EP0022134A1 - Reinforcement steel with high mechanical strength - Google Patents
Reinforcement steel with high mechanical strength Download PDFInfo
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- EP0022134A1 EP0022134A1 EP79101819A EP79101819A EP0022134A1 EP 0022134 A1 EP0022134 A1 EP 0022134A1 EP 79101819 A EP79101819 A EP 79101819A EP 79101819 A EP79101819 A EP 79101819A EP 0022134 A1 EP0022134 A1 EP 0022134A1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
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- the present invention relates to a reinforcing steel or concrete bar having high mechanical strength, easily souda- bl e to a predetermined content of carbon, which is resistant to corrosion by the air, which satisfies optimally the requirements of modern construction.
- This steel is particularly useful in the construction of concrete elements with complex properties, which must have good bearing properties and be able to be used under high temperature conditions as well as in the preparation of formwork constructions using these concrete elements.
- Concrete is one of the most used building materials, which has a high compressive strength, but a low tensile strength.
- This drawback of concrete has been resolved in construction by introducing concrete construction elements, steel bars or steel reinforcements into the traction zone which absorb the tensile stresses and relieve the concrete of such stresses. These steel reinforcements are what are called reinforcing bars.
- Concrete rods can be divided into two groups according to their way of introduction or the constraints to which they are intended to be subjected. The method of use at the same time determines the requirements for such steels.
- the concrete reinforcing bars are intended to absorb or eliminate after their introduction, the tensile and shear stresses of the construction.
- These reinforcing steels are hot rolled, they are most often round unalloyed or low alloyed steels provided with ribs and of a quality which can be welded or not.
- the hot-rolled concrete rods must have an apparent limit of elasticity guaranteed, appropriate flexibility, ribs increasing the adhesion necessary for the transfer of forces and, if necessary, they must be able to be welded.
- the tensile stresses of the construction are eliminated by the rounds at concrete, by prestressing concrete elements.
- This method of use significantly reduces the weight of the construction.
- the reinforcing steels or reinforcing bars are drawn with a tensile force corresponding to the elastic limit, are prestressed and embedded in this state in the concrete.
- the concrete element is therefore prestressed in compression by the reinforcing steel embedded in it after solidification of the concrete; the prestress corresponding to the tension used during the prestressing of steel.
- the tension resulting from the stresses of the construction which are exerted in the element of concrete is lowered to a minimum acceptable value for the concrete.
- Pre-stressed reinforcing steel must therefore function as a tension spring, which determines the requirements for such steel.
- prestressed concrete rods are already different from the requirements for hot-rolled reinforcing steel because their function is not the same.
- Their apparent elastic limit must reach at least 80% of their tensile strength and in addition, the elasticity must exhibit minimum bending, appropriate relaxation and sensitivity to corrosion under low stress.
- the high tensile strength of reinforcing steels is also an essential industrial requirement.
- the greater the strength of the steel the greater in general the allowable working stress. This increases the value of use of prestressed concrete rods, and the loss of tensile force which is inevitable following the shrinking and slow deformation of the concrete thereby loses its importance.
- the embedded non-prestressed reinforcing steel which must be used in concrete, must have a plasticity which tolerates a crack in the concrete as a result of the bending stresses of the construction before the steel breaks, but which nevertheless prevents the reinforcing steel from being subjected due to this crack to the action of environmental corrosion .
- Reinforcing steels suitable for prestressing must still have favorable rheological properties and good resistance to corrosion under stress.
- Reinforcing steels which can be used under stress or not and which have appropriate mechanical strengths are currently known.
- the chemical composition of the reinforcing steels which are not used for prestressing is characterized in that the carbon content is most often not more than 0.60% by weight and that their manganese content is between 0.50 and 1.60% by weight.
- Some steels additionally contain 0.20 - 0.60% by weight of silicon and 0.03% by weight of niobium or vanadium.
- Steels which are used in hot-rolled form and which are not suitable for prestressing are generally weldable up to a carbon content of at most 0.20%.
- Their tensile strength is generally between 350 and 6 00 N / mm 2 and can be used in 40 to 60% of constructions.
- the tensile strength of the non-weldable range is between 600 and 800 Nlmm2, but only 30 to 40% can be used for the transmission of a bending which does not require a modification of final shape.
- the reinforcing steels used for prestressing are manufactured by deformation and cold and hot treatment processes, which are expensive and complicated, or by a combination of these treatments.
- Their chemical composition can be characterized by the fact that their carbon content is generally between 0.50 and 0.80% by weight and that their silicon content is between 1.00 - 2.00%, in manganese between 0.70 - 1.20% and some other elements and even 0.50 - 1.50% chromium and 0.30 - 0.80% molybdenum.
- a characteristic of their mechanical properties is a tensile strength between 1300 and 185 0 N / mm 2 and by a traction which requires a deformation of 0.05% which remains from 800 to 1200N / mm. The relaxation of these steels presents for a loaded to 70% of tensile strength good relaxation.
- the known and used reinforcing steels have a relatively low resistance. They can only be welded in very narrow areas of resistance and produced by complicated technological processes requiring a large workforce to obtain the spring effect necessary in modern uses and construction.
