EP0149927A1 - Process for manufacturing the iron parts of a colour television tube - Google Patents

Process for manufacturing the iron parts of a colour television tube Download PDF

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Publication number
EP0149927A1
EP0149927A1 EP84400153A EP84400153A EP0149927A1 EP 0149927 A1 EP0149927 A1 EP 0149927A1 EP 84400153 A EP84400153 A EP 84400153A EP 84400153 A EP84400153 A EP 84400153A EP 0149927 A1 EP0149927 A1 EP 0149927A1
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Prior art keywords
parts
oven
atmosphere
oxidizing
oxidation
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EP84400153A
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German (de)
French (fr)
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EP0149927B1 (en
Inventor
Bernard Poncet
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Videocolor SA
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Videocolor SA
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Priority to DE8484400153T priority Critical patent/DE3478168D1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
    • 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
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/02—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/10—Oxidising
    • C23C8/16—Oxidising using oxygen-containing compounds, e.g. water, carbon dioxide
    • C23C8/18—Oxidising of ferrous surfaces
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
    • H01J9/142—Manufacture of electrodes or electrode systems of non-emitting electrodes of shadow-masks for colour television tubes

Definitions

  • the present invention relates to a method for preparing the ferrous parts of a color television tube and to an oven for carrying out such a method.
  • a first problem relating to the subject of the invention relates to the natural deposit of rust on this kind of parts during the manufacturing process. Indeed, for reasons of cost, mechanical and electrical resistance, the frame-mask assembly consists of iron which oxidizes to an oxide Fe 2 0 3 . This oxide is created on the surface of the ferrous part and gains towards the heart of the part by gnawing it. There is therefore a deterioration of the part. In addition, weakly adhering particles of rust are formed, which can detach from ferrous parts and disturb the proper functioning of the tube.
  • the tube comprises behind the already described slab a cone terminated by a glass neck which makes it possible to obtain a tube closed under vacuum.
  • the neck carries the electron guns and the magnetic deflection assembly.
  • the cone is internally lined with a magnetic shield consisting of a ferrous part which follows the shape of the cone. This ferrous part makes it possible to close the lines of the magnetic field emitted by the front of the deflection assembly (magnetic conduction) on the one hand, and on the other hand to form a black body with the mask for the various radiations.
  • the natural deposit of rust is also harmful.
  • a second problem relating to the subject of the invention relates to the natural constitution of mechanical stresses induced in metal parts. These constraints must be canceled so that the shape of each part is stable. An annealing treatment of ferrous parts is required.
  • rust is pickled by a chemical reduction when hot. Then it is known in a second step to carry out a particular oxidation. Indeed, it is known that the oxide Fe 3 O 4 , also called iron oxide II or magnetic oxide, has good qualities of magnetic conduction. It is therefore advantageous to constitute a deposit of magnetic oxide Fe 3 0 4 on the mask-frame-cone shield assembly. It should also be noted that the fineness of the masks is such that the control of reduction and oxidation must be as precise as possible.
  • the operations are carried out separately from each other in specialized ovens. There is thus an annealing and reduction furnace and an oxidation furnace.
  • An exemplary embodiment can be found in US Pat. No. 2,543,710. According to such an embodiment, one is forced to work in series of parts, which leads to blockages in the chain at the entry and exit of the treatment.
  • the present invention relates to a process for preparing ferrous parts, such as the frame, the mask or the shielding of the cone.
  • the four annealing, rust reduction, first oxidation and second oxidation operations are carried out in a single oven, so that adherent layers of iron oxide I and d are successively formed on the iron surface.
  • iron oxide II the parts to be treated continuously scrolling.
  • the invention also relates to a single oven in three sections: annealing-reduction, first and second oxidations.
  • Figure 1 shows the temperature distribution in the oven.
  • the metal parts are introduced into the furnace and advance continuously at variable speeds. Such an oven is described in Figure 2.
  • the oven has a heating body which is distributed along the axis X of the oven. On the X axis, we can determine three main sections and two airlocks. The sections are not separated by doors or airlocks. At the entrance to the oven there is an entry airlock 2.
  • the parts are introduced continuously onto a transport member, for example a conveyor belt. They then enter a first section 3, called annealing and reduction.
  • the annealing treatment makes it possible to reduce or eliminate the mechanical stresses in the parts.
  • Reduction is a chemical operation that transforms the rust formed in the open air on the ferrous parts made of pure iron.
  • first oxidation In this zone, the surface iron is transformed into iron oxide I called FeO.
  • second oxidation section 5 In this section, the oxidation operation consists in superficially transforming the layer of iron oxide I into an iron oxide II called Fe 3 0 4 .
  • the second oxidation section 5 At the end of the second oxidation section 5, one enters an exit airlock through which the prepared parts escape.
  • a temperature of approximately 760 to 780 ° is reached by temperature ramps in the example of the frames.
  • the inlet temperature of the annealing and reduction section is approximately 40 ° C., while at the outlet XI of this section it is approximately 700 ° C.
  • the temperature stabilizes at around 760 ° C.
  • a temperature down ramp begins which brings the output of the second oxidation section 5 to a temperature of approximately 500 ° C. Then the temperature decreases in the exit airlock.
  • the chemical reduction and oxidation operations are carried out by coordinating the temperature cycle described with the use of an atmosphere whose chemical constituents are dosed regularly.
  • the atmosphere used is a reducing atmosphere. That is to say that the oxidizing ratio or oxidation rate which is equal to the ratio between the number of reducing moles and the number of more reducing oxidizing moles is of value close to one.
  • such an atmosphere is obtained by a gas mixer.
  • a determination is also made of the products which are nitrogen N 2 and hydrogen H 2 , so that their relative proportions are 95 and 5 parts per cent.
  • the flow rate of the reducing atmosphere is 12.5 m 3 per hour.
  • the atmosphere used in the following sections is an oxidizing atmosphere.
  • the oxidizing ratio to a value allowing oxidation.
  • the value of this ratio is close to 0.4 (four tenths) then to 0.25 in the second oxidation section 5.
  • the reducing atmosphere composed of nitrogen and hydrogen can be obtained in particular by a gas mixer, the reducing parts of which are constantly monitored.
  • the oxidizing atmosphere is produced from such a reducing atmosphere by adding a pressure of water vapor which serves as an oxidizing body.
  • the present invention is not limited to the treatment of one or other of the metal parts included behind the panel in the television tube. Other atmospheres can be used in the same way.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Tunnel Furnaces (AREA)

