EP0169827A1 - Method for producing high-carbon steel wire rod - Google Patents

Method for producing high-carbon steel wire rod Download PDF

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Publication number
EP0169827A1
EP0169827A1 EP85870099A EP85870099A EP0169827A1 EP 0169827 A1 EP0169827 A1 EP 0169827A1 EP 85870099 A EP85870099 A EP 85870099A EP 85870099 A EP85870099 A EP 85870099A EP 0169827 A1 EP0169827 A1 EP 0169827A1
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EP
European Patent Office
Prior art keywords
cooling
phase
wire
conveyor
rod
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EP85870099A
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German (de)
French (fr)
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EP0169827B1 (en
Inventor
Norbert Bach
Marios Economopoulos
Marc Gredt
Guy Lessel
Arthur Schummer
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Centre de Recherches Metallurgiques CRM ASBL
Arcelor Luxembourg SA
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Centre de Recherches Metallurgiques CRM ASBL
Arbed SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C47/00—Winding-up, coiling or winding-off metal wire, metal band or other flexible metal material characterised by features relevant to metal processing only
    • B21C47/26—Special arrangements with regard to simultaneous or subsequent treatment of the material
    • B21C47/262—Treatment of a wire, while in the form of overlapping non-concentric rings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0224—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for wire, rods, rounds, bars
    • 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
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
    • 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
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/573—Continuous furnaces for strip or wire with cooling
    • C21D9/5732—Continuous furnaces for strip or wire with cooling of wires; of rods

Definitions

  • the present invention relates to a method for manufacturing wire rod of hard steel, that is to say of steel having a carbon content greater than 0.4%; this process according to the invention comprises an original heat treatment phase, applied to the wire as soon as it leaves the hot rolling mill.
  • the process according to the invention has the further advantage of eliminating the drawbacks arising from central segregation resulting from the continuous casting operation of the steels; this central segregation is particularly troublesome when the wires are intended to be used after drawing in the form of active reinforcements for prestressed concrete.
  • the average carbon content can reach in this case 0, B%, the content of this element in the segregated zones can exceed 1.1%; during normal cooling on modern trains, there is a precipitation of cementite which has a detrimental effect on the wire drawing.
  • the methods proposed to achieve the aim can be classified into two categories depending on whether the controlled cooling is applied online, before the formation of turns, or on the turn conveyor spread.
  • the first consists in cooling the wire to a temperature below 600 ° C, by passing through water cooling boxes between which sections of air are inserted allowing a rise in the temperature at the surface of the wire; the entire installation is calculated so as to obtain the desired reduction in the average temperature of the wire while avoiding the formation of martensite on the surface.
  • the ramp could be constructed in such a way that the surface temperature of the wire is much higher than the point Ms and this for all the diameters and all the qualities of the range of products, but the result of this obligation would be that the length of the cooling ramp would be very much greater than its maximum practical value. This would lead to very high investment costs and difficult operation of the train.
  • the second recommended system also consists in cooling the wire before depositing, but here admitting the formation of a surface layer of martensite of very limited thickness; this way of proceeding, if it makes it possible to shorten the cooling line and eliminate the drawback of making an installation comprising different cooling boxes and separated by air cooling zones, does not bring any solution to the other disadvantages which have just been mentioned, namely the difficulty of adapting the ramp to the whole range of products to be manufactured; on the other hand, this process involves an additional disadvantage in the continuation of the heat treatment because the recalescence which it is necessary to fight when the wire is spread on the conveyor is all the more important as the temperature has been lowered more sharply from the start of transformation.
  • the cooling treatment of the wire by immersion in a bath of molten salt or in a concentrated aqueous solution also has its own drawbacks, in particular the essential subsequent washing of the wire and the need to use fairly specific installations.
  • the current technique has not made it possible to recource, this value, the problem posed, namely to obtain a good average value of the properties of a hard wire in each coil of this wire, as well as a dispersion follows the properties of the wire around the mean value.
  • the reason is - except for the supply of air - that the processes considered are often economically and / or technically unusable.
  • the subject of the present invention is precisely a process for the manufacture of hard steel wire rod, by means of which a wire is obtained whose mechanical properties are similar to those obtained when the additional lead patenting operation is carried out, and whose the dispersion of the properties around the mean value, in a coil, is so low that we can consider that these properties are homogeneous.
  • the process which is the subject of the present invention is essentially characterized in that, on leaving the hot rolling mill, the wire is subjected to cooling comprising two phases, the first being applied to the wire while the latter crosses at the speed of end of rolling a cooling line located between the finishing unit and the roller drive located at the entrance to the deposition head, said cooling line being continuous, that is to say having no air cooling intervals between successive sections of intense cooling, the length of said cooling line and its power being adjusted in such a way that the surface temperature of the wire at the end of this first phase is between the start temperature of the martensitic transformation for the steel considered and this temperature + 200 ° C, in that the second cooling phase is applied to the wire as soon as it is laid out in non-concentrated spreads ique on a conveyor, the time delay between the end of the first phase and the start of the second phase being less than that for which the percentage of transformed austenite exceeds 5%, and in that the transformation of austenite is at least 95% at the end of the second phase.
  • the first cooling is carried out by means of a fluid applied using devices allowing a cooling intensity characterized by an average density of heat flow to be achieved. between 3 and 7 MW / m 2 .
  • the intensity of the cooling during the second phase is between 0.1 MW / m 2 and 0.4 MW / m2.
  • the cooling of the wire spread on the conveyor, during the second phase of the heat treatment can be obtained either by blowing air, by immersion in boiling water or by any other known means.
  • the value targeted by the surface temperature (Ts) at the outlet of the first phase is obtained, according to the invention, by choosing an appropriate combination between the values of the length (L) of the cooling line (or the duration) and the average heat flux density ( ⁇ ).
  • the couple ( ⁇ - L) chosen, according to the process, will be such that the desired mechanical properties are obtained after the treatment of the second phase.
  • the target breaking load (TS) will be close to the value given by the formula:
  • n (a) and (a ') the amount of austenite transformed is 2% while it is 98% in (b) and (b'), that is to say at the end of the second phaae.
  • This figure also shows that the second objective, elimination of the pro-eutectoid cementite at the core of the segregated wires, is automatically achieved by applying the method.
  • the temperature at the start of transformation of the heart is lowered below 600 ° C., which prevents precipitation of the pro-eutectoid cementite.
  • the finisher comprising, following the cages (2), a cooling line (3) of length (L 1 ) located in place of unused cages, the "break out box”"(4), the continuous cooling line (5) of length (L 2 ), the head (6) for winding and depositing on the conveyor (7), which is provided with a cooling device (8 ) of length (L 3 ) to ensure the second phase of the treatment.
  • phase I cooling device is characterized by a constant value of the heat flux density ( ⁇ ). It follows that the exchange coefficient taken into account for the calculations will be of the form:
  • T s is the surface temperature and T m the temperature of the coolant.
  • FIG. 3 represents all of the couples (L 2 , ⁇ ) making it possible to produce MTT in the case of the manufacture of a wire of 7 mm in diameter, made of steel at 0.63% C and 0.65% Mn, laminated with an end-of-rolling temperature (T 0 ) of 1050 ° C and an exit speed (V) of 82.8 m / s, where the ramp length (L 1 ) installed in the block is 1 m.
  • T 0 end-of-rolling temperature
  • V exit speed
  • This figure 3 also gives, for each pair (L 2 , ⁇ ) the value of the minimum surface temperature (T) reached during the first phase. It is clear that the higher the minimum permitted surface temperature, the greater the length L 2 necessary 5.
  • water cannons are used of a conventional type and the ( ⁇ ) is adjusted by acting on the supply pressure of these cannons.
  • Water-air cannons can also be used and in this case the adjustment is made by action on the air flow.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Metal Rolling (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

