EP0034761A2 - Method for the surface improvement of machine parts and cutting tools of ferrous alloys - Google Patents
Method for the surface improvement of machine parts and cutting tools of ferrous alloys Download PDFInfo
- Publication number
- EP0034761A2 EP0034761A2 EP81100963A EP81100963A EP0034761A2 EP 0034761 A2 EP0034761 A2 EP 0034761A2 EP 81100963 A EP81100963 A EP 81100963A EP 81100963 A EP81100963 A EP 81100963A EP 0034761 A2 EP0034761 A2 EP 0034761A2
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- EP
- European Patent Office
- Prior art keywords
- vessel
- pressure
- phase
- parts
- atmosphere
- 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.)
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Classifications
-
- 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
- C23C8/06—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 gases
- C23C8/08—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 gases only one element being applied
- C23C8/24—Nitriding
- C23C8/26—Nitriding of ferrous surfaces
-
- 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
- C23C8/06—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 gases
- C23C8/34—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 gases more than one element being applied in more than one step
Definitions
- the invention relates to the surface coating of machine parts and cutting tools made from iron alloys.
- polish Patent No. 72531 a chemical-thermal processing method of machine parts is known, in which the parts to be processed are placed in a closed vessel in which there is an atmosphere of partially decomposed ammonia and sulfur vapors.
- the parts to be treated remain in this atmosphere until a wear-resistant and abrasion-resistant layer has formed on the surface.
- ammonia or ammonia is used with the gas additives to be used in the nitriding process in a temperature range from 420 to 700 ° C. and at a pressure from 10 to 1000 MPa.
- Parts machined in this way have a non-fragile surface layer of high hardness.
- the process according to the invention is characterized in that after introducing the parts to be processed into a closed vessel and after heating the parts and, if appropriate, after reducing the pressure prevailing in the vessel, sulfur vapors are introduced over a period of 5 seconds to 6 minutes.
- the parts to be treated are then subjected to a two-phase nitriding process in the ammonia atmosphere or in the atmosphere containing ammonia and the known gas additives, the pressure being at least ten times lower in the first phase and at least five times longer than in the second nitriding hardening phase, in which the pressure the treatment atmosphere is less than 1070 MPa.
- the sulfur introduced into the vessel forms a thin iron (3) sulfide layer on the surface of the machine parts, which accelerates the nitriding process of the parts.
- a thick layer of high hardness is to be produced, while in the second nitriding phase a thin layer of the - or ⁇ phases with iron (3) sulfide is formed.
- This thin layer counteracts seizure of machine elements when the machine starts up.
- a cam made of tool steel is placed in a vessel and heated to 200 ° C in an ammonia atmosphere and at a pressure of 870 MPa. After the temperature of 200 ° C has been reached, sulfur vapors are introduced into the vessel using a special attachment and the temperature inside the vessel is increased to 570 ° C.
- the temperature of 570 ° C and a pressure of 60 MPa in the ammonia atmosphere is maintained for three hours.
- the pressure of the ammonia atmosphere is then increased to 650 MPa and then sulfur vapors are introduced into the vessel over the course of 15 minutes. Then the supply of sulfur vapors was stopped and the vessel was taken out of the furnace room and placed in a cooling room.
- the cam had a 75 mm thick layer with a hardness of approximately 1100 HV05. This layer is capable of transferring high surface pressures.
- the cam treated in this way also had a layer of phase f with iron (3) sulfides in a thickness of 3 ⁇ m, which protects the surface layers of the cam against seizing, in particular during the running-in period.
- Gears made of chrome-molybdenum aluminum steel used for the transmission of high moments were placed in a vessel in an ammonia atmosphere and heated to 200 ° C at a pressure of 850 MPa.
- the pressure in the vessel was raised to 1023 MPa and then the vessel was removed from the furnace chamber.
- the gearwheels treated thermally and chemically had a 400 ⁇ m thick layer with a hardness of 1050 HV05 and a layer of the ⁇ phase with a thickness of 5 ⁇ m.
- Milling cutters made from tool steel were placed in a vessel in an ammonia atmosphere and heated there to a temperature of 150 ° C. at a pressure of 850 MPa. After reaching a temperature of 150 ° C, sulfur vapors were introduced into the vessel using a special attachment until the temperature was 560 ° C inside the vessel. The sulfur feed was then stopped and the ammonia pressure in the vessel was reduced to 25 MPa. Under these conditions, the nitriding process was carried out for 30 hours.