Abstract

Selon l'invention, chaque pièce ferreuse derrière la dalle du tube de télévision, est préparée dans un four unique (1) et subit successivement un recuit, une réduction et une oxydation dans trois parties du four (3), (4) et (5), de façon à éliminer les contraintes mécaniques, décaper la rouille et déposer des couches homogènes et adhérentes d'oxydes de fer I et II.According to the invention, each ferrous part behind the slab of the television tube is prepared in a single oven (1) and successively undergoes annealing, reduction and oxidation in three parts of the oven (3), (4) and ( 5), so as to eliminate the mechanical stresses, remove the rust and deposit homogeneous and adherent layers of iron oxides I and II.

Description

La présente invention concerne un procédé de préparation des pièces ferreuses d'un tube de télévision en couleurs et un four pour la mise en oeuvre d'un tel procédé.The present invention relates to a method for preparing the ferrous parts of a color television tube and to an oven for carrying out such a method.

Afin de réaliser une image convenable, il est connu de disposer à l'intérieur du tube de verre constituant l'enveloppe du tube cathodique, des pièces ferreuses comme le blindage magnétique, le masque d'ombre et son cadre. Selon cette technologie, le masque est monté dans un cadre qui est placé sur la face arrière de l'écran. Un premier problème concernant l'objet de l'invention se rapporte au dépot naturel de rouille sur ce genre de pièces au cours du processus de fabrication. En effet pour des raisons de coût, de tenue mécanique et électrique, l'ensemble cadre-masque est constitué par du fer qui s'oxyde en un oxyde Fe203. Cet oxyde se crée en surface de la pièce ferreuse et gagne vers le coeur de la pièce en la rongeant. Il y a donc une détérioration de la pièce. De plus se forment ainsi des particules peu adhérentes de rouille qui peuvent se détacher des pièces ferreuses et perturber le bon fonctionnement du tube.In order to achieve a suitable image, it is known to have inside the glass tube constituting the envelope of the cathode ray tube, ferrous parts such as magnetic shielding, the shadow mask and its frame. According to this technology, the mask is mounted in a frame which is placed on the rear face of the screen. A first problem relating to the subject of the invention relates to the natural deposit of rust on this kind of parts during the manufacturing process. Indeed, for reasons of cost, mechanical and electrical resistance, the frame-mask assembly consists of iron which oxidizes to an oxide Fe 2 0 3 . This oxide is created on the surface of the ferrous part and gains towards the heart of the part by gnawing it. There is therefore a deterioration of the part. In addition, weakly adhering particles of rust are formed, which can detach from ferrous parts and disturb the proper functioning of the tube.