In the production of medium carbon steel wire rod, upon leaving the hot rolling mill, the rod is cooled in two phases. The first phase is operative as the rod moves at end-of-rolling speed along a cooling line disposed between the finishing block and feed rollers disposed at the entry of a head for placing the rod in overlapping turns on a conveyor, the cooling line being continuous-i.e. being devoid of air cooling breaks between consecutive intensive cooling sections, the length and capacity of the cooling line being such that the surface temperature of the rod at the end of the first phase is between, on the one hand, the start-of-martensitic-transformation temperature for the particular steel concerned and, on the other hand, the latter temperature plus 200 DEG C. The second cooling phase is operative upon the rod once it has been placed in overlapping non-concentric turns on the conveyor, the time which elapses between the end of the first phase and the start of the second phase being less than the time needed for the percentage of transformed austenite to exceed 5%. Austenite transformation is at least 95% at the departure from the second phase.

Description

La présente invention se rapporte à un procédé pour la fabrication de fil machine en acier dur, c'est-à-dire en acier présentant une teneur en carbone supérieure à 0,4 %; ce procédé suivant l'invention comporte une phase de traitement thermique originale, appliquée au fil dès sa sortie du laminoir à chaud.The present invention relates to a method for manufacturing wire rod of hard steel, that is to say of steel having a carbon content greater than 0.4%; this process according to the invention comprises an original heat treatment phase, applied to the wire as soon as it leaves the hot rolling mill.

Ce procédé permet de conférer au fil machine des propriétés mécaniques et une homogénéité de propriétés équivalentes à celles que l'on obtient lorsque l'on pratique l'opération de patentage au plomb.This process makes it possible to confer on the wire rod mechanical properties and a homogeneity of properties equivalent to those which one obtains when one practices the patenting operation with lead.

Le procédé suivant l'invention a comme autre avantage d'éliminer les inconvénients provenant de la ségrégation centrale résultant de l'opération de coulée continue des aciers; cette ségrégation centrale est notamment gênante lorsque les fils sont destinés à être utilisés après tréfilage sous forme d'armatures actives pour béton précontraint. En effet, la teneur moyenne en carbone pouvant atteindre dans ce cas 0,B %, la teneur en cet élément des zones ségrégées peut dépasser 1,1 %; lors du refroidissement normal sur les trains modernes, on assiste alors à une précipitation de cémentite qui a un effet néfaste sur la tréfilabilité.The process according to the invention has the further advantage of eliminating the drawbacks arising from central segregation resulting from the continuous casting operation of the steels; this central segregation is particularly troublesome when the wires are intended to be used after drawing in the form of active reinforcements for prestressed concrete. In fact, since the average carbon content can reach in this case 0, B%, the content of this element in the segregated zones can exceed 1.1%; during normal cooling on modern trains, there is a precipitation of cementite which has a detrimental effect on the wire drawing.

On sait que les propriétés finales d'un fil dépendent essentiellement de l'état dans lequel se trouve ce fil avant d'aborder les dernières opérations de déformation à froid telles que le tréfilage. En fait, il est bien connu que pour obtenir la structure convenant idéalement au tréfilage, il faut abaisser la température du début de transformation allotropique et d'autre part limiter le réchauffement dû à la transformation allotropique elle-même qui se produit et qui porte le nom de recalescence. Le moyen classique pour réaliser cette opération consiste à faire subir au fil un patentage au plomb.It is known that the final properties of a wire depend essentially on the state in which the wire is found before tackling the last cold deformation operations such as wire drawing. In fact, it is well known that in order to obtain the structure which is ideally suited for drawing, it is necessary to lower the temperature of the start of allotropic transformation and on the other hand to limit the heating due to the allotropic transformation itself which occurs and which carries the recalescence name. The classic way to do this is to subject the wire to lead patenting.

Grâce à cette opération et à un écrouissage approprié, on peut obtenir des fils, même de très petit diamètre, présentant les caractéristiques mécaniques finales désirées.Thanks to this operation and to an appropriate work hardening, it is possible to obtain wires, even of very small diameter, having the desired final mechanical characteristics.

Le principal inconvénient de ces procédés consiste dans le fait que le patentage et le prépatentage éventuel au plomb sont des opérations particulièrement coûteuses, d'une part en elles-mêmes et d'autre part eu égard aux manipulations et à la perte de productivité qu'elles occasionnent dans une tréfilerie.The main drawback of these methods consists in the fact that patenting and possible prepatentage with lead are particularly expensive operations, on the one hand in themselves and on the other hand having regard to the manipulations and the loss of productivity that they cause in a wire drawing.

Afin de remédier à ces inconvénients, on a déjà imaginé différents procédés; d'une façon très générale, ces procédés soit ne conduisent pas à un produit dont les propriétés soient comparables à celles des fils ayant subi un patentage au plomba soit présentent encore des inconvénients de mise en oeuvre qui n'en permettent pas une application industrielle.In order to remedy these drawbacks, various methods have already been devised; very generally, these methods either do not lead to a product whose properties are comparable to those of wires which have undergone a lead patenting or still have implementation disadvantages which do not allow their industrial application.

Les méthodes proposées pour atteindre le but visé (élimination du patentage par traitement thermique dans la chaude de laminage) peuvent être classées en deux catégories suivant que le refroidissement contrôlé est appliqué en ligne, avant la formation de spires, ou bien sur le convoyeur à spires étalées.The methods proposed to achieve the aim (elimination of patenting by heat treatment in the rolling mill) can be classified into two categories depending on whether the controlled cooling is applied online, before the formation of turns, or on the turn conveyor spread.

