EP0151838B1 - Verfahren zur Wärmebehandlung von Röhren aus härtbarem Kohlenstoffstahl - Google Patents

Verfahren zur Wärmebehandlung von Röhren aus härtbarem Kohlenstoffstahl Download PDF

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Publication number
EP0151838B1
EP0151838B1 EP84300740A EP84300740A EP0151838B1 EP 0151838 B1 EP0151838 B1 EP 0151838B1 EP 84300740 A EP84300740 A EP 84300740A EP 84300740 A EP84300740 A EP 84300740A EP 0151838 B1 EP0151838 B1 EP 0151838B1
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EP
European Patent Office
Prior art keywords
pipe
induction heater
quenching
spray
heated
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
Application number
EP84300740A
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English (en)
French (fr)
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EP0151838A1 (de
Inventor
Daniel Graham Ball
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.)
Indutech Ltd
Original Assignee
Indutech Ltd
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 to AU23195/84A priority Critical patent/AU575307B2/en
Application filed by Indutech Ltd filed Critical Indutech Ltd
Priority to EP84300740A priority patent/EP0151838B1/de
Priority to AT84300740T priority patent/ATE46192T1/de
Priority to DE8484300740T priority patent/DE3479673D1/de
Priority to ZA841054A priority patent/ZA841054B/xx
Priority to GB848427385A priority patent/GB8427385D0/en
Publication of EP0151838A1 publication Critical patent/EP0151838A1/de
Application granted granted Critical
Publication of EP0151838B1 publication Critical patent/EP0151838B1/de
Expired legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
    • C21D9/085—Cooling or quenching

