EP0407275A1 - Method of making workpieces, with excellent mechanical properties, from non-treated steel - Google Patents
Method of making workpieces, with excellent mechanical properties, from non-treated steel Download PDFInfo
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- EP0407275A1 EP0407275A1 EP90401879A EP90401879A EP0407275A1 EP 0407275 A1 EP0407275 A1 EP 0407275A1 EP 90401879 A EP90401879 A EP 90401879A EP 90401879 A EP90401879 A EP 90401879A EP 0407275 A1 EP0407275 A1 EP 0407275A1
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- Prior art keywords
- parts
- heating
- austenitization
- steel
- quenching
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Classifications
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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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
- C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
Definitions
- the present invention relates to a process for manufacturing parts with high mechanical characteristics from untreated steel, comprising a succession of heat treatment and forming operations.
- This process intended in particular for the manufacture of rail fasteners, comprises the following stages: - cold forming or preforming of parts, - austenitization heating of the parts, preferably in a fluidized bed bath or by induction, - quenching of the parts in a fluidized bed bath, - tempering of the parts preferably in a fluidized bed bath, - shot blasting, - possibly final cold forming of the parts, - protection.
- this known method still has a certain number of drawbacks.
- it involves two temperature rise operations (austenitization heating before quenching, tempering after quenching).
- tempering after quenching the fact that the parts undergo cold forming or at least preforming, before any heating, it is impossible to carry out this heating on continuous material, for example strip.
- the subject of the present invention is a process for manufacturing parts in treated steel which makes it possible to produce parts of equivalent quality or even better than that obtained by conventional methods at a lower cost.
- the process according to the invention for manufacturing parts from untreated steel comprises the following successive operations: - heating the steel to a temperature above the transformation point (austenitization), - isothermal quenching in a fluidized bed bath, immediately following the austenitization heating, - warm parts forming.
- the austenitization heating can advantageously be carried out in a fluidized bed bath or by induction, on continuous products (strips, crowns) or on blanks or pieces. It is also possible, within the framework of the invention, to carry out a cold preforming, before austenitization heating, to give the parts a shape different from their final shape, in which case the warm forming carried out after heating isothermal austenitization and quenching is intended above all to give the parts a more precise geometry and higher mechanical characteristics (thermomechanical warm treatment such as blocking in the case of springs).
- the conventional hot forming process before quenching requires heating the parts as a whole to a temperature much higher than the transformation point to take account of the cooling that the parts undergo during the hot forming operation and during transfers.
- the quenching operation (which gives the steel a bainitic structure) immediately follows the austenitization heating operation, the heat losses are very low and the lower heating temperature, since it is only used for quenching.
- the untreated part of the metal plays a complementary role for quenching and the rest of the operations, by heat diffusion.
- induction or fluidized bed heating makes it possible to carry out heat exchanges in reduced spaces, which significantly reduces the losses of the installation in operation and the start-up and shutdown times of the installation, therefore the losses who as a result.
- the replacement of oil quenching by fluidized bed quenching eliminates the need to suck oil fumes and those to wash and dry the parts.
- the additional heating necessary to compensate for the losses due to the oil quenching and washing operations is saved.
- the replacement of the two quenching and tempering operations of the usual processes with isothermal quenching allows other significant energy savings.
- the energy to bring the part to the tempering temperature is removed.
- the holding time at the isothermal quenching temperature represents less than half of the holding time at the tempering temperature according to the usual methods.
- Most of the energy induced during austenitization is returned to the fluidized quench bath isothermal, which allows this energy to be reused, for example for heating buildings.
- the parts with a bainitic structure are at a temperature above the martensite point, that is to say at a temperature of the order of 280-350 ° C. depending on the steel grades, and the residual energy that they contain can be used as the following operations are carried out warm (forming, blocking, prestressing, shot blasting, protection).
- the process according to the invention thus makes it possible to recover the major part of the energy provided during austenitization.
- Warm forming gives the parts better precision and increases the mechanical characteristics of the finished product, notably promoting the blocking of dislocations induced during forming, due in particular to the increase in mobility of carbon atoms linked to temperature. Rapid heating followed by isothermal quenching eliminates any risk of decarburization.
