EP0647723A1 - Process for manufacturing of seamless drawn medium hard/hard copper fitting tubes - Google Patents

Process for manufacturing of seamless drawn medium hard/hard copper fitting tubes Download PDF

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Publication number
EP0647723A1
EP0647723A1 EP94114354A EP94114354A EP0647723A1 EP 0647723 A1 EP0647723 A1 EP 0647723A1 EP 94114354 A EP94114354 A EP 94114354A EP 94114354 A EP94114354 A EP 94114354A EP 0647723 A1 EP0647723 A1 EP 0647723A1
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EP
European Patent Office
Prior art keywords
hard
tubes
roughened
oxygen
temperature
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EP94114354A
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German (de)
French (fr)
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EP0647723B1 (en
Inventor
Christian Dipl.-Ing. Triquet
Ulrich Fliegner
Jörg Dipl.-Ing. Matussek
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KM Europa Metal AG
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KM Kabelmetal AG
KM Europa Metal AG
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C3/00—Abrasive blasting machines or devices; Plants
    • B24C3/32—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks
    • B24C3/325—Abrasive blasting machines or devices; Plants designed for abrasive blasting of particular work, e.g. the internal surfaces of cylinder blocks for internal surfaces, e.g. of tubes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/02—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working in inert or controlled atmosphere or vacuum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon

Definitions

  • the invention relates to a method for producing seamless drawn semi-hard / hard plumbing pipes made of copper, in which the inner surfaces of the pipes are roughened.
  • EP 0 306 810 A2 discloses a method for producing pitting-resistant, hard-drawn tubes made of copper or copper alloys, in which the tubes are first degreased and then the inner surfaces of the tubes are additionally treated with an abrasive. Hereby a roughening of the inner surfaces is achieved, by which the formation of harmful films, e.g. avoid carbon-containing films on the inner surfaces of hard-drawn copper pipes.
  • pitting corrosion processes involve copper ion migration, but they follow other laws.
  • a high corrosion resistance of copper materials, in particular one against pitting corrosion type 1 does not at the same time result in a lower copper ion release to water.
  • the invention has for its object to improve this method in such a way that a reduced copper ion release to drinking water with a normal pH in the range of 6.5 to 9.0 can be guaranteed.
  • semi-hard or hard copper installation pipes can now be made available, in which the copper ion release to the drinking water can be kept decisively below the required limit values even over a long period of time.
  • Such installation pipes are also resistant to pitting corrosion and can be installed with the known connection and bending techniques.
  • the process also allows economical production in bar form with the commonly available manufacturing facilities for seamless copper tubes.
  • the method according to the invention can advantageously be used in the manufacture of fittings with reduced copper ion release.
  • a first process step there is a so-called preference, in which hot-formed front tubes are cold-formed from cast rods by pulling to an intermediate dimension.
  • the inner surfaces of these intermediate tubes are then roughened. This is not only intended to promote the oxidic reaction with the inner surfaces, but also to prevent the oxide layer from no longer uniformly covering during the later hardening process in which the inner surfaces are stretched.
  • the roughness depth Ra can range between 0.3 ⁇ m and 1.0 ⁇ m.
  • the final dimension of the installation pipes is generated by a hardness train to semi-hard / hard.
  • a thermal treatment is carried out again at 175 ° C. to 275 ° C. while introducing an oxygen-containing gas mixture into the interior of the tube in order to achieve an oxide layer in a composition of approximately 12% to 21% oxygen with the residual copper content.
  • the production process according to the invention substantially reduces the copper ion release compared to the semi-hard / hard copper installation pipes in the form of bars, which have previously been used for the central drinking water supply, with constant resistance to pitting corrosion.
  • the maximum copper ion solubility in installation pipes made in this way surprisingly only reaches a value of 1 mg / l.
  • the roughening of the inner surfaces of the intermediate tubes can be carried out according to the features of claim 2 by using blasting agents or by pickling.
  • an abrasive e.g. Silicon oxide are used.
  • the intermediate tubes are preferably annealed in accordance with the features of claim 3 with a protective gas which has an oxygen content of 1% to 7%.
  • the annealing process is preferably carried out at a temperature of about 650 ° C.
  • a thin, adherent oxide layer with a thickness of approximately 0.05 ⁇ m to 0.2 ⁇ m can thereby be produced.
  • the thermal treatment after the hardening train is advantageously carried out at a temperature of about 250 ° C.
  • the hardening tension is carried out in particular with an internal mandrel.
  • the degree of deformation here is on average 20%.
  • the heating can be carried out convectively, electrically inductively or conductively according to claim 8.
  • phosphorus deoxidized copper (SF-Cu) was melted and cast into bars. The bars were then further processed into tubes by means of hot forming and then cold formed to an intermediate dimension.
  • the intermediate tubes were then continuously heat-treated at a temperature of 650 ° C. while introducing a gas mixture into the interior of the tube.
  • the gas mixture consisted of a protective gas with an oxygen content of 3%.
  • a firmly adhering thin copper oxide layer with a layer thickness of 0.15 ⁇ m was formed on the inner surface, the oxygen content of which was determined to be 11.2% by means of X-ray diffractometry.
  • the intermediate tubes were hard-drawn to their final dimensions using a standard drawing oil with a degree of deformation of 20% and then degreased on the inside by passing a commercially available degreasing agent through the tubes.
  • Pipe sections cut to length and deburred to 300 mm were then subjected to oxidizing heat treatment in a laboratory furnace with circulated air as furnace atmosphere at 250 ° C. for a period of 30 minutes.
  • the oxygen content (O2 content) of the copper oxide layer now formed on the inner surface of the tubes was determined by means of energy dispersive analysis (EDX) to 13.8%.
  • test pipe sections were arranged vertically and filled with drinking water.
  • the copper ion release was determined in a series of tests lasting several months.
  • the amount of copper released in mg / l was measured in 24-hour intervals with an absorption spectrometer.
  • the pH of the drinking water used was 7.6.
  • the upper limit of the measured values for the copper content in drinking water was 1 mg / l.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Abstract

