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  • 专利说明
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    • 专利摘要:
    The steel wire has a carbon content in mass C such that 0.05% ≤ C <0.4% and a chromium content in Cr mass such as Cr <12%. The wire drawing process comprises: - at least a first uninterrupted series of steps (4001 - 400m) of wire drawing from a diameter D to a diameter of - at least a second uninterrupted series of steps (7001) - 700m) wire drawing wire diameter to a diameter d - one or more intermediate steps between the first and second series of uninterrupted steps (4001 - 400m, 7001 - 700m) wire drawing, the wire having a temperature lower than or equal to 300 ° C during the or each intermediate step.
    公开号:FR3013736A1
    申请号:FR1361539
    申请日:2013-11-22
    公开日:2015-05-29
    发明作者:Arnaud Verleene；Laurent Bucher；Olivier Giroux
    申请人:Michelin Recherche et Technique SA Switzerland ；Compagnie Generale des Etablissements Michelin SCA；Michelin Recherche et Technique SA France；
    IPC主号:
    专利说明:

    [0001] The invention relates to a method for drawing a steel wire and a steel wire, in particular for a tire. [2] A carcass reinforcement tire, for example radial, comprises a tread, two inextensible beads, two flanks connecting the beads to the tread and a crown reinforcement disposed circumferentially between the carcass reinforcement and the body. tread. [3] The crown and / or carcass reinforcement comprises one or more rubber plies, possibly reinforced by reinforcement elements or reinforcements such as single metal wires or metal cables coming from the assembly of several single metal wires. . The metal reinforcements are made of steel. [4] The crown reinforcement generally consists of at least two superimposed crown plies, sometimes referred to as "working" plies or "crossed" plies, whose reinforcing ropes, generally metallic, are arranged substantially parallel to each other. to others within a web, but crossed from one web to another, that is to say inclined, symmetrically or otherwise, with respect to the median circumferential plane, of an angle which is generally understood between 10 ° and 45 ° depending on the type of tire. The crossed plies may be supplemented by various other plies or layers of auxiliary rubber, of varying widths depending on the case, with or without reinforcements. As an example of simple rubber cushions, so-called "protection" plies responsible for protecting the rest of the crown reinforcement from external aggressions, perforations, or so-called "hooping" plies comprising reinforcements oriented substantially in the circumferential direction (so-called "zero degree" plies), whether radially external or internal to the crossed plies. [5] However, these metal reinforcements contribute significantly to the mass of the tire that is desired to lighten as much as possible, improving, if possible, their mechanical strength. [6] A first solution is to increase the mass ratio of steel elements, for example carbon, up to 0.9% or more, which increases the mechanical strength of the son, so to reduce the diameter and / or the density in the reinforcing plies, and thus lighten the tire. We obtain a light tire but with a relatively modest endurance. Indeed, the metal reinforcements are more sensitive to fatigue and corrosion due to the use of relatively high mass carbon content. [7] In order to manufacture such yarns, a first uninterrupted series of wire drawing steps of a diameter D to a diameter of on is carried out. Thereafter, the diameter wire is heat treated by heating the wire past the austenitizing temperature of the steel and then cooling the wire at a rate to obtain a predetermined microstructure of the steel. Then a second uninterrupted series of drawing steps of the wire of diameter to a diameter d is performed. In addition, prior to the second uninterrupted series of drawing steps, the method comprises a step of coating by successive deposits of a first layer of copper and a second layer of zinc and a step of thermodiffusion copper in the second layer and zinc in the first layer. Such a thermodiffusion step is performed at about 540 ° C which can cause a globulization of the microstructure of the steel, especially when it is ferritoperlitic, and make subsequent drawing steps impossible on an industrial scale. [008] A second solution consists in using steels comprising a high mass content of chromium, for example described in EP0648891. Such steels, generally called stainless steels, achieve a relatively high strength and a high resistance to corrosion due to the presence of chromium in the steel. However, the cost of stainless steels is very high due to the use of a high chromium mass rate. The invention aims to provide a metal reinforcement less sensitive to fatigue and corrosion, inexpensive and easy to draw on an industrial scale. [010] For this purpose, the subject of the invention is a method for drawing a steel wire in which the wire has a carbon content in mass C such that 0.05% C <0.4% and a chromium content in Cr mass such that Cr <12%, the process comprising: - at least a first uninterrupted series of wire drawing steps from a diameter D to a diameter of - at least a second uninterrupted series of drawing steps of the diameter wire to a diameter of one or more intermediate steps between the first and second uninterrupted series of wire drawing steps, the wire having a temperature of 300 ° C or less at the or of each intermediate step. [011] The wire used has a relatively low mass C of carbon. Thus, wire drawability is improved, i.e. the possibility of obtaining a relatively small diameter d from a relatively large diameter. In other words, the relatively low mass C of carbon allows rational deformation c '= 2.1n (id) high which allows to sufficiently wet the wire to give it P10-3184_FR - 3 - properties sufficiently high or even high mechanical resistance, in particular a maximum stress before rupture sufficiently high. [12] Even though its maximum stress before breaking may be in some cases lower than that of yarns of the state of the art having a higher carbon content C, the yarn obtained by the process according to the invention is much less sensitive to fatigue and corrosion which improves the endurance of the tire and offsets its initial deficit in maximum stress before rupture. [13] In addition, the diameter of the wire can be reduced while maintaining sufficient mechanical strength to reinforce the tire. [014] The use of a steel with a relatively low mass of carbon content makes it possible to obtain a relatively inexpensive wire, unlike the use of a stainless steel. [15] The temperature of 300 ° C. or less at the time of each intermediate step makes it possible to avoid modifying the microstructure of the steel, for example by globulization, which would have the effect of preventing the subsequent drawing of the steel. wire up to its final diameter d on an industrial scale. [16] The temperature of the wire may be measured by any technique known to those skilled in the art, for example by remote measurement, for example by infrared or by measurement in contact with the wire after stopping the running of the wire, for example to using a thermocouple. [17] By uninterrupted series of drawing steps, it is meant that the wire undergoes no steps, in particular heat treatment or coating, other than a drawing step between two drawing steps of the series. In other words, the wire undergoes no steps, in particular heat treatment or coating, between two directly successive drawing steps of the series. [18] Preferably, the wire has a temperature less than or equal to 350 ° C and more preferably less than 300 ° C during the or each intermediate step. [19] According to optional features: - is greater than or equal to 0.5 mm, preferably 1 mm and more preferably 1.3 mm. The diameter of is large enough to obtain high mechanical properties by hardening the wire. d is less than or equal to 2.5 mm, preferably to 2.2 mm and more preferably to 2 mm. The diameter of is small enough to allow the work hardening to the final diameter of the wire. [020] Optionally, the micro-structure of the steel is selected from ferrite, perlite, and mixtures of these microstructures. A ferritic-pearlitic or pearlitic micro-structure is distinguished from another micro-structure, in particular martensitic, by metallographic observation. The ferrito-pearlitic micro-structure exhibits ferrite grains as well as lamellar pearlitic zones. On the other hand, the martensitic microstructure comprises slats and / or needles which those skilled in the art will be able to distinguish between ferrite-pearlitic and pearlitic micro-structures from grains and lamellae. [21] More preferably, the microstructure of the steel is ferrito-pearlitic. [22] Preferably, the micro-structure of the steel is devoid of martensite and / or bainite. [023] According to an optional feature of the method, the first uninterrupted series of drawing steps of the wire of diameter D to the diameter of dry medium is carried out. [24] By drawing in a dry medium, it is understood that the wire circulates in a gaseous medium, for example ambient air. Preferably, the drawing lubricant during drawing in a dry medium is in pulverulent form. When drawing in a dry medium, the means of traction, for example capstans, are exposed to the ambient air. [25] According to another optional feature of the method, the second uninterrupted series of wire drawing steps of the wire diameter to the diameter d is performed in a wet environment. By drawing in a humid medium, it is understood that the wire circulates in a liquid medium, for example an aqueous solution. Preferably, the drawing lubricant in a wet drawing is in liquid form. When drawing in a humid environment, the traction means, for example capstans, are exposed to the liquid medium, for example the aqueous solution. [027] In one embodiment, where d and d are expressed in mm, the rational strain e '= 2.In (d' / d) is such that e '> 3. Preferably c' 5. [028] In some embodiments, c 'k 3.5, more preferably c' k 4 and even more preferably c 'k 4.5. In some other embodiments, it is 4 and preferably 3.5. [029] In one embodiment, where D and d are expressed in mm, the rational strain e = 2.In (D / d ') is such that ck 2. Preferably c 5. [30] In some modes of realization, preferably in those for which c 'k 4 and more preferably c' k 4.5, D and d being expressed in mm, the rational strain e = 2.In (D / d ') is such that c 3 preferably c <2.75 and more preferably c 2.5. [31] In other embodiments, preferably in those for which c 'P10-3184_FR - 5 - 4, preferably c' 3.5, D and d being expressed in mm, the rational strain c = 2.1 n (D / d ') is such that ck 3, preferably ck 3.5 and more preferably ck 4. [32] Thus, it limits the drawing of the wire from the diameter D to the diameter of which allows to Tightening the wire sufficiently during the second uninterrupted series of wire drawing steps from diameter to diameter d to increase its mechanical stress before breaking R. [33] Preferably, D and d being expressed in mm, the deformation rational Cr = 2.1n (D / d) is such that Cr k 6.5, preferably Cr k 6.75 and more preferably Cr k 7.2. [034] In preferred embodiments, Cr 8. [35] Optionally, D is greater than or equal to 4 mm, preferably 5 mm. [36] Preferably, the intermediate step or steps do not include a step of heating the steel beyond its austenitization temperature. [37] Thus, the intermediate step (s) do not comprise a step generally called a heat treatment step in which the wire is heated beyond its austenitization temperature to obtain an austenitic microstructure and then the