- the successive operations of the process according to the invention are carried out in a precise order making it possible to make the most of the energy stored in the material.
- the choice of temperature for each operation aims to optimize the beneficial effects, in particular on a metallurgical level for shot peening and pre-forming (or blocking), and on the electrochemical level for anti-corrosion protection.
- the method according to the invention does not require the formation of a so-called bonding layer generally obtained by chemical combination (phosphating) with the metal to be protected, the formation of this bonding layer resulting in a decrease in the surface mechanical characteristics of the parts.
- the process according to the invention reduces the number of operations, in particular temperature rise and the temperature maintenance times.
- the installations necessary for the implementation of the process are therefore of reduced dimensions.
- the investment and the surface area required for an installation using the method according to the invention are divided by a factor of approximately five.
- the process according to the invention makes it possible to considerably reduce the work in progress.
- the outstanding amount is only 40 springs for the process according to the invention, while it is 1,200 in the conventional process.
- a few minutes are sufficient to empty the installation of its parts for the implementation of the process according to the invention.
- the process according to the invention eliminates all harmful fumes and vapors and makes work much less arduous.
- the process according to the invention eliminates all the discharges (fumes, vapors, detergents, etc.) from the usual hot forming and oil quenching process.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Steel (AREA)
- Chemical Treatment Of Metals (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
La présente invention se rapporte à un procédé de fabrication de pièces à hautes caractéristiques mécaniques à partir d'acier non traité, comprenant une succession d'opérations de traitement thermique et de formage.The present invention relates to a process for manufacturing parts with high mechanical characteristics from untreated steel, comprising a succession of heat treatment and forming operations.
Les procédés classiques de fabrication de pièces en acier traité à partir d'acier non traité en barres, en bandes ou en couronnes, par exemple de ressorts, de barres stabilisatrices, d'attaches élastiques de rails de chemin de fer, comprennent un grand nombre d'opérations.Conventional methods of manufacturing steel parts treated from untreated steel in bars, strips or rings, for example springs, stabilizer bars, elastic fasteners of railway rails, include a large number of operations.
A titre d'exemple, on va donner ci-après les différentes opérations successives d'un procédé classique de fabrication de ressorts :
- dévidage des couronnes, dressage, écroutage et rectification,
- chauffage d'austénitisation dans un four à atmosphère,
- formage à chaud,
- trempe à l'huile,
- revenu dans un four,
- refroidissement,
- blocage,
- refroidissement à la température ambiante,
- grenaillage de précontrainte,
- revenu après grenaillage,
- protection (peinture ou plastification),
- cuisson ou réticulation,
- refroidissement à la température ambiante,
- contrôle.By way of example, the following successive operations of a conventional method of manufacturing springs will be given:
- unwinding of crowns, dressing, peeling and grinding,
- austenitization heating in an atmosphere furnace,
- hot forming,
- oil quenching,
- returned to an oven,
- cooling,
- blocking,
- cooling to room temperature,
- shot peening,
- income after shot blasting,
- protection (painting or plasticization),
- baking or crosslinking,
- cooling to room temperature,
- control.
Ce procédé classique comprend en particulier un grand nombre de phases de variation de température dont chacune implique des dépenses d'énergie considérables et des installations coûteuses. Le formage à chaud et la trempe à l'huile sont par ailleurs des opérations qui ont lieu dans des conditions de travail et de sécurité difficiles. Enfin la trempe à l'huile est une opération génératrice de pollution par le dégagement de fumées et de vapeurs nocives et par le lavage auxquels les pièces doivent être soumises à la suite de la trempe à l'huile.This conventional process in particular comprises a large number of temperature variation phases, each of which involves considerable energy expenditure and costly installations. Hot forming and oil quenching are also operations that take place under difficult working and safety conditions. Finally, oil quenching is an operation generating pollution by the release of noxious fumes and fumes and by the washing to which the parts must be subjected following oil quenching.
