EP0472546B1 - Process for manufacturing plated hollow blocks - Google Patents
Process for manufacturing plated hollow blocks Download PDFInfo
- Publication number
- EP0472546B1 EP0472546B1 EP90906879A EP90906879A EP0472546B1 EP 0472546 B1 EP0472546 B1 EP 0472546B1 EP 90906879 A EP90906879 A EP 90906879A EP 90906879 A EP90906879 A EP 90906879A EP 0472546 B1 EP0472546 B1 EP 0472546B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- accordance
- core
- molten
- plating
- hollow body
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 22
- 238000004519 manufacturing process Methods 0.000 title abstract description 12
- 238000007747 plating Methods 0.000 claims abstract description 46
- 239000000463 material Substances 0.000 claims abstract description 44
- 238000007654 immersion Methods 0.000 claims abstract description 12
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 8
- 238000002425 crystallisation Methods 0.000 claims description 7
- 230000008025 crystallization Effects 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 6
- 239000002826 coolant Substances 0.000 claims description 2
- 239000003779 heat-resistant material Substances 0.000 claims description 2
- 238000000926 separation method Methods 0.000 claims description 2
- 239000012768 molten material Substances 0.000 claims 1
- 238000007493 shaping process Methods 0.000 claims 1
- 239000000155 melt Substances 0.000 abstract description 21
- 239000012876 carrier material Substances 0.000 description 13
- 238000007598 dipping method Methods 0.000 description 4
- 238000001125 extrusion Methods 0.000 description 3
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- 238000005253 cladding Methods 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 238000009499 grossing Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000001192 hot extrusion Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
- C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
- C23C2/29—Cooling or quenching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/006—Pattern or selective deposits
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/38—Wires; Tubes
Definitions
- the invention relates to a method for producing clad hollow blocks for further processing into seamless metal tubes, in particular steel tubes, clad on the inside by hot or cold forming.
- the production of internally clad seamless steel tubes has hitherto generally been carried out in such a way that a hollow block composed of the carrier material and the cladding material is formed into a tube by extrusion.
- the feed material is prepared for this purpose in such a way that a cylindrical block made of a carrier material (eg low-alloy steel) is first drilled out in the axial direction, so that a hollow block is formed.
- the two nested hollow blocks are welded together in such a way that the annular gap between the two hollow blocks is tightly sealed, so that the contact surfaces of the hollow blocks do not oxidize when heated to the extrusion temperature and prevent a perfect connection between the carrier material and the plating material.
- the invention is therefore based on the object of specifying a method with which a hollow block clad only on the inside can be produced and which avoids the shortcomings indicated.
- the solution according to the invention provides that the molten carrier material is applied to the outside of the solid plating material. This ensures from the outset that the inner plating layer cannot detach from the outer layer as a result of thermal shrinkage, since the latter in any case tends to shrink more because of its higher initial temperature and thus practically shrinks onto the plating layer.
- the cylindrical hollow body used for the crystallization of the layer of the carrier material could be produced, for example, by hot-forming a corresponding block in a hole press and, if necessary, can be mechanically machined inside and outside before use in the melt of the carrier material, in order to have clean and smooth surfaces to achieve.
- the sealing of the inner surface of this hollow body during immersion in the melt of the carrier material can e.g. can be achieved by sealing cap.
- a cylindrical core for this purpose, which lies closely against the inner surface of the hollow body.
- the core is already used with particular advantage for the production of the cylindrical hollow body by immersing it in a melt of the plating material and allowing the required layer of the plating material to crystallize.
- the core must consist of a sufficiently heat-resistant material, e.g. from a mild steel.
- the heat resistance only has to allow the core to be immersed in the melt for the required time without melting itself.
- the core must be provided on its outer surface with a separating layer effective against the melt.
- a layer of rust or scale can suffice. This prevents a direct connection between the cladding material and the material of the core and enables the core to be pulled out of the hollow body.
- the possible dwell time of the steel core in the plating melt depends on its heat absorption capacity if no separate internal cooling of the core is provided.
- immersion in the melt can also be carried out in partial steps, intermediate cooling being inserted before the next immersion in the melt. This procedure is possible both in the production of the plating layer and in the production of the carrier layer.
- the chosen immersion time in the manufacture of the hollow block led on the one hand to the greatest possible growth rate of the support material St37 and on the other hand to a very good connection between the plating layer and the support material.
- the hollow block produced was then hot pressed in a known manner in an extruder to form a seamless steel tube of approximately 21 m in length with an outer diameter of 80 mm and a wall thickness of 10 mm.
