EP0157093B1 - Teeth for excavators - Google Patents

Teeth for excavators Download PDF

Info

Publication number
EP0157093B1
EP0157093B1 EP85100709A EP85100709A EP0157093B1 EP 0157093 B1 EP0157093 B1 EP 0157093B1 EP 85100709 A EP85100709 A EP 85100709A EP 85100709 A EP85100709 A EP 85100709A EP 0157093 B1 EP0157093 B1 EP 0157093B1
Authority
EP
European Patent Office
Prior art keywords
teeth
temperature
steel alloy
forging
forged
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
Application number
EP85100709A
Other languages
German (de)
French (fr)
Other versions
EP0157093A2 (en
EP0157093A3 (en
Inventor
Heinz Dr.-Ing. Lepand
Margrit Hüser
Franz-Josef Biniasz
Axel Dr.-Ing. Fuchs
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.)
Fried Krupp AG Hoesch Krupp
Original Assignee
Hoesch AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hoesch AG filed Critical Hoesch AG
Priority to AT85100709T priority Critical patent/ATE31555T1/en
Publication of EP0157093A2 publication Critical patent/EP0157093A2/en
Publication of EP0157093A3 publication Critical patent/EP0157093A3/en
Application granted granted Critical
Publication of EP0157093B1 publication Critical patent/EP0157093B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/28—Small metalwork for digging elements, e.g. teeth scraper bits
    • E02F9/2808—Teeth
    • E02F9/285—Teeth characterised by the material used

Definitions

  • excavators or suction dredgers are used to move and mine materials and minerals on land and in water.
  • Suction dredging is a funding principle in ship excavator technology, in which a rotating cutting head works according to the principle of a milling cutter. Adapters are welded to the individual blades of the cutting head in a tangential arrangement. The actual tools, d. H. the teeth are attached to the adapters with a clamping mechanism for quick interchangeability. Since the cutting heads often work under the most difficult operating conditions, the teeth have e.g. B. on rocky subsoil under sea water often only up to 15 minutes. This high wear of the teeth or their tips causes a consumption of several 100 pieces per month and suction dredger, depending on the nature of the soil and the intermediate medium, and consequently affects the productivity of the systems to a large extent.
  • the tools i. H. the excavator teeth
  • the excavator teeth in the case of the described removal method, are primarily subject to sliding wear, d. that is, there are abrasion processes on the surface of the teeth caused by contact with mineral substances;
  • these processes are reinforced by corrosion.
  • the teeth are exposed to considerable mechanical loads (pressure, bending, torsion and impact), which results in the need for a high level of shape and form strength.
  • both excavator teeth and suction excavator teeth made of cast steel of the most varied quality are used.
  • the cast steel is predominantly alloyed with Cr-Mo, Cr-Ni-Mo or Cr-Mo-V; the tools are generally remunerated to a hardness of 48-50 HRC.
  • cast excavator teeth with approx. 30 J at room temperature have relatively poor toughness properties .
  • Suction dredger teeth in particular, are therefore forged in a known manner from the aforementioned relatively expensive materials in order above all to improve their toughness.
  • the invention has for its object to avoid the disadvantages arising from the opposing requirements discussed above and to propose an inexpensive, forgeable, temper-resistant steel for excavator teeth, which is nonetheless hardness and toughness in addition to the corrosion resistance required in particular for suction excavator teeth and thus overall wear resistance to the extent required.
  • the invention teaches the use of a steel alloy Remainder iron and melting-related impurities as material for drop-forged excavator teeth, especially suction excavator teeth, which after forging are heated to a temperature above the A 3 temperature, quenched in oil and tempered.
  • the use of a steel alloy is also made Rest of iron and melting-related impurities advantageous.
  • it has proven to be particularly advantageous to drop-forge it at a forging temperature of 1 150 to 1 250 ° C, to heat it at a temperature of 880 ° C, to quench it in oil and subsequently at a temperature from below 400 ° C.
  • the steel alloy after forging, hardening and tempering has a structure of finely structured tempered martensite with a few fine embedded carbides (M 3 C) and a carbide size of 30-80 nm as well a compact fiber flow, a yield strength of more than 1 550 N / mm 2 , a tensile strength of 1 800-1 880 N / mm 2 , an elongation A 5 of more than 10%, a constriction of more than 35% and a hardness of has more than 51 HRC and a notched impact strength of more than 40 J at RT (measured on ISO-V samples).
  • the good tempering resistance of the developed material was checked by hot tensile tests at 100-600 ° C.
  • the tempering curve according to FIG. 1 initially shows a uniformly flat and from 400 ° C a steeper drop in strength with increasing temperature.
  • the strength of the steel at a tempering temperature of 400 ° C is still 1,800 N / nm 2 , ie at 400 ° C it also has approx. 51.5 HRC still the required working hardness for excavator teeth and is therefore characterized by good temper resistance.
  • the tempering temperature can be increased to 400 ° C above 350 ° C and the toughness of the material can thus be improved without significantly impairing its wear resistance, ie abrasion.
  • tempered steel shows the structure of the tempered steel (a) under light and (b) electron microscopy. It consists of finely structured tempered martensite with a few fine embedded carbides (M 3 C), (carbide size: 30-80 nm).
  • the test was carried out with a cutting head with 6 blades of 7 adapters each; the soil conditions were constant during the tests. There was a medium-heavy limestone soil with a compressive strength of 30-80 kp / cm 2 under sea water.
  • the teeth were measured and weighed before and after the experiments.
  • Table 1 shows the compilation and evaluation of the most important results of both experiments.
  • the teeth made of material C according to the invention had lost an average of 6.40 cm, the teeth made of comparison material D had lost 8.94 cm. This corresponds to a 39.7% higher wear of teeth made of material D compared to teeth made of material C.
  • the evaluation of the tooth weights gives a similar result: The teeth made of material C had an average weight loss of 2.05 kg, those made of material D of 2.97 kg, which is equivalent to a 44.9% higher weight loss.
  • Forging shaping in the die on the teeth according to the invention realizes a particularly compact fiber course, as a result of which their structural strength is considerably increased in comparison with the cast comparison teeth.
  • the resulting improved toughness is a particular advantage when the teeth are used under the most difficult conditions. (See table 1 page 5 f.)