Definitions

  • the present invention relates to an apparatus for hardening steel pipe by heating and then quenching and also to a process therefore.
  • the usual method of heat treating eutectoid steel is to first convert the ferrite phase to austenite by heating the steel to temperatures of the order of 1000°C. The steel is then cooled sufficiently rapidly for the austenite phase to convert to martensite rather than to ferrite and carbide. Cooling times of more than the order of one second can result in significant formation of the softer ferrite-carbide phase. Achieving controlled quenching within such a time constraint for large objects such as long pipes has proven to be difficult.
  • Methods such as immersing the heated pipe into a water bath are subject to splashing onto the upper areas of the pipe or rapid steam formation contacting the upper areas of the pipe both of which result in localized ferrite-carbide formation and resultant nonuniform hardening of the pipe.
  • Another problem with conventional methods is that they generally necessitate heating long sections of pipe and thus encounter difficulties in transporting the pipe, in deformation due to sag in the heated area and cooling during transport to the quenching bath.
  • Cooling the heated pipe close to the heat source in order to avoid cooling through radiation, heat conduction along the pipe and local heat transfer to rollers in other parts contacting the pipe in its travel from the heater to the quenching spray.
  • Such heat loss not only represents a lower efficiency of operation but exposes the pipe to development of nonuniformity of hardness due to the aforesaid localized cooling. Cooling the pipe close to the heater also reduces the length of heated pipe and thus avoids problems associated with sag.
  • DE-752084 discloses a process for heat treating steel pipes comprising heating an annular zone to an austenizing temperature, which zone moves at a preselected speed in the direction along the pipe towards an end thereof and simultaneously quenching the heated pipe proximate said annular zone thereof with the spray of an even conical sheet of cooling liquid travelling at a preselected angle to the internal surface of the pipe.
  • the purpose of this process is surface hardening at the internal surface and the frequency of the alternating current supplied to the induction coil is selected to concentrate the heat at this surface.
  • the present invention on the other hand is arranged to heat the total thickness of the annular zone of the pipe.
  • the spray is generated at great force and from a head spaced from the surface so that air is educted from the upstream end of the pipe by the spray causing an airflow in the direction of the longitudinal component of the velocity of the spray, thus assisting in preventing backflow or the development of a vapour barrier along the pipe surface.
  • the spray head is virtually in contact with the surface quenched, thus leaving virtually no passage for air between the spray head and the pipe and liquid will thus creep around the edges of the nozzles and travel along the outer surface of the spray head and the inner surface of the pipe to the heated region.
  • the spray or quench head is not only spaced from the inner surface of the pipe but also is positioned upstream in terms of pipe movement, of the induction heater.
  • the jet or spray of liquid which is produced by the spray head passes through the plane of the induction heater before it strikes the inner surface of the pipe.
  • a process for heat treating hardenable carbon steel pipe to provide differential hardening of the pipe the hardness and ductility decreasing radially outwardly comprises heating an annular zone of the pipe to an austenizing temperature using an annular induction heater through which the, pipe is passed at a preselected speed, simultaneously quenching the internal surface of the heated pipe proximate said annular zone with a spray of an even conical sheet of cooling liquid which is directed at a preselected angle of less than 40° to the internal surface of the pipe from a quench head located within the pipe, characterised in that the conical sheet of cooling liquid passes through the plane containing the induction heater before it strikes the internal surface of the pipe.
  • the cooling liquid is water and the temperature of the water in the spray is maintained at a level less than 80°C.
  • a quench hardened bend is produced.
  • an annular zone of a width lying in the range of 2.5 to 5 cm (1 to 2 inches) is produced by utilizing a narrow induction coil.
  • apparatus for heat treating hardenable carbon steel pipe comprising an annular induction heater, means for supporting and moving said pipe through said induction heater so that an annular zone of the pipe is heated and a quench head surrounded by the pipe said quench head being adapted to produce an even conical sheet spray of coolant liquid which is directed at an angle of less than 40° onto the interior surface of the pipe after the pipe has passed through the induction heater to effect rapid cooling of the pipe, said coolant remaining in contact with the surface of the pipe after impact, said spray of coolant liquid educting air flow from the upstream end of the pipe characterised in that the quench head is positioned upstream of the plane containing the induction heater so that the coolant liquid spray passes through said plane before it contacts the surface of the pipe.
  • the quench head has an adjustable annular orifice for directing cooling liquid onto the pipe surface so that adjustment of the angle of impact of the conical sheet of spray is possible in order to optimize the flow of cooling liquid along the pipe surface after impact.