- the plating layer had a thickness of about 2 mm and was perfectly connected to the carrier material.
- a hollow block of 250 mm outer diameter, 60 mm inner diameter, a plating layer thickness of approximately 25 mm and again approximately 1 m long was to be produced and formed into a seamless tube, the procedure according to claim 3 being chosen for the plating fraction.
- a rod made of St37 with an outer diameter of 60 mm, which was covered with a scale layer was immersed in a melt of material 1.4301 heated to 30 K above the liquidus temperature. The rod was pulled out of the melt after a dipping time of approximately 35 seconds, during which a plating layer of approximately 17 mm had formed on the surface.
- the rod provided with the plating layer 25 mm thick was then immersed in a melt of St37 heated to 20 K above the liquidus temperature in accordance with the first exemplary embodiment.
- a block with an outer diameter of 236 mm had formed.
- a last dipping process of 53 seconds was carried out.
- the rod from St37 used as the immersion core was pulled out of the hollow block on a pull-out device. Because of the scale layer on the rod acting as a separating layer, this separation could be carried out without difficulty.
- the outer surface of the block was then smoothed while still warm.
- the inner surface (plating layer) of the hollow block was also subjected to a smoothing and cleaning action in order to eliminate the irregularities caused by the scale layer.
- the block was then again hot-formed in an extrusion press to form a seamless tube. With an outer diameter of 80 mm, an inner diameter of 30 mm, the tube length was over 20 m and the thickness of the plating layer was 1.6 mm. The connection between the two layers was again perfect.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Coating With Molten Metal (AREA)
- Laminated Bodies (AREA)
- Pressure Welding/Diffusion-Bonding (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Chemically Coating (AREA)
- ing And Chemical Polishing (AREA)
- Electroplating Methods And Accessories (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Herstellung von plattierten Hohlblöcken für die Weiterverarbeitung zu auf der Innenseite plattierten nahtlosen Metallrohren, insbesondere Stahlrohren, durch Warm- oder Kaltumformung.The invention relates to a method for producing clad hollow blocks for further processing into seamless metal tubes, in particular steel tubes, clad on the inside by hot or cold forming.
Die Herstellung von innenplattierten nahtlosen Stahlrohren wird bisher in der Regel in der Weise vorgenommen, daß ein aus dem Trägerwerkstoff und dem Plattierungswerkstoff zusammengesetzter Hohlblock durch Strangpressen zu einem Rohr umgeformt wird. Das Einsatzmaterial wird zu diesem Zweck in der Weise vorbereitet, daß zunächst ein zylindrischer Block aus einem Trägerwerkstoff (z.B. niedriglegierter Stahl) in axialer Richtung ausgebohrt wird, so daß ein Hohlblock entsteht. In diesen Hohlblock wird dann ein seinem Innendurchmesser entsprechender zylindrischer Block gleicher Länge, der ebenfalls innen ausgebohrt ist und aus dem Plattierungswerkstoff (z.B. hochlegierter Stahl) besteht, eingesetzt.The production of internally clad seamless steel tubes has hitherto generally been carried out in such a way that a hollow block composed of the carrier material and the cladding material is formed into a tube by extrusion. The feed material is prepared for this purpose in such a way that a cylindrical block made of a carrier material (eg low-alloy steel) is first drilled out in the axial direction, so that a hollow block is formed. A cylindrical block of the same length corresponding to its inside diameter, which is also drilled out on the inside and is made of the plating material (for example high-alloy steel), is then inserted into this hollow block.
An den Stirnseiten werden die beiden ineinandergesetzten Hohlblöcke derart miteinander verschweißt, daß der Ringspalt zwischen den beiden Hohlblöcken dicht verschlossen ist, damit die Kontaktflächen der Hohlblöcke beim Erhitzen auf die Strangpreßtemperatur nicht oxidieren und eine einwandfreie Verbindung zwischen dem Trägerwerkstoff und dem Plattierungswerkstoff verhindern.At the end faces, the two nested hollow blocks are welded together in such a way that the annular gap between the two hollow blocks is tightly sealed, so that the contact surfaces of the hollow blocks do not oxidize when heated to the extrusion temperature and prevent a perfect connection between the carrier material and the plating material.