- the object of the invention is the preparation of a reinforcing steel which has a high mechanical resistance even in the hot rolled state and which can be welded up to a determined carbon content, which can be used as steel of prestressed reinforcement after a simple heat treatment for a higher carbon content than that previously possible, which exhibits excellent relaxation and stability to stress corrosion and which is suitable for the production of concrete or structural elements formwork which optimally meets the requirements of the construction but which can also be used at higher temperatures.
- the reinforcing steel according to the invention comprises, in addition to iron, at most 1.20% of carbon, at most 3.5% by weight of manganese, at most 2.80% by weight of silicon, at most 1.00% by weight of molybdenum, at most 3.00% by weight of copper and / or nickel, at most 0.15% by weight of zirconium and / or cerium, 0.04 to 0.30% by weight of niobium and / or vanadium, 0.008 to 0.035% by weight of nitrogen, 0.0005 to 0.025% by weight of calcium, 0.02 - 0.15% by weight of aluminum and 0.001 at 0.05% by weight of boron and / or beryllium.
- Steels more particularly preferred according to the invention comprise, in addition to iron and the usual residual elements, the following elements in the proportions indicated below.
- the properties of the constituents and their appropriate proportions in the alloy system according to the invention create physicochemical, kinetic as well as germination conditions such, during their dissolution, solidification, recrystallization and hot deformation that the availability of the constituents to enter interstitially into solution, the quantity of these constituents as well as the number and the degree of stress, of the networks prestressed in this way are markedly increased. Thanks to the increase in the number of networks with interstitial prestressing and their degree of stress, the number of metallurgical dislocations which promote or determine the formation, of metallic precipitates and the density of their disposition, is appreciably increased, which has the effect of increasing the effectiveness of the anchoring function precipitation during the frontal displacement of the dislocations caused by the charges.
- the speed of diffusion or the number of neighboring metal atoms is reduced, thereby also reducing the formation of inconsistent seeds.
- This avoids the formation of an inhomogeneous zone along the grain boundaries, by alloying elements or precipitation and that their mechanical resistance or their creep resistance decreases.
- the bursting which previously occurred at the grain boundaries as a result of the loads is therefore delayed and their elongation and contraction is increased during rupture by creep.
- the elements according to the invention, and their proportion make it possible to automatically obtain a remarkable metallurgical quality of the reinforcing steel during its production.
- the mechanical resistance as well as the endurance limit of the steel is increased by several times without cold treatment or deformation but by an effective combination of the consolidation mechanism.
- the non-weldable field it is possible to obtain in a very simple manner and with lower expenses mechanical strengths in particular higher as well as rheological properties more favorable than for known reinforcing steels.
- the reinforcing steel according to the invention contains in its chemical composition also alloying compounds which concentrate if necessary on the surface of the steel during the hot deformation process, and which form over time, at following atmospheric action on this surface a protective layer. This layer protects the steel from corrosion of the air and markedly reduces the corrosion rate in comparison with known non-alloy reinforcing steels.
- the reinforcing steel according to the invention is well weldable up to a determined carbon content and its properties are similar in the zone of thermal influence during welding, to the properties of the starting product.
- the reinforcing steel according to the invention can be prepared and worked with the same installations as the known reinforcing steels, which means that it does not require new installations and investments to be prepared in large quantities. It has remarkable mechanical properties and guarantees stability to air corrosion if necessary and widens the resistance range in which a welded joint can be used.
- the manufacturing costs of the products prepared from the steel according to the invention do not exceed the average level currently reached due to the improved mechanical strength.
- Three charges of a steel according to the invention are prepared.
- the charges bearing the references 1 and 2 which belong to the weldable area were prepared in a 70-ton arc furnace and then poured into 3.5-ton molds quadratic profile.
- the resulting cast ingots were then rolled under normal conditions into square blocks having a section of 180 mm, they were then rolled into concrete rods with grooves and a diameter of 16 mm and allowed to cool to air on a cooler.
- the load bearing the reference 3 which does not belong to the weldable field, was prepared in a 20-ton arc furnace and poured into an ingot mold of 6 tonnes with a quadratic profile. This charge was rolled in a similar manner to that of charges 1 and 2, and was prepared in the form of a grooved concrete rod with a diameter of 8 mm in rolled form and air-cooled.
- the results of the material tests are as follows:
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Abstract
Description
La présente invention est relative à un acier d'armature ou rond à béton à haute résistance mécanique, aisément souda- ble jusqu'à une teneur déterminée de carbone, qui est résistant à la corrosion par l'air, qui satisfait de façon optimale les exigences de la construction moderne. Cet acier est intéressant en particulier dans la construction d'éléments de béton à propriétés complexes, qui doivent présenter de bonnes propriétés de portance et pouvoir être utilisés dans des conditions de température élevée ainsi que dans la préparation de constructions par coffrage à l'aide de ces éléments en béton.The present invention relates to a reinforcing steel or concrete bar having high mechanical strength, easily souda- bl e to a predetermined content of carbon, which is resistant to corrosion by the air, which satisfies optimally the requirements of modern construction. This steel is particularly useful in the construction of concrete elements with complex properties, which must have good bearing properties and be able to be used under high temperature conditions as well as in the preparation of formwork constructions using these concrete elements.
