EP0161408B1 - Process for surface-hardening by remelting cast iron cylinders - Google Patents
Process for surface-hardening by remelting cast iron cylinders Download PDFInfo
- Publication number
- EP0161408B1 EP0161408B1 EP85102673A EP85102673A EP0161408B1 EP 0161408 B1 EP0161408 B1 EP 0161408B1 EP 85102673 A EP85102673 A EP 85102673A EP 85102673 A EP85102673 A EP 85102673A EP 0161408 B1 EP0161408 B1 EP 0161408B1
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- Prior art keywords
- hardening
- process according
- cylinder
- tig
- tig burner
- Prior art date
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- 238000000034 method Methods 0.000 title claims description 13
- 229910001018 Cast iron Inorganic materials 0.000 title claims description 3
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 238000007747 plating Methods 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 238000002485 combustion reaction Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 229910001060 Gray iron Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical group C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Images
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
- C21D5/00—Heat treatments of cast-iron
-
- 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
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/14—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
Definitions
- the invention relates to a method for remelting the surfaces of cylinders made of carbon-containing cast iron, in particular cylinders of a reciprocating piston internal combustion engine, according to the preamble of patent claim 1.
- the object of the invention is to further develop the generic method for remelt hardening in such a way that low-stress hardening free of harmful hardening cracks can be achieved without additional heat supply (for example preheating), which also requires only a slight reworking of the cylinder surfaces.
- the outlay on the device compared to electron or laser beam hardening is initially reduced; it was also recognized that remelting of cylinders, particularly in the case of large-volume production using a TIG torch, is more favorable in terms of accessibility, production control and monitoring.
- the defined pulsing of the energy density of the TIG torch results in a targeted segmentation of the hardening path, which leads to a considerable reduction in the surface tension and to a complete elimination of distortion due to the hardening without adverse consequences in operation.
- the hardening sheet contains approximately 2 to 6 segments each, which are deliberately scaled due to the pulsed remelting. As tests have shown, this segmented hardness track is in no way prone to further cracking or chipping; especially when operating internal combustion engines due to the higher temperature on the cylinder surface relative to the cylinder jacket predominantly compressive stresses anyway.
- the repeated melting of the remelting zones also causes a secondary cementite precipitation in the structure, which allows a hardness of 850 to 950 HV 10 to be achieved without problems.
- the upper value of the current strength ensures a sufficiently deep melting or a sufficient depth of hardness, while at a lower value of the pulsed current the local melt calms down and cools down. It is also important that when changing the current strengths - even at the beginning and at the end of remelt hardening - there is no blowing effect, which would cause fine craters and peaks in the melt.
- the distribution of the segmentation in the hardness track can advantageously also be influenced within the specified pulse frequency of the plasma torch and by the remelting speed.
- the features of claim 6 relate to a particularly cost-effective method for hardening the cylinders of reciprocating piston internal combustion engines, which enables short cycle times in series production.
- the upper reversal point of the upper piston ring, which is closest to the combustion chamber, on the cylinder surface is the most susceptible point to wear, so that it is the case with many internal combustion engines it may be sufficient to secure only this one point using a hardening track.
- the remelting can be followed by electrochemical removal and then mechanical processing.
- this exposes the martensitic / graphitic edge areas of the hardening sheets in an open-pore manner, so that increased oil retention or optimized lubrication of the sliding partner piston: cylinder surface is achieved.
- a cylinder block 2 of a multi-cylinder reciprocating piston internal combustion engine made of lamellar gray cast iron a plurality of cylinders 4 are arranged, which are machined to a finished size in the usual way.
- each cylinder 4 is in the upper reversal point of the upper;
- a ring-shaped hardening track 6 is incorporated in the piston chamber closest to the respective combustion chamber of a piston (not shown) sliding in the cylinder 4.
- the hardening web 6 is produced by locally melting the layer of the cylinder close to the surface and by subsequent rapid re-solidification, a ledeburitic structure forming in the immediate remelting zone 8, while the edge zones 10, which are still influenced by heat, are martensitic structure.
- the remelting zone or hardening web 6 is generated by means of a WIC burner 12 (cf. FIG. 2).
