EP0249888B1 - Aluminothermic preformed body for heating rails and process of its manufacturing - Google Patents

Aluminothermic preformed body for heating rails and process of its manufacturing Download PDF

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Publication number
EP0249888B1
EP0249888B1 EP87108434A EP87108434A EP0249888B1 EP 0249888 B1 EP0249888 B1 EP 0249888B1 EP 87108434 A EP87108434 A EP 87108434A EP 87108434 A EP87108434 A EP 87108434A EP 0249888 B1 EP0249888 B1 EP 0249888B1
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EP
European Patent Office
Prior art keywords
rail
moulding
heat
aluminothermic
insulating material
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EP87108434A
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German (de)
French (fr)
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EP0249888A2 (en
EP0249888A3 (en
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Johannes Dr. Guntermann
Roderick Donald Macrae
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Goldschmidt ETB GmbH
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Elektro Thermit GmbH
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Priority to AT87108434T priority Critical patent/ATE76441T1/en
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    • 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
    • C21D1/34—Methods of heating
    • 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
    • C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
    • 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
    • C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24V—COLLECTION, PRODUCTION OR USE OF HEAT NOT OTHERWISE PROVIDED FOR
    • F24V30/00—Apparatus or devices using heat produced by exothermal chemical reactions other than combustion

Definitions

  • the invention relates to an aluminothermic molded body for heating a rail consisting of a rail head, rail web and rail foot, with boundary surfaces which are adapted to the rail foot, the rail web and the rail head, the molded body being prepared from a material which consists of an aluminothermic mixture, a heat absorbing material Material and an alkali silicate binder, which has been solidified by the action of a CO2-containing atmosphere at elevated temperatures.
  • the invention further relates to a method for producing such a shaped body.
  • a process for the production and heat treatment of welds in which a form of exothermic material is arranged around the areas to be welded or subjected to a heat treatment, which is one for the work to be carried out and the reached temperature suitable composition, and then ignites the exothermic material of this form.
  • the desired amount of heat for heating the area is free and to the workpiece to be heated, eg. B. issued a rail. If a subsequent welding of the preheated rail ends by pouring in aluminothermally produced steel melt is intended, the mold that solidifies during the exothermic reaction can be formed directly as a casting mold.
  • DE-A-28 36 157 describes an aluminothermic composition for the heat treatment of metallic materials, in particular in the area of welded joints, consisting of a mixture of aluminum, iron oxide and silicon carbide, binder and a moderator, nitrocellulose being added to the aluminothermic mixture as moderator becomes. This prevents the development of smoke when the aluminothermic mixture burns, which should occur when other moderators, such as carboxymethyl cellulose, are used.
  • the aluminothermic molded body according to the invention is characterized in that it has a recess in its surface facing the rail web in which an insert made of heat-insulating material is arranged.
  • the heat insulating material consists of a mixture of sand, platy vermiculite and an alkali silicate binder, which has been solidified by exposure to an atmosphere containing CO2 at elevated temperatures.
  • the heat insulating material can be a mixture of the following composition: Components Parts by weight Quartz sand 67 Flaky vermiculite 33 Sodium silicate 3rd
  • the quartz sand and vermiculite can have a particle size of 0.1 to 1 mm.
  • the heat output of the incandescent body can be changed through the insert.
  • the aluminothermic mixture from which the molded body itself consists contains aluminum, e.g. B. in scale form, with a particle size ⁇ 1 mm, preferably 0.2 to 0.6 mm.
  • the aluminothermic mixture also contains iron oxide, such as in the form of scale, i.e. H. in the form of a mixture of Fe2O3 and FeO, which has preferably been heated in oxygen, so that the proportion of FeO is 5 to 30% by weight, preferably 5 to 20% by weight.
  • the particle size of the iron oxide can be 0.1 to 2 mm, with smaller particles, i. H. those less than 0.2 mm in size increase the rate of the aluminothermic reaction.
  • the moldable and hardenable material can be sand, e.g. B. silicate sand or quartz sand, as a heat-absorbing material.
  • the sand can have a particle size of up to 3 mm, preferably 0.1 to 1.0 mm.
  • the aluminothermic mixture may optionally contain a booster, such as alkali nitrates, e.g. B. NaNO3 or KNO3, and peroxides such as BaO2.
  • a booster such as alkali nitrates, e.g. B. NaNO3 or KNO3, and peroxides such as BaO2.
  • boosters are usually not necessary if the iron oxide is selected with a sufficiently small particle size.
  • Another object of the present invention is the production of the shaped body according to the invention.
  • the procedure is preferably such that the molding is first pre-consolidated and pre-hardened before the heat-insulating material is introduced.
  • This pre-consolidation and pre-hardening of the shaped body is preferably carried out at room temperature and a CO2 pressure of 0.1 to 1.15 M.Pa.
  • the final solidification of the shaped body preferably takes place in a temperature range of approximately 170 to 200 ° C.