Diese Vorgehensweise hat gravierende Nachteile. Die Verschweißung auf den Stirnseiten stellt eine Schwachstelle dar, die z.B. beim Erwärmen aufreißen kann, so daß die Kontaktflächen doch oxidieren können. Darüberhinaus erfordert die Vorbereitung eines einsatzfähigen plattierten Hohlblocks einen erheblichen Aufwand, der einerseits in der notwendigen Bearbeitung (Bohren, Schweißen) liegt und andererseits auch in dem beträchtlichen Einsatz an teurem Plattierungswerkstoff (Schrottanfall beim Ausbohren) zu sehen ist.This procedure has serious disadvantages. The welding on the end faces represents a weak point that e.g. can tear open when heated, so that the contact surfaces can still oxidize. In addition, the preparation of a ready-to-use clad hollow block requires considerable effort, which on the one hand is due to the necessary processing (drilling, welding) and on the other hand can be seen in the considerable use of expensive plating material (amount of scrap when drilling out).
Für die Herstellung von einseitig plattiertem Stahlblech wurde von der Anmelderin bereits ein Verfahren vorgeschlagen (DE-P 39 07 903), bei dem der Plattierungswerkstoff in schmelzflüssigem Zustand auf ein Trägerblech aufgebracht wird. Hierzu werden jeweils zwei Trägerbleche mit ihren Flachseiten dicht aufeinander gelegt und in eine Schmelze des Plattierungswerkstoffs so lange eingetaucht, bis sich eine ausreichend dicke Plattierungsschicht durch Ankristallisieren gebildet hat.For the production of steel sheet clad on one side, the applicant has already proposed a process (DE-P 39 07 903) in which the plating material is applied to a carrier sheet in the molten state. For this purpose, two flat sheets are placed with their flat sides close to one another and immersed in a melt of the plating material until a sufficiently thick plating layer has formed by crystallization.
Das Aufbringen einer Plattierungsschicht unmittelbar aus dem schmelzflüssigen Zustand auf den Trägerwerkstoff läßt sich jedoch nicht ohne weiteres auf die Herstellung plattierter Hohlblöcke übertragen. Beim Eintauchen eines Hohlblocks aus dem Trägerwerkstoff in eine Schmelze des Plattierungswerkstoffs bildet sich sowohl auf der Innenals auch auf der Außenoberfläche eine Plattierungsschicht aus. Letztere ist häufig nicht erforderlich und würde allein schon wegen des unnötigen Verbrauchs an Plattierungswerkstoff die Herstellkosten stark belasten.However, the application of a plating layer directly from the molten state to the carrier material cannot easily be transferred to the production of clad hollow blocks. When a hollow block made of the carrier material is immersed in a melt of the plating material, a plating layer forms on both the inside and the outside surface. The latter is often not necessary and would put a heavy burden on manufacturing costs simply because of the unnecessary consumption of plating material.
Um eine Außenplattierung zu vermeiden, wäre es möglich, einen Hohlblock des Trägerwerkstoffs mit einer Schmelze des Plattierungswerkstoffs zu füllen oder, um den Verbrauch an Plattierungsschmelze möglichst gering zu halten, mit einer Schicht dieses Materials z.B. auszuschleudern und erstarren zu lassen. Dabei tritt jedoch das Problem auf, daß sich aus Gründen unterschiedlicher thermischer Dehnungen bzw. Schrumpfungen die Plattierungsschicht von dem Trägerwerkstoff wieder ablöst, bevor die Weiterverarbeitung des plattierten Hohlblocks erfolgen kann.In order to avoid external plating, it would be possible to fill a hollow block of the carrier material with a melt of the plating material or, in order to keep the consumption of plating melt as low as possible, with a layer of this material, e.g. to be thrown out and frozen. However, the problem arises that, for reasons of different thermal expansions or shrinkages, the plating layer detaches from the carrier material again before the further processing of the plated hollow block can take place.
Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren anzugeben, mit dem ein lediglich auf der Innenseite plattierter Hohlblock herstellbar ist und das die aufgezeigten Mängel vermeidet.The invention is therefore based on the object of specifying a method with which a hollow block clad only on the inside can be produced and which avoids the shortcomings indicated.
Gelöst wird diese Aufgabe durch ein Verfahren mit den Merkmalen des Patentanspruchs 1; vorteilhafte Weiterbildungen dieses Verfahrens sind in den Unteransprüchen 2 bis 9 angegeben.This object is achieved by a method with the features of claim 1; Advantageous developments of this method are specified in subclaims 2 to 9.