- the vessel was removed from the oven and placed in a cooling room.
- the milling cutters had a surface layer of 100 ⁇ m with a hardness of 1150 HV05 and an ⁇ phase with a thickness of 3 ⁇ m.
Landscapes
- 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)
- Heat Treatment Of Articles (AREA)
- Turning (AREA)
- Electric Cable Installation (AREA)
- Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
Abstract
Description
Die Erfindung betrifft die Oberflächenvergütung von aus Eisenlegierungen hergestellten Maschinenteilen und Schneidwerkzeugen.The invention relates to the surface coating of machine parts and cutting tools made from iron alloys.
Aus der polnischen Patentschrift Nr. 72531 ist eine chemisch-thermische Bearbeitungsmethode von Maschinenteilen bekannt, bei welcher man die zu bearbeitenden Teile in ein abgeschlossenes Gefäß einbringt, in welchem eine Atmophäre aus partiell zerlegtem Ammoniak und Schwefeldämpfen vorliegt.From Polish Patent No. 72531 a chemical-thermal processing method of machine parts is known, in which the parts to be processed are placed in a closed vessel in which there is an atmosphere of partially decomposed ammonia and sulfur vapors.
In dieser Atmosphäre bleiben die zu behandelnden Teile so lange, bis sich auf der Oberfläche eine verschleiß-und abriebfeste Schicht gebildet hat.The parts to be treated remain in this atmosphere until a wear-resistant and abrasion-resistant layer has formed on the surface.
Bei dem in der polnischen Patentschrift Nr. 100 621 beschriebenen Verfahren wendet man Ammoniak oder Ammoniak mit den im Nitrierhärtungsverfahren anzuwendenden Gaszusätzen in einem Temperaturbereich von 420 bis 700°C und bei einem Druck von 10 bis 1000 MPa an.In the process described in Polish Patent No. 100 621, ammonia or ammonia is used with the gas additives to be used in the nitriding process in a temperature range from 420 to 700 ° C. and at a pressure from 10 to 1000 MPa.
Auf diese Weise bearbeitete Teile haben eine nichtbrüchige Oberflächenschicht hoher Härte.Parts machined in this way have a non-fragile surface layer of high hardness.
Das erfindungsgemäße Verfahren ist dadurch gekennzeichnet, daß nach dem Einbringen der zu bearbeitenden Tcile in ein abgeschlossenes Gefäß und nach Erwärmung der Teile und gegebenenfalls nach Verminderung des in dem Gefäß herrschenden Druckes Schwefeldämpfe während einer Zeitdauer von 5 Sekunden bis 6 Minuten eingebracht werden.The process according to the invention is characterized in that after introducing the parts to be processed into a closed vessel and after heating the parts and, if appropriate, after reducing the pressure prevailing in the vessel, sulfur vapors are introduced over a period of 5 seconds to 6 minutes.
Anschließend werden die zu behandelnden Teile einem zweiphasigen Nitrierhärtungsverfahren in der Ammoniakatmosphäre oder in der Ammoniak und die bekannten Gaszusätze enthaltenden Atmosphäre unterworfen, wobei in der ersten Phase ein mindestens zehnmal niedrigerer Druck und eine mindestens fünfmal längere Zeit als in der zweiten Nitrierhärtungsphase, in welcher der Druck der Behandlungsatmosphäre niedriger als 1070 MPa beträgt,angewendet wird.The parts to be treated are then subjected to a two-phase nitriding process in the ammonia atmosphere or in the atmosphere containing ammonia and the known gas additives, the pressure being at least ten times lower in the first phase and at least five times longer than in the second nitriding hardening phase, in which the pressure the treatment atmosphere is less than 1070 MPa.
Der in das Gefäß eingeführte Schwefel bildet auf der Oberfläche der Maschinenteile eine dünne Eisen(3)sulfidschicht, durch welche der Nitrierhärtungsprozeß der Teile beschleunigt wird.The sulfur introduced into the vessel forms a thin iron (3) sulfide layer on the surface of the machine parts, which accelerates the nitriding process of the parts.
