EP0387536A1 - Method for the boration of iron articles - Google Patents

Method for the boration of iron articles Download PDF

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Publication number
EP0387536A1
EP0387536A1 EP90102922A EP90102922A EP0387536A1 EP 0387536 A1 EP0387536 A1 EP 0387536A1 EP 90102922 A EP90102922 A EP 90102922A EP 90102922 A EP90102922 A EP 90102922A EP 0387536 A1 EP0387536 A1 EP 0387536A1
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Prior art keywords
temperature
batch
minutes
heated
parts
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EP90102922A
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German (de)
French (fr)
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EP0387536B1 (en
Inventor
Peter Dipl.-Ing. Karojet
Helmut Dr. Chem. Kunst
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Durferrit GmbH Thermotechnik
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Degussa GmbH
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
    • C23C8/68—Boronising
    • C23C8/70—Boronising of ferrous surfaces

Definitions

  • the invention relates to a method for boriding of parts made of ferrous materials by covering the to boronized surfaces with a powder, a granulate or a paste of a borating agent and heating the batch under protective gas to temperatures of 850 o C or higher in a continuous furnace.
  • Boronizing for wear protection of parts made of iron and steel has been a well-known process.
  • dense, uniform layers of the respective boride are formed, on iron e.g. the borides FeB and Fe2B.
  • the borides have significantly changed properties; in particular, most borides are very hard, corrosion-resistant and therefore extremely wear-resistant.
  • the boride layers are firmly connected to the base material by diffusion.
  • the boronization temperatures for iron materials are normally between 850 and 950 o C, the usual layer thicknesses between 30 and 150 ⁇ m. Since the two borides Fe2B and FeB have different properties and multiphase layers usually have worse properties than monophase, efforts are made to produce monophase layers during boronizing.
  • boriding in solid boriding agents is used almost exclusively.
  • the parts to be treated are packed in iron boxes in a boron-releasing powder, usually mixtures of boron carbide, aluminum oxide, silicon oxide and the like, with activating additives such as ammonium fluoride or potassium borofluoride (e.g. DE-PS 1,796,216).
  • activating additives such as ammonium fluoride or potassium borofluoride (e.g. DE-PS 1,796,216).
  • the boxes are tightly sealed and annealed for a while, the desired boride layers being formed in direct solid-to-solid reactions or by transporting the boron over the gas phase.
  • Boring with a paste is also known, the borating agent being applied to the parts in paste form.
  • Paste boriding is carried out under protective gas, preferably in a continuous furnace, the parts being exposed to temperatures of up to 900 ° C.
  • This object is achieved in that the parts are first only heated to a temperature of 550 to 600 o C, then wait for a temperature equalization within the batch without further temperature increase and then heated as quickly as possible to the boronizing temperature of 850 o C and higher .
  • the batch is kept 8 to 20 minutes at a temperature of 550 to 600 ° C and subsequently heating the batch to the Boriertemperatur of 850 o C and higher is carried out advantageously in a period not exceeding 15 minutes.
  • a Fe2B layer with only very small additions of FeB can be achieved if the temperature range between 600 and 850 o C is passed as quickly as possible. But you have to make sure that the temperature differences within the batch are as small as possible. It is therefore important to heat the batches evenly from all sides and to allow temperature compensation within the batch before a temperature of 600 o C is exceeded. This temperature compensation can be checked, for example, by means of a temperature measuring device within the batch. The subsequent heating rate depends on the oven available, but should be as large as possible.
  • Sheet metal parts made of C 45 steel were packed in boxes made of heat-resistant material in a borating agent consisting of boron carbide, silicon carbide and potassium borofluoride.
  • the boxes filled with the borating agent and the parts inside and closed with a lid were placed on the conveyor belt of a continuous furnace and heated as follows: from room temperature to 580 ° C. within 30 minutes. Hold at this temperature until the temperature inside the box is equalized (9 minutes), warm to 880 o C within 8 minutes, hold above this temperature for 32 minutes, then cool to room temperature within 68 minutes.
  • a mixture of nitrogen and hydrogen was used as a protective gas in the continuous furnace.
  • the layer obtained in the manner described had an average thickness of 33 ⁇ m with scatterings of ⁇ 3 ⁇ m. The layer only had individual FeB teeth on the edges and was otherwise FeB-free.
  • Layer composition FeB and Fe2B approx. 50:50 (due to the steel composition), only weakly interlocked with the base material. This result corresponds to the expectations regarding the layer composition, the uniformity cannot be achieved with the previously known methods.
  • Screw wheels made of 42 CrMo4 steel were packed in a box in the boron material as in Example 1 and the boxes placed on the conveyor belt of the continuous furnace. Treatment conditions: Warming room temperature to 580 o C: 43 minutes Hold at this temperature: 12 minutes Heating from 580 to 900 o C: 14 minutes Hold at this temperature: 38 minutes Cooling down to room temperature: 85 minutes Shielding gas. Nitrogen + hydrogen