Die erfindungsgemäße Lösung sieht vor, daß der schmelzflüssige Trägerwerkstoff außen auf den festen Plattierungswerkstoff aufgebracht wird. Damit ist von vornherein sichergestellt, daß sich die innere Plattierungsschicht nicht infolge thermischer Schrumpfung von der Außenschicht ablösen kann, da letztere auf jeden Fall wegen ihrer höheren Anfangstemperatur zu stärkerer Schrumpfung neigt und damit praktisch auf die Plattierungsschicht aufschrumpft. Der für das Ankristallisieren der Schicht des Trägerwerkstoffs eingesetzte zylindrische Hohlkörper könnte z.B. durch Warmumformung eines entsprechenden Blocks in einer Lochpresse hergestellt werden und kann, soweit erforderlich, vor dem Einsatz in die Schmelze des Trägerwerkstoffs gegebenenfalls innen und außen mechanisch bearbeitet werden, um saubere und glatte Oberflächen zu erzielen.The solution according to the invention provides that the molten carrier material is applied to the outside of the solid plating material. This ensures from the outset that the inner plating layer cannot detach from the outer layer as a result of thermal shrinkage, since the latter in any case tends to shrink more because of its higher initial temperature and thus practically shrinks onto the plating layer. The cylindrical hollow body used for the crystallization of the layer of the carrier material could be produced, for example, by hot-forming a corresponding block in a hole press and, if necessary, can be mechanically machined inside and outside before use in the melt of the carrier material, in order to have clean and smooth surfaces to achieve.
Damit ist eine zerspanungslose oder zumindest zerspanungsarme und folglich hinsichtlich des Plattierungswerkstoffs abfallarme Herstellung des für das Verfahren benötigten zylindrischen Hohlkörpers möglich. Die Abdichtung der Innenoberfläche dieses Hohlkörpers während des Eintauchens in die Schmelze des Trägerwerkstoffs kann z.B. durch Verschlußdeckel erzielt werden. Zweckmäßiger ist es jedoch, hierfür einen zylindrischen Kern zu verwenden, der dicht an der Innenoberfläche des Hohlkörpers anliegt. Mit ganz besonderem Vorteil wird der Kern bereits für die Erzeugung des zylindrischen Hohlkörpers benutzt, indem man ihn in eine Schmelze des Plattierungswerkstoffs eintaucht und die erforderliche Schicht des Plattierungswerkstoffs ankristallisieren läßt. Hierzu muß der Kern aus einem ausreichend hitzebeständigen Material bestehen, z.B. aus einem Baustahl. Die Hitzebeständigkeit muß lediglich erlauben, daß der Kern für die erforderliche Zeit in die Schmelze eingetaucht werden darf, ohne selbst anzuschmelzen. Hierfür ist es besonders zweckmäßig, den Kern mit einer Innenkühlung zu versehen, indem ein Kühlmittel durch diesen hindurchgeführt wird. Damit eine leichte Entfernung des Kerns aus dem Hohlkörper bzw. Hohlblock möglich ist, muß der Kern auf seiner Außenoberfläche mit einer gegenüber der Schmelze wirksamen Trennschicht versehen sein. Bei einem Stahlkern kann hierzu beispielsweise eine Rost- oder Zunderschicht ausreichen. Diese verhindert eine unmittelbare Verbindung zwischen Plattierungswerkstoff und dem Werkstoff des Kerns und ermöglicht ein Herausziehen des Kerns aus dem Hohlkörper.This makes it possible to produce the cylindrical hollow body required for the method without machining or at least with little machining and consequently with little waste with regard to the plating material. The sealing of the inner surface of this hollow body during immersion in the melt of the carrier material can e.g. can be achieved by sealing cap. However, it is more expedient to use a cylindrical core for this purpose, which lies closely against the inner surface of the hollow body. The core is already used with particular advantage for the production of the cylindrical hollow body by immersing it in a melt of the plating material and allowing the required layer of the plating material to crystallize. For this, the core must consist of a sufficiently heat-resistant material, e.g. from a mild steel. The heat resistance only has to allow the core to be immersed in the melt for the required time without melting itself. For this purpose, it is particularly expedient to provide the core with internal cooling by passing a coolant through it. So that an easy removal of the core from the hollow body or hollow block is possible, the core must be provided on its outer surface with a separating layer effective against the melt. In the case of a steel core, for example, a layer of rust or scale can suffice. This prevents a direct connection between the cladding material and the material of the core and enables the core to be pulled out of the hollow body.