Le béton est l'un des matériaux de construction les plus utilisés, qui présente une résistance à la compression élevée, mais une résistance à la traction faible. Cet inconvénient du béton a été résolu dans la construction en introduisant dans la zone de traction des éléments de construction en béton, des barres d'acier ou des armatures d'acier qui absorbent les contraintes de traction et déchargent le béton de telles contraintes. Ces armatures d'acier sont ce qu'on appelle les ronds à béton. Les ronds à béton peuvent être divisés en deux groupes suivant leur façon d'introduction ou les contraintes auxquelles ils sont destinés à être soumis. Le mode d'utilisation détermine en même temps les exigences requises pour de tels aciers.Concrete is one of the most used building materials, which has a high compressive strength, but a low tensile strength. This drawback of concrete has been resolved in construction by introducing concrete construction elements, steel bars or steel reinforcements into the traction zone which absorb the tensile stresses and relieve the concrete of such stresses. These steel reinforcements are what are called reinforcing bars. Concrete rods can be divided into two groups according to their way of introduction or the constraints to which they are intended to be subjected. The method of use at the same time determines the requirements for such steels.
Dans l'un des modes d'utilisation, les ronds à béton sont destinés à absorber ou à éliminer après leur introduction, ]es contraintes de traction et de cisaillements de la construction. Ces aciers d'armature sont laminés à chaud, il s'agit le plus souvent d'aciers ronds non alliés ou faiblement alliés pourvus de nervures et d'une qualité pouvant être soudée ou non.In one of the modes of use, the concrete reinforcing bars are intended to absorb or eliminate after their introduction, the tensile and shear stresses of the construction. These reinforcing steels are hot rolled, they are most often round unalloyed or low alloyed steels provided with ribs and of a quality which can be welded or not.
Les ronds à béton laminés à chaud doivent présenter une limite apparente d'élasticité garantie, une flexibilité appropriée, des nervures augmentant l'adhérence nécessaire pour le transfert des forces et en cas de nécessité ils doivent pouvoir être soudés.The hot-rolled concrete rods must have an apparent limit of elasticity guaranteed, appropriate flexibility, ribs increasing the adhesion necessary for the transfer of forces and, if necessary, they must be able to be welded.
Dans l'autre mode d'utilisation, les sollicitations de traction de la construction sont éliminées par les ronds à béton, par une précontrainte des éléments en béton. Cette méthode d'utilisation permet de diminuer de façon sensible le poids de la construction. Dans ce cas, les aciers d'armature ou ronds à béton sont étirés avec une force de traction correspondant à la limite d'élasticité, sont précontraints et encastrés dans cet état dans le béton.In the other mode of use, the tensile stresses of the construction are eliminated by the rounds at concrete, by prestressing concrete elements. This method of use significantly reduces the weight of the construction. In this case, the reinforcing steels or reinforcing bars are drawn with a tensile force corresponding to the elastic limit, are prestressed and embedded in this state in the concrete.
L'élément en béton est de ce fait précontraint en compression par l'acier d'armature noyé dans celui-ci après solidification du béton; la précontrainte correspondant à la traction utilisée au cours de la précontrainte de l'acier. Ainsi, la traction résultant des sollicitations de la construction qui s'exercent dans l'élément de béton, est abaissée à une valeur minimale acceptable pour le béton. L'acier d'armature précontraint doit de ce fait fonctionner comme un ressort de traction, ce qui détermine les exigences requises pour un tel acier.The concrete element is therefore prestressed in compression by the reinforcing steel embedded in it after solidification of the concrete; the prestress corresponding to the tension used during the prestressing of steel. Thus, the tension resulting from the stresses of the construction which are exerted in the element of concrete, is lowered to a minimum acceptable value for the concrete. Pre-stressed reinforcing steel must therefore function as a tension spring, which determines the requirements for such steel.
Les exigences requises pour les ronds à béton précontraints sont déjà, du fait que leur fonction ne sont pas les mêmes, différentes des exigences requises pour les aciers d'armature laminés à chaud. Leur limite d'élasticité apparente doit atteindre au moins 80 % de leur résistance à la traction et en plus, l'é- lasticité doit présenter une flexion minimale, une relaxation appropriée et une sensibilité à la corrosion sous contrainte faible.The requirements for prestressed concrete rods are already different from the requirements for hot-rolled reinforcing steel because their function is not the same. Their apparent elastic limit must reach at least 80% of their tensile strength and in addition, the elasticity must exhibit minimum bending, appropriate relaxation and sensitivity to corrosion under low stress.
La résistance à la traction élevée des aciers d'armature est également une exigence industrielle essentielle. Ainsi, plus la résistance de l'acier est grande, plus est grande de façon générale sa contrainte utile permise. On augmente de ce fait la valeur d'utilisation des ronds à béton précontraints, et la perte en force de traction qui est inévitable à la suite du retrait et de la déformation lente du béton perd de ce fait de son importance.The high tensile strength of reinforcing steels is also an essential industrial requirement. Thus, the greater the strength of the steel, the greater in general the allowable working stress. This increases the value of use of prestressed concrete rods, and the loss of tensile force which is inevitable following the shrinking and slow deformation of the concrete thereby loses its importance.
