of the front boundary line of the bore 132, and is indicated by two crosses 138 in FIG. 3.
  • the approximately circular cross-sectional profile 136 offers the advantage that when the compact is extruded, the insert 130 made of soft iron or a similar metal together with the cover 110, the weld seams 116, 118 and the neighboring ones Parts of the outer jacket 102 and the inner jacket 104 form the first part of the tube, which is cut off after extrusion or even falls off by itself when the connection to the subsequent tube, which is preferably made of stainless steel and is made from the powder filling of the capsule has no or no sufficient strength.
  • the approximately circular arc of the boundary line 136 of the insert 130 ensures that the dividing line between the front, waste section of the extruded pipe and the actual pipe, which is made of high-quality stainless material, is formed sharply and as a separating surface which extends essentially perpendicular to the longitudinal axis of the pipe is.
  • the cover 110 also has an approximately cylindrical section 117, which is welded at 116 to the outer casing 102 of the capsule, and an approximately cylindrical inner section 119, which bears against the inner casing 104 and at 118 by means of a circumferential weld seam tightly to the inner casing connected is.
  • the transition from the wall of the central bore 132 to the circular cross-sectional profile 136 is rounded off at 139.
  • lid 10 and bottom 20 can be omitted.
  • the insert according to FIG. 3 can be used in an analogous manner
  • WIPO are directly welded tightly to the outer jacket 102 and the inner jacket 104.
  • inserts 30, 40, 130 When using sheet metal inserts as a cover or base, it may be expedient to attach inserts 30, 40, 130 to them by spot welding. In many cases, however, it is also sufficient to fix the inserts 30, 40 and 130 through the flanged ends 15, 25 and 115 of the outer jacket 2 and 102, respectively.
  • this insert is made of ductile material, e.g. ductile iron, soft iron, low-alloy carbon steel or cast iron.
  • the pressure which is required in the container of the extrusion press to extrude the compact is reduced if the front insert is made of ductile material and this material is easier to flow than the powder filling of the compact. Once the flow process that takes place during extrusion is initiated, it also spreads to the powder filling, even if the flow limit of the powder filling is higher than the flow limit of the ductile material of the insert; so there is a kind of tunnel effect.
  • the outer jacket 102 has a bulge 103 which is opposite to the shrinkage during cold isostatic pressing.
  • the insert 140 in the area of the capsule base 120 also has an approximately circular cross-sectional profile 146, which in the area of the central bore 142 merges into the wall of the bore 142 via a rounded region 149.
  • the insert 140 On the outside, the insert 140 has an essentially cylindrical section 147, against which a cylindrical section 127 of the base 120 comes to rest.
  • the cylindrical section 127 is welded at 126 to a substantially cylindrical section 166 of the outer jacket 102.
  • the cover 120 lies with its cylindrical section 129 on the inner casing 104 and is welded to the inner casing at 128.
  • the outer end face 144 of the insert 140 is flat and rounded or beveled at the outer edge at 145, so that the flanged lower edge 125 of the outer casing 102 can hold the insert 140 in place.
  • the bulge 103 is dimensioned such that the inner surface of the outer casing 102 shrinks after the cold isostatic pressing up to the line 170, which corresponds to the ideal cylindrical shape. Accordingly, the cylindrical sections 156 and 166 of the outer casing 102 are preferably drawn in by rolling until they are aligned with the line 170.
  • the outer casing 102 in the area indicated at 150 essentially has a constant outer diameter. It has proven to be particularly advantageous to connect to the cylindrical sections 156, 166 towards the center of the capsule a region 157 or 167 with an outwardly concave cross-sectional profile and an intermediate region 158 or 168 in the shape of a truncated cone and this region 159, 169 to follow, which has an outwardly convex cross-sectional profile and merges into the cylindrical, axially parallel central region 150.
  • outwardly concave regions 157 and 167 are approximately mirror images of the cross-sectional profile 136 and 146 of the inserts, the line 170 representing the mirror symmetry axis and the angle of curvature of the outer shell indicated at P approximately in the ratio of the percentage shrinkage to Curvature angle 0 of the adjacent insert is reduced.
  • FIG. 4 shows a modified embodiment, similar to FIG. 3, in which all the same or similar parts are provided with reference numbers increased by a hundred.
  • the inserts 230 and 240 have a cross-sectional profile which is substantially tapered at 239 and 249, so that the correspondingly designed cover 210 and the appropriately designed floor 220 extends directly to the inner jacket 204 and forms an obtuse angle a or a 'with the latter.
  • this design is advantageous for exact centering of the compact.
  • bulging of the inner jacket 204 is not necessary.
  • a slight outward bulge of the inner jacket can be advantageous.
  • the bulge of the outer and / or inner jacket can be advantageous according to the invention in connection with any desired inserts.
  • the bulge in combination with a spiral welded outer and / or inner tube can also be advantageous.
  • FIG. 5 shows a modified embodiment, similar to FIG. 4, in which all the same or similar parts are provided with reference numbers increased by a hundred.
  • the main difference is that the inserts 330 and 340 are provided with tips 339 and 349 and that no sheet metal inserts are provided.