D'autre part, le tube comporte derrière la dalle déjà décrite un cône terminé par un col en verre qui permettent d'obtenir un tube fermé sous vide. Comme il est connu le col porte les canons à électrons et l'ensemble de déviation magnétique. Le cône est doublé intérieurement d'un blindage magnétique constitué d'une pièce ferreuse qui épouse la forme du cône. Cette pièce ferreuse permet de fermer les lignes du champ magnétique émis par l'avant de l'ensemble de déviation (conduction magnétique) d'une part, d'autre part de former un corps noir avec le masque pour les divers rayonnements. Le dépot naturel de rouille est lui aussi préjudiciable.On the other hand, the tube comprises behind the already described slab a cone terminated by a glass neck which makes it possible to obtain a tube closed under vacuum. As is known, the neck carries the electron guns and the magnetic deflection assembly. The cone is internally lined with a magnetic shield consisting of a ferrous part which follows the shape of the cone. This ferrous part makes it possible to close the lines of the magnetic field emitted by the front of the deflection assembly (magnetic conduction) on the one hand, and on the other hand to form a black body with the mask for the various radiations. The natural deposit of rust is also harmful.

Un second problème concernant l'objet de l'invention se rapporte à la constitution naturelle de contraintes mécaniques induites dans les pièces métalliques. Ces contraintes doivent être annullées pour que la forme de chaque pièce soit stable. Un traitement de recuit des pièces ferreuses s'impose.A second problem relating to the subject of the invention relates to the natural constitution of mechanical stresses induced in metal parts. These constraints must be canceled so that the shape of each part is stable. An annealing treatment of ferrous parts is required.

Dans l'art antérieur la rouille est décapée par une réduction chimique à chaud. Puis il est connu dans un second temps de réaliser une oxydation particulière. En effet, il est connu que l'oxyde Fe3O4, dit aussi oxyde de fer II ou oxyde magnétique, possède de bonnes qualités de conduction magnétique. Il est donc intéressant de constituer un dépot d'oxyde magnétique Fe304 sur l'ensemble masque-cadre-blindage de cône. Il faut indiquer aussi que la finesse des masques est telle que le contrôle de la réduction et de l'oxydation doit être aussi précis que possible.In the prior art rust is pickled by a chemical reduction when hot. Then it is known in a second step to carry out a particular oxidation. Indeed, it is known that the oxide Fe 3 O 4 , also called iron oxide II or magnetic oxide, has good qualities of magnetic conduction. It is therefore advantageous to constitute a deposit of magnetic oxide Fe 3 0 4 on the mask-frame-cone shield assembly. It should also be noted that the fineness of the masks is such that the control of reduction and oxidation must be as precise as possible.

Dans l'art antérieur, les opérations sont réalisées séparément les unes des autres dans des fours spécialisés. On a ainsi un four de recuit et de réduction et un four d'oxydation. On trouvera un exemple de réalisation dans le Brevet US - 2 543 710. Selon une telle réalisation, on est contraint de travailler par séries de pièces ce qui conduit à des engorgements de la chaîne à l'entrée et à la sortie du traitement. Pour porter remède à cet inconvénient la présente invention concerne un procédé de préparation de pièces ferreuses, comme le cadre, le masque ou le blindage du cône. On réalise dans un four unique les quatre opérations de recuit, de réduction de la rouille, de première oxydation et de seconde oxydation, de façon à ce que soient formées successivement sur la surface de fer des couches adhérentes d'oxyde de fer I puis d'oxyde de fer II, les pièces à traiter défilant continûment.In the prior art, the operations are carried out separately from each other in specialized ovens. There is thus an annealing and reduction furnace and an oxidation furnace. An exemplary embodiment can be found in US Pat. No. 2,543,710. According to such an embodiment, one is forced to work in series of parts, which leads to blockages in the chain at the entry and exit of the treatment. To remedy this drawback, the present invention relates to a process for preparing ferrous parts, such as the frame, the mask or the shielding of the cone. The four annealing, rust reduction, first oxidation and second oxidation operations are carried out in a single oven, so that adherent layers of iron oxide I and d are successively formed on the iron surface. iron oxide II, the parts to be treated continuously scrolling.