  • the quench head includes an adjustable lance for support and adjustment of the position of the quench head relative to the induction heater so that the spray impinges on the heated pipe adjacent the annular zone of pipe being heated.
  • a bending machine may also be provided for bending an end of the pipe as it passes over the quench head and through the induction heater.
  • the process of hardening pipe involves delivering a section of pipe 10 to be hardened onto rollers 12 at one end of the feeding and quenching apparatus.
  • the pipe is then advanced longitudinally into the induction heater 14 which heats a small annular zone of the pipe as it is moved through the heater 14 and over the quench head 16.
  • an initial adjustment is made of the quench head annular orifice by moving the pipe over the quench head and adjusting the orifice so that the angle of spray results in the water in the spray maintaining contact with the interior surface of the pipe after impact.
  • the position of the quench head 16 is also adjusted for a given diameter of pipe 10 so that it impacts on the interior of the pipe surface a short distance past the induction heater 14. After the pipe has been moved through the induction heater and quenched it is positioned over lance 18 and must therefore be reversed back to its initial position, taken off the rollers 12, a new section of pipe delivered to the rollers 12, and the process repeated.
  • the width of the zone heated is in the range of 15 to 20 cm (6 to 8 inches) which is less than the width of the induction heater.
  • FIG. 3 and 4 Shown in Figures 3 and 4 is an apparatus for producing a quench hardened bend in a section of pipe.
  • the apparatus consists of the quench head 34 supported on a lance 36 in a manner similar to the apparatus illustrated in Figures 1 and 2. However, in Figure 3 the quench head 34 is reversed from its position as shown in Figures 1 and 2.
  • the induction heating coil 38 is narrower lying in the range of 2.5 to 5 cm (1 to 2 inches).
  • An adjustable rotatable bending arm 32 clamps an end of the pipe and is movable from a position adjacent the induction heater 38 in a circular path away from the latter.
  • a ram 31 compresses the pipe against the bending arm 32.
  • Illustrated in Figure 4 is the quench head 34 and associated lance 36 in combination with the inductor coil 38 and a section of pipe 30.
  • the quench head is identical to that shown in Figures 1 and 2 except that the annular orifice is directed forwardly of the lance 36 through the induction coil 38 and onto the pipe surface a short distance beyond the induction coil 38.
  • the process of producing a quench hardened bend according to the apparatus shown in Figures 3 and 4 is initiated by positioning the pipe 30 so that it projects through the induction coil a short distance and is clamped by the bending arm 32.
  • the pipe is moved forward against the force of the bending arm 32 by ram 31.
  • the bending arm 32 rotates and the induction heater heats a small annular zone of the pipe thereby providing the flexibility for the pipe to be bent.
  • a small heated zone is desirable in such a case in order to produce an accurate, well-defined bend.
  • the spray 40 is adjusted in angle of direction in a way similar to that shown in Figures 1 and 2 in order that the water after impact on the pipe surface flows evenly along the surface to maximize cooling and minimize any tendency toward splash back in the upstream condition.
  • air is educted from the upstream end of the pipe by the spray causing an airflow in a direction of the longitudinal component of velocity of the spray.
  • the latter airflow assists in preventing back flow or the development of a vapour barrier along the pipe surface.
  • both the interior and exterior surfaces of the pipe could be quenched and the exterior surface subsequently tempered at temperatures up to approximately 700°C.
  • a single machine which provides an alternative reduced capital equipment option, may comprise one set of mechanical pipe handling equipment, rams, and drive control systems, one lance for internal quenching, various quench heads as required, two alternative induction heating ring systems (one for bending the other for straight pipe hardening since the latter can be processed faster), and one electrical/water and other service supply system
  • This single combined machine can manufacture hardened straight pipe and hardened bends by having the body of the bending machine tracked out of line and beyond the bending arm and into line with the larger induction coil, that is the coil used for straight pipe. There are speed controls, enabling straight hardened pipe to be manufactured many times faster than the bends.
  • the machine is thus a combination of the embodiments of Figures 1 and 3.
  • the direction of straight hardening over the quench lance may be reversed, i.e. the pipe travels off the lance rather than on to it as it is being hardened.
  • Other variations include means to rotate the pipe while heating and quenching are taking place; means to allow rotation of the quench head while heating and guenching straight or, especially, bent pipe and means to rotate the pipe and the guench head in opposite directions during heating and quenching.
  • Relative rotation between the pipe and the quench head provides a margin of safety for ensuring that the pipe is quenched uniformly. This is critical if irregular bending of the pipe is to be avoided.
  • the heater draws 1000W and quenching is effected by a flow of 37.9 litres per second (500 gallons per minute) of cooling water.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Carbon And Carbon Compounds (AREA)

