Facility and method for treating the surface of long products for wire drawing purposes - Patents.com

Abstract

The invention relates to a facility (5) for treating moving elongated products (3) made of metal having a surface covered with an oxide layer, comprising a peeling assembly (7) with a group (11, 11a, 11b) of lasers (13) distributed around the elongated product (3), and a control device (9) for obtaining information about the elongated product (3), the control device (9) being configured to determine operating parameters to be prescribed in the peeling assembly (7) for peeling off the oxide layer and for ablating a metal layer of a given thickness and to obtain a given roughness in the elongated product (3) by comparing them with experimental results previously recorded in the control device (9) and by prescribing the operating parameters to the peeling assembly (7).

Description

[Technical field]

[0001] The present invention relates to an installation and a method for treating the surface of a long product for the purpose of drawing the long product after the product has been exposed to an oxidizing atmosphere for some of its chemical elements, such as during a residence time in a heat treatment furnace. [Background technology]

[0002] In the remainder of the text, the field of stainless steel wire and strip of all classification categories (austenitic, ferritic, austenitic-ferritic, etc.) is considered as a privileged example of application of the invention, but it should be understood that the above is not limiting and that the invention can be applied to other metals with technical problems similar to those faced in stainless steel wire and strip, in particular to the various grades of carbon steel and to special alloys such as, in particular, ferrous alloys.

[0003] Such long products are typically produced by a series of processes including heating a semi-finished product (specifically a billet), hot rolling to produce a long product, winding the long product into a crown, and then annealing the crown in a furnace under a reducing atmosphere or in a gas furnace under an oxidizing atmosphere.

[0004] The resulting elongated product is intended to be subjected to a drawing process using wire drawing dies in order to improve the dimensional accuracy and mechanical properties of the elongated product.

[0005] The series of treatments carried out prior to drawing, more particularly hot rolling and annealing, if not carried out under a completely reducing or inert atmosphere, will result in the formation of a layer of oxides on the surface of the long products. The oxides have a composition which varies substantially depending on the composition of the base metal and on the conditions of their formation. Most commonly, the oxides of the elements Fe, Cr, Mn and Si predominate in the case of stainless steels, and also those of the elements Ni, Nb and Cu in the case of grades containing said elements.

[0006] Such undesirable oxides should specifically be removed prior to drawing to prevent the oxides from becoming embedded in the surface of the elongated product during drawing, resulting in a poor surface finish.

[0007] It should be understood that the undesirable oxide layer referred to in this specification is not the thin layer based on Cr oxide (the so-called "passive layer") that spontaneously forms in air at ambient temperature on the surface of stainless steel and protects the stainless steel from oxidation. The oxide layer that causes problems and that we want to eliminate is the layer that forms during the residence time of the product at high temperatures in an oxidizing atmosphere. When such a layer is removed, the surface of the stainless steel is exposed and the protective passive layer of Cr oxide quickly and spontaneously forms again, allowing the stainless steel to be placed under normal use conditions again.

[0008] Furthermore, before drawing takes place, the elongated product requires a surface preparation step intended to adjust the surface roughness of the product, which provides good adhesion of the soap that is deposited on the surface of the elongated product immediately prior to drawing of the elongated product, thereby facilitating drawing.

[0009] Conventionally, the unwanted oxide layer is removed using a chemical stripping method, an electrolytic stripping method, or a series of these strips.

[0010] Chemical stripping is performed in one or more baths of hydrofluoric, hydrochloric, sulfuric, or nitric acid. Electrolytic stripping is typically performed in a bath of sodium sulfate or a bath of acid (nitric or sulfuric).

[0011] Chemical stripping is the most drastic method to remove unwanted oxides. Stripping is performed on long products during crown formation or while they are moving. Chemical stripping is also used to change the surface roughness of long products to make them easier to draw.

[0012] However, chemical stripping has many drawbacks.

[0013] Specifically, chemical stripping consumes large amounts of acid and, in addition, there is little chance of recovering any portion of the acid for further use.

[0014] The infrastructure required to perform chemical stripping, ie, continuous stripping baths and their supporting equipment, is expensive and bulky.

[0015] Such facilities use hazardous products, more specifically, hydrofluoric acid. Their liquid and solid contaminated effluents (sludge containing oxides mixed with the stripping liquid) must be stored and reprocessed according to stringent regulations that will only become more stringent in the future, which is costly. The heated acid baths also release acid vapors that need to be neutralized. Nitric acid also releases NO, which needs to be captured and processed. X It is the source of the emission.

[0016] The presence of dissolved hexavalent chromium in the stripper solution also represents a high risk to human health and the environment, and the concentration of hexavalent chromium in the solution and human exposure are measured and monitored.

[0017] Furthermore, stripping times can be very long, on the order of tens of minutes, for steel grades with high corrosion resistance.

[0018] Stripping long lengths of product in the form of a crown reduces the size of the stripping facility but can result in uneven stripping of the product. In fact, the coil coating and the links holding the crown can prevent the stripping product from reaching certain areas of the product, with the centermost coils being less exposed to the stripping product than the outer coils.