En principe, on pourrait de ce fait utiliser dans le béton comme rond à béton, un type d'acier pour lequel la modification de la longueur résultant des sollicitations est faible mais pour lequel le domaine de variation de la forme est suffisamment large.In principle, it would therefore be possible to use in concrete as a concrete reinforcing rod, a type of steel for which the modification of the length resulting from the stresses is small but for which the range of variation of the shape is sufficiently wide.
L'acier d'armature non précontraint noyé, qui doit être utilisé dans le béton doit présenter une plasticité qui tolère une fissure du béton à la suite des contraintes de flexion de la construction avant la rupture de l'acier mais qui empêche cependant que l'acier d'armature soit soumis du fait de cette fissure à l'action de la corrosion de l'environnement.The embedded non-prestressed reinforcing steel, which must be used in concrete, must have a plasticity which tolerates a crack in the concrete as a result of the bending stresses of the construction before the steel breaks, but which nevertheless prevents the reinforcing steel from being subjected due to this crack to the action of environmental corrosion .
Les aciers d'armature appropriés pour la précontrainte doivent présenter encore des propriétés rhéologiques favorables et une bonne stabilité à la corrosion sous contrainte.Reinforcing steels suitable for prestressing must still have favorable rheological properties and good resistance to corrosion under stress.
On connaît actuellement des aciers d'armature utilisables sous contrainte ou non et présentant des résistances mécaniques appropriées, La composition chimique des aciers d'armature qui ne sont pas utilisés pour la précontrainte est caractérisée par le fait que la teneur en carbone est le plus souvent égale au maximum à 0,60 % en poids et que leur teneur en manganèse est comprise entre 0,50 et 1,60 % en poids. Quelques aciers contiennent en plus 0,20 - 0,60 % en poids de silicium et 0,03 % en poids de niobium ou de vanadium. Les aciers qui sont utilisés sous forme laminée à chaud et qui ne sont pas appropriés pour la précontrainte sont en général soudables jusqu'à une teneur en carbone égale au plus à 0,20 %. Leur résistance à la traction est comprise généralement entre 350 et 600 N/mm2 et peuvent être utilisés dans 40 à 60 % des constructions. La résistance à la traction du domaine non soudable est comprise entre 600 et 800 Nlmm2, mais seulement 30 à 40 % peuvent être utilisés pour la transmission d'une flexion qui ne nécessite pas une modification de forme définitive.Reinforcing steels which can be used under stress or not and which have appropriate mechanical strengths are currently known. The chemical composition of the reinforcing steels which are not used for prestressing is characterized in that the carbon content is most often not more than 0.60% by weight and that their manganese content is between 0.50 and 1.60% by weight. Some steels additionally contain 0.20 - 0.60% by weight of silicon and 0.03% by weight of niobium or vanadium. Steels which are used in hot-rolled form and which are not suitable for prestressing are generally weldable up to a carbon content of at most 0.20%. Their tensile strength is generally between 350 and 6 00 N / mm 2 and can be used in 40 to 60% of constructions. The tensile strength of the non-weldable range is between 600 and 800 Nlmm2, but only 30 to 40% can be used for the transmission of a bending which does not require a modification of final shape.
Les aciers d'armature utilisés pour la précontrainte sont fabriqués par des procédés de déformation et de traitement à froid et à chaud, coûteux et compliqués ou par la combinaison de ces traitements. Leur composition chimique peut être caractérisée par le fait que leur teneur en carbone est comprise en général entre 0,50 et 0,80 % en poids et que leur teneur en silicium est comprise entre 1,00 - 2,00 %,en manganèse entre 0,70 - 1,20 % et quelques autres éléments et même 0,50 - 1,50 % de chrome et 0,30 - 0,80 % de molybdène. Une caractéristique dé leurs propriétés mécaniques est une résistance à la traction comprise entre 1300 et 1850 N/mm 2 et par une traction qui nécessite une déformation de 0,05 % qui reste de 800 à 1200N/mm . La détente de ces aciers présente pour une chargé à 70 % de de la résistance à la traction une bonne relaxation.The reinforcing steels used for prestressing are manufactured by deformation and cold and hot treatment processes, which are expensive and complicated, or by a combination of these treatments. Their chemical composition can be characterized by the fact that their carbon content is generally between 0.50 and 0.80% by weight and that their silicon content is between 1.00 - 2.00%, in manganese between 0.70 - 1.20% and some other elements and even 0.50 - 1.50% chromium and 0.30 - 0.80% molybdenum. A characteristic of their mechanical properties is a tensile strength between 1300 and 185 0 N / mm 2 and by a traction which requires a deformation of 0.05% which remains from 800 to 1200N / mm. The relaxation of these steels presents for a loaded to 70% of tensile strength good relaxation.
Les aciers d'armature connus et utilisés présentent une résistance relativement faible. Ils peuvent uniquement être soudés dans des domaines de résistance très étroits et produits par des procédés technologiques compliqués nécessitant une main d'oeuvre nombreuse pour obtenir l'effet de ressort nécessaire dans les utilisations et la construction modernes.The known and used reinforcing steels have a relatively low resistance. They can only be welded in very narrow areas of resistance and produced by complicated technological processes requiring a large workforce to obtain the spring effect necessary in modern uses and construction.