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Chemical Vapour Deposition (AREA)
  • Drilling Tools (AREA)
  • Catalysts (AREA)
  • Drilling And Boring (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)

Abstract

In order to obtain uniform and standard layers of Fe2B on parts made of iron materials, the parts are heated with the boriding agent, initially only to 550 - 600 DEG C, after which a period is allowed until temperature equilibration takes place within the batch, and finally the batch is heated as rapidly as possible to the boriding temperatures of 850 DEG C or higher.

Description

Die Erfindung betrifft ein Verfahren zum Borieren von Teilen aus Eisenwerkstoffen durch Bedecken der zu borierenden Oberflächen mit einem Pulver, einem Granulat oder einer Paste eines Borierungsmittels und Erhitzen der Charge unter Schutzgas auf Temperaturen von 850o C und höher in einem Durchlaufofen.The invention relates to a method for boriding of parts made of ferrous materials by covering the to boronized surfaces with a powder, a granulate or a paste of a borating agent and heating the batch under protective gas to temperatures of 850 o C or higher in a continuous furnace.

Das Borieren zum Verschleißschutz von Teilen aus Eisen und Stahl ist ein schon lange bekanntes Verfahren. Durch Eindiffusion des Elementes Bor in die Oberfläche des behandelten Werkstückes und Reaktion mit dem Grundwerkstoff entstehen dichte, gleichmäßige Schichten des jeweiligen Borides, auf Eisen z.B. die Boride FeB und Fe₂B. Die Boride besitzen gegenüber den reinen Metallen erheblich veränderte Eigenschaften, insbesondere sind die meisten Boride sehr hart, korrosionsbeständig und damit überaus verschleißfest. Durch Diffusion sind die Boridschichten mit dem Grundwerkstoff fest verbunden.Boronizing for wear protection of parts made of iron and steel has been a well-known process. By diffusing the element boron into the surface of the treated workpiece and reacting with the base material, dense, uniform layers of the respective boride are formed, on iron e.g. the borides FeB and Fe₂B. Compared to pure metals, the borides have significantly changed properties; in particular, most borides are very hard, corrosion-resistant and therefore extremely wear-resistant. The boride layers are firmly connected to the base material by diffusion.

Die Borierungstemperaturen liegen bei Eisenwerkstoffen normalerweise zwischen 850 und 950o C, die üblichen Schichtdicken bei 30 bis 150 µm. Da die beiden Boride Fe₂B und FeB unterschiedliche Eigenschaften besitzen und mehrphasige Schichten meist schlechtere Eigenschaften aufweisen als monophasige, ist man bemüht, beim Borieren monophasige Schichten zu erzeugen.The boronization temperatures for iron materials are normally between 850 and 950 o C, the usual layer thicknesses between 30 and 150 µm. Since the two borides Fe₂B and FeB have different properties and multiphase layers usually have worse properties than monophase, efforts are made to produce monophase layers during boronizing.