- the corresponding surface of the cylinder 4 is locally melted in an inert atmosphere 18 by means of a tungsten electrode 14 connected to a power source by an arc 16 which jumps over to the cylinder 4.
- Further details of such a TIG torch 12 can be found, for example, in patent application P 33 39 447.4, which goes back to the same applicant.
- the TIG torch 12 is at a feed rate of 1.5 mm / sec. moved forward in the direction of arrow 20 of FIG. 2 at a uniform distance from the cylinder 4 along the hardening path 6 to be generated.
- the current intensity A in amperes over time t which determines the energy density of the arc 16 is shown in the diagram according to FIG. 3.
- the current at point E is switched on at a lower value of the current strength of 15 A, which current is then pulsed at a frequency of 1 Hz between 15 A and 80 A in the manner of a rectangular pattern.
- the TIG torch 14 is switched off again at point A at the lower value of the current strength of 15 A.
- the cylinder 4 is subjected to post-processing by electrochemical honing with subsequent mechanical friction plating. In the process, slight unevenness in the hardness web 6 is eliminated and the martensitic / graphitic structure of the edge regions 10 is exposed. Electrochemical honing and friction plating can optionally be carried out in accordance with German patent application P 31 19 847.3.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
Description
Die Erfindung betrifft ein Verfahren zum Umschmelzhärten der Oberflächen von Zylindern aus kohlenstoffhaltigem Gußeisen, insbesondere von Zylindern einer Hubkolben-Brennkraftmaschine, gemäß dem Oberbegriff des Patentanspruches 1.The invention relates to a method for remelting the surfaces of cylinders made of carbon-containing cast iron, in particular cylinders of a reciprocating piston internal combustion engine, according to the preamble of patent claim 1.
Es wurde bereits vorgeschlagen, die Zylinder insbesondere von Hubkolben-Brennkraftmaschinen zur Erhöhung deren Verschleißfestigkeit einer Umschmelzhärtung zu unterziehen. Als Energiequellen dienen dabei Elektronenstrahl- oder Laserstrahlkanonen oder auch ein WIG-Brenner. Insbesondere bei Zylinderblöcken ergibt sich durch das Umschmelzhärten der Vorteil, daß trotz der Verwendung eines. kostengünstigen Grundwerkstoffes (z. B. lamellarer Grauguß) eine hohe Verschleißfestigkeit der Zylinderoberflächen bis ca. 1000 HV 10 erzielbar ist.It has already been proposed to subject the cylinders, in particular of reciprocating piston internal combustion engines, to remelt hardening in order to increase their wear resistance. Electron beam or laser beam guns or a TIG torch are used as energy sources. In the case of cylinder blocks in particular, remelt hardening has the advantage that despite the use of a. inexpensive base material (e.g. lamellar gray cast iron) a high wear resistance of the cylinder surfaces up to approx. 1000
Allerdings ergeben sich in der Praxis noch große Probleme bei der Durchführung des Umschmelzhärtens. Zum einen können insbesondere Zylinderblöcke aufgrund ihrer großen Masse und wegen der Verzugsgefahr nicht vorgewärmt werden, so daß beim Umschmelzen extrem hohe Spannungen an den gehärteten Oberflächenbereichen auftreten ; solche Spannungen können in Extremfällen buchstäblich zum Abplatzen der Härteschichten führen.In practice, however, there are still major problems when performing remelt hardening. On the one hand, cylinder blocks, in particular, cannot be preheated due to their large mass and because of the risk of warping, so that extremely high stresses occur on the hardened surface areas during remelting; in extreme cases, such tensions can literally cause the hardness layers to flake off.
Aufgrund der großen Masse von Zylinderblöcken kann auch nicht beispielsweise auf einen Vorschlag gemäß DE-A 28 11 400 zurückgegriffen werden, bei dem zur Vermeidung von Rißbildungen vorgeschlagen wird, daß Werkstück unter Wärmezuführung derart mit unterkritischer Geschwindigkeit der Abkühlung zu überlassen, daß für unterhalb der lediburitisch erstarrten Schicht der Umschmelzzone liegende ganz oder teilweise austenitisierte Bereiche ein unterkritischer zeitlicher Temperaturverlauf entsteht.Due to the large mass of cylinder blocks, it is also not possible, for example, to fall back on a proposal according to DE-A 28 11 400, in which it is proposed to avoid cracking that the workpiece be left under cooling at such a subcritical speed that it is cooled for below the lediburitic completely or partially austenitized areas lying in the solidified layer of the remelting zone, a subcritical temporal temperature profile arises.