In this process, copper tube blanks hot-formed from cast rods are first cold-formed by drawing to an intermediate dimension. The internal surfaces of these intermediate tubes are then roughened and these roughened intermediate tubes are then heat treated at a temperature of from 350 DEG C to 650 DEG C while passing oxygen-containing protective gas into the interior of the tube. The intermediate tubes are then subjected to a medium hard/hard hardening drawing followed by a thermal treatment at a temperature of from 175 DEG C to 275 DEG C while passing an oxygen-containing gas mixture into the tube interior. This manufacturing process substantially reduces the copper ion release of hard/medium hard fitting tubes in the form of straight lengths of SF-Cu used for mains drinking water supply while retaining the same resistance to pit corrosion. The maximum copper ion solubility is about 1 mg/l for drinking water having a pH in the range from 6.5 to 9.0.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung von nahtlos gezogenen halbharten/harten Installationsrohren aus Kupfer, bei welchem die Innenoberflächen der Rohre aufgerauht werden.The invention relates to a method for producing seamless drawn semi-hard / hard plumbing pipes made of copper, in which the inner surfaces of the pipes are roughened.

Zum Transport von kalten oder erwärmten Trinkwässern ist es bekannt, korrosionsgeschützte nahtlose Installationsrohre aus phosphordesoxidiertem Kupfer (SF-Cu) einzusetzen. Derartige Installationsrohre weisen bei bestimmten Wasserqualitäten die Eigenschaft auf, daß Kupferionen in fließendes oder stehendes Wasser abgegeben werden.For the transport of cold or heated drinking water, it is known to use corrosion-protected seamless installation pipes made of phosphorus-deoxidized copper (SF-Cu). Such installation pipes have the property with certain water qualities that copper ions are released into flowing or standing water.

Gemäß der im offiziellen Journal der EG-Kommission vom 30.08. 1980 veröffentlichten Richtlinie des EG-Rates vom 15.07.1980 über die Qualitätsansprüche an zum menschlichen Verbrauch bestimmten Wässern beträgt der geforderte Maximalgrenzwert der Kupferionenabgabe an das Wasser 3 mg/l nach zwölf Stunden Stagnation in einer Rohrleitung. Ferner haben Untersuchungen ergeben (Zeitschrift "Tribune de l'eau" Vol. 41, Dezember 1988 (Nr. 4) Seiten 29 bis 35), daß korrosionsgeschützte innen oxidierte Kupferrohre für Normalwässer bei etwa 2 mg/l liegende Maximalwerte aufweisen. Das bedeutet, daß die für Hausinstallationen bislang verwendeten Qualitäts-Kupferrohre die Anforderungen der EG-Richtlinie in der Regel erfüllen.According to the in the official journal of the EC commission from 30.08. In 1980, the EC Council Directive of July 15, 1980 on the quality requirements for water intended for human consumption required a maximum limit of copper ion release to water of 3 mg / l after twelve hours of stagnation in a pipeline. Furthermore, studies have shown (Journal "Tribune de l'eau" Vol. 41, December 1988 (No. 4) pages 29 to 35) that corrosion-protected internally oxidized copper pipes for normal water have maximum values of around 2 mg / l. This means that the quality copper pipes previously used for domestic installations generally meet the requirements of the EC directive.