In der Praxis wird fast ausschließlich das Borieren in festen Boriermitteln angewendet. Dabei werden die zu behandelnden Teile in eiserne Kästen in ein borabgebendes Pulver, meist Mischungen aus Borcarbid, Aluminiumoxid, Siliziumoxid und dgl. , mit aktivierenden Zusätzen, wie Ammoniumfluorid oder Kaliumborfluorid, eingepackt (z. B. DE-PS 1 .796.216). Die Kästen werden dicht verschlossen und eine zeitlang geglüht, wobei in direkten Festkörper-Feststoff-­Reaktionen oder durch Transport des Bors über die Gasphase die erwünschten Boridschichten gebildet werden.In practice, boriding in solid boriding agents is used almost exclusively. The parts to be treated are packed in iron boxes in a boron-releasing powder, usually mixtures of boron carbide, aluminum oxide, silicon oxide and the like, with activating additives such as ammonium fluoride or potassium borofluoride (e.g. DE-PS 1,796,216). The boxes are tightly sealed and annealed for a while, the desired boride layers being formed in direct solid-to-solid reactions or by transporting the boron over the gas phase.

Bekannt ist auch das Borieren mit einer Paste, wobei das Boriermittel in Pastenform auf die Teile aufgebracht wird. Ein solches Verfahren ist beispielsweise in der DE-PS 26 33 137 beschrieben. Das Pastenborieren erfolgt unter Schutzgas vorzugsweise in einem Durchlaufofen, wobei die Teile Temperaturen bis 900o C ausgesetzt werden.Boring with a paste is also known, the borating agent being applied to the parts in paste form. Such a method is described for example in DE-PS 26 33 137. Paste boriding is carried out under protective gas, preferably in a continuous furnace, the parts being exposed to temperatures of up to 900 ° C.

Die bekannten Borierverfahren haben den Nachteil, daß es verfahrenstechnisch sehr schwierig ist, mit ihnen monophasige Eisenboridschichten zu erhalten.The known boriding processes have the disadvantage that it is technically very difficult to obtain monophase iron boride layers with them.

Es war daher Aufgabe der vorliegenden Erfindung, ein Verfahren zum Borieren von Teilen aus Eisenwerkstoffen zu entwickeln, durch Bedecken der zu borierenden Oberflächen mit einem Pulver, einem Granulat oder einer Paste eines Borierungsmittels und Erhitzen der Charge unter Schutzgas auf Temperaturen von 850o C und höher in einem Durchlaufofen, bei dem die Teile mit einer gleichmäßig dicken monophasigen Schicht aus Eisenborid (Fe₂B) bedeckt werden.It was to develop the object of the present invention, a method for boriding of parts made of ferrous materials, by covering the to boronized surfaces with a powder, a granulate or a paste of a borating agent and heating the batch under protective gas to temperatures of 850 o C or higher in a continuous furnace in which the parts are covered with a uniformly thick monophase layer of iron boride (Fe₂B).

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Teile zuerst nur auf eine Temperatur von 550 bis 600o C aufgeheizt werden, dann ohne weitere Temperaturerhöhung ein Temperaturausgleich innerhalb der Charge abgewartet wird und anschließend möglichst schnell auf die Boriertemperatur von 850o C und höher erhitzt wird.This object is achieved in that the parts are first only heated to a temperature of 550 to 600 o C, then wait for a temperature equalization within the batch without further temperature increase and then heated as quickly as possible to the boronizing temperature of 850 o C and higher .

Vorzugsweise wird die Charge 8 bis 20 Minuten bei einer Temperatur von 550 bis 600o C gehalten und das anschließende Aufheizen der Charge auf die Boriertemperatur von 850o C und höher erfolgt vorteilhafterweise in einem Zeitraum von höchstens 15 Minuten.Preferably, the batch is kept 8 to 20 minutes at a temperature of 550 to 600 ° C and subsequently heating the batch to the Boriertemperatur of 850 o C and higher is carried out advantageously in a period not exceeding 15 minutes.