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Structural Engineering (AREA)
  • Civil Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • General Engineering & Computer Science (AREA)
  • Earth Drilling (AREA)
  • Heat Treatment Of Articles (AREA)
  • Component Parts Of Construction Machinery (AREA)
  • Forging (AREA)
  • Shovels (AREA)
  • Table Equipment (AREA)

Abstract

The invention concerns the use of a wear resistant, temper resisting steel alloy of -0.30 to 0.40% carbon -1.0 to 1.60% silicon -0.50 to 0.80% manganese -2.0 to 2.6% chromium -maximum 0.025% phosphorus -maximum 0.025% sulfur -the remainder iron and limited contaminants. - The alloy is used as the work material for making dredger teeth forged in a close-die, especially suction dredger teeth, which teeth after the forging are heated to a temperature above the A3 temperature, are hardened in oil and tempered.

Description

Bei Erdbewegungsarbeiten, beim Bau und Ausbau von Kanälen und Hafenanlagen sowie zur Rohstoffgewinnung werden Bagger bzw. Saugbaggerschiffe eingesetzt, mit deren Hilfe Stoffe und Mineralien an Land und in Gewässern bewegt und abgabaut werden.In earthmoving work, in the construction and expansion of canals and port facilities, and in the extraction of raw materials, excavators or suction dredgers are used to move and mine materials and minerals on land and in water.

Ein Förderprinzip in der Schiffsbaggertechnik ist das Saugbaggern, bei dem ein rotierender Schneidkopf nach dem Prinzip eines Fräsers arbeitet. An den einzelnen Blättern des Schneidkopfes sind in tangentialer Anordnung Adapter angeschweißt. Die eigentlichen Werkzeuge, d. h. die Zähne, werden zwecks schneller Austauschbarkeit mit einem Klemmmechanismus an den Adaptern befestigt. Da die Schneidköpfe häufig unter schwierigsten Einsatzbedingungen arbeiten, haben die Zähne z. B. bei felsigem Untergrund unter Meerwasser oft nur Standzeiten bis zu 15 Minuten. Dieser hohe Verschleiß der Zähne bzw. ihrer Spitzen bewirkt je nach Bodenbeschaffenheit und Zwischenmedium einen Verbrauch von mehreren 100 Stück pro Monat und Saugbaggerschiff und beeinträchtigt demzufolge die Produktivität der Anlagen in hohem Maße.Suction dredging is a funding principle in ship excavator technology, in which a rotating cutting head works according to the principle of a milling cutter. Adapters are welded to the individual blades of the cutting head in a tangential arrangement. The actual tools, d. H. the teeth are attached to the adapters with a clamping mechanism for quick interchangeability. Since the cutting heads often work under the most difficult operating conditions, the teeth have e.g. B. on rocky subsoil under sea water often only up to 15 minutes. This high wear of the teeth or their tips causes a consumption of several 100 pieces per month and suction dredger, depending on the nature of the soil and the intermediate medium, and consequently affects the productivity of the systems to a large extent.