Le procédé suivant la demande de brevet français n° 2 391 789 remédie déjà partiellement aux inconvénients énumérés ci-dessus. Ce procédé destiné notamment à la fabrication d'attaches de rails comprend les étapes suivantes :
- formage ou préformage à froid des pièces,
- chauffage d'austénitisation des pièces, de préférence dans un bain à lit fluidisé ou par induction,
- trempe des pièces dans un bain à lit fluidisé,
- revenu des pièces de préférence dans un bain à lit fluidisé,
- grenaillage,
- éventuellement formage final à froid des pièces,
- protection.The process according to French patent application no. 2 391 789 already partially remedies the drawbacks listed above. This process, intended in particular for the manufacture of rail fasteners, comprises the following stages:
- cold forming or preforming of parts,
- austenitization heating of the parts, preferably in a fluidized bed bath or by induction,
- quenching of the parts in a fluidized bed bath,
- tempering of the parts preferably in a fluidized bed bath,
- shot blasting,
- possibly final cold forming of the parts,
- protection.
Toutefois, ce procédé connu présente encore un certain nombre d'inconvénients. En particulier, il implique deux opérations de montée en température (chauffage d'austénitisation avant trempe, revenu après trempe). Par ailleurs, du fait que les pièces subissent un formage ou au moins un préformage à froid, avant tout chauffage, il est impossible d'effectuer ce chauffage sur du matériau continu, par exemple en bande.However, this known method still has a certain number of drawbacks. In particular, it involves two temperature rise operations (austenitization heating before quenching, tempering after quenching). Furthermore, the fact that the parts undergo cold forming or at least preforming, before any heating, it is impossible to carry out this heating on continuous material, for example strip.
La présente invention a pour objet un procédé de fabrication de pièces en acier traité permettant de réaliser à moindre coût des pièces de qualité équivalente voire supérieure à celle obtenue par les procédés usuels.The subject of the present invention is a process for manufacturing parts in treated steel which makes it possible to produce parts of equivalent quality or even better than that obtained by conventional methods at a lower cost.
Le procédé conforme à l'invention de fabrication de pièces à partir d'acier non traité comprend les opérations successives suivantes :
- chauffage de l'acier à une température supérieure au point de transformation (austénitisation),
- trempe isotherme dans un bain à lit fluidisé, immédiatement à la suite du chauffage d'austénitisation,
- formage des pièces à tiède.The process according to the invention for manufacturing parts from untreated steel comprises the following successive operations:
- heating the steel to a temperature above the transformation point (austenitization),
- isothermal quenching in a fluidized bed bath, immediately following the austenitization heating,
- warm parts forming.
Contrairement à un préjugé selon lequel seul un formage après chauffage d'austénitisation et trempe martensitique permettait d'obtenir des pièces à hautes caractéristiques, il s'est avéré de façon surprenante que les pièces obtenues par formage à tiède après trempe isotherme (structure bainitique) présentaient des caractéristiques mécaniques et géométriques (notamment tenue en fatigue, corrosion sous tension, précision, tolérances plus étroites) nettement améliorées.Contrary to a prejudice according to which only a formation after austenitization heating and martensitic quenching made it possible to obtain parts with high characteristics, it was surprisingly found that the parts obtained by lukewarm forming after isothermal quenching (bainitic structure) exhibited mechanical and geometric characteristics (notably fatigue resistance, corrosion under tension, precision, tighter tolerances) significantly improved.
Dans le cadre de l'invention, le chauffage d'austénitisation peut se faire avantageusement en bain à lit fluidisé ou par induction, sur des produits continus (bandes, couronnes) ou sur des flans ou des lopins. Il est également possible, dans le cadre de l'invention, de procéder à un préformage à froid, avant chauffage d'austénitisation, pour donner aux pièces une forme différente de leur forme définitive, auquel cas le formage à tiède effectué après chauffage d'austénitisation et trempe isotherme est destiné surtout à conférer aux pièces une géométrie plus précise et des caractéristiques mécaniques plus élevées (traitement thermomécanique à tiède tel que blocage dans le cas de ressorts).In the context of the invention, the austenitization heating can advantageously be carried out in a fluidized bed bath or by induction, on continuous products (strips, crowns) or on blanks or pieces. It is also possible, within the framework of the invention, to carry out a cold preforming, before austenitization heating, to give the parts a shape different from their final shape, in which case the warm forming carried out after heating isothermal austenitization and quenching is intended above all to give the parts a more precise geometry and higher mechanical characteristics (thermomechanical warm treatment such as blocking in the case of springs).