Eine Fe₂B-Schicht mit nur sehr geringen Beimengungen an FeB kann man erreichen, wenn der Temperaturbereich zwischen 600 und 850o C möglichst rasch durchschritten wird. Dabei muß man aber darauf achten, daß die Temperaturdifferenzen innerhalb der Charge möglichst gering sind. Es ist daher wichtig, die Chargen gleichmäßig von allen Seiten zu beheizen und vor dem Überschreiten einer Temperatur von 600o C einen Temperaturausgleich innerhalb der Charge stattfinden zu lassen. Dieser Temperaturausgleich kann beispielsweise mittels einer Temperaturmeßeinrichtung innerhalb der Charge kontrolliert werden. Die anschließende Aufheizgeschwindigkeit ist von dem zur Verfügung stehenden Ofen abhängig, sollte jedoch möglichst groß sein.A Fe₂B layer with only very small additions of FeB can be achieved if the temperature range between 600 and 850 o C is passed as quickly as possible. But you have to make sure that the temperature differences within the batch are as small as possible. It is therefore important to heat the batches evenly from all sides and to allow temperature compensation within the batch before a temperature of 600 o C is exceeded. This temperature compensation can be checked, for example, by means of a temperature measuring device within the batch. The subsequent heating rate depends on the oven available, but should be as large as possible.

Mit diesem Verfahren erhält man sehr gleichmäßige monophasige Fe₂B-Schichten, die sehr gute Verschleißeigenschaften zeigen . Folgende Beispiele sollen das erfindungsgemäße Verfahren näher erläutern:With this process, very uniform monophase Fe₂B layers are obtained, which show very good wear properties. The following examples are intended to explain the process according to the invention in more detail:

Beispiel 1example 1

Blechteile (Messer für landwirtschaftliche Geräte) aus dem Stahl C 45 wurden in Kästen aus hitzebeständigem Material in ein Boriermittel eingepackt, das aus Borcarbid, Siliciumcarbid und Kaliumborfluorid bestand. Die mit dem Boriermittel und den darin befindlichen Teilen gefüllten und mit einem Deckel verschlossenen Kästen wurden auf das Transportband eines Durchlaufofens gesetzt und folgendermaßen erwärmt: Von Raumtemperatur auf 580o C innerhalb von 30 Minuten. Halten bei dieser Temperatur bis zum Temperaturausgleich im Kasteninneren (9 Minuten) Erwärmen auf 880o C innerhalb von 8 Minuten, Halten oberhalb dieser Temperatur 32 Minuten, dann Abkühlung auf Raumtemperatur innerhalb von 68 Minuten. Im Durchlaufofen wurde als Schutzgas ein Gemisch von Stickstoff und Wasserstoff verwendet. Die auf die beschriebene Weise erzielte Schicht hatte eine Dicke von im Mittel 33 µm mit Streuungen von ±3 µm. Die Schicht wies lediglich an den Kanten einzelne FeB-Zähne auf und war ansonsten FeB-frei.Sheet metal parts (knives for agricultural implements) made of C 45 steel were packed in boxes made of heat-resistant material in a borating agent consisting of boron carbide, silicon carbide and potassium borofluoride. The boxes filled with the borating agent and the parts inside and closed with a lid were placed on the conveyor belt of a continuous furnace and heated as follows: from room temperature to 580 ° C. within 30 minutes. Hold at this temperature until the temperature inside the box is equalized (9 minutes), warm to 880 o C within 8 minutes, hold above this temperature for 32 minutes, then cool to room temperature within 68 minutes. A mixture of nitrogen and hydrogen was used as a protective gas in the continuous furnace. The layer obtained in the manner described had an average thickness of 33 μm with scatterings of ± 3 μm. The layer only had individual FeB teeth on the edges and was otherwise FeB-free.