wire is cooled to obtain a predetermined microstructure. The austenitization temperature is generally between 700 and 900 ° C. [38] In a preferred embodiment, the intermediate step (s) comprise a step of coating the wire with a diameter of at least one metal layer. [39] Preferably, the step of coating the wire of diameter is selected from a step of depositing a layer of a substantially pure metal alloy, a step of depositing a first layer of a first substantially pure metal followed by a step of depositing a second layer of a substantially pure second metal, a step of depositing a layer of a substantially pure metal. [40] By substantially pure metal is meant a metal comprising at least 90%, preferably at least 95% and preferably at least 99% of a single metallic chemical element. By a substantially pure metal alloy is meant a mixture of at least two distinct metals, each metal being substantially pure, and together constituting more than 50% by weight of the alloy. Thus, an alloy may comprise additives providing properties specific to the alloy depending on its use. [41] For example, the step of depositing a layer of a substantially pure metal alloy may be a step of depositing a layer of the alloy, for example brass or bronze. This type of deposition step is generally called co-deposition because the substantially pure metals constituting the alloy are deposited simultaneously from nuggets of the alloy. [42] For example, substantially pure metals are selected from copper, zinc, tin, aluminum, cobalt and nickel and preferably from copper, zinc and tin. [43] In a preferred embodiment, the step of coating the diameter wire comprises a step of depositing a first layer of a substantially pure first metal followed by a step of depositing a second layer. of a substantially pure second metal, the intermediate step (s) do not comprise a thermodiffusion step of each first and second metal respectively in the second and the first layer. [44] The subject of the invention is also a steel wire of diameter d expressed in mm exhibiting a carbon content in mass C such that 0.05% C <0.4%, a chromium content in mass Cr such that that Cr <12% and a maximum stress before rupture R, expressed in MPa, such that R k A + 910.0 - 600.In (d) with A = 875. [45] The maximum breaking stress or breaking strength is the force required to break the wire. The measurements of maximum stress before rupture denoted R (in MPa) are carried out according to the ISO 6892 standard of 1984. [46] Such a wire is insensitive to fatigue and to corrosion, inexpensive and easy to manufacture by wire drawing to a industrial scale. [47] In one embodiment, the yarn has a carbon content by mass C such that 0.07% C 0.3%, preferably 0.1% C 0.3% and more preferably 0.15% C 0.25%. [48] Advantageously, A = 1025, preferably A = 1175 and more preferably A = 1465. [49] Advantageously, R k 1500 MPa, preferably R k 2000 MPa and more preferably R k 2500 MPa. [50] Advantageously, d is greater than or equal to 0.10 mm and preferably 0.12 mm. [051] When the diameter d is too small, the cost of manufacturing the wire becomes too important and incompatible with mass production. [52] Advantageously, d is less than or equal to 0.40 mm, preferably 0.25 mm, more preferably 0.23 mm and even more preferentially 0.20 mm. [53] When the diameter d is too large, the flexibility and endurance of the wire are too low for use of the wire in some layers of the tire, including the carcass reinforcement, for example for a truck type vehicle. P10-3184_EN - 7 - [54] Another object of the invention is a cable comprising several son as defined above. [55] For example, the cables are of the layer type or the strand type. [56] It is recalled that there are two possible techniques for assembling wires or strands: either by wiring: in such a case, the strands or strands do not undergo torsion around their own axis, because of a synchronous rotation before and after the assembly point; or by twisting: in such a case, the son or strands undergo both a collective twist and an individual twist around their own axis, which generates a torque of untwisting each of the son or strands. [57] The invention also relates to a semi-finished element, comprising a rubber matrix in which is embedded at least one wire as defined above. [58] The rubber matrix comprises at least one diene elastomer, a reinforcing filler, a vulcanization system and various additives. [59] By diene elastomer of the rubber matrix is generally meant an elastomer derived at least in part (ie a homopolymer or a copolymer) of monomers dienes (monomers carrying two carbon-carbon double bonds, conjugated or not) . [060] The diene elastomers, in known manner, can be classified into two categories: those called "essentially unsaturated" and those called "essentially saturated". In a particularly preferred manner, the diene elastomer of the rubber matrix is chosen from the group of diene elastomers (essentially unsaturated) consisting of polybutadienes (BR), synthetic polyisoprenes (IR), natural rubber (NR), copolymers of butadiene, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-copolymers of butadiene-styrene (SBIR) and mixtures of such copolymers. [61] The rubber matrix may contain a single diene elastomer or a mixture of several diene elastomers, wherein the diene elastomer (s) may be used in combination with any type of synthetic elastomer other than diene, or even with polymers other than elastomers for example thermoplastic polymers. As a reinforcing filler, carbon black P10-3184_FR - or an inorganic filler is preferably used. More particularly, carbon blacks are suitable for all carbon blacks, especially blacks of the HAF, ISAF, SAF type conventionally used in tires. By way of nonlimiting examples of such blacks, mention may be made of N115, N134, N234, N330, N339, N347 and N375 blacks.