Wie Untersuchungen ergeben haben, werden die Werkzeuge, d. h. die Baggerzähne, bei der erläuterten Abbaumethode in erster Linie auf Gleitverschleiß beansprucht, d. h., es handelt sich um Abrasionsvorgänge an der Oberfläche der Zähne, die durch Berührung mit mineralischen Stoffen erfolgen ; bei Verwendung der Baggerzähne im Wasser, insbesondere im Meerwasser, werden diese Vorgänge durch Korrosion verstärkt. Darüber hinaus sind die Zähne erheblichen mechanischen Belastungen (Druck, Biegung, Torsion und Schlag) ausgesetzt, woraus sich die Forderung nach einer hohen Form- und Gestaltfestigkeit ergibt.As studies have shown, the tools, i. H. the excavator teeth, in the case of the described removal method, are primarily subject to sliding wear, d. that is, there are abrasion processes on the surface of the teeth caused by contact with mineral substances; When using the excavator teeth in water, especially in sea water, these processes are reinforced by corrosion. In addition, the teeth are exposed to considerable mechanical loads (pressure, bending, torsion and impact), which results in the need for a high level of shape and form strength.

Die Anforderungen an Baggerzähne, insbesondere Saugbaggerzähne sind somit zu sehen in einer hohen Härte, um insbesondere einen ausreichenden Widerstand gegen das Eindringen von Stoffpartikeln in die Oberfläche zu bilden, in einer der Härte entsprechenden hohen Zugfestigkeit bei ausreichendem Korrosionswiderstand, und zwar insbesondere, um Werkstoffabtrennungen an der Oberfläche zu verhindern, ferner in einer genügenden Zähigkeit zur Verminderung der Rißbildung und schließlich in einer guten Anlaßbeständigkeit, da die Zähne bei erschwertem Arbeitseinsatz in harten Böden relativ hohen Wärmebelastungen durch Reibungswärme ausgesetzt sind, wodurch die Härte und Zugfestigkeit und somit der Verschleißwiderstand durch Anlaßeffekte vermindert werden kann.The requirements for excavator teeth, particularly suction excavator teeth, are thus to be seen in a high degree of hardness, in particular to provide sufficient resistance to the penetration of material particles into the surface, in a high tensile strength corresponding to the hardness with adequate corrosion resistance, in particular in order to separate the material to prevent the surface, in addition a sufficient toughness to reduce cracking and finally in a good temper resistance, since the teeth are subjected to relatively high thermal loads from frictional heat when working hard in hard floors, whereby the hardness and tensile strength and thus the wear resistance due to tempering effects are reduced can be.

Bekannter Weise werden sowohl Baggerzähne als auch Saugbaggerzähne aus Stahlguß unterschiedlichster Qualität eingesetzt. Nicht zuletzt um eine hohe Verschleißfestigkeit zu erzielen, wird der Stahlguß überwiegend mit Cr-Mo, Cr-Ni-Mo oder Cr-Mo-V legiert ; die Werkzeuge werden im allgemeinen auf eine Arbeitshärte von 48-50 HRC vergütet. Eingesetzt werden z. B. 26 MnCrNiMo 4 8, 23 CrNiMo 747, 34 CrNiMo 6, 48 CrMoV 67, X 38 CrMoV 51. Abgesehen von den verhältnismäßig hohen Werkstoffgrundkosten wegen der hohen Legierungsanteile, weisen gegossene Baggerzähne mit ca. 30 J bei Raumtemperatur insgesamt relativ schlechte Zähigkeitseigenschaften auf. Es werden daher in bekannter Weise aus den vorgenannten relativ teuren Werkstoffen insbesondere Saugbaggerzähne geschmiedet um vor allem ihre Zähigkeit zu verbessern.As is known, both excavator teeth and suction excavator teeth made of cast steel of the most varied quality are used. Not least in order to achieve high wear resistance, the cast steel is predominantly alloyed with Cr-Mo, Cr-Ni-Mo or Cr-Mo-V; the tools are generally remunerated to a hardness of 48-50 HRC. Be used for. B. 26 MnCrNiMo 4 8, 23 CrNiMo 747, 34 CrNiMo 6, 48 CrMoV 67, X 38 CrMoV 51. Apart from the relatively high basic material costs due to the high alloy content, cast excavator teeth with approx. 30 J at room temperature have relatively poor toughness properties . Suction dredger teeth, in particular, are therefore forged in a known manner from the aforementioned relatively expensive materials in order above all to improve their toughness.

Der Erfindung liegt die Aufgabe zugrunde, die sich aus den vorstehend erörterten, gegenläufigen Forderungen ergebenden Nachteile zu vermeiden und einen kostengünstigen, schmiedbaren, anlaßbeständigen Stahl für Baggerzähne vorzuschlagen, der nichts destoweniger Härte und Zähigkeit neben dem insbesondere für Saugbaggerzähne erforderlichen Korrosionswiderstand und somit insgesamt eine Verschleißfestigkeit im geforderten Ausmaß besitzt.The invention has for its object to avoid the disadvantages arising from the opposing requirements discussed above and to propose an inexpensive, forgeable, temper-resistant steel for excavator teeth, which is nonetheless hardness and toughness in addition to the corrosion resistance required in particular for suction excavator teeth and thus overall wear resistance to the extent required.