  • the moldable and hardenable aluminothermic mixture can take place by mixing the components with an aqueous solution of the sodium silicate and water.
  • the sodium silicate solution can have a concentration of about 38 to 48% by weight, preferably 42 to 46% by weight. This corresponds to a solution with a specific weight of 1.5 g / cm3 and 48.5 ° Be.
  • the moldable and curable material can have the following composition: component % By weight aluminum 25 to 30 Quartz sand 32 to 38 Iron oxide 27 to 31 Sodium silicate solution 6 to 7 water 2.5 to 3
  • the material can be shaped into the desired shape by pressing it into a mold. This can be done by core shooting or by hand.
  • the refractory, heat-insulating mixture can consist of about 60 to 80% by weight of the aforementioned quartz sand and about 20 to 40% by weight of vermiculite and can be bound in a similar manner by sodium silicate.
  • the heat insulating mixture z. B. about 6 to 7 wt .-% of a sodium silicate solution containing 1.5 g / cm3.
  • An insert made of an aluminothermic ignition mixture which is more flammable than the rest of the aluminothermic mixture of the molded body can be arranged in the incandescent body according to the invention. After being ignited, this insert serves to ignite the remaining aluminothermic mixture of the molded body. This insert can be on the opposite side of the insert made of heat insulating material.
  • the ignition mixture can e.g. B. consist of a mixture of about 3 parts by weight of the iron oxide already described and about 1 part by weight of aluminum and by the sodium silicate already described in similar amounts, eg. B. 6 to 7 wt .-%.
  • the ignition mixture is used after pre-consolidation and first hardening with CO2 and before the final consolidation takes place at elevated temperature.
  • Figure 1 shows a pair of molded bodies (incandescent bodies) 12 according to the invention and a cover plate made of aluminothermic material. The latter is used for additional heating and is not according to the invention.
  • the pair of molded bodies and the cover plate together form the casing 10.
  • the molded bodies 12 have contact surfaces 14, 16 and 18 which correspond to the rail foot 22, the rail web 24 and the rail head 26 of the rail 20, which is shown in FIG. 2.
  • the aluminothermic plate 13 covers the running surface 27 of the rail 20.
  • the molded bodies 12 have recesses 28 in the surface 16, which adjoin the rail web 24 of the rail 20, the recesses 28 having inserts 30 made of heat-insulating material.
  • the inserts 30 are arranged in such areas of the molded body 12 that they are in use (Figure 2) opposite the rail web 24 of the rail 20 and thereby insulate the rail web 24 against excessive heat from the glow element 12.
  • the incandescent body 12 and the plate 13 also have recesses 32 which contain inserts made of ignition mixture 34.
  • the moldable and curable aluminothermic material is mixed, shaped in a mold and solidified.
  • scale, aluminum and sand are mixed in a mixer, e.g. B. mixed for 4 minutes.
  • sodium silicate e.g. B. in the form of an aqueous solution with 44 wt .-% sodium silicate, and 3 wt .-% additional water. After a further 4 minutes of mixing time, the material is ready for shaping.
  • This formable and curable aluminothermic mixture is then pressed (stamped) into a suitable mold for shaping.
  • the shapes are designed accordingly to form the recesses 32 and 28 in the shaped bodies.
  • the ignition mixture of the ignition insert 34 and the heat insulating material of the inserts 30 are inserted into these recesses. They thus become an integral part of the incandescent body 12.
  • the insulating inserts 30 are produced in the same way by mixing the sand and the vermiculite, adding the silicate in the form of the same solution, filling the mixture into the recesses 28 provided for this purpose in the glow body 12 pre-consolidated in CO2 and shaping the inserts 30.
  • the pre-consolidation of the molded body 12 is carried out by exposing it to a CO2 pressure of about 0.1 to 0.15 M.Pa at room temperature for about 5 seconds.
  • the thickness of the components i. H. the incandescent body 12 and the plate 13, the casing 10 corresponds directly.
  • a jacket whose components have a thickness of approximately 20 mm burns in the rail 20 to achieve a temperature of approximately 350 ° C.
  • a jacket with a thickness of approximately 50 mm burns in to achieve a temperature of approximately 700 ° C. the rail 20. This thickness is designated "A" in the figures.
  • the casing can be used to heat a rail 20 for repair or surfacing the rail 20, with a pair of the glow elements 12 of the casing 10 being placed in the area of the weld 36 on opposite sides of the rail 20.
  • the position of the incandescent bodies 12 on the rail 20 is secured by side plates or clips, not shown in the figures.
  • the incandescent bodies 12 are simultaneously ignited by means of burning pyrotechnic igniters containing BaO 2 at the inserts 34 of the ignition mixture. The incandescent body is left to burn until the desired temperature of the rail is reached.
  • the annealing jacket 10 can similarly be used to preheat the ends of the adjacent rails which are to be welded by an intermediate pour of molten metal to obtain a joint weld 36.
  • incandescent bodies 12 having a thickness "A" of approximately 30 mm and a length "B" of approximately 220 mm, when applied to a typical rail 20, allow a temperature of approximately 430 ° C at the Reach top 27 of the rail head about 6 minutes after ignition. If desired, this temperature may e.g. B. be measured with a suitable thermocouple.

Abstract

Aluminothermic heating blocks for use in heating metal objects, such as rails, and methods for their manufacture are disclosed. The blocks are made by setting a mass of particulate aluminum, iron oxide, heat absorbing material, alkali metal silicate binder and water.