    [0002] However, the carbon black can of course be used in cutting with reinforcing fillers and in particular other inorganic fillers. Such inorganic fillers comprise silica, in particular highly dispersible silicas, for example the Ultrasil 7000 and Ultrasil 7005 silicas from Degussa. [63] Finally, one skilled in the art will understand that, as an equivalent load of the reinforcing inorganic filler described in this paragraph, it would be possible to use a reinforcing filler of another nature, in particular organic, since this reinforcing filler would be covered with an inorganic layer such as silica, or would comprise on its surface functional sites, especially hydroxyl, requiring the use of a coupling agent to establish the bond between the filler and the elastomer. [64] The reinforcing filler may also be added, according to the intended application, inert (non-reinforcing) fillers such as clay particles, bentonite, talc, chalk, kaolin, usable for example in flanks or belts. colored tire bearing. [065] The rubber matrix may also comprise all or part of the usual additives normally used in elastomer compositions intended for the manufacture of tires, for example plasticizers or extension oils, which are of aromatic nature. or non-aromatic, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, anti-fatigue agents, reinforcing resins, acceptors (eg novalaque phenolic resin) or donors methylene (for example HMT or H3M) as described for example in the application WO 02/10269 (or US2003-0212185). [66] The rubber matrix also comprises a vulcanization system based on either sulfur, or sulfur and / or peroxide donors and / or bismaleimides, vulcanization accelerators, vulcanization activators. [67] The vulcanization system itself is preferably based on sulfur and a primary vulcanization accelerator, in particular a sulfenamide type accelerator, as selected from the group consisting of 2-mercaptobenzothiazyl disulfide (M BTS ), N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N, N-dicyclohexyl-2-benzothiazylsulfenamide (DCBS), N-tert-butyl-2-benzothiazyl P10-3184_FR-9-sulfenamide (TBBS), N- tert-butyl-2-benzothiazyl sulfenimide (TBSI) and mixtures of these compounds. [068] Another object of the invention is a tire comprising at least one yarn as defined above. [069] Preferably, the tire is intended for passenger vehicles, industrial vehicles chosen from vans, heavy vehicles such as "heavy goods vehicles" - ie, metro, buses, road transport vehicles (trucks, tractors, trailers). , off-the-road vehicles -, agricultural or engineering machinery, aircraft, other transport or handling vehicles. More preferably, the tire is intended for heavy vehicles, agricultural or civil engineering machinery, aircraft, other transport vehicles or handling. [070] Preferably, the wire is intended to reinforce a crown reinforcement and / or tire carcass. More preferably, the wire is intended to reinforce a tire carcass reinforcement. [071] Preferably, the tire is for a truck-type vehicle comprising a carcass reinforcement comprising at least one wire as described above. [072] The invention will be better understood on reading the description which follows, given solely by way of nonlimiting example and with reference to the drawings in which: - Figure 1 a sectional view perpendicular to the direction circumferential of a tire according to the invention; - Figure 2 is a diagram illustrating steps of a drawing process according to the invention. [73] TIRE EXAMPLE ACCORDING TO THE INVENTION [74] FIG. 1 shows a tire comprising yarns obtained by the process according to the invention and designated by the general reference 10. [75] The tire 10 comprises a top 12 reinforced by a crown reinforcement 14, two flanks 16 and two beads 18, each of these beads 18 being reinforced with a rod 20. The top 12 is surmounted by a tread not shown in this schematic figure. A carcass reinforcement 22 is wrapped around the two rods 20 in each bead 18 and comprises an upturn 24 disposed to the outside of the tire 10 which is shown here mounted on a rim 26. [76] The carcass reinforcement 22 is in a manner known per se consisting of at least one ply reinforced by wires or cables. These wires or cables of the carcass reinforcement are said to be "radial", that is to say that these wires or cables are arranged practically parallel to each other and extend from one bead to the other to form an angle between 80 ° and 90 ° with the median circumferential plane (plane perpendicular to the axis of rotation of the tire which is located halfway between the two beads 18 and passes through the middle of the crown reinforcement 14 ). [77] The crown reinforcement 14 comprises at least one ply reinforced by son or cables according to the invention. In this crown reinforcement 14 schematized in a very simple manner in FIG. 1, it will be understood that the son or cables of the invention may, for example, reinforce all or part of the working crown plies, or the plies (or half-plies) vertex triangulation and / or protection top plies, when such triangulation top or protection plies are used. In addition to the working plies, those of triangulation and / or protection, the crown reinforcement 14 of the tire of the invention may of course comprise other crown plies, for example one or more crown plies. [78] Of course, the tire 10 also comprises, in a known manner, a layer of rubber or inner elastomer (commonly called "inner rubber") which defines the radially inner face of the tire and which is intended to protect the carcass reinforcement of air diffusion from the interior space to the tire. Advantageously, in particular in the case of a truck