Beispielexample

Werkzeuge zum Lochen von Stahlblech, gefertigt aus dem Stahl X 21oCrw 12, Länge 220 mm, Durchmesser 16 mm, wurden bis zur Hälfte der Länge mit einer Borierpaste eingestrichen, die aus Borcarbid, Siliciumcarbid, Kaliumborfluorid, hochdisperser Kieselsäure und Wasser bestand. Ohne einen Trocknungsvorgang wurden die eingestrichenen Werkzeuge auf das Transportband eines Durchlaufofens gelegt. Behandlungsbedingungen: Erwärmung Raumtemperatur auf 595o C: 35 Minuten Haltedauer bei dieser Temperatur: 11 Minuten Erwärmen auf 920o C: 6 Minuten Haltedauer bei dieser Temperatur: 40 Minuten Abkühlen auf Raumtemperatur: 76 Minuten Schutzgas: Stickstoff + Wasserstoff Tools for punching sheet steel, made of steel X 21oCrw 12, length 220 mm, diameter 16 mm, were coated up to half the length with a boron paste consisting of boron carbide, silicon carbide, potassium borofluoride, highly disperse silica and water. Without a drying process, the coated tools were placed on the conveyor belt of a continuous furnace. Treatment conditions: Warming room temperature to 595 o C: 35 minutes Holding time at this temperature: 11 minutes Warm up to 920 o C: 6 minutes Holding time at this temperature: 40 minutes Cooling down to room temperature: 76 minutes Shielding gas: nitrogen + hydrogen

Resultat: Schichtdicke 10 µm, Streuung ±1 µmResult: layer thickness 10 µm, scattering ± 1 µm

Schichtzusammensetzung: FeB und Fe₂B
ca. 50:50 (bedingt durch die Stahlzusammensetzung) , nur schwach mit dem Grundmaterial verzahnt. Dieses Resultat entspricht hinsichtlich der Schichtzusammensetzung den Erwartungen, die Gleichmäßigkeit ist mit den bisher bekannten Verfahren nicht zu erreichen.Layer composition: FeB and Fe₂B
approx. 50:50 (due to the steel composition), only weakly interlocked with the base material. This result corresponds to the expectations regarding the layer composition, the uniformity cannot be achieved with the previously known methods.

Beispiel 3Example 3

Schraubenräder aus dem Stahl 42 CrMo4 wurden wie bei Beispiel 1 in einem Kasten in das Boriermaterial eingepackt und die Kästen auf das Transportband des Durchlaufofens gesetzt. Behandlungsbedingungen: Erwärmung Raumtemperatur auf 580o C: 43 Minuten Halten bei dieser Temperatur: 12 Minuten Erwärmung von 580 auf 900o C: 14 Minuten Halten bei dieser Temperatur: 38 Minuten Abkühlen auf Raumtemperatur: 85 Minuten Schutzgas. Stickstoff+Wasserstoff Screw wheels made of 42 CrMo4 steel were packed in a box in the boron material as in Example 1 and the boxes placed on the conveyor belt of the continuous furnace. Treatment conditions: Warming room temperature to 580 o C: 43 minutes Hold at this temperature: 12 minutes Heating from 580 to 900 o C: 14 minutes Hold at this temperature: 38 minutes Cooling down to room temperature: 85 minutes Shielding gas. Nitrogen + hydrogen

Resultate: Schichtdicke an Zahngrund, Zahnflanke und Zahnkopf im Mittel 32 µm, Streuungen ± 2 µm, die Schichten waren völlig frei von FeB.Results: Layer thickness on the tooth base, tooth flank and tooth head on average 32 µm, scattering ± 2 µm, the layers were completely free of FeB.

Claims (3)