Description

Die Erfindung betrifft einen aluminothermischen Formkörper zum Erwärmen einer aus Schienenkopf, Schienensteg und Schienenfuß bestehenden Schiene, mit Begrenzungsflächen, die dem Schienenfuß, dem Schienensteg und dem Schienenkopf angepaßt sind, wobei der Formkörper aus einem Material bereitet ist, welches aus einem aluminothermischen Gemisch, einem hitzeabsorbierenden Material und einem Alkalisilicat-Bindemittel besteht, das durch Einwirkung einer CO₂ enthaltenden Atmosphäre bei erhöhten Temperaturen verfestigt worden ist. Die Erfindung betrifft ferner ein Verfahren zur Herstellung eines solchen Formkörpers.The invention relates to an aluminothermic molded body for heating a rail consisting of a rail head, rail web and rail foot, with boundary surfaces which are adapted to the rail foot, the rail web and the rail head, the molded body being prepared from a material which consists of an aluminothermic mixture, a heat absorbing material Material and an alkali silicate binder, which has been solidified by the action of a CO₂-containing atmosphere at elevated temperatures. The invention further relates to a method for producing such a shaped body.

Aus der FR-A-1 257 179 ist ein Verfahren zur Herstellung und Wärmebehandlung von Schweißungen bekannt, bei dem man um die zu schweißenden oder einer Wärmebehandlung zu unterwerfenden Bereiche eine Form aus exotherm reagierendem Material anordnet, welches eine für die durchzuführende Arbeit und die zu erreichende Temperatur geeignete Zusammensetzung aufweist, und dann das exotherme Material dieser Form zündet. Dabei wird die für die Erwärmung des Bereiches gewünschte Wärmemenge frei und an das zu erhitzende Werkstück, z. B. eine Schiene, abgegeben. Ist eine anschließende Schweißung der so vorerwärmten Schienenenden durch Eingießen aluminothermisch erzeugter Stahlschmelze beabsichtigt, kann die Form, welche sich bei der exothermen Reaktion verfestigt, direkt als Gießform ausgebildet werden.From FR-A-1 257 179 a process for the production and heat treatment of welds is known, in which a form of exothermic material is arranged around the areas to be welded or subjected to a heat treatment, which is one for the work to be carried out and the reached temperature suitable composition, and then ignites the exothermic material of this form. The desired amount of heat for heating the area is free and to the workpiece to be heated, eg. B. issued a rail. If a subsequent welding of the preheated rail ends by pouring in aluminothermally produced steel melt is intended, the mold that solidifies during the exothermic reaction can be formed directly as a casting mold.

In der DE-A-28 36 157 ist eine aluminothermische Masse für die Wärmebehandlung metallischer Werkstoffe, insbesondere im Bereich von Schweißverbindungen, bestehend aus einem Gemisch aus Aluminium, Eisenoxid und Siliciumcarbid, Bindemittel und einem Moderator beschrieben, wobei dem aluminothermischen Gemisch als Moderator Nitrocellulose zugesetzt wird. Hierdurch wird eine Rauchentwicklung beim Abbrand des aluminothermischen Gemisches verhindert, die bei Gebrauch sonst üblicher Moderatoren, wie Carboxymethylcellulose, auftreten soll.DE-A-28 36 157 describes an aluminothermic composition for the heat treatment of metallic materials, in particular in the area of welded joints, consisting of a mixture of aluminum, iron oxide and silicon carbide, binder and a moderator, nitrocellulose being added to the aluminothermic mixture as moderator becomes. This prevents the development of smoke when the aluminothermic mixture burns, which should occur when other moderators, such as carboxymethyl cellulose, are used.

Bei diesen exotherm reagierenden Formkörpern des Standes der Technik wirkt die bei der Reaktion freiwerdende Wärme gleichmäßig auf die Schiene ein. Dies kann insbesondere im Bereich des Schienensteges zu überhitzungen mit den bekannten nachteiligen Effekten, wie breite Erhitzungszonen im Schienenstegbereich und damit zu unerwünschten Gefügeumwandlungen führen. Setzt man den exotherm reagierenden Formkörpern jedoch zur Verminderung der freiwerdenden Wärmemenge inerte Füllstoffe zu, reicht häufig die nun freiwerdende Wärmemenge nicht mehr zur ausreichenden Erwärmung der Kopf- und/oder Fußzonen der Schienen aus.With these exothermally reacting molded articles of the prior art, the heat released during the reaction acts uniformly on the rail. In particular in the area of the rail web, this can lead to overheating with the known disadvantageous effects, such as wide heating zones in the area of the rail web, and thus to undesirable structural changes. However, if inert fillers are added to the exothermally reacting moldings to reduce the amount of heat released, the amount of heat now released is often no longer sufficient to sufficiently heat the head and / or foot zones of the rails.

Mit der vorliegenden Erfindung sollen diese Nachteile des Standes der Technik überwunden werden.These disadvantages of the prior art are to be overcome with the present invention.

