EP0035091B1 - Process for producing tension-crack corrosion-resistant non magnetizable drill collars of austenitic steels, and apparatus for carrying out this process - Google Patents

Process for producing tension-crack corrosion-resistant non magnetizable drill collars of austenitic steels, and apparatus for carrying out this process Download PDF

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Publication number
EP0035091B1
EP0035091B1 EP80890152A EP80890152A EP0035091B1 EP 0035091 B1 EP0035091 B1 EP 0035091B1 EP 80890152 A EP80890152 A EP 80890152A EP 80890152 A EP80890152 A EP 80890152A EP 0035091 B1 EP0035091 B1 EP 0035091B1
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Prior art keywords
impact
compressive stresses
residual compressive
produced
drill
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German (de)
French (fr)
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EP0035091A1 (en
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Richard Reiterer
Heinz Dr. Kohl
Josef Dipl.-Ing. Riedl
Hans Dr. Enöckl
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Schoeller Bleckmann GmbH
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Vereinigte Edelstahlwerke AG
Schoeller Bleckmann GmbH
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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
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
    • 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
    • C21D10/00—Modifying the physical properties by methods other than heat treatment or deformation

Definitions

  • non-magnetisable drill rods and rod parts are required for directional drilling in order to avoid influencing the measuring devices that are inserted into the drill hole of the rod.
  • austenitic steels based on manganese-chromium have been proposed for non-magnetizable drill collars, which are very stable austenitic and, moreover, can be hardened particularly well (AT-PS 214466).
  • AT-PS 214466 austenitic steels based on manganese-chromium
  • the usual procedure is to achieve higher strengths by cold working.
  • the drill collars are first cold-formed over the entire length and finally the ends containing the connecting threads are additionally subjected to a deformation in order to give these parts of the drill collar, which are subject to greater stress, the necessary strength properties.
  • the casting is therefore hot forged, followed by a heat treatment followed by cold working, with a cross-sectional reduction of around 10% taking place, after which the forging is turned and the hole is drilled.
  • This hollow cylinder is then u. Like. provided.
  • the properties of the drill collars manufactured in this way correspond entirely to the usual requirements in the oil field.
  • they have the disadvantage that they prevent corrosion attacks from, for example, aggressive chloride solutions which are found in boreholes e.g. occur frequently in salt domes, are not sufficiently stable and tend to stress corrosion cracking. This can lead to breaks, which then cause unpleasant and costly failures.
  • the magnetic properties can be changed significantly by high mechanical loads on non-magnetic materials.
  • high mechanical stresses could cause the magnetic martensite to develop in an intrinsically non-magnetic structure.
  • the higher the nickel content the more stable a magnetic alloy remains.
  • the higher the nickel content the higher stress corrosion cracking must be expected since the carbon activity is increased.
  • a component for a generator or electric motor which is made of an austenitic alloy and which is said to be non-magnetic at the same time, this component being shot-peened to increase the resistance to stress corrosion cracking. It is a so-called cap ring.
  • Cap rings are used in large electrical machines, namely the lead wires to the windings of the generator or motor are to be held in their groove by a ring. For reasons of the efficiency of the electrical machine, these components should be non-magnetic. If individual areas of the cap ring can be magnetized, the overall function of the motor or the generator is not endangered.
  • the invention thus relates to a method for producing stress-crack corrosion-resistant, non-magnetizable collars made of austenitic steels, which is characterized in that compressive stresses are caused in the surface area of the collars by the action of mechanically, electrically or chemically triggered impact or pressure energy.
  • This application of residual compressive stresses is preferably achieved by mechanical cold compression of the surface by means of hammering, shot peening or roller burnishing.
  • the residual compressive stresses can, however, also advantageously be caused by underwater spark discharge or by triggering detonation waves.
  • the residual tensile stresses resulting from the previous processing which are also responsible for the occurrence of stress corrosion cracking, can be eliminated in the surface area which is decisive for the corrosion attack while maintaining the non-magnetic properties.
  • the method according to the invention can be successfully applied to all austenitic steel alloys.
  • This device for carrying out the method according to the invention is characterized by an impact gas hammer, which is arranged in a housing and is preferably pressurized, the head part of which carries a firing pin for transmitting the axial impact movement, which has at least two, preferably three or four, movably mounted in guide ribs of the housing provided radially outward impact chisels, which strikes the articulated plates which convert the axial to an essentially radial impact movement.
  • a particular advantage of this device to be used according to the invention is its structurally simple structure, which makes replacing bearings, chisels and other wearing parts completely unproblematic;
  • the device is characterized by great robustness.
  • the tool can be made narrow and can therefore be used easily for machining bores of different, in particular also small, drilling widths.
  • the housing is advantageously connected to a pipe which can be inserted into the hollow, preferably the drill pipe used to produce the hollow, by a releasable connection.
  • the guide ribs of the housing are arranged symmetrically and that the articulated plates are articulated by means of bearing bolts arranged between two mutually associated guide ribs.
  • the hinge plates are approximately rectangular in shape.
  • the chisel is made of hard metal.
  • Fig. 1 the hammer operated with compressed air is shown. This is permanently installed in the housing 2, one end of which is connected to a drill pipe 5 by means of a thread 3 and a guide sleeve 4. Through this line 6 for the compressed air supply.
  • a firing pin 8 with a corresponding insertion end 9 is inserted in the head part 7 of the hammer 1.
  • This firing pin 8 is additionally guided in the guide 10 of the housing 2 and transmits the axial impact movement of the hammer 1 to the articulated plates 11.
  • These are movably arranged about bearing bolts 12 in the symmetrically arranged guide ribs 13 of the housing 2.
  • the bolts 12 are secured with lock washers 14.