[0019] Therefore, at least in some cases, the possibility of replacing chemical or electrolytic stripping of long products by methods using lasers has been investigated.

[0020] Specifically, documents CN210816759U, CN210647767U, CN108405652A, and KR101735006B1 describe installations for stripping a moving metal wire using multiple lasers distributed around the wire. More specifically, the lasers are regularly positioned around the periphery of a circle whose center is occupied by the wire to be treated.

[0021] Such a solution is not entirely satisfactory; indeed, it alone does not provide a complete stripping of the oxide layer. Moreover, replacing chemical stripping by laser treatment does not make it possible to solve the problem of wire roughness, and the stripping solutions proposed by said document provide a wire roughness that is not necessarily suitable for drawing. The roughness may then be adjusted by chemical stripping, in which case the problems associated with chemical stripping, as mentioned above, would not be solved. [Prior art documents] [Patent documents]

[0022] [Patent Document 1] CN210816759U [Patent Document 2] CN210647767U [Patent Document 3] CN108405652A [Patent Document 4] KR101735006B1 Summary of the Invention [Problem to be solved by the invention]

[0023] The object of the present invention is therefore to propose a facility and a method for the treatment of long metal products, making it possible to provide long products suitable for wire drawing without additional operations and to eliminate the aforementioned disadvantages of chemical stripping. [Means for solving the problem]

[0024] To that end, the subject of the invention is an installation for the treatment of a running metal long product when it is moving, in preparation for a wire drawing step, the long product having at least one surface covered with a layer of oxide, the installation comprising: - a peeling assembly comprising at least one group of a plurality of lasers distributed around a moving elongated product, each laser being configured to emit a beam onto a surface of the moving elongated product in order to peel the surface, each laser being intended for the treatment of an associated portion of the surface of the elongated product; - a control device which obtains information about the elongated product as it moves, the information including a speed of movement of the elongated product and at least one characteristic dimension of the elongated product in a plane perpendicular to an axis of movement of the elongated product; Equipped with The control device includes: - determining the operating parameters to be applied to the stripping assembly in order to obtain a stripping of the oxide layer on the surface of the elongated product, and in order to ablate a layer of metal of a predetermined thickness on the surface of the elongated product, and in order to obtain a predetermined roughness on the surface of the elongated product by comparing it with experimental results previously recorded in the control device; - providing said operating parameters to said stripping assembly; The facility is characterized in that it is configured to carry out the following:

[0025] According to one embodiment, the lasers of the or each group of lasers are evenly distributed around the elongated product as it moves.

[0026] According to one embodiment, the operating parameters include the radiation intensity of the or each group of lasers and / or the laser / material interaction time at each location on the surface of the elongated workpiece.

[0027] Preferably, the peeling assembly comprises a distribution system configured to shape the laser beam or to move the laser beam across the surface of the elongated product such that the laser beam emitted by the or each group of multiple lasers covers the entire surface of the elongated product during movement of the elongated product.

[0028] According to one embodiment, the distribution system comprises, for each laser of at least one group, an optical device configured to convert each beam emitted by the associated laser into a band affecting a portion of the surface of the elongated product.

[0029] In a variant, the distribution system comprises, for each laser of at least one group, a scanning device configured to move the beam generated by the associated laser over the surface of the elongated product at a predetermined scanning speed and scanning pitch so that the beam emitted by each laser affects a portion of the surface of the elongated product.

[0030] Preferably, the operating parameters include a scanning speed and a scanning pitch of the scanning device.

[0031] According to one embodiment, the portion of the surface of the elongate product is defined by two straight lines of the surface of the elongate product parallel to the axis of movement.

[0032] Preferably, the peeling assembly comprises a first group of a plurality of first lasers distributed around the moving elongated product and a second group of a plurality of second lasers distributed around the moving elongated product, each second laser being downstream of each first laser of the first group with respect to the axis of movement.

[0033] Generally, a first laser is configured to etch an oxide layer on a surface of the elongated product and ablate a metal layer of a predetermined thickness on the surface of the elongated product, and a second laser is configured to impart a predetermined roughness to the surface of the elongated product.

[0034] Preferably, the first laser is a continuous emission laser and the second laser is a continuous emission laser or a laser configured to emit a pulsed beam, in particular a nanosecond laser.

[0035] A further subject of the invention is a method for treating a moving metal long product in preparation for a wire drawing step, using a treatment facility according to the invention, the long product having at least one surface covered with a layer of oxide, - acquisition by the control device of information about the elongated product when it is moving, the information comprising a speed of movement of the elongated product and at least one characteristic dimension of the elongated product in a plane transverse to the axis of movement of the elongated product; - determining by the control device according to information about the elongated product during its movement the operating parameters to be applied to the stripping assembly in order to obtain a stripping of the oxide layer on the surface of the elongated product, and in order to ablate a metal layer of a predetermined thickness on the surface of the elongated product, and in order to obtain a predetermined roughness on the surface of the elongated product by comparison with experimental results previously recorded in the control device; - controlling, by a controller of the stripping assembly, to provide said operating parameters to the stripping assembly; - emitting a laser beam by a stripping assembly onto a surface of the moving elongated workpiece using a laser in accordance with operating parameters determined by a control device; The method includes:

[0036] According to one embodiment, during the emitting step the laser beam is emitted by a laser that is evenly distributed around the moving elongated product.