Enfin, à la suite du formage à tiède, il est possible de procéder, dans le cadre de l'invention, sans nouvelle montée en température des pièces, à un grenaillage de précontrainte à tiède et à une protection à tiède (peinture avec cuisson, plastification), en bénéficiant de la chaleur résiduelle des pièces.Finally, after lukewarm forming, it is possible, within the framework of the invention, without further temperature rise of the parts, to a shot peening with lukewarm lukewarm and to a lukewarm protection (painting with cooking, plasticization), taking advantage of the residual heat of the rooms.
Les nombreux avantages du procédé conforme à l'invention peuvent être classés comme suit :The numerous advantages of the process according to the invention can be classified as follows:
Le procédé classique de formage à chaud avant trempe nécessite un chauffage des pièces dans leur totalité à une température nettement supérieure au point de transformation pour tenir compte du refroidissement que les pièces subissent pendant l'opération de formage à chaud et pendant les transferts.The conventional hot forming process before quenching requires heating the parts as a whole to a temperature much higher than the transformation point to take account of the cooling that the parts undergo during the hot forming operation and during transfers.
Dans le procédé conforme à l'invention, du fait que l'opération de trempe (qui donne à l'acier une structure bainitique) fait immédiatement suite à l'opération de chauffe d'austénitisation, les pertes de chaleur sont très faibles et la température de chauffage plus basse, puisqu'elle sert uniquement à réaliser la trempe.In the process according to the invention, since the quenching operation (which gives the steel a bainitic structure) immediately follows the austenitization heating operation, the heat losses are very low and the lower heating temperature, since it is only used for quenching.
Suivant le procédé conforme à l'invention, il n'est d'ailleurs nécessaire que de chauffer, donc de traiter la partie travaillante du métal, ce qui constitue un gain supplémentaire d'énergie.According to the method according to the invention, it is moreover only necessary to heat, therefore to treat the working part of the metal, which constitutes an additional energy gain.
Il est à noter que dans ce cas, la partie non traitée du métal joue un rôle complémentaire pour la trempe et la suite des opérations, par diffusion de chaleur.It should be noted that in this case, the untreated part of the metal plays a complementary role for quenching and the rest of the operations, by heat diffusion.
Le choix du chauffage par induction ou en lit fluidisé permet de réaliser les échanges thermiques dans des espaces réduits, ce qui diminue sensiblement les pertes de l'installation en fonctionnement et les temps de démarrage et d'arrêt de l'installation, donc les pertes qui en découlent. Le remplacement de la trempe à l'huile par une trempe en lit fluidisé supprime la nécessité d'aspirer des fumées d'huile et celles de laver et de sécher les pièces. En plus de l'énergie que consomment ces opérations, on économise suivant l'invention le complément de chauffage nécessaire pour compenser les pertes dues aux opérations de la trempe à l'huile et du lavage.The choice of induction or fluidized bed heating makes it possible to carry out heat exchanges in reduced spaces, which significantly reduces the losses of the installation in operation and the start-up and shutdown times of the installation, therefore the losses who as a result. The replacement of oil quenching by fluidized bed quenching eliminates the need to suck oil fumes and those to wash and dry the parts. In addition to the energy consumed by these operations, according to the invention, the additional heating necessary to compensate for the losses due to the oil quenching and washing operations is saved.
Le remplacement des deux opérations de trempe et de revenu des procédés usuels par la trempe isotherme permet d'autres importantes économies d'énergie. Ainsi, l'énergie pour amener la pièce à la température de revenu est supprimée. Le temps de maintien à la température de trempe isotherme représente moins de la moitié du temps de maintien à la température de revenu suivant les procédés usuels. La plus grande partie de l'énergie induite lors de l'austénitisation est restitué dans le bain fluidisé de trempe isotherme, ce qui permet de réutiliser cette énergie par exemple pour le chauffage des bâtiments.The replacement of the two quenching and tempering operations of the usual processes with isothermal quenching allows other significant energy savings. Thus, the energy to bring the part to the tempering temperature is removed. The holding time at the isothermal quenching temperature represents less than half of the holding time at the tempering temperature according to the usual methods. Most of the energy induced during austenitization is returned to the fluidized quench bath isothermal, which allows this energy to be reused, for example for heating buildings.