Description

Bei den für Tiefbohrungen notwendigen Bohrgestängen werden für Richtbohrungen nichtmagnetisierbare Schwerstangen und Gestängeteile benötigt, um eine Beeinflussung der Messgeräte zu vermeiden, die in die Bohrung der Gestänge eingeführt werden.With the drill rods required for deep drilling, non-magnetisable drill rods and rod parts are required for directional drilling in order to avoid influencing the measuring devices that are inserted into the drill hole of the rod.

Für solche Schwerstangen wurden früher ausschliesslich Monel K-Legierungen mit mindestens 63% Nickel, mindestens 25% Kupfer und maximal 5% Aluminium verwendet, die sich als verlässlich unmagnetisch erwiesen haben und dabei gleichzeitig die erforderlichen Festigkeitseigenschaften besitzen.In the past, only Monel K alloys with at least 63% nickel, at least 25% copper and a maximum of 5% aluminum were used for such collars, which have proven to be reliably non-magnetic and at the same time have the required strength properties.

Neben diesen kostspieligen Legierungen wurde versucht, zur Herstellung nichtmagnetisierbarer Schwerstangen austenitische Stähle zu verwenden. Dabei sind bei Schwerstangen aus den üblichen 18/8 Chrom-Nickel-Stählen oft Schwierigkeiten infolge deren ungünstigen unmagnetischen Verhaltens eingetreten. Überdies waren die Festigkeitseigenschaften dieser Werkstoffe unzureichend.In addition to these costly alloys, attempts have been made to use austenitic steels to manufacture non-magnetizable drill collars. Difficulties due to their unfavorable non-magnetic behavior have often arisen with the standard 18/8 chrome-nickel steels. In addition, the strength properties of these materials were inadequate.

Zur Beseitigung dieser Nachteile sind für nichtmagnetisierbare Schwerstangen austenitische Stähle auf der Basis Mangan-Chrom vorgeschlagen worden, die sehr stabil austenitisch sind und sich darüber hinaus besonders gut verfestigen lassen (AT-PS 214466). Bei der Herstellung von homogenen, aus einem Stück bestehenden Schwerstangen aus diesen Stählen wird üblicherweise so vorgegangen, dass durch ein Kaltverformen höhere Festigkeiten erzielt werden. Bei diesem Vorgang werden die Schwerstangen zuerst über die ganze Länge kaltverformt und abschliessend die Enden, welche die Verbindungsgewinde enthalten, noch zusätzlich einer Verformung unterzogen, um diesen höher beanspruchten Teilen der Schwerstange die notwendigen Festigkeitseigenschaften zu geben. Der Guss wird also warmgeschmiedet, dann erfolgt eine Wärmebehandlung, der eine Kaltverformung folgt, wobei eine Querschnittsreduktion im Ausmass von etwa 10% stattfindet, wonach das Schmiedestück überdreht und die Bohrung vorgenommen wird. Dieser Hohlzylinder wird dann mit den erforderlichen Gewinden u. dgl. versehen.In order to eliminate these disadvantages, austenitic steels based on manganese-chromium have been proposed for non-magnetizable drill collars, which are very stable austenitic and, moreover, can be hardened particularly well (AT-PS 214466). In the manufacture of homogeneous one-piece drill collars from these steels, the usual procedure is to achieve higher strengths by cold working. In this process, the drill collars are first cold-formed over the entire length and finally the ends containing the connecting threads are additionally subjected to a deformation in order to give these parts of the drill collar, which are subject to greater stress, the necessary strength properties. The casting is therefore hot forged, followed by a heat treatment followed by cold working, with a cross-sectional reduction of around 10% taking place, after which the forging is turned and the hole is drilled. This hollow cylinder is then u. Like. provided.