Dennoch kann nicht ausgeschlossen werden, daß die in der Praxis unvermeidlichen Schwankungen in der Qualität der Trinkwässer in dem einen oder anderen Fall diese Maximalwerte überschreiten. Der sich hieraus ergebende Unsicherheitsfaktor wird indessen in der Praxis zwangsläufig in Kauf genommen.Nevertheless, it cannot be ruled out that the inevitable fluctuations in the quality of the drinking water in one case or another exceed these maximum values. The resulting uncertainty factor is inevitably accepted in practice.

Durch die EP 0 306 810 A2 ist ein Verfahren zur Herstellung lochfraßbeständiger hartgezogener Rohre aus Kupfer oder Kupferlegierungen bekannt, bei welchem die Rohre zunächst entfettet und dann die Innenoberflächen der Rohre zusätzlich mit einem Strahlmittel behandelt werden. Hierdurch wird eine Aufrauhung der inneren Oberflächen erzielt, durch das es gelingt, die Bildung von schädlichen Filmen, z.B. kohlenstoffhaltigen Filmen, auf den Innenoberflächen von hartgezogenen Kupferrohren zu vermeiden. In diesem Zusammenhang ist es außerdem bekannt, daß Lochfraßkorrosionsprozesse zwar eine Kupferionenwanderung beinhalten, diese jedoch nach anderen Gesetzmäßigkeiten ablaufen. So zählt es allgemein zum Stand der Technik, daß eine hohe Korrosionsfestigkeit von Kupferwerkstoffen, insbesondere eine solche gegen Lochfraßkorrosion Typ 1, nicht zugleich eine geringere Kupferionenabgabe an Wasser zur Folge hat.EP 0 306 810 A2 discloses a method for producing pitting-resistant, hard-drawn tubes made of copper or copper alloys, in which the tubes are first degreased and then the inner surfaces of the tubes are additionally treated with an abrasive. Hereby a roughening of the inner surfaces is achieved, by which the formation of harmful films, e.g. avoid carbon-containing films on the inner surfaces of hard-drawn copper pipes. In this context, it is also known that pitting corrosion processes involve copper ion migration, but they follow other laws. Thus, it generally belongs to the state of the art that a high corrosion resistance of copper materials, in particular one against pitting corrosion type 1, does not at the same time result in a lower copper ion release to water.

Ausgehend von dem im Oberbegriff des Patentanspruchs 1 beschriebenen Verfahren liegt der Erfindung die Aufgabe zugrunde, dieses Verfahren dahingehend zu verbessern, daß eine verminderte Kupferionenabgabe an Trinkwasser mit einem normalen pH-Wert im Bereich von 6,5 bis 9,0 gewährleistet werden kann.Based on the method described in the preamble of claim 1, the invention has for its object to improve this method in such a way that a reduced copper ion release to drinking water with a normal pH in the range of 6.5 to 9.0 can be guaranteed.

Die Lösung dieser Aufgabe besteht nach der Erfindung in den im kennzeichnenden Teil des Patentanspruchs 1 aufgeführten Merkmalen.This object is achieved according to the invention in the features listed in the characterizing part of claim 1.

Unter Anwendung des erfindungsgemäßen Verfahrens können nunmehr halbharte oder harte Installationsrohre aus Kupfer zur Verfügung gestellt werden, bei denen die Kupferionenabgabe an das Trinkwasser auch über einen langen Zeitraum entscheidend unter den geforderten Grenzwerten gehalten werden kann. Derartige Installationsrohre sind überdies widerstandsfähig gegen Lochfraßkorrosion und können mit den bekannten Verbindungs- und Biegetechniken installiert werden. Das Verfahren erlaubt außerdem eine wirtschaftliche Herstellung in Stangenform mit den üblicherweise verfügbaren Fertigungsanlagen für nahtlose Kupferrohre. Darüberhinaus kann das erfindungsgemäße Verfahren in vorteilhafter Weise bei der Herstellung von Fittings mit verminderter Kupferionenabgabe angewendet werden.Using the method according to the invention, semi-hard or hard copper installation pipes can now be made available, in which the copper ion release to the drinking water can be kept decisively below the required limit values even over a long period of time. Such installation pipes are also resistant to pitting corrosion and can be installed with the known connection and bending techniques. The process also allows economical production in bar form with the commonly available manufacturing facilities for seamless copper tubes. In addition, the method according to the invention can advantageously be used in the manufacture of fittings with reduced copper ion release.