[0037] Preferably, during the emission step, the laser beam is shaped or moved across the surface of the elongated product by a distribution system of the peeling assembly and controlled by a control device in such a way that the laser beams emitted by the or each group of multiple lasers cover the entire surface of the elongated product as the elongated product moves.

[0038] According to one embodiment, the distribution system comprises, for each laser of at least one group, an optical device which converts each beam emitted by the associated laser into a strip which affects a portion of the surface of the elongate product.

[0039] In a variant, the distribution system comprises, for each laser of at least one group, a scanning device which moves the beam generated by the associated laser across the surface of the elongated product according to a scanning speed and scanning pitch determined and controlled by the control device so that the beam emitted by each laser affects a portion of the surface of the elongated product.

[0040] For example, the scanning device moves the beam along a first direction that forms an angle with the axis of movement comprised between 0° and 90°, such as 45°, and along a second direction that is orthogonal to the first direction, the two directions being, for example, orthogonal and parallel, respectively, to the axis of movement, or each forming a non-zero angle with the axis of movement.

[0041] According to one embodiment, a portion of the surface of the elongate product is defined by two straight lines of the surface of the elongate product that are parallel to each other, in particular to the axis of movement.

[0042] Preferably, the peeling assembly comprises a first group of a plurality of first lasers distributed around the moving elongated product and a second group of a plurality of second lasers distributed around the moving elongated product, each second laser being downstream of each first laser of the first group with respect to the axis of movement, and the emitting step includes emitting laser beams onto the surface of the moving elongated product by the lasers of the first group and the lasers of the second group.

[0043] Generally, a first laser strips a layer of oxide on the surface of the elongated product and ablates a layer of metal of a predetermined thickness on the surface of the elongated product, and then a second laser imparts a predetermined roughness to the surface of the elongated product.

[0044] A further subject of the invention is a long metal product for wire drawing, which has a periodic roughness pattern on its surface, the width of the periodic pattern being comprised between 5 μm and 1 mm.

[0045] Typically, the width of the periodic pattern is comprised between 5 μm and 200 μm.

[0046] According to one embodiment, the periodic pattern consists of periodic striations including a regular alternation of protruding lines and grooves, or a pattern including a regular alternation of peaks and valleys along the first and second specific directions.

[0047] Typically, the average height between the ridges and grooves or between the peaks and valleys is comprised between 0.2 μm and 500 μm.

[0048] Specifically, the long product is a wire or a strip.

[0049] The length of product is to be drawn without undergoing surface preparation by chemical or mechanical stripping.

[0050] The invention will be better understood on reading the following description, given with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0051] [Figure 1] 1 is a schematic diagram showing an overview of a laser ablation facility according to an embodiment of the present invention; [Diagram 2] 1A-1C illustrate examples of laser placement around a moving product, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] The processing facility which will now be described in detail and illustrated by examples will be described primarily with reference to the processing of a moving stainless steel wire which has been subjected to annealing in the crown form.

[0053] The treatment facility according to the invention described can also be incorporated into a continuous treatment line with more or less equipment than described, or can be the subject of a separate facility specifically dedicated to such treatment.

[0054] Also not shown are the equipment normally present in such lines, which does not have a primary metallurgical role and which in any case does not itself intervene in the implementation of the processes carried out according to the invention: in particular, mention may be made of straighteners and wire guides for moving the long products, as well as wire sump units which serve as a "buffer" between some of the equipment, each of which may require different speeds of product movement.

[0055] The continuous line shown initially comprises a facility 1 for unwinding a crown 2 of a hot-rolled stainless steel long product 3 .

[0056] The long product 3 is, for example, a strip or a wire.

[0057] The strip has, for example, a width comprised between 1 mm and 8 mm and a thickness comprised between 0.1 mm and 3 mm.

[0058] The wire has, for example, a diameter comprised between 1 mm and 14 mm.

[0059] The long product 3, in particular a wire or strip, has a weight comprised for example between 10 kg and 1000 kg.

[0060] The elongated product 3 comprises, at its surface, a layer of oxide with a thickness generally comprised between 0.2 μm and 30 μm.

[0061] The elongated product 3 typically moves at a speed of up to 15 m / s.

[0062] According to the embodiment shown in Fig. 1, the treatment facility 5 is arranged in line downstream of the unwinding facility 1 and upstream of the wire drawing facility 6. In such an embodiment, the unwinding facility 1, the treatment facility 5 and the wire drawing facility 6 are arranged in a continuous line.

[0063] The treatment facility 5 comprises a stripping assembly 7 and a control device 9 .

[0064] The peeling assembly 7 is intended to treat the surface of the elongated product 3 in order to peel off an oxide layer on the surface of the elongated product 3, and to ablate a metal layer of a predetermined thickness on the surface of the elongated product 3, and to obtain a predetermined roughness on the surface of the elongated product 3. The peeling assembly 7 is more particularly configured to uniformly treat the surface of the elongated product 3 so that the surface condition of the elongated product 3 is uniform over the entire surface.