Au sortir de la trempe isotherme, les pièces à structure bainitique sont à une températures supérieure au point de martensite, soit à une température de l'ordre de 280-350°C selon les nuances d'acier, et l'énergie résiduelle qu'elles contiennent peut être utilisée au fur et à mesure des opérations suivantes effectuées à tiède (formage, blocage, précontrainte, grenaillage, protection).At the end of the isothermal quenching, the parts with a bainitic structure are at a temperature above the martensite point, that is to say at a temperature of the order of 280-350 ° C. depending on the steel grades, and the residual energy that they contain can be used as the following operations are carried out warm (forming, blocking, prestressing, shot blasting, protection).
Le procédé conforme à l'invention permet ainsi de récupérer la majeure partie de l'énergie apportée lors de l'austénitisation.The process according to the invention thus makes it possible to recover the major part of the energy provided during austenitization.
Le formage à tiède confère aux pièces une meilleure précision et augmente les caractéristiques mécaniques du produit fini en favorisant notablement le blocage des dislocations induites au cours du formage, en raison notamment de l'augmentation de la mobilité des atomes de carbone liée à la température. Le chauffage rapide suivi de la trempe isotherme supprime tout risque de décarburation.Warm forming gives the parts better precision and increases the mechanical characteristics of the finished product, notably promoting the blocking of dislocations induced during forming, due in particular to the increase in mobility of carbon atoms linked to temperature. Rapid heating followed by isothermal quenching eliminates any risk of decarburization.
Les opérations successives du procédé conforme à l'invention sont effectuées dans un ordre précis permettant de bénéficier au maximum de l'énergie emmagasinée dans la matière. Le choix de la température pour chaque opération vise à optimiser les effets bénéfiques notamment sur un plan métallurgique pour le grenaillage de précontrainte et la préconformation (ou blocage), et sur le plan électrochimique pour la protection anticorrosion. En effet, contrairement aux procédés usuels, le procédé conforme à l'invention ne nécessite pas la formation d'une couche dite d'accrochage obtenue généralement par combinaison chimique (phosphatation) avec le métal à protéger, la formation de cette couche d'accrochage entraînant une diminution des caractéristiques mécaniques superficielles des pièces.The successive operations of the process according to the invention are carried out in a precise order making it possible to make the most of the energy stored in the material. The choice of temperature for each operation aims to optimize the beneficial effects, in particular on a metallurgical level for shot peening and pre-forming (or blocking), and on the electrochemical level for anti-corrosion protection. In fact, unlike the usual methods, the method according to the invention does not require the formation of a so-called bonding layer generally obtained by chemical combination (phosphating) with the metal to be protected, the formation of this bonding layer resulting in a decrease in the surface mechanical characteristics of the parts.
La suppression de l'opération de trempe à l'huile et son remplacement par une trempe en bain à lit fluidisé économisent la consommation de produits pétroliers comme l'huile de trempe et les produits et l'eau de lavage. Dans la mesure où le procédé conforme à l'invention procure des pièces de meilleure qualité, il permet de réduire la quantité de matière nécessaire à une même fonction. D'un autre côté, il est possible d'utiliser, suivant l'invention, des aciers moins alliés pour obtenir des pièces ayant des caractéristiques comparables.The elimination of the oil quenching operation and its replacement by quenching in a fluidized bed bath saves the consumption of petroleum products such as quench oil and washing products and water. Insofar as the process according to the invention provides better quality parts, it makes it possible to reduce the quantity of material necessary for the same function. On the other hand, it is possible, according to the invention, to use less alloyed steels to obtain parts having comparable characteristics.
La possibilité d'utiliser le métal brut de laminage et en couronnes entraîne une réduction importante des pertes de matière et du prix de la matière première.The possibility of using raw rolling and crown metal results in a significant reduction in material losses and the price of the raw material.