En ce qui concerne le traitement au niveau de la rampe de refroidissement à l'eau avant la tête de formation de spires, on se heurte généralement à un problème qui réside dans le fait que le temps dont on dispose pour appliquer le moyen imaginé est extrêmement faible, par exemple de l'ordre de la demi seconde dans les trains de laminoir à grande vitesse de sortie; il en résulte que l'on est obligé d'appliquer des refroidissements très intenses pour abaisser la température dans les lignes visées, et cela entraîne la création de gradients thermiques importants dans la section du fil et un risque de trempe martensitique à la surface.With regard to the treatment at the level of the water-cooling ramp before the coil-forming head, there is generally encountered a problem which resides in the fact that the time available for applying the imagined means is extremely low, for example of the order of half a second in rolling mill trains with high output speed; it follows that one is forced to apply very intense cooling to lower the temperature in the targeted lines, and this leads to the creation of significant thermal gradients in the section of the wire and a risk of martensitic quenching on the surface.

Parmi les solutions techniques diverses qui ont déjà été proposées pour résoudre ce problème, on peut en citer deux qui méritent particulièrement l'attention. La première consiste à refroidir le fil jusqu'à une température inférieure à 600°C, par passage dans des boites de refroidissement à eau entre lesquelles on intercale des sections à l'air permettant une élévation de la température à la surface du fil; l'ensemble de l'installation est calculé de manière à obtenir la diminution désirée de la température moyenne du fil tout en évitant la formation de martensite en surface.Among the various technical solutions which have already been proposed to solve this problem, two can be cited which deserve particular attention. The first consists in cooling the wire to a temperature below 600 ° C, by passing through water cooling boxes between which sections of air are inserted allowing a rise in the temperature at the surface of the wire; the entire installation is calculated so as to obtain the desired reduction in the average temperature of the wire while avoiding the formation of martensite on the surface.

Ce procédé n'a jusqu'à présent pas connu un grand succès industriel parce qu'il présente quelques difficultés de mise en oeuvre; ainsi il est nécessaire d'utiliser plusieurs boites à eau dont la longueur va en décroissant rapidement dans le sens de l'avancement du fil; d'autre part puisqu'il est impérieux d'arrêter l'eau à la sortie de chaque boite afin de permettre le réchauffement de la surface, il faut utiliser des dispositifs brise-jet dont l'emploi n'est ni aisé ni efficace. D'autre part la configuration optimum d'une telle installation de refroidissement dépend du diamètre du fil, de sa teneur en carbone et des propriétés visées; il en résulte que si même on pouvait réaliser pratiquement la rampe optimum, ce ne serait que pour une seule qualité et un seul diamètre de fil. Comme les trains à fil modernes laminent une gamme très étendue de produits, pour la plupart d'entre eux, l'installation ne présenterait donc pas les caractéristiques optimum souhaitées. Enfin, pour contourner les inconvénients qui viennent d'être cités, on pourrait construire la rampe de manière telle que la température de surface du fil soit largement supérieure au point Ms et ce pour tous les diamètres et toutes les qualités de la gamme des produits, mais le résultat de cette obligation serait que la longueur de la rampe de refroidissement serait très nettement supérieure à sa valeur pratique maximum. Ceci entraînerait des frais d'investissement très élevés et une exploitation difficile du train.This process has so far not been very successful industrially because it presents some implementation difficulties; thus it is necessary to use several water boxes whose length decreases rapidly in the direction of advancement of the wire; on the other hand since it is imperative to stop the water at the outlet of each box in order to allow the heating of the surface, it is necessary to use jet-breaking devices whose use is neither easy nor effective. On the other hand, the optimum configuration of such a cooling installation depends on the diameter of the wire, its carbon content and the properties targeted; it follows that if even the optimum ramp could be achieved, it would only be for one quality and one wire diameter. As modern wire trains laminate a very wide range of products, for most of them, the installation would therefore not have the optimum characteristics desired. Finally, to circumvent the drawbacks which have just been mentioned, the ramp could be constructed in such a way that the surface temperature of the wire is much higher than the point Ms and this for all the diameters and all the qualities of the range of products, but the result of this obligation would be that the length of the cooling ramp would be very much greater than its maximum practical value. This would lead to very high investment costs and difficult operation of the train.

Le second système préconisé consiste à refroidir également le fil avant la dépose, mais en admettant ici une formation d'une couche superficielle de martensite d'épaisseur très limitée; cette manière de procéder, si elle permet de raccourcir la ligne de refroidissement et d'éliminer l'inconvénient de réaliser une installation comportant différentes boites de refroidissement et séparées par des zones de refroidissement à l'air, n'apporte quand même pas de solution aux autres inconvénients qui viennent ù'etre cités, soit la difficulté d'approprier la rampe à toute la gamme des produits à fabriquer; d'autre part, ce procédé entraîne un inconvénient supplémentaire dans la suite du traitement thermique parce que la recalescence qu'il faut combattre lorsque le fil est étalé sur le convoyeur est d'autant plus importante que l'on a abaissé plus fortement la température du début de transformation.The second recommended system also consists in cooling the wire before depositing, but here admitting the formation of a surface layer of martensite of very limited thickness; this way of proceeding, if it makes it possible to shorten the cooling line and eliminate the drawback of making an installation comprising different cooling boxes and separated by air cooling zones, does not bring any solution to the other disadvantages which have just been mentioned, namely the difficulty of adapting the ramp to the whole range of products to be manufactured; on the other hand, this process involves an additional disadvantage in the continuation of the heat treatment because the recalescence which it is necessary to fight when the wire is spread on the conveyor is all the more important as the temperature has been lowered more sharply from the start of transformation.

Si l'on considère maintenant la seconde famille des solutions proposées qui consistent à appliquer le traitement alors que le fil machine est étendu en spires non concentriques sur un convoyeur, on observe que parmi les procédés qui ont déjà été préconisés, les. uns augmentent l'efficacité du refroidissement par un choix approprié du fluide utilisé, les autres s'attaquent.. à la recalescence à l'endroit où elle a lieu.If we now consider the second family of proposed solutions which consist in applying the treatment while the wire rod is extended in non-concentric turns on a conveyor, we observe that among the methods which have already been recommended, the. some increase the cooling efficiency by an appropriate choice of the fluid used, others attack the recalescence at the place where it takes place.

Parmi ces différents procédés, on peut citer ceux dans lesquels on effectue un refroidissement à l'air soufflé ou aspiré au travers des spires. Suivant ces procédés, on a certes constaté une nette amélioration de la valeur moyenne des propriétés du fil et de la dispersion des mesures autour de cette moyenne, ainsi qu'une amélioration de la structure suffisante pour éviter un prépatentage. Dans le cas du fil machine, il n'a toutefois pas été possible d'éviter le patentage final au plomb.Among these different processes, mention may be made of those in which cooling is carried out with blown or aspirated air through turns. According to these methods, there has certainly been a marked improvement in the average value of the properties of the wire and in the dispersion of the measurements around this average, as well as an improvement in the structure sufficient to avoid prepatentage. In the case of wire rod, however, it was not possible to avoid the final lead patenting.