Zur Lösung dieser Aufgabe lehrt die Erfindung die Verwendung einer Stahllegierung aus

Figure imgb0001
Rest Eisen und erschmelzungsbedingte Verunreinigungen als Werkstoff für im Gesenk geschmiedete Baggerzähne, insbesondere Saugbaggerzähne, die nach dem Schmieden auf eine Temperatur oberhalb der A3-Temperatur erwärmt, in Öl abgeschreckt und angelassen werden.To achieve this object, the invention teaches the use of a steel alloy
Figure imgb0001
 Remainder iron and melting-related impurities as material for drop-forged excavator teeth, especially suction excavator teeth, which after forging are heated to a temperature above the A 3 temperature, quenched in oil and tempered.

In weiterer Ausgestaltung der Erfindung ist auch die Verwendung einer Stahllegierung aus

Figure imgb0002
Rest Eisen und erschmelzungsbedingte Verunreinigungen vorteilhaft. Für die Behandlung der erfindungsgemäß zusammengesetzten Stahllegierung hat es sich als besonders vorteilhaft herausgestellt, sie bei einer Schmiedetemperatur von 1 150 bis 1 250 °C im Gesenk zu schmieden, bei einer Temperatur von 880 °C zu erwärmen, in Öl abzuschrecken und nachfolgend bei einer Temperatur von unterhalb 400 °C anzulassen.In a further embodiment of the invention, the use of a steel alloy is also made
Figure imgb0002
 Rest of iron and melting-related impurities advantageous. For the treatment of the steel alloy composed according to the invention, it has proven to be particularly advantageous to drop-forge it at a forging temperature of 1 150 to 1 250 ° C, to heat it at a temperature of 880 ° C, to quench it in oil and subsequently at a temperature from below 400 ° C.

Von erfindungswesentlicher Bedeutung ist es ferner - wie sich aus den nachfolgenden Ausführungen ergibt - daß die Stahllegierung nach dem Schmieden, Härten und Anlassen ein Gefüge aus feinstrukturiertem angelassenen Martensit mit wenigen feinen eingelagerten Carbiden (M3C) und einer Carbidgröße von 30-80 nm sowie einen kompakten Faserverlauf, eine Streckgrenze von mehr als 1 550 N/mm2, eine Zugfestigkeit von 1 800-1 880 N/mm2, eine Dehnung A5 von mehr als 10 %, eine Einschnürung von mehr als 35 % sowie eine Härte von mehr als 51 HRC und eine Kerbschlagzähigkeit von mehr als 40 J bei RT (gemessen an ISO-V-Proben) aufweist.It is also of importance to the invention - as can be seen from the following explanations - that the steel alloy after forging, hardening and tempering has a structure of finely structured tempered martensite with a few fine embedded carbides (M 3 C) and a carbide size of 30-80 nm as well a compact fiber flow, a yield strength of more than 1 550 N / mm 2 , a tensile strength of 1 800-1 880 N / mm 2 , an elongation A 5 of more than 10%, a constriction of more than 35% and a hardness of has more than 51 HRC and a notched impact strength of more than 40 J at RT (measured on ISO-V samples).

Die Vorteile der Erfindung sind insbesondere darin zu sehen, daß mit der vorgeschlagenen Verwendung ein kostengünstiger, anlaßbeständiger Stahl für Baggerzähne, insbesondere Saugbaggerzähne geschaffen wird, der nichts destoweniger Härte und Zähigkeit neben dem insbesondere für Saugbaggerzähne erforderlichen Korrosionswiderstand und somit insgesamt eine Verschleißfestigkeit im geforderten Ausmaß besitzt.The advantages of the invention can be seen in particular in the fact that with the proposed use an inexpensive, temper-resistant steel for excavator teeth, in particular suction dredger teeth is created, which has nothing less hardness and toughness in addition to the corrosion resistance required in particular for suction dredger teeth and thus has overall a wear resistance to the required extent .

Die Erfindung wird nachfolgend anhand von Ausführungsbeispielen näher erläutert.The invention is explained in more detail below on the basis of exemplary embodiments.

Aus einem Stahl mit 0,35 % C, 1,15 % Si, 0,60 % Mn und 2,39 % Cr, 0,024 % P, 0,021 % Schwefel, Rest Eisen wurden nach Ermittlung der A°3-Temperatur Rundstäbe mit 30 mm Durchmesser geschmiedet und die Härtetemperatur mit 880 °C/Härten in Öl festgelegt.From a steel with 0.35% C, 1.15% Si, 0.60% Mn and 2.39% Cr, 0.024% P, 0.021% sulfur, the rest iron, round bars with 30 were determined after determining the A ° 3 temperature mm forged and the hardening temperature set at 880 ° C / hardening in oil.