Der erfindungsgemäße aluminothermische Formkörper ist dadurch gekennzeichnet, daß er in seiner dem Schienensteg zugewendeten Oberfläche eine Ausnehmung aufweist, in welcher ein Einsatz aus hitzeisolierendem Material angeordnet ist.The aluminothermic molded body according to the invention is characterized in that it has a recess in its surface facing the rail web in which an insert made of heat-insulating material is arranged.

Vorzugsweise besteht das hitzeisolierende Material aus einem Gemisch von Sand, blättchenförmigem Vermiculit und einem Alkalisilicat-Bindemittel, welches durch Einwirken einer CO₂ enthaltenden Atmosphäre bei erhöhten Temperaturen verfestigt worden ist.Preferably, the heat insulating material consists of a mixture of sand, platy vermiculite and an alkali silicate binder, which has been solidified by exposure to an atmosphere containing CO₂ at elevated temperatures.

Das hitzeisolierende Material kann eine Mischung folgender Zusammensetzung sein: Bestandteile Gew.-Teile Quarzsand 67 blättchenförmiger Vermiculit 33 Natriumsilicat 3 The heat insulating material can be a mixture of the following composition: Components Parts by weight Quartz sand 67 Flaky vermiculite 33 Sodium silicate 3rd

Der Quarzsand und das Vermiculit können eine Teilchengröße von 0,1 bis 1 mm haben.The quartz sand and vermiculite can have a particle size of 0.1 to 1 mm.

Durch Veränderung der Dicke des hitzeisolierenden Einsatzes kann die Wärmeabgabe des Glühkörpers durch den Einsatz hindurch verändert werden.By changing the thickness of the heat-insulating insert, the heat output of the incandescent body can be changed through the insert.

Das aluminothermische Gemisch, aus dem der Formkörper selbst besteht, enthält Aluminium, z. B. in Schuppenform, mit einer Teilchengröße < 1 mm, vorzugsweise 0,2 bis 0,6 mm. Das aluminothermische Gemisch enthält ferner Eisenoxid, etwa in Form von Zunder, d. h. in Form einer Mischung von Fe₂O₃ und FeO, welcher vorzugsweise in Sauerstoff erhitzt worden ist, so daß der Anteil an FeO 5 bis 30 Gew.-%, vorzugsweise 5 bis 20 Gew.-%, beträgt. Die Teilchengröße des Eisenoxids kann 0,1 bis 2 mm betragen, wobei kleinere Teilchen, d. h. solche mit weniger als 0,2 mm Größe, die Geschwindigkeit der aluminothermischen Reaktion erhöhen. Das formbare und härtbare Material kann Sand, z. B. Silicatsand oder Quarzsand, als hitzeabsorbierendes Material enthalten. Der Sand kann eine Teilchengröße bis zu 3 mm, vorzugsweise 0,1 bis 1,0 mm, aufweisen.The aluminothermic mixture from which the molded body itself consists contains aluminum, e.g. B. in scale form, with a particle size <1 mm, preferably 0.2 to 0.6 mm. The aluminothermic mixture also contains iron oxide, such as in the form of scale, i.e. H. in the form of a mixture of Fe₂O₃ and FeO, which has preferably been heated in oxygen, so that the proportion of FeO is 5 to 30% by weight, preferably 5 to 20% by weight. The particle size of the iron oxide can be 0.1 to 2 mm, with smaller particles, i. H. those less than 0.2 mm in size increase the rate of the aluminothermic reaction. The moldable and hardenable material can be sand, e.g. B. silicate sand or quartz sand, as a heat-absorbing material. The sand can have a particle size of up to 3 mm, preferably 0.1 to 1.0 mm.

Die aluminothermische Mischung kann gegebenenfalls einen Booster enthalten, wie Alkalinitrate, z. B. NaNO₃ oder KNO₃, sowie Peroxide, wie BaO₂. Es kann jedoch davon ausgegangen werden, daß bei entsprechender Auswahl des Eisenoxids mit genügend kleiner Teilchengröße Booster üblicherweise nicht notwendig sind.The aluminothermic mixture may optionally contain a booster, such as alkali nitrates, e.g. B. NaNO₃ or KNO₃, and peroxides such as BaO₂. However, it can be assumed that boosters are usually not necessary if the iron oxide is selected with a sufficiently small particle size.

Ein weiterer Gegenstand vorliegender Erfindung besteht in der Herstellung des erfindungsgemäßen Formkörpers.Another object of the present invention is the production of the shaped body according to the invention.

Es ist dadurch gekennzeichnet, daß man zunächst einen Formkörper mit Begrenzungsflächen, die dem Schienenfuß, dem Schienensteg und dem Schienenkopf angepaßt sind, wobei jedoch der Formkörper in seiner dem Schienensteg zugewendeten Oberfläche eine Ausnehmung zur Aufnahme des hitzeisolierenden Materials aufweist, in einer geeigneten Form herstellt, sodann das hitzeisolierende Material in die Form einbringt und anschließend den Formkörper einer CO₂ enthaltenden Atmosphäre aussetzt und ihn bei Temperaturen von 150 bis 250°C während eines Zeitraumes von mehr als 1 Stunde verfestigt und aushärtet.It is characterized in that a molded body with boundary surfaces which are adapted to the rail base, the rail web and the rail head, but the molded body in its surface facing the rail web has a recess for receiving the heat-insulating material, in a suitable shape, then introduces the heat-insulating material into the mold and then exposes the molded body to an atmosphere containing CO₂ and solidifies and cures it at temperatures of 150 to 250 ° C for a period of more than 1 hour.