Dans cette optique, on a également imaginé d'effectuer le traitement du fil disposé sous forme de spires étalées dans un lit fluidisé. Ce processus amène une certaine amélioration supplémentaire par rapport à celui précé- denrient cité, mais il présente cependant d'autres difficultés d'ordre essen- tielement technologique.With this in mind, it has also been imagined to carry out the treatment of the wire placed in the form of turns spread out in a fluidized bed. This process brings some additional improvement compared to the previous one, but it presents other difficulties, essentially of a technological nature.

Le traitement de refroidissement du fil par immersion dans un bain de sel fondu ou dans une solution aqueuse concentrée présente également des inconvénients propres, notamment le lavage ultérieur indispensable du fil et 1 nécessité d'utiliser des installations assez particulières.The cooling treatment of the wire by immersion in a bath of molten salt or in a concentrated aqueous solution also has its own drawbacks, in particular the essential subsequent washing of the wire and the need to use fairly specific installations.

résumé, la technique actuelle n'a pas permis de recource, ce vala- b, le problème posé, à savoir obtenir une bonne valeur moyenne des pro- p étés d'un fil dur dans chaque bobine de ce fil, ainsi qu'une dispersion r uite des propriétés du fil autour de la valeur moyenne. La cause en est - :auf en ce qui concerne le soufflage d'air - que les procédés considérés s/t souvent économiquement et/ou techniquement inexploitables.In summary, the current technique has not made it possible to recource, this value, the problem posed, namely to obtain a good average value of the properties of a hard wire in each coil of this wire, as well as a dispersion follows the properties of the wire around the mean value. The reason is - except for the supply of air - that the processes considered are often economically and / or technically unusable.

L autres procédés, appliqués au fil étalé en spires non concentriques si un convoyeur, ont pour objectif l'élimination de la recalescence en acélérant le refroidissement à l'endroit du convoyeur où cette recalescence aait lieu; on a ainsi préconisé différents types de refroidissement, par exemple par brouillard à l'eau, par pulvérisation, par immersion dans un tin, etc; ici non plus les procédés proposés n'ont pas été l'objet d'une application industrielle, car il n'a pas été possible en pratique d'appliquer à l'endroit déterminé où avait lieu la recalescence, un refroidissement sélectif qui soit en même temps intense et homogène.The other methods, applied to the wire spread in non concentric turns if a conveyor, have the objective of eliminating the recalescence by accelerating the cooling at the place of the conveyor where this recalescence takes place; various types of cooling have thus been recommended, for example by water mist, by spraying, by immersion in a tin, etc .; here either the proposed processes have not been the subject of an industrial application, because it has not been possible in practice of app quer in the determined place where the recalescence took place, a selective cooling which is at the same time intense and homogeneous.

La présente invention a précisément pour objet un procédé pour la fabrication du fil machine en acier dur, grâce auquel on obtient un fil dont les propriétés mécaniques sont analogues à celles obtenues lorsque l'on pratique l'opération supplémentaire de patentage au plomb, et dont la dispersion des propriétés autour de la valeur moyenne, dans une bobine, est tellement faible que l'on peut considérer que ces propriétés sont homogènes.The subject of the present invention is precisely a process for the manufacture of hard steel wire rod, by means of which a wire is obtained whose mechanical properties are similar to those obtained when the additional lead patenting operation is carried out, and whose the dispersion of the properties around the mean value, in a coil, is so low that we can consider that these properties are homogeneous.

Le procédé, objet de la présente invention, est essentiellement caractérisé en ce qu'au sortir du laminoir à chaud, le fil est soumis à un refroidissement comportant deux phases, la première étant appliquée au fil pendant que celui-ci traverse à la vitesse de fin de laminage une ligne de refroidissement située entre le bloc finisseur et l'entraîneur à galets se trouvant à l'entrée de la tête de dépose, la dite ligne de refroidissement étant continue, c'est-à-dire ne comportant pas d'intervalles de refroidissement à l'air entre sections successives de refroidissement intense, la longueur de la dite ligne de refroidissement et sa puissance étant réglées de telle manière que la température superficielle du fil à la fin de cette première phase soit comprise entre la température de début de la transformation martensitique pour l'acier considéré et cette température + 200°C, en ce que la seconde phase de refroidissement est appliquée au fil dès sa mise en spires étalées de façon non concentrique sur un convoyeur, le délai de temps entre la fin de la première phase et le début de la deuxième phase étant inférieur à celui pour lequel le pourcentage d'austénite transformée dépasse 5 %, et en ce que la transformation de l'austénite est d'au moins 95 % à la sortie de la deuxième phase.The process which is the subject of the present invention is essentially characterized in that, on leaving the hot rolling mill, the wire is subjected to cooling comprising two phases, the first being applied to the wire while the latter crosses at the speed of end of rolling a cooling line located between the finishing unit and the roller drive located at the entrance to the deposition head, said cooling line being continuous, that is to say having no air cooling intervals between successive sections of intense cooling, the length of said cooling line and its power being adjusted in such a way that the surface temperature of the wire at the end of this first phase is between the start temperature of the martensitic transformation for the steel considered and this temperature + 200 ° C, in that the second cooling phase is applied to the wire as soon as it is laid out in non-concentrated spreads ique on a conveyor, the time delay between the end of the first phase and the start of the second phase being less than that for which the percentage of transformed austenite exceeds 5%, and in that the transformation of austenite is at least 95% at the end of the second phase.

'Dans une mise en oeuvre préférentielle du procédé de l'invention, le premier refroidissement est effectué au moyen d'un fluide appliqué à l'aide de dispositifs permettant d'atteindre une intensité de refroidissement caracteeri- sée par une densité moyenne de flux calorifique comprise entre 3 et 7 MW/m2.In a preferred implementation of the method of the invention, the first cooling is carried out by means of a fluid applied using devices allowing a cooling intensity characterized by an average density of heat flow to be achieved. between 3 and 7 MW / m 2 .

Dans une madalité particulière de mise en oeuvre du procédé de l'invention, l'intensité du refroidissement au cours de la deuxième phase est comprise entre 0,1 MW/m2 et 0,4 MW/m2.In a particular way of implementing the method of the invention, the intensity of the cooling during the second phase is between 0.1 MW / m 2 and 0.4 MW / m2.

Suivant l'invention, le refroidissement du fil étalé sur le convoyeur, au cours de la deuxième phase du traitement thermique, peut être obtenu soit par soufflage d'air, par immersion dans l'eau bouillante ou par tout autre moyen connu.According to the invention, the cooling of the wire spread on the conveyor, during the second phase of the heat treatment, can be obtained either by blowing air, by immersion in boiling water or by any other known means.