tire, it may further comprise an intermediate reinforcing elastomer layer which is located between the carcass reinforcement and the inner layer, intended to reinforce the inner layer and, therefore, the carcass reinforcement, also intended to partially relocate the forces suffered by the carcass reinforcement. [79] The tire is manufactured by assembling the various elements described above in the form of semi-finished elements comprising a rubber matrix in which the wires or cables are embedded. [80] EXAMPLE OF CABLE ACCORDING TO INVENTION [81] In the case where the crown and / or carcass reinforcement is reinforced by cables, these are manufactured by assembling several steel wires in accordance with the invention. invention, either by wiring or by twisting. [82] In the case of a tire for industrial vehicles selected from P10-3184_FR vans, heavy vehicles such as "heavy goods vehicles" - ie, metro, buses, road transport vehicles (trucks, tractors, trailers), off-the-road vehicles, agricultural or civil engineering machinery, aircraft, other transport or handling vehicles, the crown and / or carcass reinforcement is reinforced by cables according to the invention, chosen in particular from the cables with structural layers 1 + 3 + 8, 1 + 6 + 11, 1 + 6 + 12, 2 + 7, 3 + 8, 3 + 9, 3 + 9 + 15 and structural strand cables 3 x (1 +5), (1 + 6) x (3 + 8), (1 + 6) x (3 + 9 + 15), (1 + 6) x (4 + 10 + 16). Other cables that can reinforce the crown and / or carcass reinforcement are also described in document WO 2010/139583. [083] In the case of a tire for passenger vehicles, the crown and / or carcass reinforcement is reinforced by cables in accordance with the invention and in particular chosen from the cables of structure 2 + 1, 2+ 2, 2 + 4 and 4x3. [084] The cables according to the invention can be gummed in situ, as described, inter alia, in WO 2010/139583. [085] The crown and / or carcass reinforcement may also be reinforced by one or more unitary threads according to the invention but not assembled. [86] EXAMPLE OF THE YARN OF THE INVENTION [87] The yarn is made of steel, that is to say that it consists mainly (that is to say for more than 50% by weight) or entirely ( for 100% by mass) of steel. [88] The microstructure of the steel is selected from ferrite, perlite and mixtures of these microstructures. The wire is preferably ferritoperlitic steel. The steel used comprises a carbon content C, expressed in%, by weight of steel such as 0.05% C <0.4%. Preferably, 0.07% C 0.3%, preferably 0.1% C 0.3% and more preferably 0.15% C 0.25%. [89] The steel used comprises iron, between 0.3 and 0.7% by weight of manganese, here 0.583%, between 0.1 and 0.3% by weight of silicon, here 0.161%, at most 0.045 % by weight of phosphorus, here 0.0085%, at most 0.045% by weight of sulfur, here 0.0151%, and at most 0.008% by weight of nitrogen, here 0.0029%. [090] The steel used may also comprise specific addition elements such as Ni, Co, V, or various other known elements (see for example Research Disclosure 34984 - "Micro-alloyed steel cord constructions for tires" - May 1993 Research Disclosure 34054 - "High tensile strength steel cord constructions for tires" - August 1992) to adapt the steel to a specific use. P10-3184_EN -12- [91] Optionally, the steel used comprises at most 0.1% inclusive, preferably not more than 0.05% included, and more preferably not more than 0.02% inclusive. vanadium mass, here 0%. [92] The steel used comprises a chromium content in Cr mass such that Cr <12%, preferably such as Cr 5%, more preferably such as Cr 1%, and even more preferentially such as Cr 0.2%, and here Cr = 0.039%. [93] Optionally, the steel used comprises at most 0.1% inclusive, preferably at most 0.05% included, and more preferably at most 0.02% included molybdenum, 0.009 %. [094] Optionally, the steel used comprises at most 0.1% inclusive, preferably at most 0.05% included, and more preferably at most 0.02% included mass bound vanadium, chromium and molybdenum. [095] Optionally, the steel used comprises at most 0.05% inclusive of nickel, in this case 0.026%. [096] Optionally, the steel used comprises at most 0.05% inclusive, preferably at most 0.01% inclusive, and more preferably not more than 0.005% including boron, here 0.002%. [97] Optionally, the steel used comprises at most 0.05% inclusive, preferably at most 0.01% inclusive, and more preferably at most 0.001% inclusive cobalt, here 0%. [98] The values of the mass ratios of the elements described above can be measured according to the standard FD CEN / TR 10261 entitled "Steel and iron - European standards for the determination of the chemical composition". [99] The yarn may be coated with a metal layer improving, for example, the properties of use of the yarn, or the properties of use of the yarn, the cable and / or the tire themselves, such as the properties of the yarn. adhesion, resistance to corrosion or resistance to aging. The wire is coated with a coating chosen from a layer of a substantially pure metal alloy, for example brass or bronze, a first layer of a substantially pure first metal, for example copper, coated with even a second layer of a substantially pure second metal, for example zinc, and a layer of a substantially pure metal, for example zinc. Alternatively, the wire may be free of metal coating. Table 1 shows the following son EDT1, EDT2 according to the state of the art and F1, F2 and F3 according to the invention. The son of the examples of Table 1 have a diameter d greater than or equal to 0.10 mm and preferably 0.12 mm. In addition, the yarns of the examples in Table 1 have a diameter d less than or equal to 0.40 mm, preferably 