Le but de l'invention est la préparation d'un acier d'armature qui a une résistance mécanique élevée même à l'état laminé à chaud et qui peut être soudé jusqu'à une teneur en carbone déterminée, qui peut être utilisé comme acier d'armature précontraint après un traitement thermique simple pour une teneur en carbone plus élevée que celle possible antérieurement, qui présente une relaxation excellente et une stabilité à la corrosion sous contrainte et qui est approprié pour la fabrication d'éléments de béton ou de construction en coffrage qui satisfont de façon optimale aux exigences de la construction mais qui peuvent être utilisés également à des températures plus élevées.The object of the invention is the preparation of a reinforcing steel which has a high mechanical resistance even in the hot rolled state and which can be welded up to a determined carbon content, which can be used as steel of prestressed reinforcement after a simple heat treatment for a higher carbon content than that previously possible, which exhibits excellent relaxation and stability to stress corrosion and which is suitable for the production of concrete or structural elements formwork which optimally meets the requirements of the construction but which can also be used at higher temperatures.
Ce but est atteint par le fait que l'acier d'armature selon l'invention comprend en plus du fer, au plus 1,20 % de carbone, au plus 3,5 % en poids de manganèse, au plus 2,80 % en poids de silicium, au plus 1,00 % en poids de molybdène, au plus 3,00 % en poids de cuivre et/ou nickel, au plus 0,15 % en poids de zirconium et/ou cérium, 0,04 à O,3O % en poids de niobium et/ou de vanadium, 0,008 à 0,035 % en poids d'azote, 0,0005 à 0,025 % en poids de calcium, 0,02 - 0,15 % en poids d'aluminium et 0,001 à 0,05 % en poids de bore et/ou de beryl- lium.This object is achieved by the fact that the reinforcing steel according to the invention comprises, in addition to iron, at most 1.20% of carbon, at most 3.5% by weight of manganese, at most 2.80% by weight of silicon, at most 1.00% by weight of molybdenum, at most 3.00% by weight of copper and / or nickel, at most 0.15% by weight of zirconium and / or cerium, 0.04 to 0.30% by weight of niobium and / or vanadium, 0.008 to 0.035% by weight of nitrogen, 0.0005 to 0.025% by weight of calcium, 0.02 - 0.15% by weight of aluminum and 0.001 at 0.05% by weight of boron and / or beryllium.
Des aciers plus particulièrement préférés selon l'invention comprennent en plus du fer et des éléments résiduels habituels les éléments suivants dans les proportions ci-dessous indiquées.
Quelques-uns des éléments de l'alliage, dans les proportions selon l'invention, forment des composés métalliques complexes qui pour partie forment déjà dès le stade de la coulée des germes actifs qui précontraignent le réseau du fer, en entrant en partie en solution interstitielle et qui multiplient de cette façon les défauts du réseau.Some of the elements of the alloy, in the proportions according to the invention, form complex metallic compounds which partly already form, at the stage of casting, active germs which prestress the iron network, partly entering into solution interstitial and which multiply network faults in this way.
D'autres éléments de l'alliage forment des précipités métalliques présentant une résistance au cisaillement élevée, ce qui augmente et stabilise de façon cohérente, la tension interne du réseau de base.Other elements of the alloy form metallic precipitates having a high shear strength, which increases and stabilizes coherently, the internal tension of the basic network.
D'autres éléments de l'alliage s'enrichissent par l'occupation des défauts du réseau à la limite des grains, de sorte que le phénomène de précipitation non cohérente est retardé. De cette façon l'enrichissement de tels précipités le long des limites des grains est empêché, l'homogénéité de leur disposition est assurée et la résistance des limites de grain est augmentée.Other elements of the alloy are enriched by the occupation of network defects at the grain boundary, so that the phenomenon of non-coherent precipitation is delayed. In this way the enrichment of such precipitates along the grain boundaries is prevented, the homogeneity of their arrangement is ensured and the resistance of the grain boundaries is increased.
En augmentant le nombre de germes cristallins de dimensions critiques on élève d'une façon sensible l'aptitude à la cristallisation de la coulée et l'on abaisse le temps de solidification ainsi que la dimension des grains primaires. On élève de cette façon brusquement la surface des limites de grains dans la matrice unitaire de sorte que l'on diminue sensiblement la possibilité de formation d'enrichissement et la charge spécifique résultant de la contrainte est également abaissée de façon sensible.By increasing the number of crystalline seeds of critical dimensions, the ability to crystallize of the casting is significantly increased and the solidification time and the size of the primary grains are reduced. In this way the surface of the grain boundaries in the unit matrix is suddenly raised so that the possibility of enrichment formation is considerably reduced and the specific charge resulting from the stress is also lowered appreciably.