Ferner wird in der japanischen Patentanmeldung 57-158319 vorgeschlagen, zur Stabilisierung der Schmelze beim Umschmelzharten eines Eisenwerkstoffes einen mit gepulstem Strom betriebenen WIG-Brenner einzusetzen, und zwar derart, daß das Volumenverhältnis zwischen dem Schmelzbad einerseits und der daran anschließenden über den AC,-Umwandlungspunkt erhitzten Zone andererseits höchstens ist. Dadurch soll eine stabile, haltbare und feine Härtezone (Raster) erzielt werden.Furthermore, it is proposed in Japanese Patent Application 57-158319 to use a TIG torch operated with pulsed current to stabilize the melt when remelting an iron material, in such a way that the volume ratio between the melt pool on the one hand and the subsequent one via the AC, conversion point heated zone, on the other hand, is at most. This is intended to achieve a stable, durable and fine hardness zone (grid).
Aufgabe der Erfindung ist es, das gattungsgemäße Verfahren zum Umschmelzhärten derart weiter zu bilden, daß ohne zusätzliche Wärmezufuhr (z. B. Vorwärmung) eine spannungsarme, von schädlichen Härterissen freie Härtung erzielbar ist, die zudem nur noch eine geringe Nachbearbeitung der Zylinderoberflächen erfordert.The object of the invention is to further develop the generic method for remelt hardening in such a way that low-stress hardening free of harmful hardening cracks can be achieved without additional heat supply (for example preheating), which also requires only a slight reworking of the cylinder surfaces.
Diese Aufgabe wird mit den kennzeichnenden Merkmalen des Patentanspruches 1 gelöst, wobei die nachfolgend aufgeführten Vorteile erzielbar sind.This object is achieved with the characterizing features of patent claim 1, the advantages listed below being achievable.
Durch den Einsatz eines oder mehrerer WIG-Brenner wird zunächst der Vorrichtungsaufwand gegenüber einer Elektronen- oder Laserstrahlhärtung verringert; zudem wurde erkannt, daß eine Umschmelzbehandlung von Zylindern insbesondere bei einer Fertigung in großen Stückzahlen mittels eines WIG-Brenners hinsichtlich der Zugänglichkeit, der Fertigungssteuerung und - überwachung günstiger ist.By using one or more TIG torches, the outlay on the device compared to electron or laser beam hardening is initially reduced; it was also recognized that remelting of cylinders, particularly in the case of large-volume production using a TIG torch, is more favorable in terms of accessibility, production control and monitoring.
Das definierte Pulsen der Energiedichte des WIG-Brenners bewirkt eine gezielte Segmentation der Härtebahn, die ohne nachteilige Folgen im Betrieb in erheblichem Maße zum Abbau der Oberflächenspannungen und zu einer vollständigen Eliminierung von Verzug durch die Härtung führt. Die Härtebahn enthält etwa je cm 2 bis 6 Segmente, welche aufgrund der gepulsten Umschmelzung gezielt schuppenartig vorliegen. Wie Versuche erwiesen haben, neigt diese segmentierte Härtebahn in keiner Weise zu weiterer Rißbildung oder zu Abplatzungen ; zumal im Betrieb bei Brennkraftmaschinen aufgrund der höheren Temperatur an der Zylinderoberfläche relativ zum Zylindermantel ohnehin überwiegend Druckspannungen auftreten.The defined pulsing of the energy density of the TIG torch results in a targeted segmentation of the hardening path, which leads to a considerable reduction in the surface tension and to a complete elimination of distortion due to the hardening without adverse consequences in operation. The hardening sheet contains approximately 2 to 6 segments each, which are deliberately scaled due to the pulsed remelting. As tests have shown, this segmented hardness track is in no way prone to further cracking or chipping; especially when operating internal combustion engines due to the higher temperature on the cylinder surface relative to the cylinder jacket predominantly compressive stresses anyway.