Le procédé conforme à l'invention réduit le nombre des opérations notamment de montée en température et les temps de maintien en température. Les installations nécessaires pour la mise en oeuvre du procédé sont donc de dimensions réduites.The process according to the invention reduces the number of operations, in particular temperature rise and the temperature maintenance times. The installations necessary for the implementation of the process are therefore of reduced dimensions.
A titre d'exemple, les investissements et la surface nécessaire pour une installation utilisant le procédé conforme à l'invention, compararativement à une installation classique pour produire des ressorts de suspension de véhicules automobiles, sont divisés par un facteur d'environ cinq.By way of example, the investment and the surface area required for an installation using the method according to the invention, compared with a conventional installation for producing suspension springs for motor vehicles, are divided by a factor of approximately five.
Le procédé conforme à l'invention permet de réduire considérablement les encours de fabrication. Ainsi, pour une production de 600 ressorts de suspension à l'heure, l'encours n'est que de 40 ressorts pour le procédé conforme à l'invention, alors qu'il est de 1200 dans le procédé classique. Quelques minutes suffisent pour vider de ses pièces l'installation pour la mise en oeuvre du procédé conforme à l'invention.The process according to the invention makes it possible to considerably reduce the work in progress. Thus, for a production of 600 suspension springs per hour, the outstanding amount is only 40 springs for the process according to the invention, while it is 1,200 in the conventional process. A few minutes are sufficient to empty the installation of its parts for the implementation of the process according to the invention.
Grâce à la suppression de la trempe à l'huile et grâce au formage à tiède, le procédé conforme à l'invention supprime toutes les fumées et vapeurs nocives et rend le travail beaucoup moins pénible.Thanks to the elimination of oil quenching and thanks to lukewarm forming, the process according to the invention eliminates all harmful fumes and vapors and makes work much less arduous.
La propreté des installations pour la mise en oeuvre du procédé conforme à l'invention et leurs dimensions réduites procurent une qualité d'ambiance de travail et une productivité de loin supérieures à celles du procédé classique.The cleanliness of the facilities for implementing the process according to the invention and their reduced dimensions provide a quality of working atmosphere and productivity far superior to those of the conventional process.
Le procédé conforme à l'invention supprime tous les rejets (fumées, vapeurs, produits de lavage, etc.) du procédé usuel de formage à chaud et de trempe à l'huile.The process according to the invention eliminates all the discharges (fumes, vapors, detergents, etc.) from the usual hot forming and oil quenching process.
On va décrire ci-après la succession des opérations, avec indication des températures et des temps nécessaires, pour un procédé classique de fabrication de ressorts et, à titre de comparaison, un exemple du procédé conforme à l'invention pour la fabrication de ressorts de caractéristiques comparables destinés aux suspensions de véhicules automobiles.
Claims (7)
- chauffage de l'acier à une température supérieure au point de transformation (austénitisation),
- trempe isotherme dans un bain à lit fluidisé, immédiatement à la suite du chauffage d'austénitisation, (donnant à l'acier une structure bainitique) et
- formage des pièces à tiède.1. A method of manufacturing parts from untreated steel comprising a succession of heat treatment and forming operations, characterized in that it comprises the following successive operations:
- heating the steel to a temperature above the transformation point (austenitization),
- isothermal quenching in a fluidized bed bath, immediately following the austenitization heating, (giving the steel a bainitic structure) and
- warm parts forming.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8909189 | 1989-07-07 | ||
| FR8909189A FR2649415B1 (en) | 1989-07-07 | 1989-07-07 | PROCESS FOR MANUFACTURING PARTS WITH HIGH MECHANICAL CHARACTERISTICS FROM UNTREATED STEEL |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0407275A1 true EP0407275A1 (en) | 1991-01-09 |