In einem ersten Verfahrensschritt erfolgt ein sogenannter Vorzug, bei welchem aus gegossenen Stangen warm umgeformte Vorrohre durch Ziehen auf eine Zwischenabmessung kalt umgeformt werden. Im Anschluß daran werden die Innenoberflächen dieser Zwischenrohre aufgerauht. Hiermit soll nicht nur die oxidische Reaktion mit den Innenoberflächen begünstigt werden, sondern es soll auch verhindert werden, daß bei dem späteren Härtezug, bei dem eine Streckung der Innenoberflächen erfolgt, die Oxidschicht nicht mehr gleichmäßig deckt. Die Rauhtiefe Ra kann sich hierbei zwischen 0,3 µm und 1,0 µm bewegen. In dem sich anschließenden Glühvorgang bei 350 °C bis 650 °C mit einer Einleitung einer Gasmischung in das Rohrinnere, welche aus einem Schutzgas und Sauerstoff besteht, soll eine dünne haftende Oxidschicht hergestellt werden. Nunmehr wird durch einen Härtezug auf halbhart/hart die Endabmessung der Installationsrohre erzeugt. Im Anschluß an den Härtezug erfolgt nochmals eine thermische Behandlung bei 175 °C bis 275 °C unter Einleitung eines sauerstoffhaltigen Gasgemisches in das Rohrinnere, um eine Oxidschicht in einer Zusammensetzung von etwa 12 % bis 21 % Sauerstoff mit dem Restgehalt Kupfer zu erzielen.In a first process step, there is a so-called preference, in which hot-formed front tubes are cold-formed from cast rods by pulling to an intermediate dimension. The inner surfaces of these intermediate tubes are then roughened. This is not only intended to promote the oxidic reaction with the inner surfaces, but also to prevent the oxide layer from no longer uniformly covering during the later hardening process in which the inner surfaces are stretched. The roughness depth Ra can range between 0.3 µm and 1.0 µm. In the subsequent annealing process at 350 ° C to 650 ° C with the introduction of a gas mixture into the interior of the tube, which consists of a protective gas and oxygen, a thin, adherent oxide layer is to be produced. Now the final dimension of the installation pipes is generated by a hardness train to semi-hard / hard. Following the hardening process, a thermal treatment is carried out again at 175 ° C. to 275 ° C. while introducing an oxygen-containing gas mixture into the interior of the tube in order to achieve an oxide layer in a composition of approximately 12% to 21% oxygen with the residual copper content.

Durch das erfindungsgemäße Fertigungsverfahren wird die Kupferionenabgabe im Vergleich zu den bisher für die zentrale Trinkwasserversorgung eingesetzten halbharten/harten Installationsrohren in Stangenform aus Kupfer wesentlich reduziert bei gleichbleibendem Widerstand gegen Lochfraßkorrosion. Wie interne Langzeituntersuchungen mit Trinkwässern mit einem pH-Wert im Bereich von 6,5 bis 9,0 ergeben haben, erreicht die maximale Kupferionenlöslichkeit bei so gefertigten Installationsrohren überraschenderweise nur einen bei 1 mg/l liegenden Wert.The production process according to the invention substantially reduces the copper ion release compared to the semi-hard / hard copper installation pipes in the form of bars, which have previously been used for the central drinking water supply, with constant resistance to pitting corrosion. As internal long-term investigations with drinking water with a pH value in the range of 6.5 to 9.0 have shown, the maximum copper ion solubility in installation pipes made in this way surprisingly only reaches a value of 1 mg / l.

