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EP0750683B1 - Process for influencing the changes in size and shape of workpieces during hardening - Google Patents

Process for influencing the changes in size and shape of workpieces during hardening Download PDF

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Publication number
EP0750683B1
EP0750683B1 EP95912245A EP95912245A EP0750683B1 EP 0750683 B1 EP0750683 B1 EP 0750683B1 EP 95912245 A EP95912245 A EP 95912245A EP 95912245 A EP95912245 A EP 95912245A EP 0750683 B1 EP0750683 B1 EP 0750683B1
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EP
European Patent Office
Prior art keywords
workpieces
mandrel
hardening
mandrel fixture
fixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP95912245A
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German (de)
French (fr)
Other versions
EP0750683A1 (en
Inventor
Frank Kolzarek
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.)
ZF Friedrichshafen AG
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ZF Friedrichshafen AG
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Filing date
Publication date
Application filed by ZF Friedrichshafen AG filed Critical ZF Friedrichshafen AG
Publication of EP0750683A1 publication Critical patent/EP0750683A1/en
Application granted granted Critical
Publication of EP0750683B1 publication Critical patent/EP0750683B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/62—Quenching devices
    • C21D1/673—Quenching devices for die quenching
    • 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
    • C21D9/0006—Details, accessories not peculiar to any of the following furnaces
    • C21D9/0025—Supports; Baskets; Containers; Covers
    • 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
    • C21D9/32—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like

Definitions

  • the invention relates to a method for influencing of dimensional and shape changes when hardening in particular rotationally symmetrical workpieces.
  • Martensite formation is known to be significant Steel increases hardness. Marked with hardships a heat treatment in which the workpiece, based on the hardening temperature for an austenitic structure, is cooled in a quenching medium in such a way that martensite formation occurs.
  • hardening components When hardening components occurs default that in an unavoidable proportion resulting from the structural changes, and an avoidable Share that depends on process-specific conditions can be divided.
  • the workpieces are hardened immediately after Carburizing on mechanical aids with a given Diameter applied and cooled in the quenching medium. In the course of this cooling, the workpieces shrink this diameter under plastic and elastic deformation on.
  • the mechanical aids mentioned include so-called Mandrel fixtures and force-related devices, so-called spreading tools.
  • thorn fixtures are used.
  • DE-A 41 33 799 describes a method for hardening of rotationally symmetrical workpieces, at that the quenching of the workpieces in at least two periods he follows. In a first period shrinks the workpiece to a first diameter of the mechanical aids with predominantly plastic deformation on. In a subsequent period this process is continued in such a way that the workpiece shrunk to a smaller second diameter. The amount of plastic deformation is during this period of time much less.
  • the present invention is based on the object the known methods for influencing dimensional and shape changes when hardening using mandrel fixtures simplify and cheapen.
  • the solution according to the invention becomes a method to influence dimensional and shape changes during hardening provided by workpieces according to the generic term, through the process steps: stacking the workpieces on the mandrel fixture, carburizing and quenching the on the Thorn fixture located workpieces and removal of Workpieces are marked by the mandrel fixture.
  • the proposed Procedure is valuable with a number Advantages. The hardness results are high reproducible. It is not an expensive handling of the parts required in the oven. Due to the simplified procedure can use simpler and therefore cheaper ovens will. The furnaces can be easily automated will. Different batches can be made in a single batch Parts are manufactured. By simplifying it there is a high potential for savings compared to the previous heat treatment costs available.
  • the workpieces have proven to be advantageous to be fixed on the mandrel fixture after stacking. Around In this way, the workpieces can be avoided for example, complaining.
  • a mechanical tool is preferably used for the method according to the invention Hardening workpieces in a quenching medium a given diameter under plastic and elastic Shrink deformation, which Aid consists of a mandrel fixture, which when carburizing the Do not carburize workpieces. There is therefore no conversion the surface of the mandrel fixture into a hardness structure instead of.
  • the coating can preferably be produced by nickel plating or copper plating.
  • a thorn fixture with a high resistance to Aging is characterized by the fact that it consists of a high-alloy Steel is made.
  • the process is based on the knowledge that a Time and cost savings when hardening workpieces in of ongoing production can be achieved if the individual operations: carburizing the workpieces, stacking the workpieces on the mandrel fixture and quenching under plastic and elastic deformation of the workpieces, in a process flow can be combined with each other.
  • the hardening process according to the invention continues from the work steps: stacking the workpieces a mandrel fixture, carburizing and quenching the workpieces together.
  • the mandrel fixture and the workpieces to be hardened to hardening temperature brought. Shrink under oil when quenched the workpieces on the mandrel fixture.
  • the mandrel fixture needed due to their larger mass, longer until (on the Oil temperature) is quenched. Because of the volume difference due to the temperature gradient between the workpieces and the mandrel fixture initially shrink the workpieces - with mainly plastic deformation - to a larger one Diameter of the mandrel fixture. In the further course cooling down reduces the diameter of the mandrel fixture, the workpiece follows this change in diameter. In this stage of the process, a plastic one can again Deformation take place, which, measured by the proportion of plastic Deformation in the first step, however is much lower. To quench the workpieces to keep it flat, it is advantageous to keep the workpieces after the Weighing on the mandrel fixture weighed down. After the final quenching of the work pieces shrinks the mandrel fixture to its original size, so that the workpieces can be easily removed from the mandrel fixture.
  • the proposed method sets a mandrel fixture ahead that does not carburize when the workpieces are carburized, d. H. there is no conversion of the surface of the Mandrel fixture in a hardness structure.
  • it can be nickel-plated or be copper-plated.
  • the mandrel fixture be made of a high-alloy steel, the does not follow the process of transformation into a structure of hardship.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Forging (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)