Zur Feststellung der günstigsten Vergütungstemperatur wurde ein Teil der Stäbe bei Temperaturen von 200, 250, 300 und 350 °C angelassen. Härtemessungen über den Querschnitt der Proben erbrachten bei vollständiger Durchhärtung bzw. Durchvergütung folgende Werte :

Figure imgb0003
To determine the most favorable tempering temperature, some of the bars were tempered at temperatures of 200, 250, 300 and 350 ° C. Hardness measurements across the cross-section of the samples yielded the following values when fully hardened or tempered:
Figure imgb0003

Die Ergebnisse zeigen, daß die Härte des Werkstoffs mit steigender Anlaßtemperatur nur schwach abfällt. Nach dem Anlassen bei 350 °C besitzt der Stahl noch eine Härte von 52,6 HRC. Sie liegt somit etwas höher als die für Saugbaggerzähne geforderte Arbeitshärte von 48-50 HRC.The results show that the hardness of the material drops only slightly with increasing tempering temperature. After tempering at 350 ° C, the steel still has a hardness of 52.6 HRC. It is therefore somewhat higher than the working hardness of 48-50 HRC required for suction excavator teeth.

Die sich bei den Härtemessungen abzeichnende gute Anlaßbeständigkeit des entwickelten Werkstoffs wurde durch Warmzugversuche bei 100-600 °C überprüft. Die Anlaßkurve gemäß Fig. 1 zeigt mit steigender Temperatur zunächst einen gleichmäßig flachen und ab 400 °C einen steileren Festigkeitsabfall. Ausgehend von einer durch die Härtung (880°C/Öl) eingestellten Zugfestigkeit von 2000 N/mm2, beträgt die Festigkeit des Stahles bei einer Anlaßtemperatur von 400 °C noch 1 800 N/nm2, d. h. er besitzt bei 400 °C mit ca. 51,5 HRC noch die geforderte Arbeitshärte für Baggerzähne und zeichnet sich demzufolge durch eine gute Anlaßbeständigkeit aus. Dies bedeutet aber auch, daß nach der Schmiedung und Härtung die Anlaßtemperatur über 350 °C hinaus auf 400 °C erhöht und somit die Zähigkeit des Werkstoffes verbessert werden kann, ohne seinen Verschleißwiderstand, d. h. die Abrasion wesentlich zu beeinträchtigen.The good tempering resistance of the developed material, which was evident in the hardness measurements, was checked by hot tensile tests at 100-600 ° C. The tempering curve according to FIG. 1 initially shows a uniformly flat and from 400 ° C a steeper drop in strength with increasing temperature. Starting from a tensile strength of 2000 N / mm 2 set by the hardening (880 ° C / oil), the strength of the steel at a tempering temperature of 400 ° C is still 1,800 N / nm 2 , ie at 400 ° C it also has approx. 51.5 HRC still the required working hardness for excavator teeth and is therefore characterized by good temper resistance. This also means, however, that after forging and hardening, the tempering temperature can be increased to 400 ° C above 350 ° C and the toughness of the material can thus be improved without significantly impairing its wear resistance, ie abrasion.

In Fig. 2 ist das Gefüge des vergüteten Stahles (a) licht- und (b) elektronenmikroskopisch dargestellt. Es besteht aus feinstrukturiertem angelassenen Martensit mit wenigen feinen eingelagerten Carbiden (M3C), (Carbidgröße : 30-80 nm).2 shows the structure of the tempered steel (a) under light and (b) electron microscopy. It consists of finely structured tempered martensite with a few fine embedded carbides (M 3 C), (carbide size: 30-80 nm).

In Vergleichsuntersuchungen werden Baggerzähne aus dem vorstehend erläuterten Werkstoff gemäß der Erfindung (= Werkstoff A) geschmiedet und vergütet und Proben daraus mit solchen Proben aus handelsüblichen Stahlgußzähnen der Qualität GS 26 MnCrNiMo 4 8 (= Werkstoff B), die in der Branche als besonders verschleißfest bezeichnet werden, verglichen.In comparative investigations, excavator teeth are forged and tempered from the above-described material according to the invention (= material A) and samples therefrom with such samples from commercially available cast steel teeth of the quality GS 26 MnCrNiMo 4 8 (= material B), which are described in the industry as particularly wear-resistant are compared.

In der nachfolgenden Tabelle sind die Prüfergebnisse beider Werkstoffe (bei indentischer Probenlage) gegenübergestellt:

Figure imgb0004
The table below shows the test results for both materials (with identical sample positions):
Figure imgb0004

Es ergibt sich, daß der geschmiedete Werkstoff bei ca. 190 N/mm2 höherer Streckgrenze und ca. 240 N/mm2 höherer Zugfestigkeit gleichzeitig erheblich bessere Dehnungs-, Einschnürungs- und Kerbschlagzähigkeitswerte aufweist, als der gegossene Werkstoff.It follows that the forged material at approx. 190 N / mm 2 higher yield strength and approx. 240 N / mm 2 higher tensile strength at the same time has considerably better elongation, necking and notched impact strength values than the cast material.