Dieses in der Fachwelt bislang nicht bekannte Ergebnis dürfte auf den erhöhten Sauerstoffanteil der Kupferoxidschicht im Rohrinnern beruhen. Hierbei ist die eigentliche Bremse für die Kupferionenabgabe eine dichte grüne Malachitdeckschicht, die sich bei Kontakt mit dem Trinkwasser üblicher Qualität auf der Rohrinnenoberfläche ausbildet. Malachit hat die chemische Formel Cu₂[CO₃,(OH)₂]. Zur Bildung von Malachit besteht also ein hoher Bedarf an Sauerstoff, der teils aus dem Trinkwasser und teils aus der Oxidschicht der Rohroberfläche gedeckt wird. Da nun die Rohrinnenoberfläche aufgrund der Erfindung einen höheren Sauerstoffgehalt aufweist, bildet sich erwiesenermaßen die Malachitschicht in kürzester Zeit aus und reduziert damit stark die Kupferionenabgabe.This result, which was previously unknown in the specialist world, may be due to the increased oxygen content of the copper oxide layer in the interior of the tube. The actual brake for the copper ion release is a dense green malachite top layer, which forms on the inner surface of the pipe when it comes into contact with the usual quality drinking water. Malachite has the chemical formula Cu₂ [CO₃, (OH) ₂]. For the formation of malachite there is therefore a high demand for oxygen, which is partly covered by the drinking water and partly by the oxide layer of the pipe surface. Since the inner surface of the tube now has a higher oxygen content due to the invention, it has been proven that the malachite layer forms in a very short time and thus greatly reduces the copper ion release.

Das Aufrauhen der Innenoberflächen der Zwischenrohre kann gemäß den Merkmalen des Patentanspruchs 2 durch Verwendung von Strahlmitteln oder durch Beizen durchgeführt werden. Als Strahlmittel kann z.B. Siliziumoxid zum Einsatz gelangen.The roughening of the inner surfaces of the intermediate tubes can be carried out according to the features of claim 2 by using blasting agents or by pickling. As an abrasive, e.g. Silicon oxide are used.

Das Glühen der Zwischenrohre erfolgt entsprechend den Merkmalen des Patentanspruchs 3 bevorzugt mit einem Schutzgas, das einen Sauerstoffanteil von 1 % bis 7 % aufweist.The intermediate tubes are preferably annealed in accordance with the features of claim 3 with a protective gas which has an oxygen content of 1% to 7%.

Nach Patentanspruch 4 wird der Glühvorgang vorzugsweise bei einer Temperatur von etwa 650 °C durchgeführt. Dadurch kann eine dünne haftende Oxidschicht mit einer Dicke von etwa 0,05 µm bis 0,2 µm erzeugt werden.According to claim 4, the annealing process is preferably carried out at a temperature of about 650 ° C. A thin, adherent oxide layer with a thickness of approximately 0.05 μm to 0.2 μm can thereby be produced.

Die thermische Behandlung nach dem Härtezug erfolgt entsprechend Patentanspruch 5 zweckmäßig bei einer Temperatur von etwa 250 °C. Der Härtezug wird insbesondere mit einem Innendorn durchgeführt. Der Umformgrad beträgt hierbei im Mittel 20 %.The thermal treatment after the hardening train is advantageously carried out at a temperature of about 250 ° C. The hardening tension is carried out in particular with an internal mandrel. The degree of deformation here is on average 20%.

Es kann zweckmäßig sein, die Innenoberfläche der Rohre nach dem Härtezug zu entfetten (Patentanspruch 6). Zum Entfetten kann ein handelsübliches Entfettungsmittel verwendet werden.It may be expedient to degrease the inner surface of the tubes after the hardening process (claim 6). A commercially available degreasing agent can be used for degreasing.

Desweiteren ist es gemäß Patentanspruch 7 sinnvoll, im Zuge der thermischen Behandlung nach dem Härtezug ein Gasgemisch mit mindestens 20 % Sauerstoff in das Rohrinnere zur Bildung einer Oxidschicht einzuleiten.Furthermore, according to claim 7, it makes sense to introduce a gas mixture with at least 20% oxygen into the interior of the tube in the course of the thermal treatment after the hardening train to form an oxide layer.

Die Erwärmung kann nach Patentanspruch 8 konvektiv, elektrisch induktiv oder konduktiv durchgeführt werden.The heating can be carried out convectively, electrically inductively or conductively according to claim 8.

Ein Ausführungsbeispiel der Erfindung ist nachfolgend näher erläutert.An embodiment of the invention is explained in more detail below.