Abstract

A process and device are disclosed for influencing the changes in size and shape of workpieces during hardening. Mechanical accessories, in particular mandrel fixtures, are used for hardening workpieces. In known processes, the carburised workpieces are set on said mandrel fixtures and quenched. In order to simplify and reduce the cost of a hardening process by means of mandrel fixtures, the individual operations such as carburising, stacking of workpieces on the mandrel fixture and quenching are combined in a single process. A mechanical accessory used to carry out this process is made of a material that does not carburise together with the workpieces, i.e. the surface of the mandrel fixture is not changed into a hardened microstructure during carburising.

Description

Die Erfindung bezieht sich auf ein Verfahren zum Beeinflussen von Maß- und Formänderungen beim Härten von insbesondere rotationssymmetrischen Werkstücken.The invention relates to a method for influencing of dimensional and shape changes when hardening in particular rotationally symmetrical workpieces.

Es ist bekannt, daß die Martensit-Bildung eine erhebliche Härtesteigerung von Stahl bewirkt. Mit Härten bezeichnet man eine Wärmebehandlung, bei der das Werkstück, ausgehend von der Härtetemperatur bei austenitischem Gefüge, in einem Abschreckmedium in der Weise abgekühlt wird, daß es zur Martensit-Bildung kommt. Beim Härten von Bauteilen tritt Verzug auf, der in einen unvermeidbaren Anteil, resultierend aus den Gefügeumwandlungen, und einen vermeidbaren Anteil, der von prozeßspezifischen Gegebenheiten abhängt, unterteilt werden kann.Martensite formation is known to be significant Steel increases hardness. Marked with hardships a heat treatment in which the workpiece, based on the hardening temperature for an austenitic structure, is cooled in a quenching medium in such a way that martensite formation occurs. When hardening components occurs default that in an unavoidable proportion resulting from the structural changes, and an avoidable Share that depends on process-specific conditions can be divided.

Zum Härten werden die Werkstücke unmittelbar nach dem Aufkohlen auf mechanische Hilfsmittel mit einem vorgegebenen Durchmesser aufgelegt und im Abschreckmedium abgekühlt. Im Verlauf dieser Abkühlung schrumpfen die Werkstücke auf diesen Durchmesser unter plastischer und elastischer Verformung auf.The workpieces are hardened immediately after Carburizing on mechanical aids with a given Diameter applied and cooled in the quenching medium. In the course of this cooling, the workpieces shrink this diameter under plastic and elastic deformation on.