Vorzugsweise verfährt man derart, daß man den Formkörper vor dem Einbringen des hitzeisolierenden Materials zunächst vorverfestigt und vorhärtet. Diese Vorverfestigung und Vorhärtung des Formkörpers erfolgt vorzugsweise bei Raumtemperatur und einem CO₂-Druck von 0,1 bis 1,15 M.Pa.The procedure is preferably such that the molding is first pre-consolidated and pre-hardened before the heat-insulating material is introduced. This pre-consolidation and pre-hardening of the shaped body is preferably carried out at room temperature and a CO₂ pressure of 0.1 to 1.15 M.Pa.

Nach dem Einbringen des hitzeisolierenden Materials erfolgt die endgültige Verfestigung des Formkörpers vorzugsweise in einem Temperaturbereich von etwa 170 bis 200°C.After the heat-insulating material has been introduced, the final solidification of the shaped body preferably takes place in a temperature range of approximately 170 to 200 ° C.

Besteht der Formkörper, wie oben beschrieben, aus Aluminium, Eisenoxid, Quarzsand und Natriumsilicat, kann das formbare und härtbare aluminothermische Gemisch durch Vermischen der Bestandteile mit einer wäßrigen Lösung des Natriumsilicates und Wasser erfolgen. Die Natriumsilicatlösung kann eine Konzentration von etwa 38 bis 48 Gew.-%, vorzugsweise 42 bis 46 Gew.-%, haben. Das entspricht einer Lösung mit einem spezifischen Gewicht von 1,5 g/cm³ und 48,5° Be. In diesem Falle kann das form- und härtbare Material folgende Zusammensetzung haben: Bestandteil Gew.-% Aluminium 25 bis 30 Quarzsand 32 bis 38 Eisenoxid 27 bis 31 Natriumsilicatlösung 6 bis 7 Wasser 2,5 bis 3 If the shaped body consists, as described above, of aluminum, iron oxide, quartz sand and sodium silicate, the moldable and hardenable aluminothermic mixture can take place by mixing the components with an aqueous solution of the sodium silicate and water. The sodium silicate solution can have a concentration of about 38 to 48% by weight, preferably 42 to 46% by weight. This corresponds to a solution with a specific weight of 1.5 g / cm³ and 48.5 ° Be. In this case, the moldable and curable material can have the following composition: component % By weight aluminum 25 to 30 Quartz sand 32 to 38 Iron oxide 27 to 31 Sodium silicate solution 6 to 7 water 2.5 to 3

Die Formgebung des Materials in die gewünschte Gestalt kann durch Einpressen (Einstampfen) in eine Form erfolgen. Dies kann durch Kernschießen oder von Hand erfolgen.The material can be shaped into the desired shape by pressing it into a mold. This can be done by core shooting or by hand.

Das feuerfeste, hitzeisolierende Gemisch kann aus etwa 60 bis 80 Gew.-% des bereits erwähnten Quarzsandes und etwa 20 bis 40 Gew.-% Vermiculit bestehen und kann in ähnlicher Weise durch Natriumsilicat gebunden werden. Dabei kann das hitzeisolierende Gemisch z. B. etwa 6 bis 7 Gew.-% einer Natriumsilicatlösung mit einem Gehalt von 1,5 g/cm³ enthalten.The refractory, heat-insulating mixture can consist of about 60 to 80% by weight of the aforementioned quartz sand and about 20 to 40% by weight of vermiculite and can be bound in a similar manner by sodium silicate. The heat insulating mixture z. B. about 6 to 7 wt .-% of a sodium silicate solution containing 1.5 g / cm³.

In dem erfindungsgemäßen Glühkörper kann ein Einsatz aus einem aluminothermischen Zündgemisch angeordnet sein, welches leichter entzündlich als das übrige aluminothermische Gemisch des Formkörpers ist. Dieser Einsatz dient, nachdem er entzündet ist, dazu, die übrige aluminothermische Mischung des Formkörpers zu entzünden. Dieser Einsatz kann sich auf der gegenüberliegenden Seite des Einsatzes aus hitzeisolierendem Material befinden.An insert made of an aluminothermic ignition mixture which is more flammable than the rest of the aluminothermic mixture of the molded body can be arranged in the incandescent body according to the invention. After being ignited, this insert serves to ignite the remaining aluminothermic mixture of the molded body. This insert can be on the opposite side of the insert made of heat insulating material.

Das Zündgemisch kann z. B. aus einer Mischung von etwa 3 Gew.-Teilen des bereits beschriebenen Eisenoxides und etwa 1 Gew.-Teil Aluminium bestehen und durch das bereits beschriebene Natriumsilicat in ähnlichen Mengen, z. B. 6 bis 7 Gew.-%, gebunden sein. Das Zündgemisch wird nach der Vorverfestigung und ersten Härtung mit CO₂ und vor der bei erhöhter Temperatur erfolgenden Endverfestigung eingesetzt.The ignition mixture can e.g. B. consist of a mixture of about 3 parts by weight of the iron oxide already described and about 1 part by weight of aluminum and by the sodium silicate already described in similar amounts, eg. B. 6 to 7 wt .-%. The ignition mixture is used after pre-consolidation and first hardening with CO₂ and before the final consolidation takes place at elevated temperature.