Zunächst wurde phosphordesoxidiertes Kupfer (SF-Cu) geschmolzen und zu Stangen gegossen. Mittels Warmumformung wurden die Stangen dann zu Rohren weiterverarbeitet und anschließend bis auf eine Zwischenabmessung kaltumgeformt.First, phosphorus deoxidized copper (SF-Cu) was melted and cast into bars. The bars were then further processed into tubes by means of hot forming and then cold formed to an intermediate dimension.

Sodann wurde die Innenoberfläche der Zwischenrohre mit Siliziumoxid als Strahlmittel behandelt. Als Ergebnis wurde eine Rauhigkeit Ra = 0,52 µm gemessen.The inner surface of the intermediate tubes was then treated with silicon oxide as the blasting agent. As a result, a roughness Ra = 0.52 µm was measured.

Die Zwischenrohre wurden dann bei einer Temperatur von 650 °C unter Einleitung eines Gasgemisches in das Rohrinnere kontinuierlich wärmebehandelt. Das Gasgemisch setzte sich aus einem Schutzgas mit einem sauerstoffanteil von 3 % zusammen. Es bildete sich auf der Innenoberfläche eine fest haftende dünne Kupferoxidschicht mit einer Schichtdicke von 0,15 µm aus, deren Sauerstoffgehalt mittels Röntgendiffraktometrie auf 11,2 % bestimmt wurde.The intermediate tubes were then continuously heat-treated at a temperature of 650 ° C. while introducing a gas mixture into the interior of the tube. The gas mixture consisted of a protective gas with an oxygen content of 3%. A firmly adhering thin copper oxide layer with a layer thickness of 0.15 μm was formed on the inner surface, the oxygen content of which was determined to be 11.2% by means of X-ray diffractometry.

Im nächsten Arbeitsschritt wurden die Zwischenrohre unter Verwendung eines Standardziehöls auf die Endabmessung mit einem Umformgrad von 20 % hartgezogen und anschließend innenseitig dadurch entfettet, daß ein handelsübliches Entfettungsmittel durch die Rohre geleitet wurde.In the next step, the intermediate tubes were hard-drawn to their final dimensions using a standard drawing oil with a degree of deformation of 20% and then degreased on the inside by passing a commercially available degreasing agent through the tubes.

Auf 300 mm abgelängte und entgratete Rohrabschnitte wurden dann in einem Laborofen mit umgewälzter Luft als Ofenatmosphäre bei 250 °C über eine Dauer von 30 min oxidierend wärmebehandelt. Der Sauerstoffgehalt (O₂-Gehalt) der jetzt ausgebildeten Kupferoxidschicht an der Innenoberfläche der Rohre wurde mittels energiedispersiver Analyse (EDX) auf 13,8 % bestimmt.Pipe sections cut to length and deburred to 300 mm were then subjected to oxidizing heat treatment in a laboratory furnace with circulated air as furnace atmosphere at 250 ° C. for a period of 30 minutes. The oxygen content (O₂ content) of the copper oxide layer now formed on the inner surface of the tubes was determined by means of energy dispersive analysis (EDX) to 13.8%.

Nunmehr wurden diese Rohrabschnitte (Testrohrabschnitte) senkrecht angeordnet und mit Trinkwasser gefüllt. In einer mehrmonatigen Untersuchungsreihe wurde die Kupferionenabgabe bestimmt. Hierzu wurde jeweils im 24-Stunden-Takt die abgegebene Kupfermenge in mg/l mit einem Absorptionsspektrometer gemessen. Der pH-Wert des verwendeten Trinkwassers betrug 7,6.Now these pipe sections (test pipe sections) were arranged vertically and filled with drinking water. The copper ion release was determined in a series of tests lasting several months. For this purpose, the amount of copper released in mg / l was measured in 24-hour intervals with an absorption spectrometer. The pH of the drinking water used was 7.6.

Die obere Grenze der Meßwerte für den Kupfergehalt im Trinkwasser lag bei 1 mg/l.The upper limit of the measured values for the copper content in drinking water was 1 mg / l.