Zu den erwähnten mechanischen Hilfsmitteln zählen sogenannte Dornfixturen sowie kraftgebundene Vorrichtungen, sogenannte Spreizwerkzeuge. Im Rahmen der vorliegenden Erfindung werden Dornfixturen eingesetzt.The mechanical aids mentioned include so-called Mandrel fixtures and force-related devices, so-called spreading tools. Within the scope of the present invention thorn fixtures are used.

Aus der DE-A 41 33 799 ist ein Verfahren zum Härten von rotationssymmetrischen Werkstücken bekanntgeworden, bei dem das Abschrecken der Werkstücke in mindestens zwei Zeitabschnitten erfolgt. In einem ersten Zeitabschnitt schrumpft das Werkstück auf einen ersten Durchmesser des mechanischen Hilfsmittels unter vorwiegend plastischer Verformung auf. In einem anschließenden weiteren Zeitabschnitt wird dieser Vorgang fortgesetzt in der Weise, daß das Werkstück auf einen geringeren zweiten Durchmesser aufschrumpft. Der Anteil der plastischen Verformung ist während dieses Zeitabschnitts wesentlich geringer.DE-A 41 33 799 describes a method for hardening of rotationally symmetrical workpieces, at that the quenching of the workpieces in at least two periods he follows. In a first period shrinks the workpiece to a first diameter of the mechanical aids with predominantly plastic deformation on. In a subsequent period this process is continued in such a way that the workpiece shrunk to a smaller second diameter. The amount of plastic deformation is during this period of time much less.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, die bekannten Verfahren zum Beeinflussen von Maß- und Formänderungen beim Härten unter Einsatz von Dornfixturen zu vereinfachen und zu verbilligen.The present invention is based on the object the known methods for influencing dimensional and shape changes when hardening using mandrel fixtures simplify and cheapen.

Mit der erfindungsgemäßen Lösung wird ein Verfahren zum Beeinflussen von Maß- und Formänderungen beim Härten von Werkstücken nach dem Gattungsbegriff bereitgestellt, das durch die Verfahrensschritte: Stapeln der Werkstücke auf der Dornfixtur, Aufkohlen und Abschrecken der auf der Dornfixtur befindlichen Werkstücke sowie Entfernen der Werkstücke von der Dornfixtur gekennzeichnet ist. Das vorgeschlagene Verfahren ist mit einer Reihe von wertvollen Vorteilen verbunden. Die Härteergebnisse sind in hohem Maße reproduzierbar. Es ist kein aufwendiges Handhaben der Teile im Ofen erforderlich. Durch den vereinfachten Verfahrensablauf können einfachere und damit preiswertere Öfen verwendet werden. Das Beschicken der Öfen kann einfach automatisiert werden. In einer einzigen Ofencharge können unterschiedliche Teile gefertigt werden. Durch die Vereinfachung steht ein hohes Einsparungspotential im Vergleich zu den bisherigen Kosten einer Wärmebehandlung zur Verfügung.The solution according to the invention becomes a method to influence dimensional and shape changes during hardening provided by workpieces according to the generic term, through the process steps: stacking the workpieces on the mandrel fixture, carburizing and quenching the on the Thorn fixture located workpieces and removal of Workpieces are marked by the mandrel fixture. The proposed Procedure is valuable with a number Advantages. The hardness results are high reproducible. It is not an expensive handling of the parts required in the oven. Due to the simplified procedure can use simpler and therefore cheaper ovens will. The furnaces can be easily automated will. Different batches can be made in a single batch Parts are manufactured. By simplifying it there is a high potential for savings compared to the previous heat treatment costs available.

Es hat sich als vorteilhaft herausgestellt, die Werkstücke nach dem Stapeln auf der Dornfixtur zu fixieren. Um auf diese Weise Verzug zu vermeiden, können die Werkstücke beispielsweise beschwert werden. The workpieces have proven to be advantageous to be fixed on the mandrel fixture after stacking. Around In this way, the workpieces can be avoided for example, complaining.