L'invention concerne aussi un four unique en trois sections : de recuit-réduction, de première puis de seconde oxydations.The invention also relates to a single oven in three sections: annealing-reduction, first and second oxidations.

Les avantages principaux de l'invention sont :

  • - une réduction notable de coût de fabrication unitaire,
  • - une amélioration des qualités physicochimiques des pièces ferreuses.
The main advantages of the invention are:
  • - a significant reduction in unit manufacturing cost,
  • - an improvement in the physicochemical qualities of the ferrous parts.

Selon les modalités particulières de fabrication dues à la nature ou la provenance des pièces, d'autres traitements que ceux décrits ici sont à envisager. On peut citer des opérations de dégraissage des pièces livrées à la chaîne de montage, de roulage du masque, etc. Ces opérations, non exclues ni évitées par le procédé selon l'invention, ne concernent pas l'objet de l'invention.Depending on the particular manufacturing methods due to the nature or provenance of the parts, other treatments than those described here are to be considered. We can cite degreasing operations on parts delivered to the assembly line, rolling of the mask, etc. These operations, not excluded or avoided by the method according to the invention, do not concern the subject of the invention.

D'autres avantages et caractéristiques de la présente invention seront développés à l'aide de la description et des figures qui sont :

  • - la figure 1 : un cycle thermique du four de recuit-oxydation selon l'invention dans un exemple d'utilisation,
  • - la figure 2 : un schéma de four selon l'invention.
Other advantages and characteristics of the present invention will be developed with the aid of the description and the figures which are:
  • FIG. 1: a thermal cycle of the annealing-oxidation furnace according to the invention in an example of use,
  • - Figure 2: a diagram of an oven according to the invention.

Dans la suite de la description, on va donner l'exemple du traitement des cadres. Il faut, pour les autres pièces ferreuses, adapter les cycles thermiques en fonction des capacités thermiques de chaque type de pièce.In the following description, we will give the example of the treatment of frames. It is necessary, for the other ferrous parts, to adapt the thermal cycles according to the thermal capacities of each type of part.

Selon l'invention, en une seule passe chaque pièce ferreuse subit :

  • - un recuit,
  • - une réduction,
  • - une première oxydation,
  • - une seconde oxydation.
According to the invention, in a single pass each ferrous part undergoes:
  • - annealing,
  • - a discount,
  • - a first oxidation,
  • - a second oxidation.