La valeur visée par la température superficielle (Ts) à la sortie de la première phase est obtenue, suivant l'invention, en choisissant une combinaison adéquate entre les valeurs de la longueur (L) de la ligne de refroidissement (ou la durée) et de la densité moyenne de flux calorifique (ϕ).The value targeted by the surface temperature (Ts) at the outlet of the first phase is obtained, according to the invention, by choosing an appropriate combination between the values of the length (L) of the cooling line (or the duration) and the average heat flux density (ϕ).

Le couple (ϕ- L) choisi, suivant le procédé, sera tel que les propriétés mécaniques désirées soient obtenues après le traitement de la deuxième phase. La charge de rupture (TS) visée sera voisine de la valeur donnée par la formule :

Figure imgb0001
The couple (ϕ- L) chosen, according to the process, will be such that the desired mechanical properties are obtained after the treatment of the second phase. The target breaking load (TS) will be close to the value given by the formula:
Figure imgb0001

Sur la figure 1 sont représentées les courbes de refroidissement en surface (I) et au centre (II) d'un fil de 12 mm de diamètre en acier à 0,63 % C 0,65 % Mn, auquel on a appliqué le procédé de l'invention dans les conditions suivantes :

  • - vitesse de fin de laminage (V) : 22,88 m/s
  • - longueur de rampe installée dans le bloc (L1) : 4 m
  • - longueur de la rampe principale de refroidissement à l'eau (L2) : 39,13 m
  • - densité moyenne de flux calorifique au cours de la première phase (ϕ) : 3,58 MW/m 2
  • - coefficient d'échange calorifique dans le dispositif de refroidissement au cours de la deuxième phase (a) : 0,27 kW/m2 °C
  • - MTT surface : 601°C
  • - MTT contre : 626°C
  • -MTT : 606°C
In FIG. 1 are represented the cooling curves at the surface (I) and at the center (II) of a wire 12 mm in diameter made of steel at 0.63% C 0.65% Mn, to which the process has been applied of the invention under the following conditions:
  • - end of rolling speed (V): 22.88 m / s
  • - ramp length installed in the block (L 1 ): 4 m
  • - length of the main water cooling ramp (L 2 ): 39.13 m
  • - average heat flux density during the first phase (ϕ): 3.58 MW / m 2
  • - heat exchange coefficient in the cooling device during the second phase (a): 0.27 kW / m 2 ° C
  • - MTT surface: 601 ° C
  • - MTT against: 626 ° C
  • -MTT: 606 ° C

n (a) et (a') la quantité d'austénite transformée est de 2 % tandis qu'elle est de 98 % en (b) et (b'), c'est-à-dire à la fin de la deuxième phaae.n (a) and (a ') the amount of austenite transformed is 2% while it is 98% in (b) and (b'), that is to say at the end of the second phaae.

Cette figure montre également que le second objectif visé, l'élimination de la cémentite pro-eutectoïde à coeur des fils ségrégés, est atteint automatiquement par l'application du procédé. En effet, la température de début de transformation du coeur est abaissée en dessous de 600°C, ce qui empêche la précipitaion de la cémentite pro-eutectoide.This figure also shows that the second objective, elimination of the pro-eutectoid cementite at the core of the segregated wires, is automatically achieved by applying the method. In fact, the temperature at the start of transformation of the heart is lowered below 600 ° C., which prevents precipitation of the pro-eutectoid cementite.

A titre d'exemple pratique du procédé de l'invention, on examinera ci-après le cas d'une application dans un nouveau laminoir pour lequel il s'agit de déterminer la distance à prévoir entre la sortie du bloc et l'entraineur à galets; le tableau I ci-dessous mentionne les principales données de l'installation et du produit, tandis que la figure 2 représente schématiquement l'implantation des équipements.As a practical example of the process of the invention, we will examine below the case of an application in a new rolling mill for which it is a question of determining the distance to be expected between the outlet of the block and the trainer to pebbles; Table I below lists the main data for the installation and the product, while Figure 2 schematically shows the location of the equipment.

On distingue sur cette figure en (1) le bloc finisseur comprenant, à la suite des cages (2), une ligne de refroidissement (3) de longueur (L1) située à la place de cages non utilisées, le "break out box" (4), la ligne de refroidissement continue (5) de longueur (L2), la tête (6) de mise en spires et de dépose sur le convoyeur (7), lequel est pourvu d'un dispositif de refroidissement (8) de longueur (L3) pour assurer la deuxième phase du traitement.

Figure imgb0002
We distinguish in this figure in (1) the finisher comprising, following the cages (2), a cooling line (3) of length (L 1 ) located in place of unused cages, the "break out box""(4), the continuous cooling line (5) of length (L 2 ), the head (6) for winding and depositing on the conveyor (7), which is provided with a cooling device (8 ) of length (L 3 ) to ensure the second phase of the treatment.
Figure imgb0002

On peut, à partir de cette application dans des conditions particulières, faire les remarques suivantes.We can, from this application in special conditions, make the following remarks.

Afin de minimiser l'encombrement de l'installation, on a installé une section de refroidissement de longueur L1 à la place des cages non utilisées; de ce fait, L1 est fonction du diamètre.In order to minimize the space requirement of the installation, a cooling section of length L 1 was installed in place of the unused cages; therefore, L 1 is a function of the diameter.

On suppose que le fil n'est pas refroidi dans le "break-out box". Cependant, étant donné la faible longueur de ce dispositif, l'interruption du refroidissement n'a aucun effet métallurgique et la rampe de refroidissement se comporte comme une rampe continue de longueur L1 + L2.It is assumed that the wire is not cooled in the "break-out box". However, given the short length of this device, the interruption of cooling has no metallurgical effect and the cooling ramp behaves like a continuous ramp of length L 1 + L 2 .

Si la durée de séjour du fil à l'air entre les deux phases de refroidissement accéléré doit être minime, elle ne peut cependant pas être annulée pour des raisons technologiques (entraîneur à galets, tête de dépose, chute des spires, ...); on a considéré que le séjour minimum du fil à l'air correspondait à un parcours rectiligne de 20 m.If the duration of stay of the wire in the air between the two phases of accelerated cooling must be minimal, it cannot however be canceled for technological reasons (roller drive, removal head, fall of the turns, ...) ; it was considered that the minimum stay of the air line corresponded to a straight path of 20 m.

On suppose que le dispositif de refroidissement de la phase I est caractérisé par une valeur constante de la densité de flux calorifique (ϕ). 11 en résulte que le coefficient d'échange pris en considération pour les calculs sera de la forme :It is assumed that the phase I cooling device is characterized by a constant value of the heat flux density (ϕ). It follows that the exchange coefficient taken into account for the calculations will be of the form:

Figure imgb0003
où Ts est la température superficielle et Tm la température du fluide de refroidissement.
Figure imgb0003
 where T s is the surface temperature and T m the temperature of the coolant.