Die so hergestellten Schwerstangen entsprechen in ihren Eigenschaften durchaus den üblichen Anforderungen im Ölfeld. Sie haben aber den Nachteil, dass sie gegen die Korrosionsangriffe beispielsweise'von aggressiven Chloridlösungen, die in Bohrlöchern z.B. in Salzstöcken öfters auftreten, nicht genügend beständig sind und zu Spannungsrisskorrosion neigen. Es können dadurch Brüche eintreten, die dann unangenehme und kostspielige Ausfälle verursachen.The properties of the drill collars manufactured in this way correspond entirely to the usual requirements in the oil field. However, they have the disadvantage that they prevent corrosion attacks from, for example, aggressive chloride solutions which are found in boreholes e.g. occur frequently in salt domes, are not sufficiently stable and tend to stress corrosion cracking. This can lead to breaks, which then cause unpleasant and costly failures.

Zur Vermeidung dieser Art von Korrosion wurde versucht, beständigere Legierungen für Schwerstangen heranzuziehen, welche, wie die AT-PS 308 793 zeigt, die Zusammensetzung: max. 0,07% Kohlenstoff, bis 1,00% Silizium, 0,50-2,00% Mangan, 20,00-25,00% Chrom, 10,00-15,00% Nickel, 0,05-0,50% Stickstoff, Rest Eisen und übliche Begleitelemente aufweisen. Schwerstangen aus diesen Legierungen neigen auch bei Einsatz aggressiver Spülmittel viel weniger zu Spannungsrisskorrosion, haben aber den Nachteil, verhältnismässig kostspielig zu sein.To avoid this type of corrosion, attempts have been made to use more resistant alloys for drill collars which, as shown in AT-PS 308 793, have the composition: max. 0.07% carbon, up to 1.00% silicon, 0.50-2.00% manganese, 20.00-25.00% chromium, 10.00-15.00% nickel, 0.05-0.50 % Nitrogen, remainder iron and usual accompanying elements. Collars made of these alloys are much less prone to stress corrosion cracking when using aggressive detergents, but have the disadvantage of being relatively expensive.

Wie sich im praktischen Bohrbetrieb ergeben hat, sind aber alle diese verschiedenartigen Vorschläge nicht immer in ausreichendem Masse geeignet, ein Auftreten von Spannungsrisskorrosion gänzlich auszuschalten.As has been found in practical drilling operations, however, all of these different proposals are not always sufficiently suitable to completely eliminate the occurrence of stress corrosion cracking.

Zur Verbesserung der Spannungsrisskorrosionsbeständigkeit wird in der Literatur unter anderem vorgeschlagen, Druckeigenspannungen z. B. durch Sand- oder Stahlstrahlen zu erzeugen (Werkstoffe und Korrosion 1963, Heft 9, Seiten 729-739).In order to improve the resistance to stress corrosion cracking, the literature proposes, among other things, residual compressive stresses e.g. B. by sandblasting or steel blasting (Materials and Corrosion 1963, No. 9, pages 729-739).