[0065] The stripping assembly 7 is intended to strip the oxide layer by ablation, sublimation, or evaporation of the oxide.

[0066] The layer of metal to be ablated is located under a layer of oxide. Ablation of a layer of metal of a given thickness at the surface of the elongate product 3 makes it possible to obtain a better quality surface at the end of the treatment. Indeed, the metal under the layer of oxide generally contains surface defects, internal oxides, inclusions and / or areas of a chemical composition different from that of the core of the metal, which should be removed.

[0067] The thickness of the layer of metal to be ablated is typically comprised between 5 μm and 50 μm, for example for long products made from nickel alloy 625 the thickness is comprised between 10 μm and 15 μm.

[0068] Obtaining a predetermined roughness on the surface of the elongated product 3 optimizes the adhesion of the soap used for drawing, thereby resulting in improved drawing performance.

[0069] The desired roughness depends on the metal composition, the dimensions of the metal, and the desired wire drawing performance.

[0070] Roughness is assessed according to standard NF EN ISO 4287:1998 by measurements along the transverse direction of the elongated product using a contact probe.

[0071] For example, for grades with small roughness (specifically of type 625), the cut-off frequency λc = 0.8 mm (or Ra 0.8 ) is less than 1.4 μm.

[0072] For grades with larger concave topography or relief (specifically, grade 286), the cut-off frequency λc = 2.5 mm (or Ra 2.5 ) is less than 6 μm and generally greater than 1.4 μm.

[0073] The peeling assembly 7 comprises at least one group 11 of a plurality of lasers 13 intended to be distributed around the elongated product 3 during the movement of the elongated product 3. The lasers are, for example, intended to correspond to the central axis of the elongated product during the movement of the elongated product, hereafter referred to as the axis of movement A. d The orbital axis is the center of the orbital plane.

[0074] Each laser 13 is intended to treat a portion of the surface of the elongate product 3. In particular, each portion thereby assigned to a given laser 13 is defined by two straight lines of the elongate product's surface parallel to the direction of movement.

[0075] Each portion generally extends through the length of the elongated product 3 .

[0076] Specifically, when the long product 3 is a strip, the portion assigned to each laser 13 is a strip of the product's surface of a given width (whereby the width is equal to the distance between the two straight lines that define the portion).

[0077] If the elongated product 3 is a wire, the portion assigned to each laser 13 is a portion of the surface of the wire 3 defined by two straight lines parallel to the direction of movement, the two straight lines being parallel to the axis A of movement. d And, β i θ = θ θ θ θ θ θ θ θ

[0078] A set of parts assigned to the lasers 13 of the same group 11 covers the entire surface of the product, so that in the case of a wire, the angle β i The sum of is greater than or equal to 360°.

[0079] Preferably, the sum of the surface areas of the portions assigned to the lasers 13 of the same group 11 is greater than the surface area of ​​the surface of the elongated product. In such a case, each portion assigned to a laser 13 partially covers the portions assigned to the two other lasers 13. Thereby, it is possible to prevent or minimize differences in the surface condition that may exist between the central area of ​​a portion and areas located at the periphery of the portion, which may receive a lower laser power than the central area of ​​the portion receives. The overlap of a portion by another portion actually allows an overlapping area of ​​two related portions, each located at the periphery of the respective portion, to be treated by the two lasers 13.

[0080] Preferably, the portions assigned to the lasers 13 are of equal size. For example, if the elongated product 3 is a wire, the angle β associated with the lasers of group 11 is i For example, the lasers 13 of group 11 are regularly distributed around wire 3, and the angle β associated with the lasers 13 of group 11 is i are equal to each other.

[0081] In the illustrated example, the peeling assembly 7 comprises two groups, namely a first group 11a of a plurality of first lasers 13 distributed around the moving elongated product 3 and a second group 11b of a plurality of second lasers equally distributed around the moving elongated product 3.

[0082] The second lasers of the second group 11b are downstream of the first lasers of the first group 11a in the direction of movement, more specifically, each second laser is disposed downstream of all the first lasers in the direction of movement.

[0083] Each group of lasers 11 is intended to treat the surface of an elongated product.

[0084] According to one embodiment, each group of lasers 11 is intended to treat the entire surface of the elongate product. In such an embodiment, the entire surface of the elongate product is intended to be treated successively by the lasers of the first group 11a, then by the lasers of the second group 11b and, if appropriate, by the lasers of each additional group.

[0085] In a variant, at least one group of lasers 11 is intended to treat only a portion of the surface of the elongate product. In such a variant, the groups of lasers 11 taken together are intended to treat the entire surface of the elongate product.

[0086] The or each group 11, 11a, 11b of lasers comprises at least three lasers 13. According to one embodiment, the laser groups comprise the same number of lasers. In a variant, the number of lasers 13 differs from group to group.

[0087] Each laser 13 is designated D1, . . . , D i , … , D n , where n is the number of lasers 13 in the group 11, 11a, 11b.