Die Erfindung soll nun anhand der folgenden Abbildungen noch näher erläutert werden. Dabei zeigt Abbildung 1 ein Paar erfindungsgemäßer Formkörper (Glühkörper) 12 und eine Abdeckplatte aus aluminothermischem Material. Letztere dient der zusätzlichen Beheizung und ist nicht erfindungsgemäß. Das Paar Formkörper und die Abdeckplatte bilden zusammen die Ummantelung 10. Dabei weisen die Formkörper 12 Berührungsflächen 14, 16 und 18 auf, die dem Schienenfuß 22, dem Schienensteg 24 und dem Schienenkopf 26 der Schiene 20, die in Abbildung 2 dargestellt ist, entsprechen. Die aluminothermische Platte 13 deckt die Fahrfläche 27 der Schiene 20 ab.The invention will now be explained in more detail with reference to the following figures. Figure 1 shows a pair of molded bodies (incandescent bodies) 12 according to the invention and a cover plate made of aluminothermic material. The latter is used for additional heating and is not according to the invention. The pair of molded bodies and the cover plate together form the casing 10. The molded bodies 12 have contact surfaces 14, 16 and 18 which correspond to the rail foot 22, the rail web 24 and the rail head 26 of the rail 20, which is shown in FIG. 2. The aluminothermic plate 13 covers the running surface 27 of the rail 20.

Die Formkörper 12 haben Ausnehmungen 28 in der Fläche 16, welche an den Schienensteg 24 der Schiene 20 angrenzen, wobei die Ausnehmungen 28 Einsätze 30 aus hitzeisolierendem Material aufweisen.The molded bodies 12 have recesses 28 in the surface 16, which adjoin the rail web 24 of the rail 20, the recesses 28 having inserts 30 made of heat-insulating material.

Die Einsätze 30 sind in solchen Bereichen der Formkörper 12 angeordnet, daß sie bei Gebrauch (Abbildung 2) sich gegenüber dem Schienensteg 24 der Schiene 20 befinden und dadurch den Schienensteg 24 gegen übermäßige Wärme der Glühkörper 12 isolieren.The inserts 30 are arranged in such areas of the molded body 12 that they are in use (Figure 2) opposite the rail web 24 of the rail 20 and thereby insulate the rail web 24 against excessive heat from the glow element 12.

Die Glühkörper 12 und die Platte 13 weisen außerdem Ausnehmungen 32 auf, welche Einsätze aus Zündgemisch 34 enthalten.The incandescent body 12 and the plate 13 also have recesses 32 which contain inserts made of ignition mixture 34.

Zur Herstellung der Glühkörper 12 wird das formbare und härtbare aluminothermische Material gemischt, in einer Form geformt und verfestigt.To produce the incandescent body 12, the moldable and curable aluminothermic material is mixed, shaped in a mold and solidified.

Um das form- und härtbare Material zu mischen, werden Zunder, Aluminium und Sand in einem Mischer, z. B. während 4 Minuten, gemischt. In den Mischer werden Natriumsilicat, z. B. in Form einer wäßrigen Lösung mit 44 Gew.-% Natriumsilicat, und 3 Gew.-% zusätzliches Wasser gegeben. Nach weiteren 4 Minuten Mischzeit ist das Material bereit zur Formgebung.To mix the formable and hardenable material, scale, aluminum and sand are mixed in a mixer, e.g. B. mixed for 4 minutes. In the mixer sodium silicate, e.g. B. in the form of an aqueous solution with 44 wt .-% sodium silicate, and 3 wt .-% additional water. After a further 4 minutes of mixing time, the material is ready for shaping.

Dieses form- und härtbare aluminothermische Gemisch wird nun zur Formgebung in eine geeignete Form gepreßt (gestampft). Die Formen sind entsprechend zur Bildung der Ausnehmungen 32 und 28 in den Formkörpern gestaltet. In diese Ausnehmungen werden das Zündgemisch des Zündeinsatzes 34 und das Hitze-Isoliermaterial der Einsätze 30 eingefügt. Sie werden damit integraler Bestandteil der Glühkörper 12.This formable and curable aluminothermic mixture is then pressed (stamped) into a suitable mold for shaping. The shapes are designed accordingly to form the recesses 32 and 28 in the shaped bodies. The ignition mixture of the ignition insert 34 and the heat insulating material of the inserts 30 are inserted into these recesses. They thus become an integral part of the incandescent body 12.