Il a été constaté que cette hypothèse est en accord raisonnable avec l'expérience, du moins pour des valeurs de Ts supérieures à 350-400DC.It has been found that this hypothesis is in reasonable agreement with experience, at least for values of T s greater than 350-400 D C.

Pour le refroidissement au cours de la phase II, on suppose un refroidissement du type Newtonien (a = const.) et on néglige dès lors les différences d'intensité de refroidissement entre les centres et les noeuds de la nappe des spires. Cette hypothèse est très proche de la réalité dans le cas Le refroidissement se fait par immersion de spires dans l'eau bouillante. Cependant, ces conclusions restent valables à première approximation dans Le cas où le refroidissement au cours de la deuxième phase se fait par soufflage d'air.For the cooling during phase II, we assume a Newtonian type cooling (a = const.) And we therefore neglect the differences in cooling intensity between the centers and the nodes of the water table. turns. This assumption is very close to reality in the case Cooling is done by immersion of turns in boiling water. However, these conclusions remain valid at first approximation in the case where the cooling during the second phase is done by blowing air.

Le problème consiste à déterminer :

  • - la valeur minimale de LZ permettant d'appliquer le procédé à l'ensemble du product mix (tableau I);
  • - la valeur de (ϕ) pour chaque diamètre et chaque teneur en carbone du product mix;
  • - la longueur minimale de traitement dans la phase II (L3).
The problem is to determine:
  • - the minimum value of L Z allowing the process to be applied to the entire product mix (Table I);
  • - the value of (ϕ) for each diameter and each carbon content of the product mix;
  • - the minimum length of treatment in phase II (L 3 ).

a. Longueur L2 at. Length L 2

La procédure de calcul utilisée est la suivante :The calculation procedure used is as follows:

  • Pour un diamètre donné, on considère le cas le plus difficile qui correspond :
    • - à la température de dépose maximum (105D°C dans l'exemple),
    • - à la teneur en C minimum (0,6 % dans l'exemple), car en effet c'est pour la valeur minimale de % C que le point Ms est plus élevé et, par conséquent, que la température minimale de surface pouvant être atteinte pendant la première phase est la plus élevée.
    For a given diameter, we consider the most difficult case which corresponds:
    • - at the maximum deposition temperature (105D ° C in the example),
    • - the minimum C content (0.6% in the example), because it is indeed for the minimum value of% C that the point M s is higher and, therefore, that the minimum surface temperature that can be reached during the first phase is the highest.

On connaît la relation qui existe entre TS et la température moyenne de transformation (MTT), celle-ci étant définie en un point considéré comme étant la moyenne de la courbe T = f(z) donnant en ce point la variation de la température (T) et le pourcentage d'austénite transformée (z) :

Figure imgb0004
We know the relation which exists between T S and the average temperature of transformation (MTT), this one being defined in a point considered as being the average of the curve T = f (z) giving in this point the variation of the temperature (T) and the percentage of transformed austenite (z):
Figure imgb0004

Or il est clair que MTT est une fonction du point considéré dans la section et, en supposant la symétrie cylindrique, on peut considérer que MTT est constant le long d'un cercle de rayon (r) situé dans la section droite du fil, c'est-à-dire que MTT = MTT (r); d'autre part, l'expérience montre que la charge de rupture est une fonction linéaire de MTT (soit y = a MTT + b).Now it is clear that MTT is a function of the point considered in the section and, assuming cylindrical symmetry, we can consider that MTT is constant along a circle of radius (r) located in the straight section of the wire, c 'is to say that MTT = MTT (r); on the other hand, experience shows that the breaking load is a linear function of MTT (ie y = a MTT + b).

Enfin, l'expérience a également montré que dans un fil de rayon R dans lequel MTT varie avec r [et, par conséquent, y = y (r)] , on peut appliquer la règle d'additivité pour trouver la charge de rupture macroscopique du fil :

Figure imgb0005

en posant x = r2 et en remplaçant y par sa valeur en fonction de MTT, on obtient :
Figure imgb0006
d'ou
Figure imgb0007
avec
Figure imgb0008
 Finally, experience has also shown that in a wire of radius R in which MTT varies with r [and, consequently, y = y (r)], we can apply the additivity rule to find the macroscopic breaking load some thread :
Figure imgb0005
by setting x = r 2 and replacing y by its value as a function of MTT, we obtain:
Figure imgb0006
 from where
Figure imgb0007
 with
Figure imgb0008

Cette dernière relation définit MTT pour l'ensemble de la section du fil.This last relation defines MTT for the whole section of the wire.

Les deux dernières relations montrent que MTT est la valeur de MTT constante dans la section et qui donnerait la valeur macroscopique de TS de la charge de rupture du fil.The last two relations show that MTT is the constant value of MTT in the section and which would give the macroscopic value of TS of the breaking load of the wire.

Ce qui précède montre que l'on peut par conséquent calculer la valeur visée pour

Figure imgb0009
(désignée par
Figure imgb0010
).The above shows that we can therefore calculate the target value for
Figure imgb0009
 (designated by
Figure imgb0010
 ).

Dans l'exemple choisi :

Figure imgb0011
In the example chosen:
Figure imgb0011

Si on choisit arbitrairement une valeur de L2, à cette valeur correspond une et une seule valeur de (ϕ) donnant à la fin de la transformation, c'est-à-dire après la deuxième phase,

Figure imgb0012
If we arbitrarily choose a value of L 2 , to this value corresponds one and only one value of (ϕ) giving at the end of the transformation, that is to say after the second phase,
Figure imgb0012

La figure 3 représente l'ensemble des couples (L2, ϕ) permettant de réaliser MTT dans le cas de la fabrication d'un fil de 7 mm de diamètre, en acier à 0,63 % C et 0,65 % Mn, laminé avec une température (T0) de fin de laminage de 1050°C et une vitesse de sortie (V) de 82,8 m/s, où la longueur de rampe (L1) installée dans le bloc est de 1 m. Cette figure 3 donne également, pour chaque couple (L2, ϕ) la valeur de la température minimale de surface (T) atteinte pendant la première phase. Il est clair que plus la température superficielle minimale admise est élevé, plus la longueur L2 nécessaire 5est grande.FIG. 3 represents all of the couples (L 2 , ϕ) making it possible to produce MTT in the case of the manufacture of a wire of 7 mm in diameter, made of steel at 0.63% C and 0.65% Mn, laminated with an end-of-rolling temperature (T 0 ) of 1050 ° C and an exit speed (V) of 82.8 m / s, where the ramp length (L 1 ) installed in the block is 1 m. This figure 3 also gives, for each pair (L 2 , ϕ) the value of the minimum surface temperature (T) reached during the first phase. It is clear that the higher the minimum permitted surface temperature, the greater the length L 2 necessary 5.