Für das erfindungsgemäße Verfahren wird vorzugsweise ein mechanisches Hilfsmittel eingesetzt zum Härten von Werkstücken, die in einem Abschreckmedium auf einen vorgegebenen Durchmesser unter plastischer und elastischer Verformung aufschrumpfen, welches Hilfsmittel aus einer Dornfixtur besteht, die beim Aufkohlen der Werkstücke nicht mit aufkohlt. Es findet demnach keine Umwandlung der Oberfläche der Dornfixtur in ein Härtegefüge statt.A mechanical tool is preferably used for the method according to the invention Hardening workpieces in a quenching medium a given diameter under plastic and elastic Shrink deformation, which Aid consists of a mandrel fixture, which when carburizing the Do not carburize workpieces. There is therefore no conversion the surface of the mandrel fixture into a hardness structure instead of.

Es hat sich herausgestellt, daß eine Beschichtung der Dornfixtur mit einem Material, die ein Aufkohlen verhindert, eine, insbesondere hinsichtlich ihres Verschleißes, vorteilhafte Lösung darstellt. Die Beschichtung kann vorzugsweise durch Vernickeln oder Verkupfern erzeugt werden.It has been found that a coating of the Thorn fixture with a material that prevents carburizing, one, especially with regard to its wear, represents advantageous solution. The coating can preferably be produced by nickel plating or copper plating.

Eine Dornfixtur mit einer hohen Beständigkeit gegen Altern zeichnet sich dadurch aus, daß sie aus einem hochlegierten Stahl gefertigt ist.A thorn fixture with a high resistance to Aging is characterized by the fact that it consists of a high-alloy Steel is made.

Das Verfahren nach der Erfindung sowie eine zur Durchführung des Verfahrens geeignete Vorrichtung wird im folgenden näher erläutert:The method according to the invention and one for carrying out The device suitable for the method is described below explained in more detail:

Das Verfahren beruht auf der Erkenntnis, daß eine Zeit- und Kostenersparnis beim Härten von Werkstücken in der laufenden Fertigung dann erzielt werden kann, wenn die einzelnen Arbeitsgänge: Aufkohlen der Werkstücke, Stapeln der Werkstücke auf der Dornfixtur und Abschrecken unter plastischer und elastischer Verformung der Werkstücke, in einem Verfahrensablauf miteinander kombiniert werden können. Demzufolge setzt sich das erfindungsgemäße Härteverfahren aus den Arbeitsschritten: Stapeln der Werkstücke auf einer Dornfixtur, Aufkohlen und Abschrecken der Werkstücke zusammen. Im Unterschied zu den bekannten Verfahren werden die Dornfixtur und die zu härtenden Werkstücke auf Härtetemperatur gebracht. Beim Abschrecken unter Öl schrumpfen die Werkstücke auf die Dornfixtur auf. Die Dornfixtur benötigt aufgrund ihrer größeren Masse länger, bis sie (auf die Öltemperatur) abgeschreckt ist. Wegen der Volumendifferenz aufgrund des Temperaturgefälles zwischen den Werkstücken und der Dornfixtur schrumpfen die Werkstücke zunächst - unter vorwiegend plastischer Verformung - auf einen größeren Durchmesser der Dornfixtur auf. Im weiteren Verlauf der Abkühlung verringert sich der Durchmesser der Dornfixtur, wobei das Werkstück dieser Durchmesseränderung folgt. In diesem Verfahrensabschnitt kann nochmals eine plastische Verformung stattfinden, die, gemessen am Anteil der plastischen Verformung im ersten Verfahrensschritt, jedoch wesentlich geringer ist. Um die Werkstücke beim Abschrecken plan zu halten, ist es vorteilhaft, die Werkstücke nach dem Stapeln auf der Dornfixtur mit einem Gewicht zu beschweren. Nach dem endgültigen Abschrecken der Werkstücke schrumpft die Dornfixtur auf ihr Ausgangsmaß, so daß die Werkstücke problemlos von der Dornfixtur abgenommen werden können.The process is based on the knowledge that a Time and cost savings when hardening workpieces in of ongoing production can be achieved if the individual operations: carburizing the workpieces, stacking the workpieces on the mandrel fixture and quenching under plastic and elastic deformation of the workpieces, in a process flow can be combined with each other. As a result, the hardening process according to the invention continues from the work steps: stacking the workpieces a mandrel fixture, carburizing and quenching the workpieces together. In contrast to the known methods the mandrel fixture and the workpieces to be hardened to hardening temperature brought. Shrink under oil when quenched the workpieces on the mandrel fixture. The mandrel fixture needed due to their larger mass, longer until (on the Oil temperature) is quenched. Because of the volume difference due to the temperature gradient between the workpieces and the mandrel fixture initially shrink the workpieces - with mainly plastic deformation - to a larger one Diameter of the mandrel fixture. In the further course cooling down reduces the diameter of the mandrel fixture, the workpiece follows this change in diameter. In this stage of the process, a plastic one can again Deformation take place, which, measured by the proportion of plastic Deformation in the first step, however is much lower. To quench the workpieces to keep it flat, it is advantageous to keep the workpieces after the Weighing on the mandrel fixture weighed down. After the final quenching of the work pieces shrinks the mandrel fixture to its original size, so that the workpieces can be easily removed from the mandrel fixture.