Les propriétés des constituants et leurs proportions appropriées dans le système d'alliage selon l'invention créent des conditions physico-chimiques, cinétiques ainsi que de germination telles, au cours de leur mise en solution, de la solidification, de la recristallisation et de la déformation à chaud que la disponibilité des constituants pour entrer de façon interstitielle en solution, la quantité de ces constituants ainsi que le nombre et le degré de contrainte, des réseaux précontraints de cette façon se trouvent nettement augmentés. Grâce à l'augmentation du nombre des réseaux présentant une précontrainte interstitielle et de leur degré de de contrainte, on augmente de façon sensible le nombre des dislocations créées par voie métallurgique qui favorisent ou déterminent la formation, de précipités métalliques et la densité de leur disposition, ce qui a pour effet d'élever l'efficacité de la fonction d'ancrage des précipitations lors du déplacement frontal des dislocations provoquées par les charges.The properties of the constituents and their appropriate proportions in the alloy system according to the invention create physicochemical, kinetic as well as germination conditions such, during their dissolution, solidification, recrystallization and hot deformation that the availability of the constituents to enter interstitially into solution, the quantity of these constituents as well as the number and the degree of stress, of the networks prestressed in this way are markedly increased. Thanks to the increase in the number of networks with interstitial prestressing and their degree of stress, the number of metallurgical dislocations which promote or determine the formation, of metallic precipitates and the density of their disposition, is appreciably increased, which has the effect of increasing the effectiveness of the anchoring function precipitation during the frontal displacement of the dislocations caused by the charges.
Grâce aux éléments encastrés et enrichis dans les défauts des limites des grains, on réduit la vitesse de diffusion ou le nombre des atomes de métal avoisinants, on diminue de ce fait également la formation de germes incohérents. On évite ainsi qu'il se forme le long des limites des grains, une zone inhomogène, par des éléments d'alliage ou des précipitations et que leur résistance mécanique ou leur résistance au fluage diminue. On retarde de ce fait l'éclatement qui se produisait antérieurement aux limites des grains à la suite des charges et on augmente leur allongement et contraction lors de la rupture par fluage.Thanks to the elements embedded and enriched in the grain boundary defects, the speed of diffusion or the number of neighboring metal atoms is reduced, thereby also reducing the formation of inconsistent seeds. This avoids the formation of an inhomogeneous zone along the grain boundaries, by alloying elements or precipitation and that their mechanical resistance or their creep resistance decreases. The bursting which previously occurred at the grain boundaries as a result of the loads is therefore delayed and their elongation and contraction is increased during rupture by creep.
Grâce à ce phénomène, on élève notablement la plasticité, l'aptitude à la déformation à chaud et à froid ainsi que la résistance utile de l'acier d'armature.Thanks to this phenomenon, the plasticity, the aptitude for hot and cold deformation as well as the useful resistance of the reinforcing steel are notably increased.
Les éléments selon l'invention, et leur proportion permettent d'obtenir automatiquement une qualité métallurgique remarquable de l'acier d'armature pendant son élaboration. Dans le domaine soudable, on augmente de plusieurs fois la résistance mécanique ainsi que la limite d'endurance de l'acier sans traitement ou déformation à froid mais par une combinaison effective du mécanisme de consolidation. Dans le domaine non soudable, on peut obtenir de façon très simple et avec des dépenses plus faibles des résistances mécaniques notamment plus élevées ainsi que des propriétés rhéologiques plus favorables que pour les aciers d'armature connus.The elements according to the invention, and their proportion make it possible to automatically obtain a remarkable metallurgical quality of the reinforcing steel during its production. In the weldable field, the mechanical resistance as well as the endurance limit of the steel is increased by several times without cold treatment or deformation but by an effective combination of the consolidation mechanism. In the non-weldable field, it is possible to obtain in a very simple manner and with lower expenses mechanical strengths in particular higher as well as rheological properties more favorable than for known reinforcing steels.
L'acier d'armature selon l'invention contient dans sa composition chimique également des composés d'alliage qui se concentrent si nécessaire à la surface de l'acier au cours du procédé de déformation à chaud, et qui forment avec le temps, à la suite de l'action atmosphérique sur cette surface une .couche de protection. Cette couche protège l'acier de la corrosion de l'air et diminue nettement la vitesse de corrosion en comparaison avec les aciers d'armature non alliés connus.The reinforcing steel according to the invention contains in its chemical composition also alloying compounds which concentrate if necessary on the surface of the steel during the hot deformation process, and which form over time, at following atmospheric action on this surface a protective layer. This layer protects the steel from corrosion of the air and markedly reduces the corrosion rate in comparison with known non-alloy reinforcing steels.
L'acier d'armature selon l'invention est bien soudable jusqu'à une teneur en carbone déterminée et ses propriétés sont semblables dans la zone d'influence thermique au cours du soudage, aux propriétés du produit de départ.The reinforcing steel according to the invention is well weldable up to a determined carbon content and its properties are similar in the zone of thermal influence during welding, to the properties of the starting product.
L'acier d'armature selon l'invention peut être préparé et travaillé avec les mêmes installations que les aciers d'armature connus, ce qui signifie qu'il ne nécessite pas de nouvelles installations et investissements pour être préparé en grandes quantités. Il présente des propriétés mécaniques remarquables et garantit si nécessaire une stabilité à la corrosion à l'air et élargit l'intervalle de résistance dans lequel on peut utiliser un assemblage par soudage.The reinforcing steel according to the invention can be prepared and worked with the same installations as the known reinforcing steels, which means that it does not require new installations and investments to be prepared in large quantities. It has remarkable mechanical properties and guarantees stability to air corrosion if necessary and widens the resistance range in which a welded joint can be used.