0.25 mm, more preferably 0.23 mm, and even more preferentially at 0. , 20 mm. EDT 1 EDT 2 F1 F2 F3 C (%) 0.71 0.585 0.21 0.21 0.21 d mm 0.18 0.18 0.18 0.15 0.15 R (MPa) 2820 2903 2730 2798 2705 Table 1 [0102] The son F1 to F3 are such that the maximum stress before rupture R of the wire, expressed in MPa, is such that R k A + 910.0 - 600.In (d) with A = 875 and d expressed in MM . It will be noted that the wires F1 to F3 are such that A = 1025, preferably A = 1175 for the son F1 to F3 and more preferably A = 1465 for the F1 and F2 son. It will be noted that the wires F1 to F3 are such that R k 1500 MPa, preferably R 2000 MPa and more preferably R k 2500 MPa. EXAMPLE OF A WIRE THREADING PROCESS ACCORDING TO THE INVENTION FIG. 2 shows a diagram of a method for wire drawing as described above. In a unwinding step 100, a steel wire of initial diameter Dk4, preferably Dk5, in this case equal to 5.5 mm and having a maximum breaking stress of between 300 MPa and 700 MPa, is unrolled. the species R = 525 MPa. The wire, called wire rod, is stored in the form of a boot on a reel from which it is unrolled by means of automated unwinding means, for example a unwinder. The micro-structure of the steel is ferrito-pearlitic. In a descaling step 200 of the machine wire, the machine wire is passed through several successive pulleys and in two trainers each formed by several pulleys, the pulleys of each blocker being mounted in rotation along an axis perpendicular to the axis. rotation of the pulleys of the other trainer. This removes a layer of iron oxides, called calamine, present on the surface of the wire rod. In a step 300, the wire rod is coated with a layer of an adhesion promoter of a drawing lubricant. Steps 4001 to 400 are intended to reduce the diameter of the wire from the initial diameter D to an intermediate diameter of, for example greater than or equal to 0.5 mm, preferably greater than or equal to 1 mm and more preferably to 1.3 mm and for example less than or equal to 2.5 mm, preferably to 2.2 mm and more preferably to 2 mm. The steps 4001 to 400, (n varying from 6 to 12) form a first uninterrupted series of drawing steps in a dry medium of the wire from the initial diameter D to the intermediate diameter of. Each step 4001 to 400 is a drawing step in a dry medium in which the wire is passed through a die of diameter less than the diameter of the wire upstream of the die. Thus, the wire has a diameter downstream of the die less than the diameter upstream of the die. The diameter of each die is less than the diameter of the die upstream. For the first uninterrupted series of drawing steps in the dry medium of the wire from the initial diameter D to the intermediate diameter of, we define the rational strain c = 2.1n (D / d '). Thread pulling means positioned downstream of each die, here capstans, allow to exert sufficient traction force to pull the wire through each die. A drawing lubricant is used in pulverulent form. In a step 600, the intermediate diameter wire is coated with at least one metal layer. The coating step 600 of the intermediate diameter wire is selected from a step of depositing a layer of a substantially pure metal alloy, a step of depositing a first layer of a substantially pure first metal followed by a deposition step of a second layer of a substantially pure second metal, a step of depositing a layer of a substantially pure metal. Here, the coating step 600 of the intermediate diameter wire is a deposition step a deposition step of a first layer of a first substantially pure metal followed by a deposition step of a second layer of a second substantially pure metal, here a layer of copper and a layer of zinc. Steps 7001 to 700, (m varying for example from 8 to 23) are intended to reduce the diameter of the wire of the intermediate diameter to the final diameter d and increase the maximum breaking stress of the wire. Steps 7001 to 700 form a second, uninterrupted series of wet wire drawing steps of the intermediate diameter wire to the final diameter d.
    [0003] Each step 7001 to 700 is a wet drawing step in which the wire is passed through a die of diameter less than the diameter of the wire upstream of the die. Thus, the wire has a diameter downstream of the die less than the diameter upstream of the die. The diameter of each die is less than the diameter of the die upstream. For the second uninterrupted series of wet wire drawing steps from the wire of the intermediate diameter to the final diameter d, the rational deformation c '= 2.1n (d / d) is defined. P10-3184_EN -15- [0116] In a variant, steps 7001 to 700 will be carried out in a dry medium. Thread pulling means positioned downstream of each die, here stage capstans, allow to exert sufficient traction force to pull the wire through each die. The traction means and the dies are immersed in a liquid bath of drawing lubricant, for example as described in WO 2008/113481. The drawing process thus comprises N uninterrupted series of drawing steps, for example one in a dry medium and one in a humid medium. Here N = 2. Thus, one can define the total rational strain for the wire drawing process Cr = 2.1n (D / d). Thus, the method comprises one or more intermediate steps between the first and second uninterrupted series of steps 4001 - 400 ,, 7001 - 700, drawing the wire. During the or each of these intermediate steps, the wire has a temperature of less than or equal to 300 ° C. Here, the process comprises a single intermediate step, here the coating step 600, during which the wire has a temperature between 15 ° C and 300 ° C and preferably between 15 ° C and 200 ° C. The intermediate step (s) do not comprise a