Weiters ist es bekannt, dass die magnetischen Eigenschaften durch hohe mechanische Beanspruchungen von amagnetischen Werkstoffen wesentlich verändert werden können. Bei Stahl ist es beispielsweise bekannt, dass durch hohe mechanische Beanspruchungen in einem an sich amagnetischen Gefüge der magnetische Martensit auftreten könnte. Weiters ist es bekannt, dass eine Stahllegierung, je höher der Nickelanteil ist, umso beständiger amagnetisch bleibt, wobei allerdings, je höher der Nickelgehalt ist, eine höhere Spannungsrisskorrosion erwartet werden muss, da die Kohlenstoffaktivität erhöht wird.Furthermore, it is known that the magnetic properties can be changed significantly by high mechanical loads on non-magnetic materials. In the case of steel, for example, it is known that high mechanical stresses could cause the magnetic martensite to develop in an intrinsically non-magnetic structure. Furthermore, it is known that the higher the nickel content, the more stable a magnetic alloy remains. However, the higher the nickel content, the higher stress corrosion cracking must be expected since the carbon activity is increased.

Aus der DE-A 1 227491 wird ein Bauteil für einen Generator oder Elektromotor bekannt, welcher aus einer austenitischen Legierung aufgebaut ist und der gleichzeitig amagnetisch sein soll, wobei zur Erhöhung der Beständigkeit gegen Spannungsrisskorrosion dieser Bauteil kugelgestrahlt werden soll. Es handelt sich hiebei um einen sogenannten Kappenring. Kappenringe werden bei grossen elektrischen Maschinen eingesetzt, und zwar sollen die Zuführungsdrähte zu den Wicklungen des Generators oder Motors durch einen Ring in ihrer Nut gehalten werden. Diese Bauteile sollen aus Gründen des Wirkungsgrades der elektrischen Maschine amagnetisch sein. Sind einzelne Bereiche des Kappenringes magnetisierbar, so wird jedoch die Gesamtfunktion des Motors oder des Generators nicht gefährdet.From DE-A 1 227491 a component for a generator or electric motor is known which is made of an austenitic alloy and which is said to be non-magnetic at the same time, this component being shot-peened to increase the resistance to stress corrosion cracking. It is a so-called cap ring. Cap rings are used in large electrical machines, namely the lead wires to the windings of the generator or motor are to be held in their groove by a ring. For reasons of the efficiency of the electrical machine, these components should be non-magnetic. If individual areas of the cap ring can be magnetized, the overall function of the motor or the generator is not endangered.

Eingehende Untersuchungen haben nun gezeigt, dass sich die Spannungsrisskorrosion bei amagnetischen Schwerstangen aus austenitischen Stählen auch bei den kostengünstigeren Mangan-Chrom-Stählen sicher vermeiden lässt, wenn man im Oberflächenbereich Druckeigenspannungen aufbringt.In-depth investigations have now shown that stress corrosion cracking on non-magnetic austenitic steel collars can also be reliably avoided with the less expensive manganese-chromium steels by applying residual compressive stresses in the surface area.

Gegenstand der Erfindung ist somit ein Verfahren zur Herstellung von spannungsrisskorrosionsbeständigen, nichtmagnetisierbaren Schwerstangen aus austenitischen Stählen, welche dadurch gekennzeichnet ist, dass im Oberflächenbereich der Schwerstangen Druckeigenspannungen durch Einwirkung mechanisch, elektrisch oder chemisch ausgelöster Stoss- bzw. Druckenergie hervorgerufen werden.The invention thus relates to a method for producing stress-crack corrosion-resistant, non-magnetizable collars made of austenitic steels, which is characterized in that compressive stresses are caused in the surface area of the collars by the action of mechanically, electrically or chemically triggered impact or pressure energy.

Gemäss einem weiteren Merkmal der vorliegenden Erfindung werden zusätzlich im Oberflächenbereich des Hohls der Schwerstangen Druckeigenspannungen durch Einwirkung mechanisch, elektrisch oder chemisch ausgelöster Stoss- bzw. Druckenergie hervorgerufen.According to a further feature of the present invention, in the surface Chen range of the hollow of the collars compression internal stresses caused by the action of mechanically, electrically or chemically triggered impact or pressure energy.

Dieses Aufbringen von Druckeigenspannungen wird bevorzugt durch mechanisches Kaltverdichten der Oberfläche mittels Hämmern, Kugelstrahlen oder Rollieren erreicht.This application of residual compressive stresses is preferably achieved by mechanical cold compression of the surface by means of hammering, shot peening or roller burnishing.