Zur weiteren Erprobung wurden aus einem Stahl mit

Figure imgb0005
Zähne im Gesenk geschmiedet, bei 880°C/ÖI ohne « Werkzeugverzug gehärtet und auf 350 °C angelassen. Stichproben ergaben Zahnhärten zwischen 52,4 und 52,9 HRC.For further testing were made from a steel
Figure imgb0005
 Teeth drop forged, hardened at 880 ° C / oil without tool distortion and tempered to 350 ° C. Samples showed tooth hardness between 52.4 and 52.9 HRC.

Diese Zähne wurden mit Zähnen gemäß dem Stand der Technik aus dem Gußwerkstoff GS 26 MnCrNiMo 4 8 (= Werkstoff D) unter Betriebsbedingungen getestet und verglichen.These teeth were tested and compared with teeth according to the prior art made of the casting material GS 26 MnCrNiMo 4 8 (= material D) under operating conditions.

Die Erprobung wurde mit einem Schneidkopf mit 6 Blättern zu je 7 Adaptern durchgeführt; während der Versuche waren die Bodenverhältnisse konstant. Es lag ein mittelschwerer Kalkboden mit einer Druckfestigkeit von 30-80 kp/cm2 unter Meerwasser vor.The test was carried out with a cutting head with 6 blades of 7 adapters each; the soil conditions were constant during the tests. There was a medium-heavy limestone soil with a compressive strength of 30-80 kp / cm 2 under sea water.

Es wurden zwei Versuche gefahren :Two attempts were made:

1. Versuch1st attempt

Alle Blätter waren mit Zähnen aus dem Werkstoff C gemäß Erfindung bestückt ; die Laufzeit des Schneidkopfes betrug 17 h 50 min. ; während dieser Zeit wurde einen Menge von 24100 m3, entsprechend = 1 351 m3/h gefördert.All sheets were equipped with teeth made of material C according to the invention; the running time of the cutting head was 17 h 50 min. ; during this time, an amount of 24100 m 3 , corresponding to = 1 351 m 3 / h, was produced.

2. VersuchSecond attempt

Alle Blätter'waren mit Zähnen aus dem Werkstoff D bestückt ; die Laufzeit des Schneidkopfes betrugt 19 h 50 min. ; während dieser Zeit wurde eine Menge von 18 200 m3, entsprechend = 918 m3/h gefördert.All sheets were equipped with teeth made of material D; the running time of the cutting head was 19 h 50 min. ; During this time, an amount of 18 200 m 3 , corresponding to = 918 m 3 / h, was produced.

Vor Beginn und nach Beendigung der Versuche wurden die Zähne vermessen und gewogen.The teeth were measured and weighed before and after the experiments.

Tabelle 1 zeigt die Zusammenstellung und Auswertung der wichtigsten Ergebnisse beider Versuche.Table 1 shows the compilation and evaluation of the most important results of both experiments.

Gegenüber der Ausgangslänge hatten die Zähne aus dem Werkstoff C gemäß der Erfindung im Mittel 6,40 cm, die Zähne aus dem Vergleichswerkstoff D 8,94 cm verloren. Das entspricht einem um 39,7 % höheren Verschleiß der Zähne aus Werkstoff D gegenüber den Zähnen aus Werkstoff C. Die Auswertung der Zahngewichte erbringt ein ähnliches Resultat: Die Zähne aus Werkstoff C hatten im Mittel einen Gewichtsverlust von 2,05 kg, diejenigen aus Werkstoff D von 2,97 kg, was einem um 44,9 % höheren Gewichtsverlust gleichkommt.Compared to the initial length, the teeth made of material C according to the invention had lost an average of 6.40 cm, the teeth made of comparison material D had lost 8.94 cm. This corresponds to a 39.7% higher wear of teeth made of material D compared to teeth made of material C. The evaluation of the tooth weights gives a similar result: The teeth made of material C had an average weight loss of 2.05 kg, those made of material D of 2.97 kg, which is equivalent to a 44.9% higher weight loss.