thermodiffusion step of each first and second metal respectively in the second and the first layer, here copper in the second layer and zinc in the first layer. The intermediate step or steps do not include a step of heating the steel beyond its austenitization temperature. Table 2 shows different values of the characteristics of the yarns according to the invention and of the state of the art. EDT1 EDT2 F1 F2 F3 C (%) 0.71 0.585 0.21 0.21 0.21 of (mm) 1 1.3 1.75 0.75 1.30 d (mm) 0.18 0.18 0.18 0.15 0.15 E 2.6 2.8 2.3 4.0 2.9 E. 3.6 4 4.5 3.2 4.3 AND 6.2 6.8 6.8 7.2 Table 2 P10-3184_EN -16- [0123] It will be noted that the rational deformation e '= 2.In (d' / d) is such that 3 <c '5 for the wires F1 to F3. Preferably, k '3.5 for the F1 and F3 yarns, more preferably c' k 4 for the F1 and F3 yarns and even more preferentially c 'k 4.5 for the F1 yarn. It will also be noted that c '4 and preferably c' 3.5 for the wire F2. It will be noted that the rational strain e = 2.In (D / d ') is such that 2 c 5 for the son F1 to F3. It will also be noted that for the wires for which c 'k 4 (case of the wires F1 and F3) and more preferentially c' k 4.5 (case of the wire F1), the rational strain e = 2.In (D / d ') is such that c 3 for the F1 and F3 yarns, preferably c 2.75 for the F1 yarn and more preferably c 2.5 for the F1 yarn. It will also be noted that for the wires for which c '4, preferably c' 3.5 (case of wire F2), the rational strain e = 2.In (D / d ') is such that ck 3, preferably ck 3.5 and more preferably ck 4 for the wire F2. It will also be noted that, for the F1 and F2 yarns, cT k 6.5, preferably cT 6.75 and more preferably cT k 7.2. It will also be noted that cT 8. [0128] TESTS AND COMPARATIVE TESTS [0129] The yarns of the state of the art and the yarns F1, F2 and F3 were compared during a rotary bending test carried out in a humid atmosphere. (at least 60% relative humidity). This test is used to measure the maximum resistance to endurance in wet flexing oF * of each wire tested. During this test, 105 cycles are imposed on the wire tested around its axis of revolution at a predetermined stress. If the wire breaks, we repeat the test with a lower stress and if the wire does not break, we start the test with a higher stress. The value of oF * is thus gradually determined, for example, by the so-called staircase method. The results of this test are summarized in Table 3 below. EDT1 EDT2 F1 F2 F3 C (%) 0.71 0.585 0.21 0.21 0.21 d mm 0.18 0.18 0.18 0.15 0.15 R (MPa) 2820 2903 2730 2798 2705 aF * (m Pa) <500 <500 655 711 746 Table 3 P10-3184_EN -17- [0130] In wet medium, the son F1 to F3 according to the invention break at significantly higher stresses than those of the state of the illustrative of one of the advantages of the invention. Thus, even if the initial breaking stress of the son F1 to F3 according to the invention is lower than that of the son EDT1 and EDT2, the fatigue-corrosion endurance of the son F1 to F3 is significantly greater than that of the son EDT1 and EDT2 . The invention is not limited to the previously described embodiments. Indeed, the descaling step 200 can be carried out by the action of a chemical agent, for example acid. P10-3184_FR
    权利要求:
    Claims (30)
    [0001]
    REVENDICATIONS1. A method for drawing a steel wire (F1; F2; F3), characterized in that the wire (F1; F2; F3) has a carbon content in mass C such that 0.05% C <0.4 % and a chromium content in Cr mass such that Cr <12%, the method comprising: - at least a first uninterrupted series of steps (4001 - 400,) of wire drawing (F1; F2; F3) of a diameter D to a diameter of - at least a second uninterrupted series of steps (7001 - 700) of wire drawing (F1; F2; F3) of diameter to a diameter d - one or more intermediate steps between the first and second uninterrupted series of steps (4001 - 400 ,, 7001 - 700,) of wire drawing (F1; F2; F3), the wire (F1; F2; F3) having a temperature of less than or equal to 300 ° C during the or each intermediate step.
    [0002]
    2. Method according to any one of the preceding claims, wherein d 'is greater than or equal to 0.5 mm, preferably 1 mm and more preferably 1.3 mm.
    [0003]
    3. Method according to any one of the preceding claims, wherein d 'is less than or equal to 2.5 mm, preferably to 2.2 mm and more preferably to 2 mm.
    [0004]
    4. Method according to any one of the preceding claims, wherein is selected from ferrite, perlite and mixtures of these microstructures.
    [0005]
    5. Method according to any one of the preceding claims, wherein the first uninterrupted series of steps (4001 - 400,) of wire drawing of the diameter D to the diameter of dry medium is carried out.
    [0006]
    6. A method according to any one of the preceding claims, wherein the second uninterrupted series of steps (7001-700) of drawing wire of the diameter of diameter to diameter in the wet medium is carried out.
    [0007]
    7. A method according to any one of the preceding claims, wherein d 'and d being expressed in mm, the rational deformation c' = 2.1n (d '/ d) is such that c'> 3.
    [0008]
    8. A method according to any one of the preceding claims, wherein d 'and d being expressed in mm, the rational deformation c' = 2.1n (d '/ d) is such that c' 5.
    [0009]
    9. A method according to any one of claims 1 to 8, wherein d 'and d being expressed in mm, the rational strain c' = 2.1n (d / d) is such that c '3.5, preferably c 'k 4 and more preferably c' k 4.5. P10-3184_FR-19-
    [0010]
    10. Process according to any one of claims 1 to 8, wherein d 'and d being expressed in mm, the rational strain E' = 2.In (d '/ d) is such that c' 4, preferably c 3.5.