[0088] When the long product 3 is a wire, the main radiation direction D1, ..., D i , … , D n is the center of the wire, i.e., the axis of movement A d are all oriented toward

[0089] Preferably, in each group 11, 11a, 11b, the laser 13 is aligned along the axis A of movement of the wire 3. d are equidistant from

[0090] For example, the or each group 11, 11a, 11b of lasers may have a center about the axis of movement A. dThen, the lasers 13 are distributed around the circumference of the same circle belonging to the main radiation directions D1, ..., D i , … , D n The two points converge to a single point, and the axis of movement is A. d They intersect at .

[0091] In a variant, the lasers 13 of the same group 11, 11a, 11b are not distributed around a circle, but along the axis of movement A. d or around at least two circles centered on the axis of movement A of the helix. d The radii are distributed around a circular spiral where

[0092] Preferably, the surface areas of the portions of the surface intended to be treated by the different lasers 13 of the groups 11, 11a, 11b are identical.

[0093] According to one embodiment, the surface area of ​​the portion intended to be treated by each laser 13 of the group is equal for each group. In a variant, the surface area of ​​the portion intended to be treated by each laser 13 of the group is different for each group.

[0094] The lasers 13 are preferably distributed regularly around the elongated product.

[0095] For example, the lasers are distributed in such a way that the main emission direction of each laser of group 11, 11a, 11b forms a non-zero angle, called the spacing angle α, with the main emission directions of the other two lasers of group 11, 11a, 11b, the angle α being the same whatever the lasers under consideration in group 11.

[0096] In such a case, in the case of a wire, the angle α is determined by two straight lines that define a portion assigned to each laser 13, and the axis of movement A d When the angle α is smaller than the angle β, the portions overlap each other.

[0097] Specifically, when the number of lasers in the groups 11, 11a, 11b is equal to 3, the angle α is equal to 120°, and when the number of lasers in the groups 11, 11a, 11b is equal to 6, the angle α is equal to 60°.

[0098] According to one embodiment, the spacing angle α is equal for each group.

[0099] In a variant, the spacing angle α of the lasers of one group 11a, 11b differs from the spacing angle α of the lasers of at least one other group 11b, 11a.

[0100] Furthermore, according to one embodiment, the lasers 13 of the different groups 11a, 11b are aligned along the axis of movement A. d For example, in the case of two groups 11a, 11b, the lasers of the first group 11a are aligned with the lasers 13 of the second group 11b along the axis of movement A. d , whereby the main emission direction of each laser 13 in the first group 11a forms a non-zero angle, called a phase shift angle, with the main emission direction of the lasers in the second group 11b, which is less than the spacing angle α of the lasers of the first and second groups.

[0101] For example, if the laser spacing angle of the first group 11a and the laser spacing angle of the second group 11b are the same, the phase shift angle is equal to half the spacing angle.

[0102] Such a phase shift prevents a given area of ​​the surface of the elongated product 3 from being located in the central area of ​​the portion assigned to the lasers 13 of the first group 11a and in the central area of ​​the portion assigned to the lasers 13 of the second group 11b, or conversely, in the peripheral areas of the two portions, thereby providing for a more uniform quality of the surface.

[0103] In the example shown in FIG. 2, the group of lasers 11 comprises six lasers evenly distributed around the wire 3 and centered on the axis of movement A.d Therefore, the main emission direction D of each laser 13 is i is the main emission direction D of the two other lasers 13 of the group 11 i-1 , D i+1 , forming a fixed angle of 60°.

[0104] The lasers 13 of the same group 11, 11a, 11b are preferably identical. The lasers 13 are preferably lasers operating in the near infrared, i.e. with a wavelength comprised between 1000 nm and 1100 nm.

[0105] The laser 13 is, for example, a fiber laser.

[0106] Laser 13 is preferably suitable for selectively emitting a continuous beam or a pulsed beam, the pulsed beam having a pulse duration, for example, on the order of nanoseconds, microseconds, or milliseconds.

[0107] The laser 13 comprises, for example, a Nd:YAG laser and / or a YLS laser.

[0108] If the peeling assembly 7 comprises two groups of lasers 11a, 11b, the first group of lasers 11a is intended to peel off an oxide layer on the surface of the elongated product 3, for example by ablating at least part of a layer of metal of a predetermined thickness on the surface of the elongated product 3, and the second group of lasers 11b is intended to finish the ablation of the layer of metal of a predetermined thickness while imparting a predetermined roughness to the surface of the elongated product 3.

[0109] In such a case, the lasers of the first group 11a preferably operate in a mode different from that of the lasers of the second group 11b: in effect, the lasers of the first group 11a are therefore configured to effectively strip the oxide layer and, optionally, partially adjust the roughness at the surface of the stripped wire, while the lasers of the second group 11b are configured to adjust the roughness at the surface of the stripped wire while, where appropriate, finishing the stripping.

[0110] For example, the lasers in the first group 11a are YLS lasers configured to operate in continuous mode, while the lasers in the second group 11b are Nd:YAG lasers configured to operate in pulsed mode, specifically with pulse durations on the order of nanoseconds.