Claims (13)

1. Gerät zur Wärmebehandlung eines härtbaren Kohlenstoffstahlrohres (10, 30), wobei das Gerät eine ringförmige Induktionsheizeinrichtung (14, 38), eine Einrichtung (12,31), um das Rohr (10, 30) zu halten und so durch die Induktionsheizeinrichtung (14, 38) zu bewegen, daß ein Ringbereich des Rohres erwärmt wird, sowie einen Abschreckkopf (16, 34) enthält, der vom Rohr (10, 30) umgeben ist, wobei der Abschreckkopf (16, 34) so eingerichtet ist, daß er eine regelmäßige Kegelfläche eines Kühlflüssigkeits-Sprühnebels (22, 40) erzeugt, der unter einem Winkel kleiner als 40° auf die Innenfläche des Rohres (10, 30) gerichtet ist, nachdem das Rohr die Induktionsheizeinrichtung (14,38) durchlaufen hat, um ein rasches Abkühlen des Rohres zu erreichen, wobei das Kühlmittel nach dem Auftreffen mit der Rohrfläche in Berührung bleibt, wobei der Kühlflüssigkeits-Sprühnebel vom stromaufwärts liegenden Rohrende einen Luftstrom abzieht, dadurch gekennzeichnet, daß der Abschreckkopf (16, 34) stromaufwärts jener Ebene angeordnet ist, in der die Induktionsheizeinrichtung (14, 38) liegt, so daß der Kühlflüssigkeits-Sprühnebel (22, 40) diese Ebene durchläuft, bevor er die Rohroberfläche berührt.
2. Gerät gemäß Anspruch 1, wobei der Abschreckkopf (16 oder 34) so aufgebaut ist, daß er Wasser abgibt.
3. Gerät gemäß Anspruch 2, wobei der Abschreckkopf (16 oder 34) eine einstellbare Lanze (18 oder 36) aufweist, um den Abschreckkopf (16 oder 34) zu halten und seine Lage relativ zur Induktionsheizeinrichtung (14 oder 38) einzustellen, so daß der Sprühnebel (22) auf dem erwärmten Rohr (10 oder 30) neben dem Ringbereich des Rohres (10 oder 30) auftrifft, der erwärmt werden soll.
4. Gerät gemäß jedem der Ansprüche 1 bis 3 zur Wärmebehandlung eines Rohres (10), wobei beide Enden des Rohres (10) koaxial ausgerichtet bleiben, wobei eine Einrichtung vorgesehen ist, um eine relative Drehung zwischen dem Rohr (10) und dem Abschreckkopf (16) hervorzurufen.
5. Gerät gemäß jedem der Ansprüche 1 bis 3,- wobei das Gerät weiters eine Biegemaschine (32) aufweist, um ein Ende des Rohres (30) zu biegen, wenn das Rohr (30) über den Abschreckkopf (34) und durch die Induktionsheizeinrichtung (38) läuft, um gleichzeitig einen Bereich des Rohres nahe der Induktionsheizeinrichtung (38) zu erwärmen und die Innenfläche des Rohres (30) abzuschrecken, um eine martensitische Phase auszubilden.
6. Gerät gemäß Anspruch 1 bis 3, wobei das Gerät eine Einrichtung aufweist, um die Außenfläche des Rohres abzuschrecken.
7. Verfahren zur Wärmebehandlung eines härtbaren Kohlenstoffstahlrohres, um eine unterschiedliche Härtung des Rohres zu liefern, wobei die Härte und die Verformbarkeit radial nach außen abnehmen, wobei das Verfahren das Erwärmen eines Ringbereichs des Rohres auf eine austenitbildende Temperatur unter Verwendung einer ringförmigen Induktionsheizeinrichtung, die das Rohr mit einer vorgewählten Geschwindigkeit durchläuft, sowie das gleichzeitige Abschrecken der Innenfläche des erwärmten Rohres in der Nähe des Ringbereichs mit einem Kühlflüssigkeits-Sprühnebel in Form einer regelmäßigen Kegelfläche enthält, der unter einem vorgewählten Winkel kleiner als 40° auf die Rohrinnenfläche von einem Abschreckkopf gerichtet wird, der innerhalb des Rohres angeordnet ist, dadurch gekennzeichnet, da8 die Kegelfläche der Kühlflüssigkeit jene Ebene durchläuft, in der die Induktionsheizeinrichtung liegt, bevor sie auf die Rohrinnenfläche fällt.
8. Verfahren gemäß Anspruch 7, wobei die Fläche (22 oder 40) der Kühlflüssigkeit auf das Rohr (10 oder 30) an einer Stelle auftrifft, an der sich das Rohr in der austenitischen Phase befindet wobei die rasche Abschrekkung zur Ausbildung eines martensitischen Gefüges führt.
9. Verfahren gemäß Anspruch 7 oder 8, wobei die Innen- und Außenfläche des Rohres erwärmt und abgeschrecktwerden, um ein martensitisches Gefüge auszubilden, wobei nur die Außenfläche warm angelassen wird.
10. Verfahren gemäß jedem der Ansprüche 7 bis 9, wobei beide Enden des Rohres (10) koaxial ausgerichtet bleiben und die Breite des erwärmten Bereichs im Bereich von 15 bis 20 cm liegt.
11. Verfahren gemäß jedem der Ansprüche 7 bis 10, wobei dem Rohr (10) und dem Abschreckkopf (22) eine relative Drehung aufgeprägt wird.
12. Verfahren gemäß Anspruch 7 oder 8, wobei das Verfahren das Bewegen eines Endes des Rohres (30), das neben der Stelle liegt, wo die Induktionsheizung und die Abschreckung erfolgen, in einer Kreisbahn mit einem ausgewählten Radius vom Heizbereich und Abschreckbereich weg durch einen Stempel (31) aufweist, der das Rohr (30) gegen einen Biegearm (32) drückt, wodurch ein abschreckgehärtetes Kniestück erzeugt wird.
13. Verfahren gemäß Anspruch 7, wobei die Breite des erwärmten Bereichs in der Größenordnung von Z,5 bis 5 cm liegt.
EP84300740A 1984-01-10 1984-02-07 Verfahren zur Wärmebehandlung von Röhren aus härtbarem Kohlenstoffstahl Expired EP0151838B1 (de)

Priority Applications (6)