In gleicher Weise werden Zunder und Aluminium der Zündmischung in einem Mischer z. B. 4 Minuten gemischt. Danach wird Natriumsilicat in Form einer Lösung wie oben beschrieben zugegeben. Es wird noch einmal 4 Minuten gemischt. Nach der Vorverfestigung des Glühkörpers 12 mit CO₂ wird die Zündmischung von Hand in die Ausnehmungen 32 der Glühkörper 12 und der Platte 13 eingefüllt, um die Einsätze 34 zu bilden.In the same way, scale and aluminum of the ignition mixture are mixed in a mixer e.g. B. 4 minutes mixed. Then sodium silicate is added in the form of a solution as described above. Mix again for 4 minutes. After pre-solidification of the incandescent body 12 with CO₂, the ignition mixture is filled by hand into the recesses 32 of the incandescent body 12 and the plate 13 to form the inserts 34.

Die isolierenden Einsätze 30 werden in gleicher Weise durch Vermischen des Sandes und des Vermiculits, Zugabe des Silicates in Form der gleichen Lösung, Einfüllen des Gemisches in die hierfür vorgesehenen Ausnehmungen 28 der in CO₂ vorverfestigten Glühkörper 12 von Hand und Formen der Einsätze 30 hergestellt.The insulating inserts 30 are produced in the same way by mixing the sand and the vermiculite, adding the silicate in the form of the same solution, filling the mixture into the recesses 28 provided for this purpose in the glow body 12 pre-consolidated in CO₂ and shaping the inserts 30.

Die Vorverfestigung der Formkörper 12 erfolgt dadurch, daß man sie einem CO₂-Druck von etwa 0,1 bis 0,15 M.Pa bei Raumtemperatur für etwa 5 Sekunden aussetzt.The pre-consolidation of the molded body 12 is carried out by exposing it to a CO₂ pressure of about 0.1 to 0.15 M.Pa at room temperature for about 5 seconds.

Um die Teile der Glühummantelung vollends auszuhärten und zu verfestigen, werden sie auf eine Temperatur von wenigstens 150°C, z. B. 200°C, etwa 75 Minuten lang erhitzt.In order to fully harden and solidify the parts of the glow jacket, they are heated to a temperature of at least 150 ° C, e.g. B. 200 ° C, heated for about 75 minutes.

Es sollte beim Gebrauch beachtet werden, daß die Temperatur, die beim Abbrennen der Teile der Ummantelung erreicht wird, der Dicke der Bestandteile, d. h. der Glühkörper 12 und der Platte 13, der Ummantelung 10 direkt entspricht. So brennt eine Ummantelung, deren Bestandteile eine Dicke von etwa 20 mm aufweisen, unter Erzielung einer Temperatur von etwa 350°C in der Schiene 20. Eine Ummantelung mit einer Dicke von etwa 50 mm brennt dagegen unter Erzielung einer Temperatur von etwa 700°C in der Schiene 20. Diese Dicke ist in den Abbildungen mit "A" bezeichnet.It should be noted in use that the temperature reached when the parts of the jacket burn off, the thickness of the components, i. H. the incandescent body 12 and the plate 13, the casing 10 corresponds directly. For example, a jacket whose components have a thickness of approximately 20 mm burns in the rail 20 to achieve a temperature of approximately 350 ° C. A jacket with a thickness of approximately 50 mm, on the other hand, burns in to achieve a temperature of approximately 700 ° C. the rail 20. This thickness is designated "A" in the figures.

Die Ummantelung kann zum Aufheizen einer Eisenbahnschiene 20 für die Reparatur- oder Auftragsschweißung der Schiene 20 verwendet werden, wobei ein Paar der Glühkörper 12 der Ummantelung 10 im Bereich der Schweißstelle 36 an gegenüberliegenden Seiten der Schiene 20 angelegt werden. Die Glühkörper 12 werden in ihrer Lage an der Schiene 20 durch in den Abbildungen nicht gezeigte Seitenplatten oder Klammern gesichert. Die Glühkörper 12 werden gleichzeitig mittels brennenden, BaO₂ enthaltenden pyrotechnischen Anzündern an den Einsätzen 34 des Zündgemisches entzündet. Man läßt die Glühkörper so lange brennen, bis die gewünschte Temperatur der Schiene erreicht ist.The casing can be used to heat a rail 20 for repair or surfacing the rail 20, with a pair of the glow elements 12 of the casing 10 being placed in the area of the weld 36 on opposite sides of the rail 20. The position of the incandescent bodies 12 on the rail 20 is secured by side plates or clips, not shown in the figures. The incandescent bodies 12 are simultaneously ignited by means of burning pyrotechnic igniters containing BaO 2 at the inserts 34 of the ignition mixture. The incandescent body is left to burn until the desired temperature of the rail is reached.

Bei der Schienenverbindungsschweißung kann die Glühummantelung 10 in ähnlicher Weise benutzt werden, um die Enden der benachbarten Schienen, welche durch einen Zwischenguß von geschmolzenem Metall verschweißt werden sollen, vorzuheizen, um eine Verbindungsschweißung 36 zu erhalten.In the case of rail joint welding, the annealing jacket 10 can similarly be used to preheat the ends of the adjacent rails which are to be welded by an intermediate pour of molten metal to obtain a joint weld 36.