A la figure 1, on a indiqué la répartition des températures dans le four. Les pièces métalliques sont introduites dans le four et avancent continûment à des vitesses variables. Un tel four est décrit à la figure 2. Le four comporte un corps chauffant qui est réparti le long de l'axe X du four. Sur l'axe X, on peut déterminer trois sections principales et deux sas. Les sections ne sont pas séparées par des portes ou des sas. A l'entrée du four on dispose d'un sas d'entrée 2. Les pièces sont introduites continûment sur un organe de transport, par exemple un tapis roulant. Elles pénètrent alors dans une première section 3, dite de recuit et de réduction. Le traitement de recuit permet de réduire ou d'éliminer les contraintes mécaniques dans les pièces. La réduction est une opération chimique qui permet de transformer la rouille formée à l'air libre sur les pièces ferreuses en fer pur. A la fin de la section 3 de recuit et de réduction, on obtient donc des pièces mécaniquement satisfaisantes et sans rouille. On rentre ensuite dans une seconde section 4 dite de première oxydation. Dans cette zone, on transforme le fer superficiel en oxyde de fer I dit FeO. A la fin de cette section 4 on pénètre dans une seconde section d'oxydation 5. Dans cette section, l'opération d'oxydation consiste à transformer superficiellement la couche d'oxyde de fer I en un oxyde de fer II dit Fe304. A la fin de la deuxième section d'oxydation 5, on pénètre dans un sas de sortie par lequel s'échappe les pièces préparées. Le long du corps de chauffe, on atteint par des rampes de températures une température d'environ 760 à 780° dans l'exemple des cadres. La température d'entrée de la section de recuit et de réduction, est de 40°C environ, tandis qu'à la sortie XI de cette section elle est d'environ 700°C. Dans la seconde section dite section de première oxydation 4, la température se stabilise à environ 760°C. A l'abssice X2, on commence une rampe de descente de température qui amène en sortie de la section de seconde oxydation 5 à une température d'environ 500°C. Puis la température décroit dans le sas de sortie.Figure 1 shows the temperature distribution in the oven. The metal parts are introduced into the furnace and advance continuously at variable speeds. Such an oven is described in Figure 2. The oven has a heating body which is distributed along the axis X of the oven. On the X axis, we can determine three main sections and two airlocks. The sections are not separated by doors or airlocks. At the entrance to the oven there is an entry airlock 2. The parts are introduced continuously onto a transport member, for example a conveyor belt. They then enter a first section 3, called annealing and reduction. The annealing treatment makes it possible to reduce or eliminate the mechanical stresses in the parts. Reduction is a chemical operation that transforms the rust formed in the open air on the ferrous parts made of pure iron. At the end of the annealing and reduction section 3, therefore, mechanically satisfactory parts are obtained without rust. We then enter a second section 4 called first oxidation. In this zone, the surface iron is transformed into iron oxide I called FeO. At the end of this section 4, we enter a second oxidation section 5. In this section, the oxidation operation consists in superficially transforming the layer of iron oxide I into an iron oxide II called Fe 3 0 4 . At the end of the second oxidation section 5, one enters an exit airlock through which the prepared parts escape. Along the heating body, a temperature of approximately 760 to 780 ° is reached by temperature ramps in the example of the frames. The inlet temperature of the annealing and reduction section is approximately 40 ° C., while at the outlet XI of this section it is approximately 700 ° C. In the second section known as the first oxidation section 4, the temperature stabilizes at around 760 ° C. At absection X2, a temperature down ramp begins which brings the output of the second oxidation section 5 to a temperature of approximately 500 ° C. Then the temperature decreases in the exit airlock.

Une telle préparation des parties ferreuses permet d'obtenir des couches d'oxydes très homogènes et une bonne adhérence sur le fer superficiel. En effet, on passe d'un degré d'oxydation 0 jusqu'à un degré d'oxydation 2 en croissant continûment. Cette préparation est d'une qualité nettement améliorée par rapport à l'art antérieur où l'oxydation se faisait séparément de la réduction de la rouille.Such preparation of the ferrous parts makes it possible to obtain very homogeneous oxide layers and good adhesion to the surface iron. Indeed, one goes from an oxidation state 0 to an oxidation state 2 continuously increasing. This preparation is of a clearly improved quality compared to the prior art where the oxidation was done separately from the reduction of rust.

D'autre part, on réalise une économie dans le coût de traite ment puisqu'un seul four est utilisé avec un défilement continu et que le temps de traitement est réduit. On augmente ainsi la capacité de la chaine de fabrication des tubes.On the other hand, there is a saving in the processing cost since only one oven is used with continuous scrolling and the processing time is reduced. This increases the capacity of the tube manufacturing line.