  • Outer jacket 302 remains substantially constant and adjoins an area 359, 369 in which the outer jacket 302 has an outwardly convex cross-sectional profile and gradually and continuously merges into an axially parallel central area 350.
  • the regions with a changing cross section of the outer jacket 302 each form a transition region 355, 365, which is arranged in the region of an insert 330 or 340.
  • the cross-sectional contour 336, 346 of the inserts 330, 340 is approximately a reflection of the contour of the outer casing in the transition areas 355, 365, which is mirrored on the line 370 of the desired cylinder shape of the compact, but is stretched in the radial direction, the extent of the stretch being approximately corresponds to the ratio of the difference between the outer and inner diameter of the compact to the diameter shrinkage of the capsule, preferably taking into account the change in the cross-sectional area as the radius becomes smaller.
  • the inserts 330 and 340 are directly welded to the outer and inner jacket, respectively.
  • 337 and 347 are cylindrical portions of the inserts 330 and 340, respectively, which correspond to the cylindrical portions 137, 147 and 237, 247 of Figures 3 and 4, respectively.
  • a sheet-metal insert forming a bottom was welded similarly to insert 120 in FIG. 3, on the one hand tightly to the outer jacket and on the other hand tightly to an inner jacket which consisted of a 590 mm long, longitudinally welded tube with a wall thickness of 1.5 m and an inner diameter of 40 mm.
  • annular or funnel-shaped insert similar to insert 140, made of low-alloy carbon steel with approximately 0.004% carbon stock was inserted from said first end of the outer jacket and fastened by means of spot welding.
  • IP The capsule was placed upright on a plate, filled with powder and vibrated at 80 Hz and compressed to about 68% of the theoretical density and at the same time provided with a funnel-shaped sheet-metal insert similar to 110 in FIG. 3, which is located between the inner and outer jacket of was pushed in at the top with great pressure. Then the sheet metal insert was tightly welded to the inner and outer jacket, as indicated in FIG. 3 at 116 and 118. Then the front ring-shaped or funnel-shaped insert was inserted from above, which was constructed similarly to 130 in FIG. 3 and consisted of low-alloy carbon steel with approx. 0.004% C. This ring-shaped insert was advantageously welded to the funnel-shaped sheet metal insert or the inner or outer jacket by means of spot welding.
  • the capsule was cold isostatically pressed at 4700 bar in water to a density of 88% of the theoretical density.
  • the compact shrank to 144 mm outer diameter, 'that is the same dimension as the retracted cylindrical sections at the ends.
  • the dimension of 144 mm also corresponded to the inner diameter of the container of the extrusion press. This ensured perfect centering.
  • the inside diameter of the compact was almost exactly 40 mm.
  • the compact was otherwise completely straight and, after induction heating to 1200 ° C., could be extruded directly into the desired seamless tube made of stainless steel, without further processing being necessary.
  • the front section of the tube made of low-alloy carbon steel was cut off. None was cut from the stainless steel.
  • a glass layer can be made according to the invention on the surface of the front insert facing the powder filling 308 be applied.
  • Such an intermediate glass layer makes the separation between the low-alloy carbon steel and the stainless steel considerably easier when the extruded tube is obtained, so that the two types of steel are obtained completely separately from one another and without mixing.
  • the surface of the bottom-side insert 340 adjoining the powder filling 308 can also be provided with a glass layer, which facilitates the separation of stainless material and low-alloy carbon steel.
  • the inserts 30, 40, 130, 140, 230, 240, 330 and 340 can also be pressed from powdered starting material.
  • powdered starting material e.g. water-atomized soft iron or water-atomized low-carbon steel can be used, which is cold isostatically pressed to the desired shape of the inserts mentioned and then sintered.
  • the soft iron powder can be pressed cold isostatically in a plastic mold, the pressure preferably being at least as high, if not higher, than the pressure selected for the cold isostatic pressing; which is used to make the capsules.
  • a dense material can be obtained by subsequent hot sintering.
  • a seal can be obtained by applying an outer glass layer, in this case also on the end faces 34, 134, 234, 334 or 44, 144, 244 and 344 and the peripheral surfaces.
  • the embodiment according to FIG. 6 largely corresponds to that according to FIG. 5. Only the insert pieces have a modified shape.
  • the front insert 330 ' is there
  • the bottom-side insert 340 "consists of an annular plate.
  • additional rings with a graduated outer diameter and / or a graduated inner diameter can be provided to approximate the desired ideal profile, for example to achieve an approximation to the profile 346 according to FIG. 3.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Formation And Processing Of Food Products (AREA)
  • Extrusion Of Metal (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
  • Jellies, Jams, And Syrups (AREA)
  • Closures For Containers (AREA)
  • Auxiliary Devices For And Details Of Packaging Control (AREA)
  • Food-Manufacturing Devices (AREA)
  • Meat, Egg Or Seafood Products (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
  • Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
  • Forging (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)