    [0011]
    11. A method according to any one of the preceding claims, wherein D and d being expressed in mm, the rational strain E = 2.In (D / d ') is such that E k 2.
    [0012]
    12. A method according to any one of the preceding claims, wherein D and d being expressed in mm, the rational strain E = 2.In (D / d ') is such that e 5.
    [0013]
    13. A method according to any one of claims 1 to 12, wherein, D and d being expressed in mm, the rational strain E = 2.In (D / d ') is such that c 3, preferably c 2 , 75 and more preferably c 2.5.
    [0014]
    14. A method according to any one of claims 1 to 12, wherein, D and d being expressed in mm, the rational strain E = 2.In (D / d ') is such that ck 3, preferably ck 3 , 5 and more preferably ck 4.
    [0015]
    15. A method according to any one of the preceding claims, wherein, D and d being expressed in mm, the rational strain ET = 2.In (D / d) is such that ET k 6.5, preferably AND k 6 , 75, more preferably ET k 7.2.
    [0016]
    16. The method according to any one of the preceding claims, AND 8.
    [0017]
    17. A method according to any one of the preceding claims, wherein D is greater than or equal to 4 mm, preferably 5 mm.
    [0018]
    18. The method as claimed in any one of the preceding claims, in which the intermediate step or steps do not comprise a step of heating the steel beyond its austenitization temperature.
    [0019]
    19. The method as claimed in any one of the preceding claims, in which the intermediate step or steps comprise a step of coating (600) the wire with a diameter of at least one metal layer.
    [0020]
    20. The method of claim 19, wherein the step of coating the wire of diameter is selected from a step of depositing a layer of a substantially pure metal alloy, a step of depositing a first layer. a first substantially pure metal followed by a step of depositing a second layer of a substantially pure second metal, a step of depositing a layer of a substantially pure metal.
    [0021]
    The method of claim 19 or 20, wherein the step of coating the diameter wire includes a step of depositing a first layer of a substantially pure first metal followed by a step of depositing a In the second layer of a substantially pure second metal, the intermediate step (s) do not comprise a thermodiffusion step of each first and second metal respectively in the second and the first layer.
    [0022]
    22. Wire (F1; F2; F3) of steel of diameter d expressed in mm, characterized in that the wire (F1; F2; F3) has a carbon content in mass C such that 0.05% C <0 , 4%, a chromium content in Cr mass such that Cr <12% and a maximum stress before rupture R, expressed in MPa, such that R k A + 910.0 - 600.In (d) with A = 875.
    [0023]
    23. Yarn (F1; F2; F3) according to claim 22, having a carbon content by mass C such that 0.07% C 0.3%, preferably 0.1% C 0.3% and more preferably 0 15% C 0.25%.
    [0024]
    24. Wire (F1; F2; F3) according to any one of claims 22 or 23, wherein A = 1025, preferably A = 1175 and more preferably A = 1465.
    [0025]
    25. The yarn (F1, F2, F3) according to any one of claims 22 to 24, wherein R k 1500 MPa, preferably R k 2000 MPa and more preferably R 2500 MPa.
    [0026]
    26. The yarn (F1; F2; F3) according to any one of claims 22 to 25, wherein d is greater than or equal to 0.10 mm and preferably 0.12 mm.
    [0027]
    27. Wire (F1; F2; F3) according to any one of claims 22 to 26, wherein d is less than or equal to 0.40 mm, preferably 0.25 mm, more preferably 0.23 mm and still more preferably at 0.20 mm.
    [0028]
    28. Cable (01; C2), characterized in that it comprises a plurality of wires (F1; F2; F3; F4) according to any one of claims 22 to 27.
    [0029]
    29. Semi-finished element (14, 22), characterized in that it comprises a rubber matrix in which is embedded at least one wire (F1; F2; F3) according to any one of claims 22 to 27.
    [0030]
    30. Pneumatic tire (10), characterized in that it comprises at least one wire (F1; F2; F3) according to any one of claims 22 to 27. P10-3184_EN
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    法律状态:
    2015-11-19| PLFP| Fee payment|Year of fee payment: 3 |
    2016-11-18| PLFP| Fee payment|Year of fee payment: 4 |
    2017-11-21| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1361539A|FR3013736B1|2013-11-22|2013-11-22|TREFILING METHOD AND WIRE OBTAINED BY THIS TREFILING METHOD|FR1361539A| FR3013736B1|2013-11-22|2013-11-22|TREFILING METHOD AND WIRE OBTAINED BY THIS TREFILING METHOD|
    CN201480063540.2A| CN105992828B|2013-11-22|2014-11-21|Drawing method and the silk thread prepared by the drawing method|
    PCT/EP2014/075225| WO2015075164A1|2013-11-22|2014-11-21|Drawing method and wire produced by said drawing method|
    US15/037,499| US20160281297A1|2013-11-22|2014-11-21|Drawing Method And Wire Produced By Said Drawing Method|
    EP14802047.2A| EP3071715A1|2013-11-22|2014-11-21|Drawing method and wire produced by said drawing method|
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