Die Druckeigenspannungen können aber auch vorteilhaft durch Unterwasser-Funkenentladung oder durch Auslösung von Detonationswellen hervorgerufen werden.The residual compressive stresses can, however, also advantageously be caused by underwater spark discharge or by triggering detonation waves.

Mit dem erfindungsgemässen Aufbringen von Druckeigenspannungen können die von der vorhergehenden Bearbeitung herrührenden Zugeigenspannungen, die für das Auftreten der Spannungsrisskorrosion auch verantwortlich sind, im für den Korrosionsangriff entscheidenden Oberflächenbereich bei Beibehaltung der amagnetischen Eigenschaften beseitigt werden. Das erfindungsgemässe Verfahren kann mit Erfolg auf alle austenitischen Stahllegierungen angewendet werden.With the application of residual compressive stresses according to the invention, the residual tensile stresses resulting from the previous processing, which are also responsible for the occurrence of stress corrosion cracking, can be eliminated in the surface area which is decisive for the corrosion attack while maintaining the non-magnetic properties. The method according to the invention can be successfully applied to all austenitic steel alloys.

Es hat sich gezeigt, dass Bearbeitungsmethoden, bei welchen das Verdichten der Oberfläche der Bohrung durch mechanische Einwirkung in Richtung etwa senkrecht zur Oberfläche erfolgt, für den angestrebten Abbau der Zugeigenspannungen und den Aufbau von Druckeigenspannungen am vorteilhaftesten sind. Dementsprechend sind Kugelstrahlen, ein Vorgang, bei welchem ähnlich dem Sandstrahlen ein Strahl von Stahlkugeln gegen die Oberfläche gerichtet wird, und Hämmern für die Behandlung der Schwerstangen besonders bevorzugt.It has been shown that machining methods in which the surface of the bore is compressed by mechanical action in the direction approximately perpendicular to the surface are most advantageous for the desired reduction of the residual tensile stresses and the build-up of residual compressive stresses. Accordingly, shot peening, a process in which a shot of steel balls is directed against the surface, similar to sandblasting, and hammers are particularly preferred for the treatment of the collar.

Am günstigsten ist es, wenn das Werkzeug, welches die Druckeigenspannungen aufbringt, in der Bohrung der Schwerstange vorgeschoben, die Stange jedoch gedreht wird. Auf diese Weise wird ein besonders gleichmässiges Verdichten der zu bearbeitenden Hohloberfläche erreicht.It is most favorable if the tool that applies the residual compressive stress is advanced in the drill hole of the drill collar, but the rod is rotated. In this way, a particularly uniform compression of the hollow surface to be machined is achieved.

Da die Bohrungen der Schwerstangen im Durchmesser verhältnismässig klein sind, die Stangenlängen jedoch mindestens 9,15 m betragen, wurde für das erfindungsgemässe Verdichten der Oberfläche durch Hämmern eine spezielle Vorrichtung entwickelt, welche nach dem Prinzip eines Pressluft-Schlagwerkzeuges arbeitet. Diese Vorrichtung zur Durchführung des erfindungsgemässen Verfahrens ist gekennzeichnet durch einen in einem Gehäuse angeordneten, vorzugsweise pressgasbetriebenen, Schlaghammer, dessen Kopfteil zur Übertragung der axialen Schlagbewegung einen Schlagbolzen trägt, welcher an mindestens zwei, vorzugsweise drei oder vier, in Führungsrippen des Gehäuses beweglich gelagerten, mit radial nach aussen gerichteten Schlagmeisseln versehene, die axiale in eine im wesentlichen radiale Schlagbewegung umwandelnde, Gelenkplatten anschlägt.Since the drill holes of the drill collars are relatively small in diameter, but the rod lengths are at least 9.15 m, a special device was developed for the surface compaction by hammering according to the invention, which works on the principle of a compressed air impact tool. This device for carrying out the method according to the invention is characterized by an impact gas hammer, which is arranged in a housing and is preferably pressurized, the head part of which carries a firing pin for transmitting the axial impact movement, which has at least two, preferably three or four, movably mounted in guide ribs of the housing provided radially outward impact chisels, which strikes the articulated plates which convert the axial to an essentially radial impact movement.