[0111] In a variant, the lasers of the first group 11a and the second group 11b are identical. By way of example, the lasers of the first group 11a and the second group 11b are lasers operating in pulsed mode, in particular Nd:YAG lasers, or lasers operating in continuous mode, in particular YLS lasers. In such a case, the lasers of the first group are preferably configured with operating parameters that differ from those of the lasers of the second group, for example in terms of intensity or frequency.

[0112] The peeling assembly 7 preferably comprises a mechanical or optical distribution system enabling each laser 13 to cover a portion of the surface of the elongate product assigned to said laser.

[0113] More specifically, the distribution system is intended to shape the laser beams emitted by each group of lasers 13 and / or move the laser beams across the surface of the elongated product 3 in such a way that the laser beams emitted by each group of lasers cover the entire surface of the elongated product 3 during the movement of the elongated product 3.

[0114] For example, in the case of a wire, the angles β associated with the different lasers 13 of groups 11, 11a, and 11b i But the angle β i The distribution system is configured in such a way that the entire surface of the wire 3 is covered by the laser, which means that the sum of is greater than or equal to 360°.

[0115] In particular, the distribution system is intended to shape the laser beams emitted by the lasers of each group 11, 11a, 11b and / or to create a scan of the surface of the elongated product 3 by the laser beams in such a way that the laser beams emitted by each laser cover the portion assigned to said laser.

[0116] The distribution system is, for example, an optical system 15 configured to shape the beam coming from each laser 13 in such a way that the beam, once formed, covers the portion allocated to that laser 13 .

[0117] Such a system comprises, for example, for each laser 13, an optical device 15 (FIG. 2) configured to transform the spot of the beam emitted by the laser 13 into a strip orthogonal to the direction of movement of the elongate product 3. The strip is of a length equal to the width of the portion assigned to each laser (i.e. the distance between two straight lines on the surface of the elongate product that define the portion).

[0118] The width of each flake along the direction of movement varies depending on the speed of wire movement, the flake width being comprised between 20 μm and 200 μm, typically being of the order of 50 μm.

[0119] In this way, the entire surface of the elongated product 3 can be treated with a limited number of lasers 13 .

[0120] Each optical device may include, for example, a lens, a spherical mirror, and / or a cylindrical mirror that will adjust the shape and size of the laser beam.

[0121] In such an embodiment, lasers 13 are preferably high average power or high pulse power lasers so as to maintain a sufficiently high energy density throughout the portion associated with each laser.

[0122] In a variant, the distribution system is an optical and mechanical scanning system.

[0123] Such a scanning system comprises, for example, for each laser 13, optical and mechanical devices suitable for shaping the beam generated by the laser 13, for concentrating the output of the laser 13 and for moving the shaped beam across the surface of the moving elongated product 3 in such a way that the beam affects the entire portion assigned to the laser 13.

[0124] More specifically, optical and mechanical devices move the beams generated by the lasers 13 across the surface of the elongated product 3 so that each laser can affect a portion of the surface assigned to it.

[0125] For example, the optical and mechanical devices are configured to move the beam along first and second scanning directions that are orthogonal to each other, specifically along a plurality of successive parallel lines, whereby scanning is performed along the first direction for each line and along the second direction to move from one line to the next.

[0126] The first and second directions of scanning form an angle with the axis of motion comprised between 0° and 90°, for example the directions are parallel and orthogonal, respectively, to the axis of motion, or orthogonal and parallel, respectively, to the axis of motion, or each form a non-zero angle, e.g., approximately 45°, with the axis of motion.

[0127] Optical and mechanical devices are configured to produce such scans at a scan speed and scan pitch suited to the desired process, as described hereinafter.

[0128] For example, the beam coming from each laser 13 scans the portion associated with said laser along lines parallel to the first direction of scanning, the lines being offset from one another according to a selected scanning pitch.

[0129] Such an optical and mechanical system may, for example, comprise at least one galvanometer mirror and may further include a polygon wheel.

[0130] Such an embodiment does not require the use of lasers with as much power as in optical system 15 due to the small size of each beam impingement generated by the laser.

[0131] Preferably, the peeling assembly 7 comprises an enclosure 17 within which the groups 11, 11a, 11b of lasers 13 and the dispensing system are housed. Naturally, the enclosure 17 comprises two openings in two opposite walls to allow the movement of the elongated products 3 through the enclosure 17. The enclosure 17 is made, for example, from stainless steel.

[0132] The use of such an enclosure 17 protects the operator as well as outside elements from the laser radiation.

[0133] Preferably, the walls of the enclosure 17 are equipped with active and / or passive safety systems to shut down the laser in case of a problem (e.g., in case of overheating or destruction of the enclosure). For example, the enclosure may have a double wall containing a fluid whose pressure or height is continuously measured.

[0134] Additionally, a camera is preferably installed inside the enclosure to monitor the smooth progress of the process.