Abstract

Boitier pour des pieces embouties comprimees isostatiquement, ainsi que pieces embouties qui servent a l'extrusion d'objets metalliques, en particulier de tubes metalliques en acier inoxydable. Les enveloppes exterieure et interieure (302, 304) du boitier (301) sont composees d'une tole a paroi mince: l'enveloppe exterieure (302) au moins presente, le long de sa circonference, des proprietes de resistance a peu pres uniformes dans la direction axiale et elle consiste, en particulier, en un tube soude en spirale et elle est pourvue, de preference, d'un renflement dirige vers l'exterieur, oppose au retrecissement. Il est prevu, au moins a la partie frontale du boitier, une piece intercalaire qui est faite en une ou plusieurs parties; cette piece etant obtenue a partir d'une matiere ductile ou a partir d'une matiere issue de la compression d'une poudre. L'invention concerne egalement un procede de fabrication de ces boitiers et de ces pieces embouties et un procede d'extrusion des tubes ainsi que les tubes obtenus par ce procede.
EP79901411A 1978-10-26 1980-05-07 Boitiers annulaires et procédé pour la production de tubes par métallurgie des poudres et procédé de production de ces boitiers Expired EP0020536B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
DE19782846658 DE2846658C2 (de) 1978-10-26 1978-10-26 Metallische Hülle für die Herstellung von Strangpreßbolzen zur pulvermetallurgischen Erzeugung von Rohren
DE2846660A DE2846660C2 (de) 1978-10-26 1978-10-26 Ringkörperförmige Hülle für Strangpreßbolzen zur pulvermetallurgischen Herstellung von Rohren
DE2846660 1978-10-26
DE2846658 1978-10-26
DE2846659 1978-10-26
DE19782846659 DE2846659A1 (de) 1978-10-26 1978-10-26 Kapseln und presslinge zum extrudieren von gegenstaenden, insbesondere rohren, und verfahren zum herstellen der kapseln und presslinge

Publications (2)

Publication Number Publication Date
EP0020536A1 true EP0020536A1 (fr) 1981-01-07
EP0020536B1 EP0020536B1 (fr) 1985-02-20

Family

ID=27187716

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79901411A Expired EP0020536B1 (fr) 1978-10-26 1980-05-07 Boitiers annulaires et procédé pour la production de tubes par métallurgie des poudres et procédé de production de ces boitiers

Country Status (23)

Country Link
EP (1) EP0020536B1 (fr)
AT (2) AT374387B (fr)
BE (1) BE879623A (fr)
BR (1) BR7906929A (fr)
CA (1) CA1120005A (fr)
CH (1) CH652054A5 (fr)
CS (1) CS216687B2 (fr)
DE (1) DE2967396D1 (fr)
DK (1) DK153742C (fr)
ES (3) ES8104027A1 (fr)
FI (1) FI61649C (fr)
FR (1) FR2439639A1 (fr)
GB (1) GB2034226B (fr)
HU (1) HU179975B (fr)
IT (1) IT1127798B (fr)
MX (1) MX150474A (fr)
NL (1) NL7907894A (fr)
NO (1) NO151779C (fr)
PL (1) PL132096B1 (fr)
RO (1) RO79124A (fr)
SE (1) SE441336B (fr)
SU (1) SU1369666A3 (fr)
WO (1) WO1980000803A1 (fr)