In der ersten Nitrierhärtungsphase soll eine dicke Schicht von hoher Härte erzeugt werden, während in der zweiten Nitrierhärtungsphase eine dünne Schicht der 
Diese dünne Schicht wirkt einem Festfressen von Maschinenelementen beim Anfahren der Maschine entgegen.This thin layer counteracts seizure of machine elements when the machine starts up.
Die Erfindung wird in den nachfolgenden Beispielen näher erläutert:The invention is explained in more detail in the following examples:
Ein aus Werkzeugstahl hergestellter Nocken wird in ein Gefäß eingcbracht und dort in einer Ammoniakatmosphäre und bei einem Druck von 870 MPa auf 200°C erwärmt. Nach Erreichen der Temperatur von 200°C werden in das Gefäß mittels eines Spezialaufsatzes Schwefeldämpfe eingeleitet und die Temperatur im Inneren des Gefäßes auf 570°C erhöht.A cam made of tool steel is placed in a vessel and heated to 200 ° C in an ammonia atmosphere and at a pressure of 870 MPa. After the temperature of 200 ° C has been reached, sulfur vapors are introduced into the vessel using a special attachment and the temperature inside the vessel is increased to 570 ° C.
Die Temperatur von 570°C und ein Druck von 60 MPa in der Ammoniakatmosphäre wird drei Stunden aufrechterhalten. Dann wird der Druck der Ammoniakatmosphäre bis auf 650 MPa erhöht und dann im Laufe von 15 Minuten Schwefeldämpfe in das Gefäß eingeführt. Dann wurde die Zufuhr von-Schwefeldämpfen gestoppt und das Gefäß wurde aus dem Ofenraum entnommen und in einen Abkühlraum gestellt.The temperature of 570 ° C and a pressure of 60 MPa in the ammonia atmosphere is maintained for three hours. The pressure of the ammonia atmosphere is then increased to 650 MPa and then sulfur vapors are introduced into the vessel over the course of 15 minutes. Then the supply of sulfur vapors was stopped and the vessel was taken out of the furnace room and placed in a cooling room.
Nach dieser thermisch-chemischen Behandlung hatte der Nocken eine 75 mm dicke Schicht mit einer Härte von etwa 1100 HV05. Diese Schicht ist zur Übertragung von hohen Oberflächendrücken fähig.After this thermal-chemical treatment, the cam had a 75 mm thick layer with a hardness of approximately 1100 HV05. This layer is capable of transferring high surface pressures.
Der so behandelte Nocken hatte auch eine Schicht der Phase f mit Eisen(3)sulfiden in einer Dicke von 3 µm, wodurch die Oberflächenschichten des Nockens gegen ein Festfressen, insbesondere während der Einlaufperiode geschützt wird.The cam treated in this way also had a layer of phase f with iron (3) sulfides in a thickness of 3 μm, which protects the surface layers of the cam against seizing, in particular during the running-in period.
Für die Übertragung großer Momente verwendete Zahnräder aus einem Chrom-Molybdän-Aluminiumstahl wurden in ein Gefäß in eine Ammoniakatmosphäre eingebracht und dort bei einem Druck von 850 MPa auf 200°C erwärmt.Gears made of chrome-molybdenum aluminum steel used for the transmission of high moments were placed in a vessel in an ammonia atmosphere and heated to 200 ° C at a pressure of 850 MPa.
Nach Erreichen der Temperatur in dem Gefäß von 200°C wurde mittels eines speziellen Aufsatzes auf das Gefäß Schwefeldämpfe eingeleitet, bis die Temperatur im Inneren des Gefäßes 540°C betrug. Bei dieser Temperatur wurde die Schwefelzufuhr abgestoppt und der Ammoniakdruck im Gefäß auf 40 MPa erniedrigt. Unter diesen Bedingungen wurde das Filtrierhärtungsverfahren 30 Stunden betrieben.After the temperature in the vessel reached 200 ° C., sulfur vapors were introduced into the vessel by means of a special attachment until the temperature inside the vessel was 540 ° C. At this temperature the sulfur supply was stopped and the ammonia pressure in the vessel was reduced to 40 MPa. Under these conditions, the filter curing process was operated for 30 hours.