Die mögliche Verweilzeit des Stahlkerns in der Plattierungsschmelze richtet sich, wenn keine gesonderte Innenkühlung des Kerns vorgesehen ist, nach seinem Wärmeaufnahmevermögen. Um dickere Schichten ankristallisieren zu lassen, kann das Eintauchen in die Schmelze auch in Teilschritten durchgeführt werden, wobei jeweils vor dem nächsten Eintauchen in die Schmelze eine Zwischenabkühlung eingelegt wird. Dieses Vorgehen ist sowohl bei der Erzeugung der Plattierungsschicht als auch bei der Erzeugung der Trägerschicht möglich.The possible dwell time of the steel core in the plating melt depends on its heat absorption capacity if no separate internal cooling of the core is provided. In order to allow thicker layers to crystallize, immersion in the melt can also be carried out in partial steps, intermediate cooling being inserted before the next immersion in the melt. This procedure is possible both in the production of the plating layer and in the production of the carrier layer.
Soweit die durch das Ankristallisieren des Plattierungswerkstoffs und/oder des Trägerwerkstoffs entstehenden Oberflächen zu unregelmäßig ausfallen, kann noch im warmen Zustand des Materials und daher mit geringem Aufwand ein Glätten durch Walzen vorgesehen werden. Wenn die Herstellung des aus dem Plattierungswerkstoff bestehenden Hohlkörpers gemäß dem Verfahrensanspruch 3 vorgenommen wurde, muß vor einer Weiterverarbeitung des Hohlblocks zum nahtlosen Rohr eine mechanische Bearbeitung der Innenoberfläche vorgenommen werden, damit eine saubere und glatte Oberfläche sichergestellt ist. Dabei entsteht nur wenig Abfallmaterial. Die Weiterverarbeitung selbst kann z.B. durch Strangpressen in warmem Zustand oder auch durch Warm- oder Kaltpilgern erfolgen. Das erfindungsgemäße Verfahren ist in besonderer Weise für Stahlwerkstoffe geeignet, läßt sich jedoch auch bei andersartigen metallischen Werkstoffen verwenden.Insofar as the surfaces resulting from the crystallization of the plating material and / or the carrier material turn out to be irregular, smoothing by rolling can be provided while the material is still warm and therefore with little effort. If the production of the hollow body consisting of the plating material has been carried out according to the method claim 3, mechanical processing of the inner surface must be carried out before further processing of the hollow block to form a seamless tube, so that a clean and smooth surface is ensured. Only a little waste material is created. The further processing itself can e.g. by hot extrusion or by warm or cold pilgrims. The method according to the invention is particularly suitable for steel materials, but can also be used with other types of metallic materials.
Anhand der nachfolgenden zwei Ausführungsbeispiele zur Herstellung nahtloser innenplattierter Stahlrohre aus St37 wird die Erfindung näher erläutert.The invention is explained in more detail with the aid of the following two exemplary embodiments for producing seamless internally clad steel tubes from St37.
Ein stirnseitig durch Deckel verschlossenes Rohr von ca. 1 m Länge, 120 mm Außendurchmesser und 30 mm Wanddicke aus dem Plattierungswerkstoff 1.4301 (X5 CrNi 18 9) wurde für ca. 25 sek in eine um 20 K über Liquidustemperatur erhitzte Schmelze aus St37 eingetaucht und dann zur Zwischenabkühlung auf etwa Raumtemperatur wieder herausgezogen. Während der Tauchzeit kristallisierte außen an dem Rohr eine Schicht aus St37 von etwa 22 mm Dicke an. Dieser Tauchvorgang mit anschließender Zwischenabkühlung wurde noch zweimal wiederholt bis ein Hohlblock von insgesamt 252 mm Außendurchmesser entstanden war. Die Außenoberfläche des Hohlblocks wurde anschließend in warmem Zustand durch Kalibrierwalzen geglättet.A tube of approx. 1 m length, 120 mm outer diameter and 30 mm wall thickness made of the plating material 1.4301 (X5 CrNi 18 9), which was closed by a cover at the end, was immersed for about 25 seconds in a melt of St37 heated to 20 K above the liquidus temperature and then pulled out to cool down to about room temperature. During the dipping time, a layer of St37 of about 22 mm thickness crystallized on the outside of the tube. This dipping process with subsequent intermediate cooling was repeated two more times until a hollow block with a total outer diameter of 252 mm had formed. The outer surface of the hollow block was then smoothed while warm by calibration rollers.