Das wiederholte Aufschmelzen der Umschmelzzonen bewirkt ferner eine Sekundärzementitausscheidung in der Gefügestruktur, welche problemlos eine Härte von 850 bis 950 HV 10 erreichen läßt.The repeated melting of the remelting zones also causes a secondary cementite precipitation in the structure, which allows a hardness of 850 to 950
Ferner hat sich herausgestellt, daß sich aufgrund der Überlappung der aufgeschmolzenen Zonen eine hervorragende Glättung und Formbeständigkeit der gehärteten Bereiche einstellt, welche nur einer geringen, problemlosen Nachbearbeitung durch Honen, etc. bedarf.It has also been found that the overlapping of the melted zones results in an excellent smoothing and dimensional stability of the hardened areas, which requires only a slight, problem-free finishing by honing, etc.
Weitere zweckmäßige und vorteilhafte Verfahrensschritte sind den Merkmalen der Patentansprüche 2 bis 4 entnehmbar. Mit dem oberen Wert der Stromstärke wird einerseits ein ausreichend tiefes Durchschmelzen bzw. eine ausreichende Härtetiefe sichergestellt, während bei niedrigerem Wert des gepulsten Stromes eine Beruhigung und Abkühlung der örtlichen Schmelze eintritt. Wichtig ist dabei auch, daß beim Wechsel der Stromstärken - auch zu Beginn und am Ende des Umschmelzhärtens - kein Blaseffekt entsteht, welcher feine Krater und Aufwürfe in der Schmelze bewirken würde. Die Verteilung der Segmentation in der Härtespur kann vorteilhaft auch innerhalb der angegebenen Pulsfrequenz des Plasmabrenners und durch die Umschmelzgeschwindigkeit beeinflußt werden.Further expedient and advantageous method steps can be found in the features of claims 2 to 4. The upper value of the current strength on the one hand ensures a sufficiently deep melting or a sufficient depth of hardness, while at a lower value of the pulsed current the local melt calms down and cools down. It is also important that when changing the current strengths - even at the beginning and at the end of remelt hardening - there is no blowing effect, which would cause fine craters and peaks in the melt. The distribution of the segmentation in the hardness track can advantageously also be influenced within the specified pulse frequency of the plasma torch and by the remelting speed.
Die Merkmale des Patentanspruches 6 betreffen ein besonders kostengünstiges Verfahren zur Härtung der Zylinder von Hubkolben-Brennkraftmaschinen, welches bei einer Serienfertigung kurze Taktzeiten ermöglicht. Wie sich herausgestellt hat, ist bei den Zylindern von Brennkraftmaschinen der obere Umkehrpunkt des oberen, dem Brennraum am nächsten liegenden Kolbenringes an der Zylinder-Oberfläche die verschleißanfälligste Stelle, so daß es bei vielen Brennkraftmaschinentypen ausreichend sein kann, nur diese eine Stelle mittels einer Härtebahn abzusichern.The features of claim 6 relate to a particularly cost-effective method for hardening the cylinders of reciprocating piston internal combustion engines, which enables short cycle times in series production. As has been found, in the cylinders of internal combustion engines, the upper reversal point of the upper piston ring, which is closest to the combustion chamber, on the cylinder surface is the most susceptible point to wear, so that it is the case with many internal combustion engines it may be sufficient to secure only this one point using a hardening track.
Gemäß Patentanspruch 6 kann der Umschmelzhärtung ein elektrochemischer Abtrag und anschließend eine mechanische Bearbeitung folgen. Damit werden unter anderem die martensitisch/graphitischen Randbereiche der Härtebahnen offenporig freigelegt, so daß hier eine verstärkte Ölhaltung bzw. eine optimierte Schmierung der Gleitpartner Kolben : Zylinderfläche erreicht ist..According to claim 6, the remelting can be followed by electrochemical removal and then mechanical processing. Among other things, this exposes the martensitic / graphitic edge areas of the hardening sheets in an open-pore manner, so that increased oil retention or optimized lubrication of the sliding partner piston: cylinder surface is achieved.