Nach Beendigung des Nitrierhärtungsverfahrens wurde der Druck in dem Gefäß auf 1023 MPa erhöht und dann wurde das Gefäß aus dem Ofenraum herausgenommen.After the nitriding process was completed, the pressure in the vessel was raised to 1023 MPa and then the vessel was removed from the furnace chamber.
Die so thermisch-chemisch behandelten Zahnräder hatten eine 400 µm dicke Schicht einer Härte von 1050 HV05 sowie eine Schicht der ε-Phase mit einer Dicke von 5 µm.The gearwheels treated thermally and chemically had a 400 µm thick layer with a hardness of 1050 HV05 and a layer of the ε phase with a thickness of 5 µm.
Aus Werkzeugstahl hergestellte Fräser wurden in eine Gefäß in einer Ammoniakatmosphäre eingebracht und dort bei einem Druck von 850 MPa auf eine Temperatur von 150°C erwärmt. Nach Erreichen einer Temperatur von 150°C wurde mittels eines speziellen Aufsatzes Schwefeldämpfe in das Gefäß eingeleitet, bis die Temperatur 560°C im Inneren des Gefäßes betrug. Dann wurde die Schwefelzufuhr abgestoppt und der Ammoniakdruck in dem Gefäß auf 25 MPa erniedrigt. Unter diesen Bedingungen wurde das Nitrierhärtungsverfahren 30 Stunden durchgeführt.Milling cutters made from tool steel were placed in a vessel in an ammonia atmosphere and heated there to a temperature of 150 ° C. at a pressure of 850 MPa. After reaching a temperature of 150 ° C, sulfur vapors were introduced into the vessel using a special attachment until the temperature was 560 ° C inside the vessel. The sulfur feed was then stopped and the ammonia pressure in the vessel was reduced to 25 MPa. Under these conditions, the nitriding process was carried out for 30 hours.
Nach Beendigung des Nitrierhärtungsverfahrens wurde das Gefäß aus dem Ofen entnommen und in einen Abkühlraum gebracht.After the nitriding process was completed, the vessel was removed from the oven and placed in a cooling room.
Die Fräser hatten nach dieser thermisch-chemischen Behandlung eine Oberflächenschicht von 100 µm mit einer Härte von 1150 HV05 sowie eine ε-Phase mit einer Dicke von 3 µm.After this thermal-chemical treatment, the milling cutters had a surface layer of 100 µm with a hardness of 1150 HV05 and an ε phase with a thickness of 3 µm.
Claims (1)
daß man die zu behandelnden Teile dann einem zweiphasigen Nitrierhärtungsverfahren in einer Ammoniakatmosphäre oder in einer Ammoniak und bekannte Gaszusätze enthaltenden Atmosphäre unterwirft,
wobei das Nitrierhärtungsverfahren in der ersten Phase bei einem mindestens zehnmal niedrigeren Druck und einer fünfmal längeren Zeit als in der zweiten Phase des Nitrierhärtungsverfahrens vorgenommen wird, in welcher der Druck der Behandlungsatmosphäre niedriger als 1070 MPa ist.Process for the surface treatment of machine parts and cutting tools made of iron alloys, in which the machine parts and cutting tools to be treated are placed in a vessel, characterized in that the parts to be treated are heated and the pressure in the vessel is reduced, if necessary, and then for 5 seconds to Introduces sulfur vapors into the vessel for 60 minutes,
that the parts to be treated are then subjected to a two-phase nitriding process in an ammonia atmosphere or in an atmosphere containing ammonia and known gas additives,
wherein the nitriding process is carried out in the first phase at a pressure at least ten times lower and five times longer than in the second phase of the nitriding process, in which the pressure of the treatment atmosphere is lower than 1070 MPa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT81100963T ATE13696T1 (en) | 1980-02-11 | 1981-02-11 | PROCESS FOR FINISHING THE SURFACE OF MACHINE PARTS AND CUTTING TOOLS MADE OF FERROUS ALLOYS. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PL221929 | 1980-02-11 | ||
| PL1980221929A PL126128B1 (en) | 1980-02-11 | 1980-02-11 | Method of cementation of machine elements and cutting tools |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0034761A2 true EP0034761A2 (en) | 1981-09-02 |