Die gewählte Tauchzeit bei der Herstellung des Hohlblocks führte einerseits zu einer größtmöglichen Anwachsrate des Trägerwerkstoffs St37 und andererseits zu einer sehr guten Verbindung zwischen der Plattierungsschicht und dem Trägerwerkstoff. Der erzeugte Hohlblock wurde anschließend in bekannter Weise in einer Strangpresse warm zu einem nahtlosen Stahlrohr von etwa 21 m Länge mit 80 mm Außendurchmesser und 10 mm Wanddicke ausgepreßt. Die Plattierungsschicht hatte eine Dicke von etwa 2 mm und war einwandfrei mit dem Trägerwerkstoff verbunden.The chosen immersion time in the manufacture of the hollow block led on the one hand to the greatest possible growth rate of the support material St37 and on the other hand to a very good connection between the plating layer and the support material. The hollow block produced was then hot pressed in a known manner in an extruder to form a seamless steel tube of approximately 21 m in length with an outer diameter of 80 mm and a wall thickness of 10 mm. The plating layer had a thickness of about 2 mm and was perfectly connected to the carrier material.
Im zweiten Ausführungsbeispiel sollte ein Hohlblock von 250 mm Außendurchmesser, 60 mm Innendurchmesser, einer Plattierungsschichtdicke von etwa 25 mm und wiederum etwa 1 m Länge hergestellt und zu einem nahtlosen Rohr umgeformt werden, wobei für den Plattierungsanteil die Vorgehensweise gemäß Anspruch 3 gewählt werden sollte. Hierzu wurde eine Stange aus St37 von 60 mm Außendurchmesser, die mit einer Zunderschicht bedeckt war, in eine um 30 K über Liquidustemperatur erhitzte Schmelze aus dem Werkstoff 1.4301 getaucht. Die Stange wurde nach einer Tauchzeit von ca. 35 sek, in der sich auf der Oberfläche eine Plattierungsschicht von ca. 17 mm gebildet hatte, aus der Schmelze herausgezogen. Nach Zwischenabkühlung auf etwa Raumtemperatur wurde sie erneut in die Schmelze des Plattierungswerkstoffs eingetaucht, um die Plattierungsschichtdicke von insgesamt 25 mm zu erreichen. Hierzu wurde die Tauchzeit auf ca. 47 sek verlängert, d.h. es wurde so lange gewartet, bis die zweite aufgewachsene Plattierungsschicht, die nach etwa 35 sek ihr Maximum erreicht hatte, teilweise wieder abgeschmolzen war. Eine kürzere Tauchzeit als 35 sek zur Erzielung der an der gewünschten Schichtdicke noch fehlenden 8 mm wäre unzweckmäßig gewesen, da dann die Haftung zur ersten Plattierungsschicht unzureichend gewesen wäre. Nach erfolgter Zwischenabkühlung wurde dann die mit der Plattierungsschicht von 25 mm Dicke versehene Stange entsprechend dem ersten Ausführungsbeispiel in eine um 20 K über Liquidustemperatur erhitzte Schmelze aus St37 getaucht.In the second exemplary embodiment, a hollow block of 250 mm outer diameter, 60 mm inner diameter, a plating layer thickness of approximately 25 mm and again approximately 1 m long was to be produced and formed into a seamless tube, the procedure according to claim 3 being chosen for the plating fraction. For this purpose, a rod made of St37 with an outer diameter of 60 mm, which was covered with a scale layer, was immersed in a melt of material 1.4301 heated to 30 K above the liquidus temperature. The rod was pulled out of the melt after a dipping time of approximately 35 seconds, during which a plating layer of approximately 17 mm had formed on the surface. After intermediate cooling to about room temperature, it was immersed again in the melt of the plating material in order to achieve a total plating layer thickness of 25 mm. For this purpose, the immersion time was extended to approx. 47 seconds, that is to say, it was waited until the second grown plating layer, which had reached its maximum after approx. 35 seconds, had partially melted again. A shorter immersion time than 35 seconds to achieve the 8 mm still missing in the desired layer thickness would have been inappropriate since the adhesion to the first plating layer would then have been insufficient. After intermediate cooling, the rod provided with the plating layer 25 mm thick was then immersed in a melt of St37 heated to 20 K above the liquidus temperature in accordance with the first exemplary embodiment.