Les opérations chimiques de réduction et d'oxydation sont réalisées par la coordination du cycle de température décrit avec l'utilisation d'atmosphère dont les constituants chimiques sont dosés régulièrement. Dans la section de recuit et de réduction 3, l'atmosphère utilisée est une atmosphère réductrice. C'est à dire que le rapport oxydant ou taux d'oxydation qui est égal au rapport entre le nombre de môles réductrices et le nombre de môles oxydantes plus réductrices est de valeur proche de un. Selon la présente invention, une telle atmosphère est obtenue par un mélangeur de gaz. On réalise aussi un dosage des produits qui sont l'azote N2 et l'hydrogène H2, de façon à ce que leurs proportions relatives soient de 95 et de 5 parties pour cent. Dans l'exemple de réalisation, le débit de l'atmosphère réductrice est de 12,5m3 par heure.The chemical reduction and oxidation operations are carried out by coordinating the temperature cycle described with the use of an atmosphere whose chemical constituents are dosed regularly. In the annealing and reduction section 3, the atmosphere used is a reducing atmosphere. That is to say that the oxidizing ratio or oxidation rate which is equal to the ratio between the number of reducing moles and the number of more reducing oxidizing moles is of value close to one. According to the present invention, such an atmosphere is obtained by a gas mixer. A determination is also made of the products which are nitrogen N 2 and hydrogen H 2 , so that their relative proportions are 95 and 5 parts per cent. In the exemplary embodiment, the flow rate of the reducing atmosphere is 12.5 m 3 per hour.

L'atmosphère utilisée dans les sections suivantes est une atmosphère oxydante. Dans une telle atmosphère le rapport oxydant à une valeur permettant l'oxydation. Dans l'exemple de réalisation décrit plus haut, dans la section d'oxydation 4 la valeur de ce rapport est proche de 0,4 (quatre dixièmes) puis de 0,25 dans la section de seconde oxydation 5.The atmosphere used in the following sections is an oxidizing atmosphere. In such an atmosphere the oxidizing ratio to a value allowing oxidation. In the embodiment described above, in the oxidation section 4 the value of this ratio is close to 0.4 (four tenths) then to 0.25 in the second oxidation section 5.

L'atmosphère réductrice composée d'azote et d'hydrogène peut être obtenue notamment par un mélangeur de gaz dont on contrôle en permanence les parties réductrices. L'atmosphère oxydante est réalisée à partir d'une telle atmosphère réductrice par adjonction d'une pression de vapeur d'eau qui sert de corps oxydant.The reducing atmosphere composed of nitrogen and hydrogen can be obtained in particular by a gas mixer, the reducing parts of which are constantly monitored. The oxidizing atmosphere is produced from such a reducing atmosphere by adding a pressure of water vapor which serves as an oxidizing body.

La séparation chimique des sections est obtenue en maintenant la pression à l'intérieur du four relativement plus forte que la pression atmosphérique extérieure au four. Le mélange réducteur est injecté en un flux continu dirigé vers la sortie du four. Puis la partie oxydante désirée est injectée plus loin dans le même sens au niveau des sections 4 , 5 où elle se mélange avec le flux réducteur. L'avantage d'une telle disposition est de permettre :

  • - d'éviter que l'atmosphère extérieure pénètre dans le four sans qu'il soit besoin de sas compliqués,
  • - d'éliminer les maniements de portes entre les différentes zones de traitement.
The chemical separation of the sections is obtained by keeping the pressure inside the oven relatively higher than the atmospheric pressure outside the oven. The reducing mixture is injected in a continuous flow directed towards the exit of the furnace. Then the desired oxidizing part is injected further in the same direction at the level of sections 4, 5 where it mixes with the reducing flow. The advantage of such a provision is to allow:
  • - to prevent the outside atmosphere from entering the oven without the need for complicated airlocks,
  • - to eliminate the handling of doors between the different treatment zones.

La présente invention n'est pas limitée au traitement de l'une ou l'autre des pièces métalliques incluses derrière la dalle dans le tube de télévision. D'autres atmosphères peuvent être utilisées de la même façon.The present invention is not limited to the treatment of one or other of the metal parts included behind the panel in the television tube. Other atmospheres can be used in the same way.

Les temps de traitement sont, par exemple :

  • - d'environ sept minutes pour le recuit-réduction,
  • - d'environ six minutes pour la première oxydation,
  • - d'environ trois minutes trente secondes pour la seconde oxydation,
  • - d'environ neuf minutes vingt secondes pour ramener les pièces à leur température de sortie.
Processing times are, for example:
  • - approximately seven minutes for reduction-annealing,
  • - about six minutes for the first oxidation,
  • - about three and a half seconds for the second oxidation,
  • - about nine minutes and twenty seconds to bring the parts back to their outlet temperature.