En ce qui concerne le transfert des forces, il nécessite une section d'acier d'armature nettement inférieure et le poids de la construction en béton peut de ce fait être diminué de façon significative tout en maintenant la couche de béton prescrite.With regard to the transfer of forces, it requires a significantly smaller section of reinforcing steel and the weight of the concrete construction can therefore be significantly reduced while maintaining the prescribed concrete layer.
Les coûts de fabrication des produits préparés à partir de l'acier selon l'invention ne dépassent pas du fait de la résistance mécanique améliorée le niveau moyen actuellement atteint.The manufacturing costs of the products prepared from the steel according to the invention do not exceed the average level currently reached due to the improved mechanical strength.
Les résultats industriels obtenus grâce aux avantages techniques des aciers d'armature selon 'linvention tels que par exemple la diminution du poids et l'économie en énergie ainsi que les coûts d'entretien faibles, etc. ne sont pas grevés par des coûts élevés nécessaires pour la fabrication et l'utilisation du nouveau matériau de base.The industrial results obtained thanks to the technical advantages of the reinforcing steels according to the invention such as, for example, the reduction in weight and the energy saving as well as the low maintenance costs, etc. are not burdened by the high costs necessary for the manufacture and use of the new base material.
L'acier d'armature selon l'invention, ainsi que ses propriétés mécaniques sont décrits ci-après à l'aide de quelques exemples de réalisation.The reinforcing steel according to the invention, as well as its mechanical properties are described below with the aid of a few exemplary embodiments.
On prépare trois charges d'un acier selon l'invention. Les charges portant les références 1 et 2 qui appartiennent au domaine soudable ont été préparées dans un four à arc de 70 tonnes et ensuite coulées dans des lingotières de 3,5 tonnes de profil quadratique. Les lingots coulés résultants ont ensuite été laminés dans les conditions normales en des blocs carrés ayant une section de 180 mm, ils ont ensuite, été laminés en des ronds à béton avec des rainures et un diamètre de 16 mm et amenés à refroidir à l'air sur un refroidisseur.Three charges of a steel according to the invention are prepared. The charges bearing the references 1 and 2 which belong to the weldable area were prepared in a 70-ton arc furnace and then poured into 3.5-ton molds quadratic profile. The resulting cast ingots were then rolled under normal conditions into square blocks having a section of 180 mm, they were then rolled into concrete rods with grooves and a diameter of 16 mm and allowed to cool to air on a cooler.
La charge portant la référence 3, qui n'appartient pas au domaine soudable, a été préparée dans un four à arc de 20 tonnes et coulée dans une lingotière de 6 tonnes de profil quadratique. Cette charge a été laminée de façon similaire à celle des charges 1 et 2, et a été préparée sous forme d'un rond à béton rainuré d'un diamètre de 8 mm sous forme enroulée et refroidie à l'air. Les résultats des essais de matériaux sont les suivants :
Claims (2)
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT79101819T ATE15816T1 (en) | 1979-06-08 | 1979-06-08 | REINFORCEMENT STEEL WITH HIGH MECHANICAL STRENGTH. |
| DE7979101819T DE2967517D1 (en) | 1979-06-08 | 1979-06-08 | Reinforcement steel with high mechanical strength |
| EP79101819A EP0022134B1 (en) | 1979-06-08 | 1979-06-08 | Reinforcement steel with high mechanical strength |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP79101819A EP0022134B1 (en) | 1979-06-08 | 1979-06-08 | Reinforcement steel with high mechanical strength |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0022134A1 true EP0022134A1 (en) | 1981-01-14 |
| EP0022134B1 EP0022134B1 (en) | 1985-09-25 |
Family
ID=8186133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP79101819A Expired EP0022134B1 (en) | 1979-06-08 | 1979-06-08 | Reinforcement steel with high mechanical strength |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0022134B1 (en) |
| AT (1) | ATE15816T1 (en) |
| DE (1) | DE2967517D1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2535343A1 (en) * | 1982-10-28 | 1984-05-04 | Nippon Kokan Kk | STEEL MATERIAL HAVING SUPERIOR STRENGTH RESISTANCE TO HYDROGEN CRACKING IN A WET AND CORROSIVE GASEOUS ENVIRONMENT |
| GB2164057A (en) * | 1984-08-27 | 1986-03-12 | Tatu Sa Marchesan Implementos | High carbon, low alloy steel comprising niobium |
| EP0270952A2 (en) * | 1986-11-28 | 1988-06-15 | Nippon Steel Corporation | Highly tough ERW steel pipe with distinguished sour resistance |