Das vorgeschlagene Verfahren setzt eine Dornfixtur voraus, die beim Aufkohlen der Werkstücke nicht mit aufkohlt, d. h. es erfolgt keine Umwandlung der Oberfläche der Dornfixtur in ein Härtegefüge. Um dieses Aufkohlen der Dornfixtur zu verhindern, kann sie beispielsweise vernikkelt oder verkupfert sein. Alternativ hierzu kann die Dornfixtur aus einem hochlegierten Stahl gefertigt sein, der den Umwandlungsprozeß in Härtegefüge nicht mitvollzieht.The proposed method sets a mandrel fixture ahead that does not carburize when the workpieces are carburized, d. H. there is no conversion of the surface of the Mandrel fixture in a hardness structure. To this carburizing To prevent thorn fixation, for example, it can be nickel-plated or be copper-plated. Alternatively, the mandrel fixture be made of a high-alloy steel, the does not follow the process of transformation into a structure of hardship.

Sowohl eine vernickelte als auch verkupferte Oberfläche der Dornfixtur als auch eine Dornfixtur aus einem hochlegierten Stahl haben bei praktischen Einsätzen eine hervorragende Alterungsbeständigkeit gezeigt. Both a nickel-plated and a copper-plated surface the mandrel fixture as well as a mandrel fixture made of a high alloy Steel has an excellent practical application Resistance to aging shown.

Die Vorteile des erfindungsgemäßen Verfahrens bestehen zusammenfassend darin, daß die Härteergebnisse sehr gut reproduzierbar sind. Die aufwendige Handhabung der Werkstücke im Ofen, wie sie teilweise bei den bekannten Verfahren anfällt, entfällt. Es können einfachere und damit preiswertere Öfen verwendet werden. Ferner kann das Beschicken der Öfen mit einfachen Mitteln automatisiert werden. Es ist eine chaotische Fertigung unterschiedlicher Teile in einer Ofencharge möglich. Darüber hinaus zeichnet sich das Verfahren durch ein hohes Einsparungspotential aus.The advantages of the method according to the invention exist in summary that the hardness results very well are reproducible. The complex handling of the workpieces in the oven, as is sometimes the case with the known processes occurs, does not apply. It can be simpler and therefore cheaper stoves can be used. The loading can also the furnaces can be automated with simple means. It's a messy fabrication of different Parts possible in one oven batch. It also draws the process has a high potential for savings out.