Soit une durée totale d'environ vingt six minutes, les pièces étant translatées en permanence dans le four.That is to say a total duration of approximately twenty six minutes, the pieces being permanently translated in the oven.

Claims (8)

1. Procédé de préparation des pièces ferreuses d'un tube de télévision en couleurs, chaque pièce ferreuse subissant un traitement de recuit en atmosphère réductrice pour éliminer la rouille, puis étant oxydée par des atmosphères oxydantes à taux d'oxydation variable pour former à partir de la surface de fer pur des couches successives d'oxydes de fer I et II, caractérisé en ce que les pièces défilent en continu dans les diverses sections d'un four unique.1. Process for preparing the ferrous parts of a color television tube, each ferrous part undergoing an annealing treatment in a reducing atmosphere to remove rust, then being oxidized by oxidizing atmospheres with variable oxidation rate to form from from the surface of pure iron of the successive layers of iron oxides I and II, characterized in that the pieces pass continuously through the various sections of a single oven. 2. Procédé selon la revendication 1, caractérisé en ce que le rapport oxydant de l'atmosphère du four, en une première étape réductrice, est proche de la valeur unité pour une température de chauffe de 760° maximum de façon à réaliser une réduction de la rouille.2. Method according to claim 1, characterized in that the oxidizing ratio of the furnace atmosphere, in a first reducing step, is close to the unit value for a heating temperature of 760 ° maximum so as to achieve a reduction of rust. 3. Procédé selon la revendication 2, caractérisé en ce que le rapport oxydant est proche de la valeur 0,4 (quatre dixième) pour une température de chauffe d'au moins 700° de façon à réaliser une oxydation superficielle en oxyde de fer 1.3. Method according to claim 2, characterized in that the oxidizing ratio is close to the value 0.4 (four tenths) for a heating temperature of at least 700 ° so as to carry out a surface oxidation to iron oxide 1 . 4. Procédé selon la revendication 3, caractérisé en ce que le rapport oxydant est proche de la valeur 0,25 pour une température inférieure de peu à 550°C de façon à réaliser une oxydation superficielle en oxyde de fer II.4. Method according to claim 3, characterized in that the oxidizing ratio is close to the value 0.25 for a temperature slightly below 550 ° C so as to carry out a surface oxidation to iron oxide II. 5. Procédé selon la revendication 1, caractérisé en ce que l'atmosphère oxydante est obtenue à partir de l'atmosphère réductrice par addition d'un flux de vapeur d'eau, au niveau de la seconde section (x 1) ou de la troisième section (x2).5. Method according to claim 1, characterized in that the oxidizing atmosphere is obtained from the reducing atmosphere by addition of a flow of water vapor, at the second section (x 1 ) or the third section (x 2 ). 6. Procédé selon la revendication 1 ou 5, caractérisé en ce que l'atmosphère réductrice est constituée d'azote et d'hydrogène, dans des proportions respectives de 95 et 5 parties pour cent.6. Method according to claim 1 or 5, characterized in that the reducing atmosphere consists of nitrogen and hydrogen, in respective proportions of 95 and 5 parts per cent. 7. Procédé selon la revendication 6, caractérisé en ce que l'atmosphère azote-hydrogène est obtenue par un mélangeur de gaz.7. Method according to claim 6, characterized in that the nitrogen-hydrogen atmosphere is obtained by a gas mixer. 8. Four de préparation mettant en oeuvre le procédé selon l'une des revendications précédentes, caractérisé en ce qu'il comporte un corps (1) chauffant séparé en autant de sections (3, 4, 5) qu'il y a d'étapes de traitement, les flux gazeux injectés selon le procédé revendiqué réalisant le long du déplacement des pièces (x) les séparations entre sections du four (3 , 4 , 5).8. Preparation oven implementing the method according to one of the preceding claims, characterized in that it com carries a heating body (1) separated into as many sections (3, 4, 5) as there are treatment steps, the gas streams injected according to the claimed process performing along the movement of the parts (x) the separations between sections of the oven (3, 4, 5).
EP84400153A 1982-08-20 1984-01-24 Process for manufacturing the iron parts of a colour television tube Expired EP0149927B1 (en)