Ein Ausführungsbeispiel der Erfindung ist im folgenden mit weiteren Einzelheiten näher erläutert. Die Zeichnung zeigt in
- Fig. 1 einen Abschnitt eines Zylinderblockes einer Brennkraftmaschine mit einer nach dem erfindungsgemäßen Verfahren gehärteten Zylinder-Oberfläche,
- Fig. 2 eine Einzelheit der Fig. 1 in vergrößerter Darstellung während des Umschmelzens mit einem WIG-Brenner und
- Fig. 3 ein Diagramm zur Darstellung der Stromstärke und der Pulsfrequenz des WIG-Brenners.
- 1 shows a section of a cylinder block of an internal combustion engine with a cylinder surface hardened by the method according to the invention,
- Fig. 2 shows a detail of Fig. 1 in an enlarged view during the remelting with a TIG torch and
- Fig. 3 is a diagram showing the current strength and the pulse frequency of the TIG torch.
In einem Zylinderblock 2 einer mehrzylindrigen Hubkolben-Brennkraftmaschine aus lamellarem Grauguß sind mehrere Zylinder 4 angeordnet, die in üblicher Weise nahezu auf Fertigmaß bearbeitet sind. Bei einem jeden Zylinder 4 ist in die obere Umkehrstelle des oberen ; dem jeweiligen Brennraum am nächsten liegenden Kolbenringes eines nicht dargestellten, im Zylinder 4 gleitenden Kolbens eine kreisringförmige Härtebahn 6 eingearbeitet.In a cylinder block 2 of a multi-cylinder reciprocating piston internal combustion engine made of lamellar gray cast iron, a plurality of cylinders 4 are arranged, which are machined to a finished size in the usual way. In each cylinder 4 is in the upper reversal point of the upper; A ring-shaped hardening track 6 is incorporated in the piston chamber closest to the respective combustion chamber of a piston (not shown) sliding in the cylinder 4.
Die Härtebahn 6 ist durch örtliches Aufschmelzen der oberflächennahen Schicht des Zylinders und durch anschließendes schnelles Wiedererstarren hergestellt, wobei sich in der unmittelbaren Umschmelzzone 8 ein ledeburitisches Gefüge ausbildet, während die noch wärmebeeinflußten Randzonen 10 martensitischer Struktur sind.The hardening web 6 is produced by locally melting the layer of the cylinder close to the surface and by subsequent rapid re-solidification, a ledeburitic structure forming in the
Die Umschmelzzone bzw. Härtebahn 6 wird mittels eines WIC-Brenners 12 (vgl. Fig. 2) erzeugt. Dabei wird die Korrespondierende Oberfläche des Zylinders 4 mittels einer an eine Stromquelle angeschlossenen Wolframelektrode 14 durch einen zum Zylinder 4 überspringenden Lichtbogen 16 in inerter Atmosphäre 18 örtlich aufgeschmolzen. Nähere Details eines derartigen WIG-Brenners 12 können beispielsweise der auf die gleiche Anmelderin zurückgehenden Patentanmeldung P 33 39 447.4 entnommen werden. Der WIG-Brenner 12 wird mit einer Vorschubgeschwindigkeit von 1,5 mm/sec. in Richtung des Pfeiles 20 der Fig. 2 mit einem gleichmäßigen Abstand zum Zylinder 4 entlang der zu erzeugenden Härtebahn 6 vorwärts bewegt.The remelting zone or hardening web 6 is generated by means of a WIC burner 12 (cf. FIG. 2). The corresponding surface of the cylinder 4 is locally melted in an inert atmosphere 18 by means of a
Die die Energiedichte des Lichtbogens 16 bestimmende Stromstärke A in Ampere über der Zeit t ist in dem Diagramm gemäß Fig. 3 dargestellt. Die Einschaltung des Stromes an dem Punkt E erfolgt bei einem unteren Wert der Stromstärke von 15 A, welcher Strom dann mit einer Frequenz von 1 Hz zwischen 15 A und 80 A nach Art eines Rechteckmusters gepulst wird. Die Ausschaltung des WIG-Brenners 14 erfolgt wiederum am Punkt A beim unteren Wert der Stromstärke von 15 A. Dabei erfolgt eine schuppenartige Überlappung von ca. 60 bis 70 % der durch das Pulsen der Stromstärke erzeugten Einzelsegmente 22 der Härtebahn deren Härte etwa 850 bis 950 HV 10 erreicht.The current intensity A in amperes over time t which determines the energy density of the