Im praktischen Betrieb, bei Reparaturschweißungen, ermöglichen Glühkörper 12 mit einer Dicke "A" von etwa 30 mm und einer Länge "B" von etwa 220 mm, wenn sie an eine typische Schiene 20 angelegt werden, eine Temperatur von etwa 430°C an der Oberseite 27 des Schienenkopfes etwa 6 Minuten nach der Zündung zu erreichen. Falls erwünscht, kann diese Temperatur z. B. mit einem geeigneten Thermoelement gemessen werden.In practical operation, for repair welds, incandescent bodies 12 having a thickness "A" of approximately 30 mm and a length "B" of approximately 220 mm, when applied to a typical rail 20, allow a temperature of approximately 430 ° C at the Reach top 27 of the rail head about 6 minutes after ignition. If desired, this temperature may e.g. B. be measured with a suitable thermocouple.

Claims (6)

  1. Aluminothermic moulding for heating a rail consisting of rail head, rail stem and rail foot, with peripheries which are matched to the rail foot, the rail stem and the rail head, the moulding being prepared from a material which consists of an aluminothermic mixture, a heat-absorbent material and an alkali metal silicate binder, which material has been hardened by the action of a CO₂-containing atmosphere at elevated temperatures, characterised in that the moulding has a recess in its surface facing towards the rail stem, in which recess an inset of heat-insulating material is arranged.
  2. Moulding according to Claim 1, characterised in that the heat-insulating material consists of a mixture of sand, lamellar vermiculite and an alkali metal silicate binder and has been hardened by the action of a CO₂-containing atmosphere at elevated temperatures.
  3. Process for the production of a moulding according to Claim 1 or 2, characterised in that a moulding having peripheries which are matched to the rail foot, the rail stem and the rail head, the moulding however having a recess in its surface facing towards the rail stem for accommodating the heat-insulating material, is first produced in a suitable mould, the heat-insulating material is then introduced into the mould and the moulding is then exposed to a CO₂-containing atmosphere and hardened and cured at temperatures of 150 to 250°C for a period of more than one hour.
  4. Process according to Claim 3, characterised in that the moulding is first prehardened and precured before introducing the heat-insulating material.
  5. Process according to Claim 4, characterised in that the prehardening and precuring of the moulding is carried out at room temperature and under a CO₂ pressure of 0.1 to 1.15 M.Pa.
  6. Process according to Claim 3, 4 or 5, characterised in that the final hardening of the moulding is carried out in a temperature range from about 170 to 200°C.
EP87108434A 1986-06-18 1987-06-11 Aluminothermic preformed body for heating rails and process of its manufacturing Expired - Lifetime EP0249888B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87108434T ATE76441T1 (en) 1986-06-18 1987-06-11 ALUMINOTHERMAL MOLDING FOR HEATING A NOTE AND PROCESS FOR ITS MANUFACTURE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA864553 1986-06-18
ZA864553 1986-06-18

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EP0249888A2 EP0249888A2 (en) 1987-12-23
EP0249888A3 EP0249888A3 (en) 1989-07-12
EP0249888B1 true EP0249888B1 (en) 1992-05-20

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EP (1) EP0249888B1 (en)
AT (1) ATE76441T1 (en)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5306361A (en) * 1992-10-02 1994-04-26 Besch Gordon O Method for improving service life of rail welds by aluminothermic heat treatment
DE19514789A1 (en) * 1995-04-21 1996-10-24 Kuehne Michael Process for the production of a raw material
US5965046A (en) * 1996-04-17 1999-10-12 Applied Materials, Inc. Method and apparatus for baking out a gate valve in a semiconductor processing system
US6460535B1 (en) 2000-01-24 2002-10-08 Forrest Paint Company Heat source for rail expansion
RU2677295C1 (en) * 2018-01-29 2019-01-16 РЕЙЛ 1520 АйПи ЛТД Method of thermal anti-flocking treatment of railway wheels

Family Cites Families (9)

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Publication number Priority date Publication date Assignee Title
US2809265A (en) * 1956-03-16 1957-10-08 Pittsburgh Des Moines Steel Temperature conditioning portions of a metal shape
GB856233A (en) * 1958-01-03 1960-12-14 Exomet Improvements in process for relieving stress in welded steel
GB913225A (en) * 1960-01-29 1962-12-19 Kemwell A G Heat treatment of metals
FR1257179A (en) * 1960-02-18 1961-03-31 Process for the establishment and heat treatment of welds
US3833338A (en) * 1971-06-08 1974-09-03 Cooperheat Surface combustion burner
US4137966A (en) * 1977-04-19 1979-02-06 The United States Of America As Represented By The Secretary Of The Navy Simulation oven
DD140675B1 (en) * 1977-10-05 1983-01-26 Werner Gilde SMOKLESS, WATER-FREE ALUMINOTHERMIC ANTIQUE MASS
GB2146571B (en) * 1983-09-12 1987-12-23 Yen Wei Hsiung Apparatus for heating the end of a plastic pipe
US4673122A (en) * 1986-05-22 1987-06-16 Dubey Thomas W Method and apparatus for repairing copper pipes

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EP0249888A2 (en) 1987-12-23
US4830611A (en) 1989-05-16
AU592513B2 (en) 1990-01-11
ATE76441T1 (en) 1992-06-15
DE3779185D1 (en) 1992-06-25
AU7407787A (en) 1987-12-24
EP0249888A3 (en) 1989-07-12

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