Besonderer Vorteil dieser erfindungsgemäss einzusetzenden Vorrichtung ist ihr konstruktiv einfacher Aufbau, der ein Auswechseln von Lagern, Meisseln und anderen Verschleissteilen völlig unproblematisch macht; darüber hinaus zeichnet sich die Vorrichtung durch grosse Robustheit aus. Schliesslich kann das Werkzeug schmal gebaut sein und so leicht zur Bearbeitung von Bohrungen verschiedener, insbesondere auch kleiner Bohrweiten eingesetzt werden. Vorteilhaft ist bei dem Werkzeug das Gehäuse mit einem in das Hohl einführbaren Rohr, vorzugsweise dem zur Herstellung des Hohls dienenden Bohrrohr, durch eine lösbare Verbindung verbunden.A particular advantage of this device to be used according to the invention is its structurally simple structure, which makes replacing bearings, chisels and other wearing parts completely unproblematic; In addition, the device is characterized by great robustness. Finally, the tool can be made narrow and can therefore be used easily for machining bores of different, in particular also small, drilling widths. In the case of the tool, the housing is advantageously connected to a pipe which can be inserted into the hollow, preferably the drill pipe used to produce the hollow, by a releasable connection.

Gemäss einer bevorzugten Ausführungsform der Vorrichtung ist vorgesehen, dass die Führungsrippen des Gehäuses symmetrisch angeordnet und dass die Gelenkplatten mittels zwischen je zwei einander zugeordneten Führungsrippen angeordneten Lagerbolzen gelenkig gelagert sind. Durch diese Ausbildungsform lässt sich ein einfacher Aufbau bei gleichzeitig hoher Arbeitspräzision erreichen.According to a preferred embodiment of the device, it is provided that the guide ribs of the housing are arranged symmetrically and that the articulated plates are articulated by means of bearing bolts arranged between two mutually associated guide ribs. This type of training enables a simple setup with a high level of work precision.

Im allgemeinen haben die Gelenkplatten etwa Rechteckform. Insbesondere um deren Gewicht ohne wesentliche Festigkeitseinbusse zu verringern, wird es bevorzugt, die Gelenkplatten im wesentlichen rechteckförmig und die dem Schlagmeissel abgekehrte Seite der Platten vorzugsweise abgeschrägt auszubilden.In general, the hinge plates are approximately rectangular in shape. In particular in order to reduce their weight without any significant loss of strength, it is preferred to design the joint plates to be essentially rectangular and the side of the plates facing away from the chisel preferably beveled.

Zur Verminderung des Verschleisses ist es vorteilhaft, wenn der Schlagmeissel aus HartmetalJ gefertigt ist.To reduce wear, it is advantageous if the chisel is made of hard metal.

Anhand der Zeichnung wird die erfindungsgemässe Vorrichtung im folgenden näher erläutert:The device according to the invention is explained in more detail below with reference to the drawing:

Es zeigen:

  • Fig. 1 einen Längsschnitt durch die Vorrichtung, welche sich im Hohl einer Schwerstange befindet; Fig. 2 eine Vorderansicht eines dreistrahlig und Fig. eine Vorderansicht eines vierstrahlig ausgebildeten Werkzeuges.
Show it:
  • 1 shows a longitudinal section through the device, which is located in the hollow of a drill collar. Fig. 2 is a front view of a three-jet and Fig. A front view of a four-jet tool.