Claims (8)

Verfahren zur Herstellung von nahtlos gezogenen halbharten/harten Installationsrohren aus Kupfer, bei welchem die Innenoberflächen der Rohre aufgerauht werden, dadurch gekennzeichnet, daß zunächst aus gegossenen Stangen warmumgeformte Vorrohre durch Ziehen auf eine Zwischenabmessung kaltumgeformt werden, worauf die Innenoberflächen dieser Zwischenrohre aufgerauht und dann diese aufgerauhten Zwischenrohre bei einer Temperatur von 350 °C bis 650 °C sowie bei in das Rohrinnere eingeleitetem, Sauerstoff enthaltendem Schutzgas geglüht werden, und daß danach die Zwischenrohre einem halbharten/harten Härtezug unterworfen werden, an den sich eine thermische Behandlung mit einer Temperatur von 175 °C bis 275 °C unter Einleitung eines sauerstoffhaltigen Gasgemisches in das Rohrinnere anschließt.A process for the production of seamless drawn semi-hard / hard plumbing pipes made of copper, in which the inner surfaces of the pipes are roughened, characterized in that hot-formed front pipes are first cold-formed from cast rods by pulling to an intermediate dimension, whereupon the inner surfaces of these intermediate pipes are roughened and then roughened Intermediate tubes are annealed at a temperature of 350 ° C to 650 ° C and with an inert gas containing oxygen introduced into the interior of the tube, and that the intermediate tubes are then subjected to a semi-hard / hard hardening process, to which a thermal treatment at a temperature of 175 ° is applied C to 275 ° C while introducing an oxygen-containing gas mixture into the interior of the pipe. Verfahren nach Patentanspruch 1, dadurch gekennzeichnet, daß die Innenoberflächen der Zwischenrohre durch Strahlen oder Beizen aufgerauht werden.Method according to claim 1, characterized in that the inner surfaces of the intermediate tubes are roughened by blasting or pickling. Verfahren nach Patentanspruch 1 oder 2, dadurch gekennzeichnet, daß der Glühvorgang bei einer Schutzgasatmosphäre im Rohrinneren mit einem Sauerstoffanteil von 1 % bis 7 % durchgeführt wird.Method according to claim 1 or 2, characterized in that the annealing process is carried out in a protective gas atmosphere in the interior of the tube with an oxygen content of 1% to 7%. Verfahren nach einem der Patentansprüche 1 bis 3, dadurch gekennzeichnet, daß der Glühvorgang bei einer Temperatur von etwa 650 °C durchgeführt wird.Method according to one of claims 1 to 3, characterized in that the annealing process is carried out at a temperature of about 650 ° C. Verfahren nach einem der Patentansprüche 1 bis 4, dadurch gekennzeichnet, daß die nach dem Härtezug erfolgende thermische Behandlung bei einer Temperatur von etwa 250 °C durchgeführt wird.Process according to one of Claims 1 to 4, characterized in that the thermal treatment which takes place after the hardening process is carried out at a temperature of approximately 250 ° C. Verfahren nach einem der Patentansprüche 1 bis 5, dadurch gekennzeichnet, daß nach dem Härtezug die Innenoberfläche der Rohre entfettet wird.Method according to one of the claims 1 to 5, characterized in that the inner surface of the tubes is degreased after the hardening process. Verfahren nach einem der Patentansprüche 1 bis 6, dadurch gekennzeichnet, daß bei der thermischen Behandlung der Rohre nach dem Härtezug ein Gasgemisch mit mindestens 20 % Sauerstoff verwendet wird.Method according to one of claims 1 to 6, characterized in that a gas mixture with at least 20% oxygen is used in the thermal treatment of the tubes after the hardening train. Verfahren nach einem der Patentansprüche 1 bis 7, dadurch gekennzeichnet, daß die Erwärmung bei der thermischen Behandlung konvektiv, elektrisch induktiv oder konduktiv durchgeführt wird.Method according to one of the claims 1 to 7, characterized in that the heating during the thermal treatment is carried out convectively, electrically inductively or conductively.
EP19940114354 1993-10-09 1994-09-13 Process for manufacturing of seamless drawn medium hard/hard copper fitting tubes Expired - Lifetime EP0647723B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4334536 1993-10-09
DE19934334536 DE4334536A1 (en) 1993-10-09 1993-10-09 Process for the production of seamless drawn semi-hard / hard installation pipes

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EP0647723A1 true EP0647723A1 (en) 1995-04-12
EP0647723B1 EP0647723B1 (en) 2000-04-12