| EP0034761A3 EP0034761A3 (en) | 1981-09-09 |
| EP0034761B1 EP0034761B1 (en) | 1985-06-05 |
Family
ID=20001275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP81100963A Expired EP0034761B1 (en) | 1980-02-11 | 1981-02-11 | Method for the surface improvement of machine parts and cutting tools of ferrous alloys |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0034761B1 (en) |
| JP (1) | JPS56127769A (en) |
| AT (1) | ATE13696T1 (en) |
| AU (1) | AU2516788A (en) |
| DE (1) | DE3170794D1 (en) |
| PL (1) | PL126128B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0464799A1 (en) * | 1990-07-05 | 1992-01-08 | Hitachi Construction Machinery Co., Ltd. | Sliding member and method for producing the same by gas sulphonitriding |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS602233U (en) * | 1983-06-16 | 1985-01-09 | 三洋電機株式会社 | Air conditioner remote controller |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1057237A (en) * | 1952-05-19 | 1954-03-05 | Partiot Cementation Atel | Surface heat treatment process for ferrous metals |
| FR1104196A (en) * | 1954-05-04 | 1955-11-17 | Process for obtaining sulfo-cementation of ferrous alloys, with a view to improving the wear resistance and the coefficient of friction of hardened and hardened steel parts | |
| DE2336680A1 (en) * | 1973-07-19 | 1975-01-30 | Degussa | Nitriding steel in a low pressure gas atmosphere - by heating the workpiece to the nitriding temp. in a mixt. of ammonia and a carbon gas carrier |
-
1980
- 1980-02-11 PL PL1980221929A patent/PL126128B1/en unknown
-
1981
- 1981-02-10 JP JP1886281A patent/JPS56127769A/en active Granted
- 1981-02-11 DE DE8181100963T patent/DE3170794D1/en not_active Expired
- 1981-02-11 EP EP81100963A patent/EP0034761B1/en not_active Expired
- 1981-02-11 AT AT81100963T patent/ATE13696T1/en not_active IP Right Cessation
-
1988
- 1988-11-16 AU AU25167/88A patent/AU2516788A/en not_active Abandoned
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1057237A (en) * | 1952-05-19 | 1954-03-05 | Partiot Cementation Atel | Surface heat treatment process for ferrous metals |
| FR1104196A (en) * | 1954-05-04 | 1955-11-17 | Process for obtaining sulfo-cementation of ferrous alloys, with a view to improving the wear resistance and the coefficient of friction of hardened and hardened steel parts | |
| DE2336680A1 (en) * | 1973-07-19 | 1975-01-30 | Degussa | Nitriding steel in a low pressure gas atmosphere - by heating the workpiece to the nitriding temp. in a mixt. of ammonia and a carbon gas carrier |
Non-Patent Citations (2)
| Title |
|---|
| CHEMICAL ABSTRACTS, Band 64, 1966, Spalte 3120b Columbus, Ohio, USA HAS "Sulfatizing and nitriding of high-speed steels in H2S and NH2 gases" & ZESZYTY NAUK POLITCH.LODZ.MECH No. 12, 89-107 (1965) * |
| CHEMICAL ABSTRACTS, Band 87, 1977 Seite 420, Zusammenfassung 91160n Columbus. Ohio. USA GRABKE et al. "Chemisorption of sulfur on iron and its influence on iron-gas reactions, surface self diffusion and sintering of iron" & React. solids, (Proc. Int. Symp.) 8th, 1976 (Pub. 1977) 55-61. * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0464799A1 (en) * | 1990-07-05 | 1992-01-08 | Hitachi Construction Machinery Co., Ltd. | Sliding member and method for producing the same by gas sulphonitriding |
| US5187017A (en) * | 1990-07-05 | 1993-02-16 | Hitachi Construction Machinery Co., Ltd. | Sliding member, and method and apparatus for producing the same by gas sulphonitriding |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0034761A3 (en) | 1981-09-09 |
| JPS56127769A (en) | 1981-10-06 |
| ATE13696T1 (en) | 1985-06-15 |
| AU2516788A (en) | 1989-03-16 |
| DE3170794D1 (en) | 1985-07-11 |
| PL221929A1 (en) | 1981-08-21 |
| EP0034761B1 (en) | 1985-06-05 |
| PL126128B1 (en) | 1983-07-30 |
| JPS5749628B2 (en) | 1982-10-22 |
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