[0135] The control device 9 is intended to control the peeling assembly 7 to provide operating parameters to the peeling assembly 7 for obtaining the entire peeling of the oxide layer over the entire surface of the long product 3, the ablation of the metal layer on the surface of the long product 3, a metal layer of a predetermined thickness, and for obtaining a predetermined roughness on the surface of the long product 3 at the end of the treatment.

[0136] The control device 9 specifically includes a storage device, a calculation device, and a human / machine interface.

[0137] To that end, the control device 9 is adapted to obtain information about the elongate product 3 when it is moving.

[0138] Such information specifically includes the speed of movement of the elongated product 3 in the treatment facility 5. Knowledge of said speed is needed to adjust the operating parameters of the stripping assembly 7 so that each location on the surface of the wire is exposed to the laser radiation for an appropriate period of time.

[0139] Such information further comprises at least one characteristic dimension of the elongate product 3 in a plane transverse to the direction of movement of the elongate product 3. For a wire, the dimension is for example the diameter of the wire. If the elongate product is a strip, the characteristic dimension is for example the width and thickness of the strip. Such a dimension serves to know the scale of the surface to be treated and to accurately focus the laser radiation emitted by the peeling assembly 7 on the surface to be treated.

[0140] Such information is preferably related to the axis of movement A in a plane perpendicular to said axis. d In fact, the axis of movement A d is axis A d , which may require changing the focus of the laser 13 and / or changing the laser beam distribution to ensure the desired surface condition.

[0141] The information acquired by the control device 9 is, for example, input by an operator via an interface of the control device 9 and recorded in a storage device.

[0142] In a variant or addition, the treatment facility 5 may further comprise a system for determining, in particular for measuring, the speed of movement of the elongated product 3 and / or the position of the elongated product 3 in the peeling assembly 7, in particular the axis of movement A. d In such a case, information about the moving elongated product is provided in real time by the determination system to the control device.

[0143] The controller 9 is also configured to obtain desired processing parameters for the elongated product 3 to be processed.

[0144] The processing parameters in particular include the desired roughness for the elongated product 3 at the end of processing.

[0145] The process parameters preferably include parameters relating to the thickness of the ablated oxide layer and / or the ablated metal layer at the surface of the elongated product 3 .

[0146] The process parameters are entered, for example, by an operator via an interface of the control device 9 and recorded in a memory device of the control device 9, or are entered automatically depending on the product to be processed.

[0147] Alternatively or additionally, at least some of the processing parameters, more particularly the desired roughness for the elongated product 3 at the end of processing, are provided by a wire drawing facility 6, which makes it possible to adjust in real time the condition of the surface of said wire in order to facilitate drawing the wire.

[0148] The control device 9 is configured to determine the operating parameters to be applied to the stripping assembly 7, and more specifically to the lasers of the groups of lasers 11, 11a, 11b, in order to obtain a stripping of the oxide layer on the surface of the elongated product 3, in order to ablate a metal layer of a predetermined thickness on the surface of the elongated product 3 and in order to obtain a predetermined roughness on the surface of the elongated product 3. The thickness of the metal layer and the predetermined roughness are parameters which have been previously obtained by the control device 9, as described above.

[0149] To this end, the control device 9 is suitable for recording in a memory device experimental reference data enabling the computer to determine the operating parameters to be applied to the peeling assembly 7 according to the desired processing parameters and information regarding the moving long product.

[0150] The operating parameters include, for example, the radiation intensity of the laser 13, the operating mode of the laser 13 (continuous beam or pulsed beam), and the duration of the laser / material interaction (corresponding to the duration that the laser beam impacts the surface of the product).

[0151] Indeed, whatever the speed of movement, each portion of the surface must be treated and must receive the energy density requested and given by the controller 9. The energy density is a function of the laser / material interaction time and the power density of the laser beam.

[0152] For a laser in continuous mode, the laser / material interaction time, which depends on the speed of movement, depends on the settings of the distribution system. For example, if the distribution system comprises, at least for a particular laser 13, an optical device 15, the laser / material interaction time is adjusted by varying the width of the stripe formed from the laser spot by the optical device 15.

[0153] If the delivery system includes a scanning system, at least for the particular laser 13, the laser / material interaction time is adjusted by varying the scanning speed and scanning pitch.

[0154] For pulsed lasers, as for continuous lasers, the laser / material interaction time, which depends on the speed of movement, depends on the settings of the distribution system. For example, if the distribution system comprises, at least for certain lasers 13, an optical device 15, the laser / material interaction time is adjusted by varying the width of the stripe formed from the laser spot by the optical device 15. If the distribution system comprises, at least for certain lasers 13, a scanning system, the laser / material interaction time is adjusted by varying the scanning speed and the scanning pitch.

[0155] For pulsed lasers, the laser / material interaction time is further tuned by varying the pulse duration and frequency of the pulsed beam.

[0156] The operating parameters thereby optionally include the width of the stripe formed by the optical device 15, the scan speed, the scan pitch, and / or the pulse duration and frequency of the pulsed beam.

[0157] For example, the radiation intensity of the laser 13 is selected to be greater the faster the speed of movement of the elongate product 3 and / or the greater the thickness of the layer of metal to be ablated.