Nach erfolgtem Umschmelzhärten wird der Zylinder 4 in der Nachbearbeitung durch elektrochemisches Honen mit anschließendem mechanischen Reibplatieren unterzogen. Dabei werden geringe Unebenheiten in der Härtebahn 6 beseitigt und die martensitisch/graphitische Struktur der Randbereiche 10 freigelegt. Das elektrochemische Honen und Reibplatieren kann gegebenenfalls entsprechend der deutschen Patentanmeldung P 31 19 847.3 ausgeführt werden.After remelt hardening has been carried out, the cylinder 4 is subjected to post-processing by electrochemical honing with subsequent mechanical friction plating. In the process, slight unevenness in the hardness web 6 is eliminated and the martensitic / graphitic structure of the
Claims (6)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3418555 | 1984-05-18 | ||
| DE3418555A DE3418555C1 (en) | 1984-05-18 | 1984-05-18 | Process for remelting the surface of cylinders made of carbon-containing cast iron |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0161408A2 EP0161408A2 (en) | 1985-11-21 |
| EP0161408A3 EP0161408A3 (en) | 1986-07-23 |
| EP0161408B1 true EP0161408B1 (en) | 1989-04-26 |
Family
ID=6236254
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP85102673A Expired EP0161408B1 (en) | 1984-05-18 | 1985-03-08 | Process for surface-hardening by remelting cast iron cylinders |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0161408B1 (en) |
| JP (1) | JPS60245725A (en) |
| DE (2) | DE3418555C1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1700923A1 (en) * | 2005-03-10 | 2006-09-13 | Ognibene S.p.A. | Method and device for hardening the inner surface of holes, in mechanical pieces of cast iron of predominantly ferritic matrix |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3510393C1 (en) * | 1985-03-22 | 1986-04-03 | Daimler-Benz Ag, 7000 Stuttgart | Cylinder crankcase for an internal combustion engine |
| DE4124644A1 (en) * | 1991-07-25 | 1993-01-28 | Audi Ag | Hardening internal surface of esp. cylinders - using structured rollers to heat surface by electro-resistance heating and movement of roller electrode over workpiece surface |
| DE4241527A1 (en) * | 1992-12-10 | 1994-06-16 | Opel Adam Ag | Process for hardening and possibly smoothing machine components as well as machine components manufactured according to this process |
| DE102013219784A1 (en) | 2013-09-30 | 2015-04-02 | Federal-Mogul Friedberg Gmbh | Slip rings with leatherburitic structure on the surface |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2134662A1 (en) * | 1971-07-12 | 1973-01-25 | Teves Thompson Gmbh | Strengthening metal parts - partic increasing the strength of valves in ic engines |
| DE2811400C3 (en) * | 1978-03-16 | 1981-12-17 | Aeg-Elotherm Gmbh, 5630 Remscheid | Process for remelt hardening of workpieces |
-
1984
- 1984-05-18 DE DE3418555A patent/DE3418555C1/en not_active Expired
-
1985
- 1985-03-08 DE DE8585102673T patent/DE3569751D1/en not_active Expired
- 1985-03-08 EP EP85102673A patent/EP0161408B1/en not_active Expired
- 1985-05-10 JP JP60100372A patent/JPS60245725A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1700923A1 (en) * | 2005-03-10 | 2006-09-13 | Ognibene S.p.A. | Method and device for hardening the inner surface of holes, in mechanical pieces of cast iron of predominantly ferritic matrix |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0161408A3 (en) | 1986-07-23 |
| DE3569751D1 (en) | 1989-06-01 |
| JPH0149773B2 (en) | 1989-10-26 |
| DE3418555C1 (en) | 1985-07-25 |
| EP0161408A2 (en) | 1985-11-21 |
| JPS60245725A (en) | 1985-12-05 |
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