In Fig. 1 ist der mit Pressluft betriebene Schlaghammer dargestellt. Dieser ist im Gehäuse 2 fix eingebaut, dessen eines Ende mittels Gewinde 3 und Führungshülse 4 mit einem Bohrrohr 5 verbunden ist. Durch dieses führt die Leitung 6 für die Pressluftzufuhr. In den Kopfteil 7 des Schlaghammers 1 ist ein Schlagbolzen 8 mit entsprechendem Einsteckende 9 eingeführt. Dieser Schlagbolzen 8 wird zusätzlich in der Führung 10 des Gehäuses 2 geführt und überträgt die axiale Schlagbewegung des Schlaghammers 1 auf die Gelenkplatten 11. Diese sind um Lagerbolzen 12 beweglich in den symmetrisch angeordneten Führungsrippen 13 des Gehäuses 2 angeordnet. Die Bolzen 12 sind mit Sicherungsscheiben 14 gesichert. Die Gelenkplatten 11, deren Anzahl, wie Fig. 2 zeigt, 3 Stück, aber je nach Grösse des Gehäuses, wie Fig. 3 zeigt, auch 4 Stück (dies ist von der zu bearbeitenden Bohrungsgrösse abhängig) betragen kann, übertragen die Axialbewegung des Schlagbolzens 8 in eine Radialbewegung. Die in den Gelenkplatten 11 eingebauten Schlagmeissel 15 z. B. aus Hartmetallhämmern mit der hohen Schlagfrequenz des Schlaghammers 1 auf die Oberfläche 16 der Bohrung der Schwerstange und bewirken so die gewünschte Kaltverdichtung der Oberfläche. Bezüglich der Grössenordnung der Schlagfrequenz kann angegeben werden, dass sich für die Ausführung mit 3 Schlagmeisseln eine solche von 6000-8000 Schlägen/min und für diejenige mit 4 Schlagmeisseln eine solche von 4000-5000 Schlägen/min gut bewährt hat.In Fig. 1 the hammer operated with compressed air is shown. This is permanently installed in the housing 2, one end of which is connected to a drill pipe 5 by means of a thread 3 and a guide sleeve 4. Through this line 6 for the compressed air supply. In the head part 7 of the hammer 1, a firing pin 8 with a corresponding insertion end 9 is inserted. This firing pin 8 is additionally guided in the guide 10 of the housing 2 and transmits the axial impact movement of the hammer 1 to the articulated plates 11. These are movably arranged about bearing bolts 12 in the symmetrically arranged guide ribs 13 of the housing 2. The bolts 12 are secured with lock washers 14. The joint plates 11, the number of which, as shown in FIG. 2, can be 3 pieces, but depending on the size of the housing, as shown in FIG. 3, can also be 4 pieces (this depends on the size of the bore to be machined) transmit the axial movement of the firing pin 8 in a radial movement. The built in the hinge plates 11 chisel 15 z. B. from hard metal hammers with the high impact frequency of the impact hammer 1 on the surface 16 of the bore of the drill collar and thus bring about the desired cold compression of the surface. Regarding the magnitude of the impact frequency, it can be stated that there is one for the version with 3 impact chisels of 6000-8000 strokes / min and for those with 4 chisels a 4000-5000 strokes / min has proven itself.

Claims (9)

1. A method of manufacturing stress-corrosion- resistant non-magnetizable drill-stems made of austenitic steels, characterized in that in the surface region of the drill-stems residual compressive stresses are produced by the effect of mechanically, electrically, or chemically released impact or compression energy.
2. A method according to claim 1, characterized in that additionally in the surface region of the hollow of the drill-stems residual compressive stresses are produced by the effect of mechanically, electrically, or chemically released impact or compression energy.
3. A method according to claim 1 or 2, characterized in that the residual compressive stresses are produced by means of hammering, shot-peening, or rolling.
4. A method according to claim 1 or 2, characterized in that the residual compressive stresses are produced by underwater spark discharge.
5. A method according to claim 1 or 2, characterized in that the residual compressive stresses are produced by releasing detonation waves.
6. Apparatus for carrying out the method according to claims 1, 2 or 3, having an impact hammer (1), preferably pressure-gas operated, disposed in a housing (2), characterized in that the head part (7) of the impact hammer (1) bears an impact pin (8), for transmitting the axial impact movement, which strikes at least two, preferably three or four, hinged plates (11) which are movably mounted in symmetrically disposed guide ribs (13) of the housing (2), are provided with radially outwardly directed impact bits (15), and convert the axial impact movement into a substantially radial impact movement.
7. Apparatus according to claim 6, characterized in that the hinged plates (11) are mounted in an articulated manner by means of bearing bolts (12) disposed in each case between two guide ribs (13) which are associated with each other.
8. Apparatus according to claims 6 and 7, characterized in that the hinged plates (11) are substantially rectangular in shape, the side of the plates (11) facing away from the impact bit (15) being preferably bevelled.
9. Apparatus according to one of claims 6 to 8, characterized in that the impact bit (15) is made of hard metal.
EP80890152A 1980-01-25 1980-12-19 Process for producing tension-crack corrosion-resistant non magnetizable drill collars of austenitic steels, and apparatus for carrying out this process Expired EP0035091B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT405/80 1980-01-25
AT40580A AT364592B (en) 1980-01-25 1980-01-25 METHOD FOR PRODUCING TENSION RACK CORROSION-RESISTANT, NON-MAGNETIZABLE HEAVY RODS FROM AUSTENITIC STEELS AND DEVICE FOR IMPLEMENTING THE METHOD