Setzt man diesen Verschleiß in Bezug zur jeweils geförderten Menge, so zeigt sich, daß mit den Zähnen aus Werkstoff C 85 % mehr gefördert werden können, als mit den Vergleichszähnen, bevor der gleiche Längenverschleiß, und 92% mehr, bevor der gleiche Gewichtsverlust eintritt. Der erheblich stärkere Verschleiß der Vergleichszähne gegenüber den erfindungsgemäßen Zähnen wird noch deutlicher, wenn man die Förderleistung in m3/h in Betracht zieht. Bei gleichem Längenverschleiß ist die Förderleistung in m3/h bei erfindungsgemäßen Zähnen um 104,9% und bei gleichem Gewichtsverlust sogar um 113,3% gegenüber den Vergleichszähnen verbessert. Nicht zuletzt wird - wie sich aus weiteren metallographischen Untersuchungen erQ!bt - durch die. Schmiedeformgebung im Gesenk an den erfindungsgemäßen Zähnen ein besonders kompakter Faserverlauf realisiert, wodurch sich ihre Gestaltfestigkeit gegenüber den gegossenen Vergleichszähnen erheblich erhöht. Die dadurch ebenfalls verbesserte Zähigkeit stellt sich beim Arbeitseinsatz der Zähne unter schwersten Bedingungen als besonderer Vorteil dar.
(Siehe Tabelle 1 Seite 5 f.)If this wear is related to the amount conveyed, it can be seen that 85% more can be extracted with the teeth made of material C than with the comparison teeth before the same length wear and 92% more before the same weight loss occurs. The considerably greater wear of the comparison teeth compared to the teeth according to the invention becomes even clearer if one takes into account the delivery rate in m 3 / h. With the same length wear, the delivery rate in m 3 / h for teeth according to the invention is improved by 104.9% and with the same weight loss even by 113.3% compared to the comparison teeth. Last but not least - as is evident from further metallographic examinations - the. Forging shaping in the die on the teeth according to the invention realizes a particularly compact fiber course, as a result of which their structural strength is considerably increased in comparison with the cast comparison teeth. The resulting improved toughness is a particular advantage when the teeth are used under the most difficult conditions.
(See table 1 page 5 f.)

Figure imgb0006
Figure imgb0006

Claims (4)

1. Use of an abrasion-resistant heavy-duty steel alloy comprising :
Figure imgb0009
balance iron and smelting impurities, as the material for drop-forged dredger teeth, in particular suction dredger teeth, which after forging are heated to a temperature above the A3 temperature, quenched in oil and annealed.
2. Use of a steel alloy according to claim 1, comprising :
Figure imgb0010
as the material for the purpose according to claim 1.
3. Use of a steel alloy according to claim 1 or 2, which has been drop-forged at a forging temperature of 1,150° to 1,250 °C, heated to a temperature of 880 °C, quenched in oil and subsequently annealed at a temperature below 400 °C, for the purpose according to claim 1.
4. Use of a steel alloy according to claim 1 or 2, which after forging, hardening and annealing has a structure comprising a fine-grained annealed martensite with a few fine occluded carbides (M3C) and a carbide magnitude of 30-80 nm, as well as compact grain flow lines and an elastic limit of more than 1,550 N/mm2, a tensile strength of 1,800-1,880 N/mm2, an elongation A4 of more than 10 %. a shrinkage of more than 35 % as well as a hardness of more than 51 HRC and a notch impact strength of more than 40 J at RT (measured on ISO-V probes), for the purpose according to claim 1.
EP85100709A 1984-04-03 1985-01-24 Teeth for excavators Expired EP0157093B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85100709T ATE31555T1 (en) 1984-04-03 1985-01-24 EXCAVATOR TEETH.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3412405 1984-04-03
DE3412405A DE3412405C1 (en) 1984-04-03 1984-04-03 Use of a wear-resistant, temper-resistant steel alloy for excavator teeth

Publications (3)

Publication Number Publication Date
EP0157093A2 EP0157093A2 (en) 1985-10-09
EP0157093A3 EP0157093A3 (en) 1986-01-02
EP0157093B1 true EP0157093B1 (en) 1987-12-23

Family

ID=6232485

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85100709A Expired EP0157093B1 (en) 1984-04-03 1985-01-24 Teeth for excavators

Country Status (6)

Country Link
US (1) US4710244A (en)
EP (1) EP0157093B1 (en)
JP (1) JPS60224759A (en)
AT (1) ATE31555T1 (en)
DE (2) DE3412405C1 (en)
ES (1) ES8801710A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117448685B (en) * 2023-11-08 2024-08-20 广州航海学院 Cast steel for rake tooth crowns and preparation method thereof

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2332441A (en) * 1941-04-04 1943-10-19 Timken Roller Bearing Co Carburized article
CH311324A (en) * 1952-03-12 1955-11-30 Gussstahlwerk Witten Aktienges Process for producing a workpiece from a steel alloy.
JPS5423329B2 (en) * 1974-02-12 1979-08-13
FR2264887A1 (en) * 1974-03-20 1975-10-17 Centro Speriment Metallurg Steel of high strength and good ductility - comprising chromium manganese, silicon, and carbon, having high delay at start of perlitic transformation and metastable austenitic phase
SU667609A1 (en) * 1977-10-13 1979-06-15 Физико-технический институт АН Белорусской ССР Steel
DE7828385U1 (en) * 1978-09-23 1979-01-18 Berchem & Schaberg Gmbh, 4650 Gelsenkirchen Tooth that can be placed on an adapter for the suction head of suction head excavators
SE426177B (en) * 1979-12-03 1982-12-13 Uddeholms Ab Hot work tool steel
SU1067078A1 (en) * 1982-03-02 1984-01-15 Московское Ордена Ленина, Ордена Октябрьской Революции И Ордена Трудового Красного Знамени Высшее Техническое Училище Им. Н.Э.Баумана Steel