Cette valeur minimale admise dépend de la qualité du contrôle installé sur le train.This minimum value allowed depends on the quality of the control installed on the train.

Pour un contrôle précis par ordinateur et grâce à la rampe unique, d'une trés grande gouvernabilité ne peut

Figure imgb0013
Figure imgb0014
+30°. Dans ces conditions, la figure 3 permet de trouver (L2 min) et le (ϕ) correspondant pour le diamètre de 7 mm, soit en l'occurrence L2 min = 45,2 m et ϕ = 6,77 MW/m2. En répétant la même procédure pour tous les diamètres laminés, on établit la variation de L2 min avec le diamètre (figure 4). On constate que la plus grande valeur de L2 min correspond, pour l'exemple choisi, au diamètre de 12 mm et c'est cette valeur qui sera choisie pour L2 (49,1 m). La figure 4 donne également la variation de en fonction du diamètre à laminer.For precise control by computer and thanks to the single ramp, very great governability cannot
Figure imgb0013
Figure imgb0014
+ 30 °. Under these conditions, Figure 3 makes it possible to find (L 2 min) and the corresponding (ϕ) for the diameter of 7 mm, that is to say L 2 min = 45.2 m and ϕ = 6.77 MW / m 2. By repeating the same procedure for all the rolled diameters, the variation of L 2 min is established with the diameter (FIG. 4). It is found that the largest value of L 2 min corresponds, for the example chosen, to the diameter of 12 mm and it is this value which will be chosen for L 2 (49.1 m). FIG. 4 also gives the variation of as a function of the diameter to be laminated.

b. Calcul de ϕ.b. Calculation of ϕ.

Connaissant L2, on peut calculer, pour les autres diamètres, les valeurs de (ϕ) et de la température minimale de surface :

Figure imgb0015
Knowing L 2 , we can calculate, for the other diameters, the values of (ϕ) and the minimum surface temperature:
Figure imgb0015

On constate que la sécurité vis-à-vis de M s va en croissant au fur et à mesure que le diamètre décroît; elle devient considérable pour le diamètre 5,5 mm, car pour ce dernier, le flux massique instantané du train est réduit.It can be seen that the security vis-à-vis M s increases as the diameter decreases; it becomes considerable for the diameter 5.5 mm, because for the latter, the instantaneous mass flow of the train is reduced.

On constate également que pour appliquer le procédé de l'invention dans les conditions de l'exemple, il faut être à même de réaliser sur la même installation des flux compris entre 3,5 et 6,5 MW/m2.It is also noted that in order to apply the process of the invention under the conditions of the example, it is necessary to be able to produce on the same installation flows of between 3.5 and 6.5 MW / m 2 .

Les calculs ci-dessus peuvent être effectués pour les fils à carbone plus élevé avec des résultats tout à fait comparables sauf en ce qui concerne la sécurité vis-à-vis du Ms qui sera plus grande.The above calculations can be carried out for the higher carbon wires with completely comparable results except with regard to the security with respect to the M s which will be greater.

c. Détermination de (L3).vs. Determination of (L 3 ).

Le tableau ci-dessous donne pour une densité de spires de 25 m, la vitesse du convoyeur, la durée du traitement nécessaire pour que la transformation sont terminée à 98 % et la longueur (L3) correspondante :

Figure imgb0016
The table below gives for a density of turns of 25 m, the speed of the conveyor, the duration of the treatment necessary for the transformation to be completed at 98% and the corresponding length (L 3 ):
Figure imgb0016

On retiendra la plus grande des valeurs calculées pour L3 (7 m). Si le refroidissement durant la deuxième phase se fait par soufflage d'air, il faudra tenir compte du fait que, dans ce cas, le refroidissement des noeuds est nettement plus lent.The largest of the values calculated for L 3 (7 m) will be retained. If the cooling during the second phase is done by blowing air, it will have to be taken into account that, in this case, the cooling of the nodes is much slower.

La technologie mise en oeuvre pour appliquer le procédé de l'invention est, dans son ensemble, connue.The technology used to apply the method of the invention is, as a whole, known.

Dans la première phase, on utilise par exemple des "canons à eau" d'un type classique et on règle (ϕ) en agissant sur la pression d'alimentation de ces canons. On peut également utiliser des canons à eau-air et dans ce cas le réglage se fait par action sur le débit d'air.In the first phase, for example "water cannons" are used of a conventional type and the (ϕ) is adjusted by acting on the supply pressure of these cannons. Water-air cannons can also be used and in this case the adjustment is made by action on the air flow.

Claims (4)

1. Procédé pour la fabrication de fil machine en acier dur, caractérisé en ce qu'au sortir du laminoir à chaud, le fil est soumis à un refroidissement comportant deux phases, la première étant appliquée au fil pendant que celui-ci traverse à la vitesse de fin de laminage une ligne de refroidissement située entre le bloc finisseur et l'entraîneur à galets se trouvant à l'entrée de la tête de déposé du fil en spires étalées sur un convoyeur, la dite ligne de refroidissement étant continue, c'est-à-dire ne comportant pas d'intervalles de refroidissement à l'air entre sections successives de refroidissement intense, la longueur de la dite ligne de refroidissement et sa puissance étant réglées de telle manière que la température superficielle du fil à la fin de cette première phase soit comprise entre la température de début de la transformation martensitique pour l'acier considéré et cette température + 200°C, en ce que la seconde phase de refroidissement est appliquée au fil dès sa mise en spires étalées de façon non concentrique sur le convoyeur, le délai de temps entre la fin de la première phase et le début de la deuxième phase étant inférieur à celui pour lequel le pourcentage d'austénite transformée dépasse 5 %, et en ce que la transformation de l'austénite est d'au moins 95 %, à la sortie de la deuxième phase.1. A method for manufacturing hard steel wire rod, characterized in that at the exit from the hot rolling mill, the wire is subjected to cooling comprising two phases, the first being applied to the wire while the latter passes through the end of rolling speed a cooling line located between the finishing unit and the roller drive located at the entrance to the head for depositing the wire in coils spread on a conveyor, the said cooling line being continuous, it that is to say having no air cooling intervals between successive sections of intense cooling, the length of said cooling line and its power being adjusted in such a way that the surface temperature of the wire at the end of this first phase is between the temperature at the start of the martensitic transformation for the steel in question and this temperature + 200 ° C., in that the second cooling phase is applied to the wire as soon as it is set. n turns spread non-concentrically on the conveyor, the time delay between the end of the first phase and the start of the second phase being less than that for which the percentage of transformed austenite exceeds 5%, and in that the transformation of austenite is at least 95%, at the end of the second phase. 2. Procédé de fabrication de fil machine suivant la revendication 1, caractérisé en ce que le premier refroidissement est effectué au moyen d'un fluide appliqué à l'aide de dispositifs permettant d'atteindre une intensité de refroidissement caractérisée par une densité moyenne de flux calorifique comprise entre 3 et 7MW/m.2. A wire rod manufacturing method according to claim 1, characterized in that the first cooling is carried out by means of a fluid applied using devices allowing to reach a cooling intensity characterized by an average flux density. calorific between 3 and 7MW / m. 3. Procédé suivant l'une ou l'autre des revendications 1 et 2, caractérisé en ce que l'intensité du refroidissement au cours de la deuxième phase est comprise entre 0,1 MW/m2 et 0,4 MW/m2.3. Method according to either of Claims 1 and 2, characterized in that the intensity of the cooling during the second phase is between 0.1 MW / m 2 and 0.4 MW / m 2 . 4. Procédé suivant l'une ou l'autre des revendications 1 à 3, caractérisé en ce que le refroidissement du fil étalé sur le convoyeur, au cours de la deuxième phase du traitement thermique, est assuré par immersion dans l'eau bouillante.4. Method according to either of claims 1 to 3, characterized in that the cooling of the wire spread on the conveyor, during the second phase of the heat treatment, is ensured by immersion in boiling water.
EP85870099A 1984-07-23 1985-07-18 Method for producing high-carbon steel wire rod Expired EP0169827B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85870099T ATE35154T1 (en) 1984-07-23 1985-07-18 PROCESS FOR MAKING HARBOR STEEL WIRE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
LU85475A LU85475A1 (en) 1984-07-23 1984-07-23 PROCESS FOR PRODUCING HARD STEEL MACHINE WIRE
LU85475 1984-07-23