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DE (2) DE4334536A1 (en)
DK (1) DK0647723T3 (en)
ES (1) ES2144475T3 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0955394A2 (en) * 1998-05-05 1999-11-10 KM Europa Metal AG Process for producing a protective coating on the interior surface of a copper pipe
EP0976845A1 (en) * 1998-07-30 2000-02-02 Outokumpu Oyj Method for producing copper tubes
US6434967B2 (en) 1999-06-18 2002-08-20 Elkay Manufacturing Company Process for forming copper containing components providing water effluent with lowered copper concentrations
WO2004078372A1 (en) * 2003-03-07 2004-09-16 Outokumpu Oyj Method for treating the inner surface of a tube
DE19533410B4 (en) * 1995-09-09 2005-11-24 Km Europa Metal Ag Method for producing a protective layer on the inner surface of a copper pipe and use of drawing agents
TWI719750B (en) * 2019-12-10 2021-02-21 金允成企業股份有限公司 Forging and forming method of aluminum alloy pipe fittings

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007055446A1 (en) * 2007-11-12 2009-05-14 Hansgrohe Ag Provision of water-bearing components from brass alloys with reduced metal ion release

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2028184A (en) * 1978-08-07 1980-03-05 Crane Enfield Metals Pty Production of copper tubing
GB2055061A (en) * 1979-07-31 1981-02-25 Liege Usines Cuivre Zinc Improvements concerning copper or copper-alloy tubes for pipes used in sanitary, condenser and other installations
GB2075391A (en) * 1980-05-10 1981-11-18 Kabel Metallwerke Ghh Process for treating copper tubes
EP0128846A1 (en) * 1983-06-09 1984-12-19 Trefimetaux Process for improving the flexibility of cold-worked copper tubes by partial annealing
EP0281641A1 (en) * 1987-03-07 1988-09-14 Wieland-Werke Ag Process for improving the corrosion resistance of hard or semi-hard copper fitting tubes
FR2668170A1 (en) * 1990-10-18 1992-04-24 Trefimetaux PROCESS FOR IMPROVING THE STRENGTH OF HARD COPPER TUBES BY DYNAMIC THERMAL TREATMENT.

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2028184A (en) * 1978-08-07 1980-03-05 Crane Enfield Metals Pty Production of copper tubing
GB2055061A (en) * 1979-07-31 1981-02-25 Liege Usines Cuivre Zinc Improvements concerning copper or copper-alloy tubes for pipes used in sanitary, condenser and other installations
GB2075391A (en) * 1980-05-10 1981-11-18 Kabel Metallwerke Ghh Process for treating copper tubes
EP0128846A1 (en) * 1983-06-09 1984-12-19 Trefimetaux Process for improving the flexibility of cold-worked copper tubes by partial annealing
EP0281641A1 (en) * 1987-03-07 1988-09-14 Wieland-Werke Ag Process for improving the corrosion resistance of hard or semi-hard copper fitting tubes
FR2668170A1 (en) * 1990-10-18 1992-04-24 Trefimetaux PROCESS FOR IMPROVING THE STRENGTH OF HARD COPPER TUBES BY DYNAMIC THERMAL TREATMENT.

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19533410B4 (en) * 1995-09-09 2005-11-24 Km Europa Metal Ag Method for producing a protective layer on the inner surface of a copper pipe and use of drawing agents
EP0955394A2 (en) * 1998-05-05 1999-11-10 KM Europa Metal AG Process for producing a protective coating on the interior surface of a copper pipe
EP0955394A3 (en) * 1998-05-05 2000-04-12 KM Europa Metal AG Process for producing a protective coating on the interior surface of a copper pipe
EP0976845A1 (en) * 1998-07-30 2000-02-02 Outokumpu Oyj Method for producing copper tubes
US6434967B2 (en) 1999-06-18 2002-08-20 Elkay Manufacturing Company Process for forming copper containing components providing water effluent with lowered copper concentrations
WO2004078372A1 (en) * 2003-03-07 2004-09-16 Outokumpu Oyj Method for treating the inner surface of a tube
EA007545B1 (en) * 2003-03-07 2006-10-27 Отокумпу Оюй Method for treating the inner surface of a tube
TWI719750B (en) * 2019-12-10 2021-02-21 金允成企業股份有限公司 Forging and forming method of aluminum alloy pipe fittings

Also Published As

Publication number Publication date
EP0647723B1 (en) 2000-04-12
DE59409284D1 (en) 2000-05-18
ES2144475T3 (en) 2000-06-16
DE4334536A1 (en) 1995-04-13
DK0647723T3 (en) 2000-08-28

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