| EP0407275B1 EP0407275B1 (en) | 1994-12-14 |
Family
ID=9383594
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP90401879A Expired - Lifetime EP0407275B1 (en) | 1989-07-07 | 1990-06-29 | Method of making workpieces, with excellent mechanical properties, from non-treated steel |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0407275B1 (en) |
| JP (1) | JPH0353018A (en) |
| AT (1) | ATE115638T1 (en) |
| CA (1) | CA2020595C (en) |
| DE (1) | DE69015028T2 (en) |
| ES (1) | ES2068354T3 (en) |
| FR (1) | FR2649415B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2585621A4 (en) * | 2010-06-24 | 2018-05-09 | Magna International Inc. | Tailored properties by post hot forming processing |
| EP2641990B1 (en) | 2010-11-18 | 2019-03-20 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Highly formable high-strength steel sheet, warm working method, and warm-worked automotive part |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0593225A (en) * | 1991-09-30 | 1993-04-16 | Nissan Motor Co Ltd | Production of cast iron gear |
| DE102010027179B3 (en) * | 2010-07-14 | 2011-11-10 | Benteler Automobiltechnik Gmbh | Production of automotive components e.g. structural/body parts of a car, comprises heating metal part in fluidized bed and subjecting metal part to forming, hardening or aging process, and forming metal part in warm state |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1543101A (en) * | 1967-10-30 | 1968-10-18 | British Iron And Steel | Thermo-mechanical treatment of steel |
| FR2359901A1 (en) * | 1976-07-29 | 1978-02-24 | Lasalle Steel Co | STEELS COMBINING STRENGTH AND WORKABILITY AND THEIR PROCESS OF OBTAINING THERMAL TREATMENT |
| FR2391789A1 (en) * | 1977-05-25 | 1978-12-22 | Renault | Cold forgings, esp. railway rail clips - made from coiled metal strip and locally heat treated in fluidised beds |
| FR2448573A1 (en) * | 1979-02-06 | 1980-09-05 | Physique Appliquee Ind | Continuous automatic heat treatment plant - using row of fluidised beds, esp. for isothermal treatment of steel in absence of air |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3240634A (en) * | 1964-07-23 | 1966-03-15 | Lasalle Steel Co | Steels and improved method of manufacture |
-
1989
- 1989-07-07 FR FR8909189A patent/FR2649415B1/en not_active Expired - Lifetime
-
1990
- 1990-06-29 EP EP90401879A patent/EP0407275B1/en not_active Expired - Lifetime
- 1990-06-29 ES ES90401879T patent/ES2068354T3/en not_active Expired - Lifetime
- 1990-06-29 AT AT90401879T patent/ATE115638T1/en not_active IP Right Cessation
- 1990-06-29 DE DE69015028T patent/DE69015028T2/en not_active Expired - Fee Related
- 1990-07-06 CA CA002020595A patent/CA2020595C/en not_active Expired - Lifetime
- 1990-07-06 JP JP2179421A patent/JPH0353018A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1543101A (en) * | 1967-10-30 | 1968-10-18 | British Iron And Steel | Thermo-mechanical treatment of steel |
| FR2359901A1 (en) * | 1976-07-29 | 1978-02-24 | Lasalle Steel Co | STEELS COMBINING STRENGTH AND WORKABILITY AND THEIR PROCESS OF OBTAINING THERMAL TREATMENT |
| FR2391789A1 (en) * | 1977-05-25 | 1978-12-22 | Renault | Cold forgings, esp. railway rail clips - made from coiled metal strip and locally heat treated in fluidised beds |
| FR2448573A1 (en) * | 1979-02-06 | 1980-09-05 | Physique Appliquee Ind | Continuous automatic heat treatment plant - using row of fluidised beds, esp. for isothermal treatment of steel in absence of air |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2585621A4 (en) * | 2010-06-24 | 2018-05-09 | Magna International Inc. | Tailored properties by post hot forming processing |
| EP2641990B1 (en) | 2010-11-18 | 2019-03-20 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Highly formable high-strength steel sheet, warm working method, and warm-worked automotive part |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2649415A1 (en) | 1991-01-11 |
| EP0407275B1 (en) | 1994-12-14 |
| DE69015028T2 (en) | 1995-07-20 |
| JPH0353018A (en) | 1991-03-07 |
| FR2649415B1 (en) | 1991-10-31 |
| ATE115638T1 (en) | 1994-12-15 |
| DE69015028D1 (en) | 1995-01-26 |
| CA2020595A1 (en) | 1991-01-08 |
| ES2068354T3 (en) | 1995-04-16 |
| CA2020595C (en) | 2001-07-03 |
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