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DE8484400153T DE3478168D1 (en) 1984-01-24 1984-01-24 Process for manufacturing the iron parts of a colour television tube

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FR8214436A FR2532108A1 (en) 1982-08-20 1982-08-20 PROCESS FOR PREPARING THE FERROUS PARTS OF A COLOR TELEVISION TUBE AND AN OVEN FOR CARRYING OUT SUCH A METHOD

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EP0271135A1 (en) * 1986-11-20 1988-06-15 Philips Patentverwaltung GmbH Cleaning process for metal elements of cathode ray tubes
EP0284233A1 (en) * 1987-03-07 1988-09-28 Kabushiki Kaisha Toshiba Furnace for formation of black oxide film on the surface of thin metal sheet and method for formation of black oxide film on the surface of shadow mask material by use of said furnace
FR2690167A1 (en) * 1992-04-16 1993-10-22 Lorraine Laminage Continuous thermal blueing treatment for steel sheet - by heating to first temp., cooling to maturing temp. and holding in oxidising atmos., and cooling

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FR2532108A1 (en) * 1982-08-20 1984-02-24 Videocolor Sa PROCESS FOR PREPARING THE FERROUS PARTS OF A COLOR TELEVISION TUBE AND AN OVEN FOR CARRYING OUT SUCH A METHOD
US4612061A (en) * 1984-03-15 1986-09-16 Kabushiki Kaisha Toshiba Method of manufacturing picture tube shadow mask
NL8600141A (en) * 1986-01-23 1987-08-17 Philips Nv METHOD FOR MANUFACTURING A SHADOW MASK, SHADOW MASK MADE ACCORDING TO A METHOD AND COLOR IMAGE TUBE PROVIDED WITH SUCH A SHADOW MASK.
US4859251A (en) * 1987-03-07 1989-08-22 Kabushiki Kaisha Toshiba Furnace for formation of black oxide film on the surface of thin metal sheet and method for formation of black oxide film on the surface of shadow mask material by use of said furnace
JP2768389B2 (en) * 1991-04-03 1998-06-25 中外炉工業 株式会社 Method for blackening Ni-Fe based shadow mask
US5292274A (en) * 1993-03-25 1994-03-08 Thomson Consumer Electronics, Inc. Method of manufacturing a color CRT to optimize the magnetic performance
DE4439440C2 (en) * 1994-11-04 1997-05-15 Nokia Deutschland Gmbh Device for maintaining an oxidation process
US6045628A (en) * 1996-04-30 2000-04-04 American Scientific Materials Technologies, L.P. Thin-walled monolithic metal oxide structures made from metals, and methods for manufacturing such structures
US5814164A (en) * 1994-11-09 1998-09-29 American Scientific Materials Technologies L.P. Thin-walled, monolithic iron oxide structures made from steels, and methods for manufacturing such structures
US6461562B1 (en) 1999-02-17 2002-10-08 American Scientific Materials Technologies, Lp Methods of making sintered metal oxide articles
US6277214B1 (en) 1999-07-09 2001-08-21 Powertech Labs Inc. Protective iron oxide scale on heat-treated irons and steels
EP3176436B1 (en) * 2012-02-20 2018-05-16 Panasonic Corporation Slide member, refrigerant compressor incorporating slide member, refrigerator and air conditioner

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US4919157A (en) * 1986-11-20 1990-04-24 U.S. Philips Corporation Method of cleaning metal components for cathode ray tubes
EP0284233A1 (en) * 1987-03-07 1988-09-28 Kabushiki Kaisha Toshiba Furnace for formation of black oxide film on the surface of thin metal sheet and method for formation of black oxide film on the surface of shadow mask material by use of said furnace
FR2690167A1 (en) * 1992-04-16 1993-10-22 Lorraine Laminage Continuous thermal blueing treatment for steel sheet - by heating to first temp., cooling to maturing temp. and holding in oxidising atmos., and cooling

Also Published As

Publication number Publication date
EP0149927B1 (en) 1989-05-10
US4714497A (en) 1987-12-22
HK49294A (en) 1994-05-27
FR2532108A1 (en) 1984-02-24
FR2532108B1 (en) 1985-05-03
JPH0742565B2 (en) 1995-05-10
JPS60174867A (en) 1985-09-09

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