Publications (2)

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EP0169827A1 true EP0169827A1 (en) 1986-01-29
EP0169827B1 EP0169827B1 (en) 1988-06-15

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US (1) US4704166A (en)
EP (1) EP0169827B1 (en)
JP (1) JPS6184331A (en)
AT (1) ATE35154T1 (en)
BE (1) BE902931A (en)
DE (1) DE3563361D1 (en)
LU (1) LU85475A1 (en)

Cited By (4)

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EP0282472A1 (en) * 1987-02-11 1988-09-14 VOEST-ALPINE INDUSTRIEANLAGENBAU GESELLSCHAFT m.b.H. Method and device for cooling bars and wire rods
WO1991000368A1 (en) * 1989-07-03 1991-01-10 Centre De Recherches Metallurgiques Method and device for continuously cooling a drawn steel wire
EP0496715A1 (en) * 1991-01-21 1992-07-29 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Method and device for the manufacture of high strength wire rod from high carbon steel
EP1956292A1 (en) * 2005-11-08 2008-08-13 Kobelco Eco-Solutions Co., Ltd. Secondary combustion method and unit in incineration system

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CA2098160A1 (en) * 1993-04-12 1994-10-13 Charles N.A. Tonteling Process for producing patented steel wire
US20040261918A1 (en) * 1999-05-20 2004-12-30 Honda Giken Kogyo Kabushiki Kaisha Billet for cold forging, method of manufacturing billet for cold forging, method of continuously cold-forging billet, method of cold-forging
US20080011394A1 (en) * 2006-07-14 2008-01-17 Tyl Thomas W Thermodynamic metal treating apparatus and method
US8372766B2 (en) * 2007-07-31 2013-02-12 Kimberly-Clark Worldwide, Inc. Conductive webs
US8058194B2 (en) * 2007-07-31 2011-11-15 Kimberly-Clark Worldwide, Inc. Conductive webs

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DE2529272A1 (en) * 1974-07-05 1976-01-22 Centre Rech Metallurgique METHOD AND DEVICE FOR TREATMENT OF ROLLED WIRE
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US3547421A (en) * 1966-05-07 1970-12-15 Schloemann Ag Adjustable length for production of patented steel wire
LU57682A1 (en) * 1968-02-15 1969-04-15
FR2023878A1 (en) * 1968-11-22 1970-08-21 Centre Nat Rech Metall
BE737682A (en) * 1969-08-19 1970-02-19 Wire rod manufacturing process
FR2066203A5 (en) * 1969-10-17 1971-08-06 Centre Nat Rech Metall
US4123296A (en) * 1973-12-17 1978-10-31 Kobe Steel, Ltd. High strength steel rod of large gauge
DE2529272A1 (en) * 1974-07-05 1976-01-22 Centre Rech Metallurgique METHOD AND DEVICE FOR TREATMENT OF ROLLED WIRE
DE2612918A1 (en) * 1975-04-02 1976-10-21 Florin Stahl Walzwerk Rolled steel prodn. with softened edge - and strong core by two-step cooling heat-treatable steel
GB1595281A (en) * 1978-02-27 1981-08-12 Hamburger Stahlwerke Gmbh Method of continuously cooling rolled wire
FR2445858A1 (en) * 1979-01-05 1980-08-01 Salzgitter Peine Stahlwerke WELDABLE CONCRETE STEEL AND PROCESS FOR OBTAINING SAME
EP0058324A2 (en) * 1981-02-14 1982-08-25 Sms Schloemann-Siemag Aktiengesellschaft Device for the controlled cooling of wire at rolling temperature

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Publication number Priority date Publication date Assignee Title
EP0282472A1 (en) * 1987-02-11 1988-09-14 VOEST-ALPINE INDUSTRIEANLAGENBAU GESELLSCHAFT m.b.H. Method and device for cooling bars and wire rods
AT396074B (en) * 1987-02-11 1993-05-25 Voest Alpine Ind Anlagen METHOD FOR COOLING ROD OR WIRE MATERIAL, AND APPARATUS FOR CARRYING OUT THIS METHOD
WO1991000368A1 (en) * 1989-07-03 1991-01-10 Centre De Recherches Metallurgiques Method and device for continuously cooling a drawn steel wire
EP0496715A1 (en) * 1991-01-21 1992-07-29 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Method and device for the manufacture of high strength wire rod from high carbon steel
EP1956292A1 (en) * 2005-11-08 2008-08-13 Kobelco Eco-Solutions Co., Ltd. Secondary combustion method and unit in incineration system
EP1956292A4 (en) * 2005-11-08 2010-12-15 Kobelco Eco Solutions Co Ltd Secondary combustion method and unit in incineration system

Also Published As

Publication number Publication date
US4704166A (en) 1987-11-03
DE3563361D1 (en) 1988-07-21
JPS6184331A (en) 1986-04-28
EP0169827B1 (en) 1988-06-15
BE902931A (en) 1986-01-20
LU85475A1 (en) 1986-02-12
ATE35154T1 (en) 1988-07-15

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