Publications (2)

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EP0035091A1 EP0035091A1 (en) 1981-09-09
EP0035091B1 true EP0035091B1 (en) 1985-04-10

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EP80890152A Expired EP0035091B1 (en) 1980-01-25 1980-12-19 Process for producing tension-crack corrosion-resistant non magnetizable drill collars of austenitic steels, and apparatus for carrying out this process

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EP (1) EP0035091B1 (en)
AT (1) AT364592B (en)
DE (1) DE3070489D1 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58167724A (en) * 1982-03-26 1983-10-04 Kobe Steel Ltd Method of preparing blank useful as stabilizer for drilling oil well
AT392802B (en) * 1988-08-04 1991-06-25 Schoeller Bleckmann Stahlwerke METHOD FOR THE PRODUCTION OF TUBE-SHAPED CORROSION-RESISTANT BODY-BODIES, IN PARTICULAR NON-MAGNETIZABLE HEAVY RODS FROM AUSTENITIC STEELS
GB0023296D0 (en) 2000-09-22 2000-11-08 Rolls Royce Plc Prestressing of components
EP2069544A1 (en) 2006-09-27 2009-06-17 Rolls-Royce plc A method and an apparatus for prestressing components by electrical discharge
DE102015203487A1 (en) * 2015-02-26 2016-09-01 Ecoroll Ag Werkzeugtechnik Clamping device for influencing workpieces and associated method
DE102017213045B4 (en) * 2017-07-28 2023-02-23 Gühring KG ROLLING TOOL
CN112795753B (en) * 2020-12-25 2022-06-03 兰州理工大学 Surface strengthening device and strengthening method for large-diameter metal pipe

Citations (7)

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Publication number Priority date Publication date Assignee Title
GB1054979A (en) * 1900-01-01
DE324509C (en) * 1913-06-18 1920-08-30 Diamond Blower Company Ltd Tapping tool for removing the scale from pipes
FR800143A (en) * 1935-01-23 1936-06-27 Standard Oil Dev Co Process of cold treatment of the surface of special steel objects
AT214466B (en) * 1959-06-04 1961-04-10 Schoeller Bleckmann Stahlwerke Steel alloys for the manufacture of drill collars for deep drill rods
DE1227491B (en) * 1957-03-06 1966-10-27 Krupp Ag Huettenwerke Non-magnetic cap rings resistant to stress corrosion cracking
US3610008A (en) * 1969-06-27 1971-10-05 Northrop Corp Peening tool
US3648510A (en) * 1969-08-01 1972-03-14 Gardner Newell J Internal peening tool

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT308793B (en) * 1968-12-02 1973-07-25 Schoeller Bleckmann Stahlwerke Austenitic chrome-nickel-nitrogen-steel alloy for non-magnetizable drill collar and rod parts

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1054979A (en) * 1900-01-01
DE324509C (en) * 1913-06-18 1920-08-30 Diamond Blower Company Ltd Tapping tool for removing the scale from pipes
FR800143A (en) * 1935-01-23 1936-06-27 Standard Oil Dev Co Process of cold treatment of the surface of special steel objects
DE1227491B (en) * 1957-03-06 1966-10-27 Krupp Ag Huettenwerke Non-magnetic cap rings resistant to stress corrosion cracking
AT214466B (en) * 1959-06-04 1961-04-10 Schoeller Bleckmann Stahlwerke Steel alloys for the manufacture of drill collars for deep drill rods
US3610008A (en) * 1969-06-27 1971-10-05 Northrop Corp Peening tool
US3648510A (en) * 1969-08-01 1972-03-14 Gardner Newell J Internal peening tool

Also Published As

Publication number Publication date
EP0035091A1 (en) 1981-09-09
DE3070489D1 (en) 1985-05-15
ATA40580A (en) 1981-03-15
AT364592B (en) 1981-10-27

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