Nach dreimaligem Tauchen und Zwischenabkühlen hatte sich ein Block von 236 mm Außendurchmesser gebildet. Um den angestrebten Außendurchmesser von 250 mm zu erreichen, wurde dann ein letzter Tauchvorgang von 53 sek Dauer ausgeführt. Nach Herausnehmen aus der Schmelze und vollständigem Erstarren der äußeren Oberfläche wurde die als Tauchkern benutzte Stange aus St37 auf einer Ausziehvorrichtung aus dem Hohlblock herausgezogen. Wegen der als Trennschicht wirkenden Zunderschicht auf der Stange ließ sich diese Trennung ohne Schwierigkeiten ausführen. Die äußere Oberfläche des Blockes wurde danach in noch warmem Zustand geglättet Ebenfalls wurde die Innenoberfläche (Plattierungsschicht) des Hohlblocks einer glättend und säubernd wirkenden Bearbeitung unterzogen, um die durch die Zunderschicht hervorgerufenen Unregelmäßigkeiten zu eliminieren. Danach wurde der Block wiederum warm in einer Strangpresse zu einem nahtlosen Rohr verformt. Bei einem Außendurchmesser von 80 mm, einem Innendurchmesser von 30 mm ergab sich eine Rohrlänge von über 20 m und eine Dicke der Plattierungsschicht von 1,6 mm. Die Verbindung zwischen den beiden Schichten war wiederum einwandfrei.After three dips and intermediate cooling, a block with an outer diameter of 236 mm had formed. In order to achieve the desired outer diameter of 250 mm, a last dipping process of 53 seconds was carried out. After removal from the melt and complete solidification of the outer surface, the rod from St37 used as the immersion core was pulled out of the hollow block on a pull-out device. Because of the scale layer on the rod acting as a separating layer, this separation could be carried out without difficulty. The outer surface of the block was then smoothed while still warm. The inner surface (plating layer) of the hollow block was also subjected to a smoothing and cleaning action in order to eliminate the irregularities caused by the scale layer. The block was then again hot-formed in an extrusion press to form a seamless tube. With an outer diameter of 80 mm, an inner diameter of 30 mm, the tube length was over 20 m and the thickness of the plating layer was 1.6 mm. The connection between the two layers was again perfect.
Claims (9)
- Process for producing plated blocks bodies for additional processing of plated weldless steel pipes by means of single or multiple immersion of a pipe-shaped body in molten metal,
wherein,
to produce hollow block for further processing of pipes which are plated inside, a hollow body formed from plating material is dipped into molten support material and, after crystallization, a sufficiently thick support layer is removed from molten metal, whereby an inside surface of a hollow body is protected against contact with molten metal during immersion. - Process in accordance with claim 1,
wherein
protection against contact with molten material involved occurs by means of a cylindrical core in a hollow body, said core lying tightly against an inside surface, and this core is removed from a said hollow block after the end of crystallization. - Process in accordance with claim 2,
wherein
a hollow body is produced by immersing a rod-shaped core made of heat-resistant material, which is provided with a separation layer, into molten plating material and, after crystallization of a sufficiently thick plating layer is removed from this molten plating material. - Process in accordance with claim 2 or claim 3,
wherein
crystallization of plating material and/or a layer of support material occurs in each case in at least two stages, in that a hollow body or hollow block is always removed from molten metal after a set period of time and is subjected to cooling, before being immersed in a same molten metal again to allow a crystallized layer to further accumulate. - Process in accordance with claim 3 or claim 4,
a surface of a core provided with plating material is smoothed and flattened before immersion in molten support material. - Process in accordance with any one of claims 1 to 5,
wherein
a surface of crystallized support material is smoothed and flattened before further processing of a hollow block. - Process in accordance with either of claims 5 or 6,
wherein
flattening occurs by means of sheet rollers. - Process in accordance with any one of claims 3 to 7,
wherein
a core is cooled inside, during immersion in molten plating material and/or support material, by means of a flow of coolant. - Process in accordance with any one of claims 3 to 5,
wherein
a surface of a hollow block is cleaned and flattened after a core has been removed, before shaping into a pipe occurs.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3916114 | 1989-05-16 | ||