Also Published As

Publication number Publication date
JPS60224759A (en) 1985-11-09
ES8801710A1 (en) 1988-02-16
DE3561249D1 (en) 1988-02-04
US4710244A (en) 1987-12-01
ATE31555T1 (en) 1988-01-15
EP0157093A2 (en) 1985-10-09
ES541810A0 (en) 1988-02-16
DE3412405C1 (en) 1985-06-20
EP0157093A3 (en) 1986-01-02

Similar Documents

Publication Publication Date Title
DE2741894A1 (en) TOOL FOR REMOVING ROCKS AND MINERALS
DE69708190T2 (en) High temperature resistant alloys, exhaust valves and catalyst supports for exhaust systems
DE69512039T2 (en) DEEP-HARDENING BORDE-CONTAINING STEEL ITEM WITH INCREASED BREAKDUCTIVITY AND IMPROVED WEAR PROPERTIES
DE2824803C2 (en) Use of a steel as a material for fine-grain structural steel with improved machinability properties
DE2447137B2 (en) STEEL ALLOY RESISTANT AGAINST PITCH CORROSION
DE69218779T2 (en) POWDER METALLURGICALLY PRODUCED FAST WORK STEEL
DE4202828C2 (en) Use of a wear-resistant alloy
DE2423963A1 (en) EARTH WORKING TOOL
DE2651695A1 (en) COMPOSITE HARD CAST IRON PROCESSING ROLLER
CH365880A (en) Process for the production of workpieces with high damping capacity, workpiece produced according to this process and its use
DE2915688A1 (en) STEEL ALLOY AND USE OF THE SAME
EP0157093B1 (en) Teeth for excavators
DE69018064T2 (en) Wire for dot matrix printers.
DE69912228T2 (en) Weaving machine part made of an abrasion-resistant steel
DE602004002906T2 (en) High temperature resistant member for use in gas turbines
DE102005013538A1 (en) Plate-shaped element for a belt in a belt type continuously variable transmission
DE3335224A1 (en) STEEL FOR OBJECTS EXPOSED TO HIGH AREA PRESSURE LIKE ROLLER BEARINGS
DE4302635C2 (en) Use a low alloy steel
AT500728B1 (en) Cutting tool, especially wood chipper blade, comprises an iron alloy containing defined amounts of carbon, silicon, manganese, sulfur, chromium, molybdenum, nickel, vanadium, tungsten and aluminum
EP0060577B1 (en) Turbine blade material with high fatigue-corrosion resistance, method of production and use
AT151518B (en) Hot-stressed tools and parts made of steels with one or more of the known alloying elements, which cause precipitation hardening, and any other composition.
DE766033C (en) Steel alloy for drawing tools to be hardened in water
DE593837C (en) Erosion-resistant blade for internal combustion turbines operated with dust-like fuels
DE1093394B (en) Process for the manufacture of rolled products from stable austenitic chromium-nickel steels
DE2039438B2 (en) Use of high-performance tool steel for cold plastic deformation

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

ITCL It: translation for ep claims filed

Representative=s name: RICCARDI SERGIO & CO.

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

EL Fr: translation of claims filed
TCNL Nl: translation of patent claims filed
AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17P Request for examination filed

Effective date: 19860212

17Q First examination report despatched

Effective date: 19870318

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

REF Corresponds to:

Ref document number: 31555

Country of ref document: AT

Date of ref document: 19880115

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3561249

Country of ref document: DE

Date of ref document: 19880204

ET Fr: translation filed
ITF It: translation for a ep patent filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19901210

Year of fee payment: 7

Ref country code: FR

Payment date: 19901210

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19901212

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19901217

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19901220

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19901221

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: LU

Payment date: 19910108

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19910131

Year of fee payment: 7

EPTA Lu: last paid annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19920124

Ref country code: GB

Effective date: 19920124

Ref country code: AT

Effective date: 19920124

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19920125

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Effective date: 19920131

Ref country code: LI

Effective date: 19920131

Ref country code: CH

Effective date: 19920131

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19920318

Year of fee payment: 8

BERE Be: lapsed

Owner name: HOESCH A.G.

Effective date: 19920131

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19920801

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19920930

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19931103

EUG Se: european patent has lapsed

Ref document number: 85100709.6

Effective date: 19920806