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FR2492291A1 (fr) * 1980-10-22 1982-04-23 Uk I Sp Conteneur pour l'extrudage a chaud de poudres metalliques
DE3530741C1 (de) * 1985-08-28 1993-01-14 Avesta Nyby Powder AB, Torshälla Verfahren zur Herstellung pulvermetallurgischer Gegenstaende
US4640815A (en) * 1985-10-17 1987-02-03 Crucible Materials Corporation Method and assembly for producing extrusion-clad tubular product
US4640814A (en) * 1985-10-17 1987-02-03 Crucible Materials Corporation Method for producing clad tubular product
SE8603686D0 (sv) * 1986-09-03 1986-09-03 Avesta Nyby Powder Ab Halning
FR2704465B1 (fr) * 1993-04-29 1995-06-23 Alsthom Intermagnetics Sa Pièce de fermeture de billette composite mono- ou multifilamentaire.
SE505247C2 (sv) * 1994-12-07 1997-07-21 Sandvik Ab Förfarande för tillverkning av rör av minnesmetall
US5689976A (en) * 1996-10-24 1997-11-25 Ansell Edmont Industrial, Inc. Reinforced glove and method for forming the same
RU2176569C2 (ru) * 1999-06-23 2001-12-10 Открытое акционерное общество "Новосибирский завод химконцентратов" Заготовка оболочки биметаллических изделий и устройство для ее изготовления
GB201119240D0 (en) * 2011-11-08 2011-12-21 Rolls Royce Plc A hot isostatic pressing tool and a method of manufacturing an article from powder material by hot isostatic pressing
GB201119238D0 (en) * 2011-11-08 2011-12-21 Rolls Royce Plc A hot isostatic pressing tool and a method of manufacturing an article from powder material by hot isostatic pressing
CZ308392B6 (cs) * 2017-09-08 2020-07-22 UJP PRAHA a.s. Zásobník práškových výlisků pro efektivní sintraci

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CH316476A (de) * 1952-06-13 1956-10-15 Ici Ltd Verfahren zum Schützen von aus Metallpulver gebildeten Körpern gegen Oxydation
FR1164348A (fr) * 1956-01-10 1958-10-08 Oerlikon Buehrle Ag Procédé de fabrication de corps profilés extrudés en poudre ferreuse
BE709814A (fr) * 1968-01-24 1968-05-30
US3823463A (en) * 1972-07-13 1974-07-16 Federal Mogul Corp Metal powder extrusion process
DE2419014C3 (de) * 1974-04-19 1985-08-01 Nyby Bruks AB, Nybybruk Verfahren zum Herstellen von Rohren aus rostfreiem Stahl und Anwendung des Verfahrens auf das Herstellen von Verbundrohren
US3892030A (en) * 1974-04-29 1975-07-01 Us Air Force Method of fabricating a billet from metal preforms and metal powder
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Publication number Publication date
FI61649C (fi) 1982-09-10
DK445879A (da) 1980-04-27
DK153742C (da) 1989-01-23
RO79124A (fr) 1982-06-25
ES251782Y (es) 1981-11-01
DE2967396D1 (en) 1985-03-28
ES485385A0 (es) 1981-04-16
MX150474A (es) 1984-05-14
FR2439639A1 (fr) 1980-05-23
CS216687B2 (en) 1982-11-26
CH652054A5 (de) 1985-10-31
ES251782U (es) 1981-05-01
FI61649B (fi) 1982-05-31
BE879623A (fr) 1980-02-15
NO151779B (no) 1985-02-25
FR2439639B1 (fr) 1983-04-29
IT1127798B (it) 1986-05-21
IT7984147A0 (it) 1979-10-26
CA1120005A (fr) 1982-03-16
ES8104027A1 (es) 1981-04-16
FI793336A7 (fi) 1980-04-27
PL219241A1 (fr) 1980-06-02
ATE11881T1 (de) 1985-03-15
EP0020536B1 (fr) 1985-02-20
HU179975B (en) 1983-01-28
DK153742B (da) 1988-08-29
NO793403L (no) 1980-04-29
AT374387B (de) 1984-04-10
ATA692379A (de) 1983-09-15
ES251783U (es) 1981-05-01
SU1369666A3 (ru) 1988-01-23
GB2034226A (en) 1980-06-04
ES251783Y (es) 1981-11-01
SE441336B (sv) 1985-09-30
BR7906929A (pt) 1980-06-24
NO151779C (no) 1985-06-05
SE7908702L (sv) 1980-04-27
PL132096B1 (en) 1985-01-31
GB2034226B (en) 1982-09-29
NL7907894A (nl) 1980-04-29
WO1980000803A1 (fr) 1980-05-01

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