| GB2290800A (en) * | 1994-06-27 | 1996-01-10 | Neturen Co Ltd | High strength high weldability steel bars and wires for pretressed concrete |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102013208413B4 (en) * | 2013-05-07 | 2019-10-10 | Badische Stahlwerke Gmbh | Reinforcing steel, production method for reinforcing steel |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1059615A (en) * | 1964-02-20 | 1967-02-22 | Huetten Und Bergwerke Rheinhau | Prestressed concrete |
| FR1542343A (en) * | 1966-11-17 | 1968-10-11 | United States Steel Corp | Process for improving the strength and toughness of steels |
| GB1201031A (en) * | 1966-04-15 | 1970-08-05 | G K N South Wales Ltd | Improvements relating to precipitation hardening steels |
| FR2103905A5 (en) * | 1970-08-04 | 1972-04-14 | Thy Marcinelle Monceau | |
| US3900347A (en) * | 1974-08-27 | 1975-08-19 | Armco Steel Corp | Cold-drawn, straightened and stress relieved steel wire for prestressed concrete and method for production thereof |
| SU570657A1 (en) * | 1975-12-09 | 1977-08-30 | Предприятие П/Я А-7615 | Cold-resistant steel |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT193914B (en) * | 1954-06-02 | 1957-12-10 | Oesterr Alpine Montan | Steel for reinforcement in construction |
| FR1424921A (en) * | 1965-02-18 | 1966-01-14 | Huetten Und Bergwerke Rheinhau | High tensile steel for structural elements placed under tensile stress for a long time, in particular steel for prestressed concrete with high resistance to cracking corrosion |
| US3432368A (en) * | 1965-02-25 | 1969-03-11 | Ishikawajima Harima Heavy Ind | Method for manufacturing nitride-containing low-carbon structural steels |
| JPS527408B2 (en) * | 1972-05-26 | 1977-03-02 | ||
| NL161504C (en) * | 1973-04-16 | 1980-02-15 | Hoogovens Ijmuiden Bv | METHOD FOR MANUFACTURING WELDABLE CONCRETE BARS |
| NL170159C (en) * | 1973-06-04 | 1982-10-01 | Estel Hoogovens Bv | METHOD FOR MANUFACTURING WELDABLE LOW CARBON STEEL MATERIAL BY CONTROLLED COOLING |
| FR2339678A1 (en) * | 1976-01-28 | 1977-08-26 | Ugine Aciers | New low alloy steels with increased hardenability - due to balanced addns. of boron, aluminium and nitrogen |
| DE2621330B2 (en) * | 1976-05-14 | 1979-02-15 | Fels-Werke Peine-Salzgitter Gmbh, 3380 Goslar | Method of manufacturing steel reinforcing bars |
| DE3126984A1 (en) * | 1980-07-09 | 1982-03-25 | Kabushiki Kaisha Kobe Seiko Sho, Kobe | Steel for mechanical engineering, having excellent cold-forgeability and machinability |
-
1979
- 1979-06-08 DE DE7979101819T patent/DE2967517D1/en not_active Expired
- 1979-06-08 AT AT79101819T patent/ATE15816T1/en not_active IP Right Cessation
- 1979-06-08 EP EP79101819A patent/EP0022134B1/en not_active Expired
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1059615A (en) * | 1964-02-20 | 1967-02-22 | Huetten Und Bergwerke Rheinhau | Prestressed concrete |
| GB1201031A (en) * | 1966-04-15 | 1970-08-05 | G K N South Wales Ltd | Improvements relating to precipitation hardening steels |
| FR1542343A (en) * | 1966-11-17 | 1968-10-11 | United States Steel Corp | Process for improving the strength and toughness of steels |
| FR2103905A5 (en) * | 1970-08-04 | 1972-04-14 | Thy Marcinelle Monceau | |
| US3900347A (en) * | 1974-08-27 | 1975-08-19 | Armco Steel Corp | Cold-drawn, straightened and stress relieved steel wire for prestressed concrete and method for production thereof |
| SU570657A1 (en) * | 1975-12-09 | 1977-08-30 | Предприятие П/Я А-7615 | Cold-resistant steel |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2535343A1 (en) * | 1982-10-28 | 1984-05-04 | Nippon Kokan Kk | STEEL MATERIAL HAVING SUPERIOR STRENGTH RESISTANCE TO HYDROGEN CRACKING IN A WET AND CORROSIVE GASEOUS ENVIRONMENT |
| GB2164057A (en) * | 1984-08-27 | 1986-03-12 | Tatu Sa Marchesan Implementos | High carbon, low alloy steel comprising niobium |
| AU583292B2 (en) * | 1984-08-27 | 1989-04-27 | Marchesan Implementos E Maquinas Agricolas "Tatu" S.A. | Improvement in steels for the manufacture of disks and other agricultural tools which work on the soil |
| EP0270952A2 (en) * | 1986-11-28 | 1988-06-15 | Nippon Steel Corporation | Highly tough ERW steel pipe with distinguished sour resistance |
| EP0270952A3 (en) * | 1986-11-28 | 1989-08-30 | Nippon Steel Corporation | Highly tough erw steel pipe with distinguished sour resistance |
| GB2290800A (en) * | 1994-06-27 | 1996-01-10 | Neturen Co Ltd | High strength high weldability steel bars and wires for pretressed concrete |
| GB2290800B (en) * | 1994-06-27 | 1997-07-23 | Neturen Co Ltd | High strength,high weldability steel bars and wires for prestressed concrete |
Also Published As
| Publication number | Publication date |
|---|---|
| ATE15816T1 (en) | 1985-10-15 |
| EP0022134B1 (en) | 1985-09-25 |
| DE2967517D1 (en) | 1985-10-31 |
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