Claims (3)

  1. Process for influencing changes in size and shape when hardening workpieces which shrink in a quenching medium onto mechanical accessories in the form of a mandrel fixture, with a predetermined diameter, while undergoing plastic and elastic deformation, characterised by the process steps: stacking the workpieces on the mandrel fixture, carburising and quenching the workpieces disposed on the mandrel fixture and removing the workpieces from the mandrel fixture.
  2. Process according to claim 1, characterised in that the workpieces are fixed on the mandrel fixture following stacking.
  3. Process according to claim 2, characterised in that the workpieces are weighted.
EP95912245A 1994-03-16 1995-03-11 Process for influencing the changes in size and shape of workpieces during hardening Expired - Lifetime EP0750683B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4408924A DE4408924A1 (en) 1994-03-16 1994-03-16 Method and device for influencing dimensional and shape changes when hardening workpieces
DE4408924 1994-03-16
PCT/EP1995/000913 WO1995025182A1 (en) 1994-03-16 1995-03-11 Process and device for influencing the changes in size and shape of workpieces during hardening

Publications (2)

Publication Number Publication Date
EP0750683A1 EP0750683A1 (en) 1997-01-02
EP0750683B1 true EP0750683B1 (en) 1998-11-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP95912245A Expired - Lifetime EP0750683B1 (en) 1994-03-16 1995-03-11 Process for influencing the changes in size and shape of workpieces during hardening

Country Status (8)

Country Link
EP (1) EP0750683B1 (en)
JP (1) JPH09510261A (en)
KR (1) KR970701794A (en)
AT (1) ATE173300T1 (en)
BR (1) BR9507081A (en)
DE (2) DE4408924A1 (en)
ES (1) ES2124537T3 (en)
WO (1) WO1995025182A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103032069A (en) * 2012-10-22 2013-04-10 安徽省皖江机电设备制造有限公司 Production method of cutting picks of coal mining machine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103447758A (en) * 2013-07-18 2013-12-18 陕西奥邦锻造有限公司 Integrated technique of hard alloy brazing and heat treatment for cutting pick
CN112522499B (en) * 2020-11-11 2022-08-02 中国航发中传机械有限公司 Heat treatment method of oblique-amplitude plate cylindrical gear for aviation

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3177563A (en) * 1960-06-28 1965-04-13 Laval Turbine Method of treating gears and the like
US4212690A (en) * 1979-03-23 1980-07-15 Nasa Heat treat fixture and method of heat treating
CH647811A5 (en) * 1981-06-19 1985-02-15 Maag Zahnraeder & Maschinen Ag METHOD FOR REDUCING THE DISTANCE OF HARDNESS IN THE USE OF LARGE STEEL SPROCKETS AND SUITABLE SUPPORT BODIES THEREFOR.
FR2593192B1 (en) * 1986-01-20 1992-01-24 Stein Heurtey HEATING AND TEMPERING UNDER PRESS OF METAL PARTS
DE3906217C1 (en) * 1989-02-28 1989-11-23 Daimler-Benz Aktiengesellschaft, 7000 Stuttgart, De Rod- or ring-shaped workpiece-adapted receiving device for rotationally symmetrical workpieces
DE59102384D1 (en) * 1990-10-15 1994-09-01 Zahnradfabrik Friedrichshafen METHOD AND DEVICE FOR INFLUENCING DIMENSIONS AND DIMENSIONS IN HARDENING WORKPIECES.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103032069A (en) * 2012-10-22 2013-04-10 安徽省皖江机电设备制造有限公司 Production method of cutting picks of coal mining machine
CN103032069B (en) * 2012-10-22 2015-01-14 安徽省皖江机电设备制造有限公司 Production method of cutting picks of coal mining machine

Also Published As

Publication number Publication date
DE4408924A1 (en) 1995-09-21
JPH09510261A (en) 1997-10-14
BR9507081A (en) 1997-09-16
EP0750683A1 (en) 1997-01-02
KR970701794A (en) 1997-04-12
WO1995025182A1 (en) 1995-09-21
DE59504224D1 (en) 1998-12-17
ATE173300T1 (en) 1998-11-15
ES2124537T3 (en) 1999-02-01

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