Application Number Priority Date Filing Date Title
AU23195/84A AU575307B2 (en) 1984-01-10 1984-01-10 Differential hardening of carbon steel pipe
EP84300740A EP0151838B1 (de) 1984-01-10 1984-02-07 Verfahren zur Wärmebehandlung von Röhren aus härtbarem Kohlenstoffstahl
AT84300740T ATE46192T1 (de) 1984-01-10 1984-02-07 Verfahren zur waermebehandlung von roehren aus haertbarem kohlenstoffstahl.
DE8484300740T DE3479673D1 (en) 1984-01-10 1984-02-07 Heat treating hardenable carbon steel pipe
ZA841054A ZA841054B (en) 1984-01-10 1984-02-14 Heat treating hardenable carbon steel pipe
GB848427385A GB8427385D0 (en) 1984-01-10 1984-10-30 Heat treating carbon workpieces

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AU23195/84A AU575307B2 (en) 1984-01-10 1984-01-10 Differential hardening of carbon steel pipe
EP84300740A EP0151838B1 (de) 1984-01-10 1984-02-07 Verfahren zur Wärmebehandlung von Röhren aus härtbarem Kohlenstoffstahl
ZA841054A ZA841054B (en) 1984-01-10 1984-02-14 Heat treating hardenable carbon steel pipe

Publications (2)

Publication Number Publication Date
EP0151838A1 EP0151838A1 (de) 1985-08-21
EP0151838B1 true EP0151838B1 (de) 1989-09-06

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP84300740A Expired EP0151838B1 (de) 1984-01-10 1984-02-07 Verfahren zur Wärmebehandlung von Röhren aus härtbarem Kohlenstoffstahl

Country Status (6)

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EP (1) EP0151838B1 (de)
AT (1) ATE46192T1 (de)
AU (1) AU575307B2 (de)
DE (1) DE3479673D1 (de)
GB (1) GB8427385D0 (de)
ZA (1) ZA841054B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12129533B2 (en) 2020-08-07 2024-10-29 Tenaris Connections B.V. Ultra-fine grained steels having corrosion- fatigue resistance

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9120424D0 (en) * 1991-09-25 1991-11-06 Sps Ltd Heat treatment of hardenable carbon steel pipes
US20160281188A1 (en) * 2015-03-27 2016-09-29 Tenaris Coiled Tubes, Llc Heat treated coiled tubing

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE752084C (de) * 1938-04-08 1952-11-04 Ohio Crankshaft Company Einrichtung zum fortlaufenden Oberflaechenhaerten der Innenflaeche hohler metallenerWerkstuecke durch Erhitzen und Abschrecken
DE945930C (de) * 1949-01-01 1956-07-19 Gewerkschaft Reuss Verfahren zur Herstellung verschleissfester Rohre fuer die hydraulische und pneumatische Foerderung von Schuettguetern
DE2105886A1 (de) * 1971-02-01 1972-08-24 Mannesmann Ag Verfahren und Vorrichtung zum Abschreckhärten von Rohren
DE2137627C3 (de) * 1971-07-28 1974-02-14 Ludwig-Ofag-Indugas Industrieofenanlagen Gmbh, 4300 Essen Vorrichtung zum Innenabschrecken von Rohren
JPS518159A (en) * 1974-07-11 1976-01-22 Nippon Steel Corp Kyokukanno seizoho
DE2620377A1 (de) * 1976-05-08 1977-11-17 Aeg Elotherm Gmbh Verfahren zur waermebehandlung von dickwandigen stahlroehren
US4123301A (en) * 1977-01-07 1978-10-31 Republic Steel Corporation Method for quench hardening steel casings
US4110092A (en) * 1977-01-26 1978-08-29 Nippon Kokan Kabushiki Kaisha Method of apparatus for cooling inner surface of metal pipe

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12129533B2 (en) 2020-08-07 2024-10-29 Tenaris Connections B.V. Ultra-fine grained steels having corrosion- fatigue resistance

Also Published As

Publication number Publication date
GB8427385D0 (en) 1984-12-05
AU2319584A (en) 1985-07-18
AU575307B2 (en) 1988-07-28
DE3479673D1 (en) 1989-10-12
ZA841054B (en) 1984-08-10
ATE46192T1 (de) 1989-09-15
EP0151838A1 (de) 1985-08-21

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