| DE3916114 | 1989-05-16 | ||
| PCT/DE1990/000335 WO1990014446A1 (en) | 1989-05-16 | 1990-05-08 | Process for manufacturing plated hollow blocks |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0472546A1 EP0472546A1 (en) | 1992-03-04 |
| EP0472546B1 true EP0472546B1 (en) | 1994-12-14 |
Family
ID=6380841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP90906879A Expired - Lifetime EP0472546B1 (en) | 1989-05-16 | 1990-05-08 | Process for manufacturing plated hollow blocks |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US5232740A (en) |
| EP (1) | EP0472546B1 (en) |
| JP (1) | JP2925093B2 (en) |
| KR (1) | KR930010337B1 (en) |
| CN (1) | CN1028847C (en) |
| AT (1) | ATE115643T1 (en) |
| BR (1) | BR9007180A (en) |
| CA (1) | CA2033079C (en) |
| DE (1) | DE59008036D1 (en) |
| WO (1) | WO1990014446A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1042805C (en) * | 1994-03-28 | 1999-04-07 | 本溪钢铁公司 | Anti-oxidation method for inwall of steel pipe inlaid in casting |
| CN1057242C (en) * | 1995-12-19 | 2000-10-11 | 苌保俊 | Bearing alloy on-site no-die pouring-casting technology |
| CN1067928C (en) * | 1997-09-23 | 2001-07-04 | 曾征 | Thin wall alloy product immersion crystalline forming method |
| ITMI20012098A1 (en) * | 2001-10-11 | 2003-04-11 | Giorgio Enrico Falck | PROCEDURE FOR THE PRODUCTION OF METAL INGOTS WITH STAINLESS STEEL CORE |
| AU2002343118A1 (en) * | 2001-10-11 | 2003-04-28 | Corinox S.R.L. | A method for the production of hollow metallic ingots or compound metallic ingots |
| CN101440467B (en) * | 2008-12-12 | 2010-06-02 | 南车四方车辆有限公司 | Protecting method for metal component screwed hole in hot-dip galvanizing antiseptic treatment |
| CN103317124B (en) * | 2013-06-05 | 2015-04-08 | 无锡舒玛天科新能源技术有限公司 | Method for preparing rotary copper, indium and gallium target |
| CN116732459B (en) * | 2023-06-14 | 2024-03-29 | 江苏塞恩斯金属新材料科技有限公司 | High-strength low-temperature-resistant steel pipe and preparation process thereof |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1938257A (en) * | 1931-12-29 | 1933-12-05 | Jones Ernest Fraser | Production of hollow ingots |
| AT302223B (en) * | 1970-09-22 | 1972-10-10 | Voest Ag | Process for the production of three-layer rolled products |
| JPS54141343A (en) * | 1978-04-25 | 1979-11-02 | Nitto Aen Tokin Kk | Wet galvanizing method for steel pipe outside |
| DE3134758A1 (en) * | 1981-09-02 | 1983-03-17 | Kocks Technik Gmbh & Co, 4010 Hilden | METHOD FOR PRODUCING METALLIC HOLLOW BLOCKS |
| JPS58103937A (en) * | 1981-12-17 | 1983-06-21 | Sumitomo Metal Ind Ltd | Production of hollow steel ingot |
| JPS6021174A (en) * | 1983-07-15 | 1985-02-02 | Toyota Motor Corp | Production of bottomed hollow body |
| JPS613874A (en) * | 1984-06-15 | 1986-01-09 | Kubota Ltd | Production of double-layered pipe |
| JPS6152357A (en) * | 1984-08-18 | 1986-03-15 | Sumitomo Metal Ind Ltd | Manufacture of seamless clad tube |
| US4759399A (en) * | 1986-05-15 | 1988-07-26 | Kawasaki Steel Corporation | Method and apparatus for producing hollow metal ingots |
| JPH01218759A (en) * | 1988-02-29 | 1989-08-31 | Kawasaki Steel Corp | Production of hollow ingot |
-
1990
- 1990-05-08 BR BR909007180A patent/BR9007180A/en not_active IP Right Cessation
- 1990-05-08 WO PCT/DE1990/000335 patent/WO1990014446A1/en active IP Right Grant
- 1990-05-08 AT AT90906879T patent/ATE115643T1/en not_active IP Right Cessation
- 1990-05-08 CA CA002033079A patent/CA2033079C/en not_active Expired - Fee Related
- 1990-05-08 JP JP2506900A patent/JP2925093B2/en not_active Expired - Lifetime
- 1990-05-08 KR KR1019900702693A patent/KR930010337B1/en not_active IP Right Cessation
- 1990-05-08 EP EP90906879A patent/EP0472546B1/en not_active Expired - Lifetime
- 1990-05-08 DE DE59008036T patent/DE59008036D1/en not_active Expired - Fee Related
- 1990-05-08 US US07/776,306 patent/US5232740A/en not_active Expired - Fee Related
- 1990-05-12 CN CN90102770A patent/CN1028847C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2033079A1 (en) | 1990-11-17 |
| DE59008036D1 (en) | 1995-01-26 |
| JP2925093B2 (en) | 1999-07-26 |
| US5232740A (en) | 1993-08-03 |
| CN1047235A (en) | 1990-11-28 |
| EP0472546A1 (en) | 1992-03-04 |
| JPH04505184A (en) | 1992-09-10 |
| KR920700304A (en) | 1992-02-19 |
| ATE115643T1 (en) | 1994-12-15 |
| BR9007180A (en) | 1992-01-28 |
| CN1028847C (en) | 1995-06-14 |
| CA2033079C (en) | 1998-12-29 |
| WO1990014446A1 (en) | 1990-11-29 |
| KR930010337B1 (en) | 1993-10-16 |
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