1. Verfahren zum Borieren von Teilen aus Eisenwerkstoffen durch Bedecken der zu borierenden Oberflächen mit einem Pulver, einem Granulat oder einer Paste eines Borierungsmittels und Erhitzen der Charge unter Schutzgas auf Temperaturen von 850o C höher in einem Durchlaufofen,
dadurch gekennzeichnet,
daß die Teile zuerst nur auf eine Temperatur von 550 bis 600o C aufgeheizt werden, dann ohne weitere Temperaturerhöhung ein Temperaturausgleich innerhalb der Charge abgewartet wird und anschließend möglichst schnell auf die Boriertemperatur erhitzt wird.1. A method for boriding of parts made of ferrous materials by covering the surfaces to be borided with a powder, a granulate or a paste of a borating agent and heating the batch under protective gas to temperatures of 850 o C higher in a continuous furnace,
characterized,
that the parts are first only heated to a temperature of 550 to 600 o C, then a temperature equalization within the batch is waited for without a further increase in temperature and then is heated to the boronizing temperature as quickly as possible. 2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet,
daß die Charge 8 bis 20 Minuten bei einer Temperatur von 550 bis 600o C gehalten wird.2. The method according to claim 1,
characterized,
that the batch is kept at a temperature of 550 to 600 o C for 8 to 20 minutes. 3. Verfahren nach Anspruch 1 oder 2,
dadurch gekennzeichnet,
daß das Aufheizen der Charge von 600 auf 850o C in einem Zeitraum von höchstens 15 Minuten erfolgt.3. The method according to claim 1 or 2,
characterized,
that the batch is heated from 600 to 850 o C in a maximum of 15 minutes.
EP90102922A 1989-03-14 1990-02-15 Method for the boration of iron articles Expired - Lifetime EP0387536B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3908200A DE3908200C1 (en) 1989-03-14 1989-03-14
DE3908200 1989-03-14

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EP0387536A1 true EP0387536A1 (en) 1990-09-19
EP0387536B1 EP0387536B1 (en) 1993-06-30

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EP (1) EP0387536B1 (en)
JP (1) JPH0310062A (en)
AT (1) ATE91158T1 (en)
DE (2) DE3908200C1 (en)
DK (1) DK0387536T3 (en)
ES (1) ES2044259T3 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013138597A1 (en) * 2012-03-14 2013-09-19 Jennings Drake Carlisle Knife for wood processing and methods for plating and surface treating a knife for wood processing

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JP4588213B2 (en) * 1997-12-15 2010-11-24 フオルクスワーゲン・アクチエンゲゼルシヤフト Plasma boriding treatment

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DE2361017C3 (en) * 1973-12-04 1985-12-05 Vac-Hyd Processing Gmbh, 2358 Kaltenkirchen Method for boronizing the surface of a metallic workpiece
DE2633137C2 (en) * 1976-07-23 1983-12-01 Degussa Ag, 6000 Frankfurt Boronizing agent for boronizing parts by mass of iron and non-ferrous metals

Non-Patent Citations (3)

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Title
CHEMICAL ABSTRACTS, Band 101, Nr. 24, Dezember 1984, Seite 199, Zusammenfassung Nr. 214618k, Columbus, Ohio, US; L.A. SHCHEGLOVITOV et al.: "Boronizing of stamping die inserts", & TEKHNOL. ORGAN. PROIZVOD. 1984, (3), 30-1 *
SOVIET INVENTIONS ILLUSTRATED, Woche 8609, 17. März 1986, Derwent Publications Ltd, London, GB; & SU-A-618 190 (PERM OIL IND. RES. DE) 07-08-1985 *
SOVIET INVENTIONS ILLUSTRATED, Woche K08, 6. April 1983, Derwent Publications Ltd, London, GB; & SU-A-962 487 (ROST AGRIC. ENG. INST.) 16-04-1982 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013138597A1 (en) * 2012-03-14 2013-09-19 Jennings Drake Carlisle Knife for wood processing and methods for plating and surface treating a knife for wood processing
US8894770B2 (en) 2012-03-14 2014-11-25 Andritz Iggesund Tools Inc. Process and apparatus to treat metal surfaces
US9068260B2 (en) 2012-03-14 2015-06-30 Andritz Iggesund Tools Inc. Knife for wood processing and methods for plating and surface treating a knife for wood processing

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EP0387536B1 (en) 1993-06-30
DE3908200C1 (en) 1989-09-07
ATE91158T1 (en) 1993-07-15
DK0387536T3 (en) 1993-08-02
JPH0310062A (en) 1991-01-17
ES2044259T3 (en) 1994-01-01
DE59001874D1 (en) 1993-08-05

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