[0158] Furthermore, the higher the travel speed, the higher the frequency of the pulses to ensure that a given portion is adequately processed by its associated laser 13 .

[0159] Furthermore, the scanning speed is selected to be higher the faster the elongated product is moving.

[0160] Generally, when the thickness of the layer of metal to be ablated is small, a high speed of movement is selected, and therefore a high scanning speed is used.

[0161] The operating parameters are also selected to obtain a surface of a given roughness, as described above.

[0162] The desired roughness is obtained by adapting the operating mode of the laser 13, for example by selecting a pulsed mode, and by adapting the laser / material interaction time on the surface of the elongated product in such a way that the laser impingement generates craters with dimensions and spacing on the surface of the elongated product 3 or overlaps to impart the desired roughness to the surface.

[0163] When the distribution system is an optical and mechanical scanning system, the roughness is adjusted, for example, by selecting the scanning pitch as a function of the width of the laser beam.

[0164] For example, if the beam width is 75 μm, the beam coming from each laser scans a portion along a line with a width equal to 75 μm, forming grooves of said width. If the scanning pitch is selected to be less than 75 μm, in particular 25 μm, the scanning of the portion will produce a surface with very little roughness. On the other hand, if the scanning pitch is selected to be greater than the width of the beam, for example 100 μm, ridges will be present between each groove, imparting a greater roughness to the surface of the product.

[0165] The operating parameters of the lasers of the same group 11, 11a, 11b are generally identical to one another, more particularly when the portions of the surface treated by the lasers 13 are of the same dimensions and the lasers are located at the same distance from the portions to be treated.

[0166] On the other hand, if the stripping assembly 7 comprises two or more groups, the operating parameters generally differ for each group.

[0167] In particular, since the peeling assembly 7 comprises two groups, the operating parameters of the lasers of the first group 11a are preferably selected to effectively peel off the oxide layer, and the operating parameters of the lasers of the second group 11b are selected to impart a desired roughness to the surface of the peeled elongated product.

[0168] For example, the lasers of the first group 11a are configured to operate in continuous mode, with the laser power selected to ablate the entire oxide layer, and the lasers of the second group 11b are configured in pulsed mode, with the pulse duration and, where appropriate, the scanning pitch selected such that the impingement of the pulses creates the desired roughness on the surface of the elongated product 3.

[0169] The controller 9 will control the stripping assembly 7 in accordance with the operating parameters thus determined.

[0170] The control device 9 is configured to determine the operating parameters prior to peeling and preferably during processing, more specifically following detection of a change in one or more of the parameters relating to the moving elongated product or the desired processing parameters.

[0171] For example, if the speed of movement is determined continuously or at a specific time by a system for determining the speed of movement and supplied to the control device 9, the control device 9 is configured to determine new operating parameters in the event of a change in the speed of movement and apply the new operating parameters to the peeling assembly 7.

[0172] Also, the axis of movement A d If the position of is determined continuously or at a specific time by a system for determining its position and supplied to the control device 9, the control device 9 is configured to determine new operating parameters in the event of a change in said position and to apply the new operating parameters to the peeling assembly 7.

[0173] According to another example, if the elongated product is pulled directly at the outlet of the peeling assembly 7 and if the pulling of the elongated product proves to be insufficient, the desired roughness can be changed in order to increase the pulling. The control device 9 is configured to accept the new desired roughness, to determine new operating parameters suitable for obtaining the new roughness and to apply the new operating parameters to the peeling assembly 7.

[0174] A method of processing elongate products 3 according to one embodiment will now be described. The processing method is preferably carried out using a processing facility 5 as described hereinbefore.

[0175] In this example, a facility 5 is considered in which the stripping assembly 7 comprises two groups of lasers, one after the other along the direction of movement of the products.

[0176] It is further taken into account that the elongated product 3 is a wire and that each group of lasers 11a, 11b comprises six lasers 13 evenly spaced around the wire 3 and positioned around a circle whose center is occupied by the center of the wire 3.

[0177] Thereby, each laser 13 of each group 11a, 11b is aligned with the axis A of movement of the wire 3. d It is intended to treat a portion of the surface of the wire extending between two straight lines parallel to the axis and defining an angle β of at least 60° with the axis.

[0178] The treatment method is carried out after an annealing treatment carried out on a long product 3, for example in the form of a crown.

[0179] The treatment method is carried out on the moving elongated product 3 following unwinding of the elongated product 3 .

[0180] The method comprises a step of obtaining, by a control device 9, parameters or information relating to the moving elongated product and the desired processing parameters.

[0181] As mentioned above, the parameters relating to the moving long product include the nature of the long product 3 (e.g. wire or strip), the speed of movement of the long product 3 in the treatment facility 5 and / or characteristic dimensions of the long product 3 in a plane transverse to the direction of movement of the long product 3. Such information is, for example, entered by an operator via an interface of the control device 9 or automatically entered and recorded in a memory device when the long product 3 is introduced into the facility.

[0182] In a variant or addition, information about the moving long product is determined by a system for detecting the speed of movement of the long product 3 and / or a system for detecting the position of the long product 3 within the peeling assembly.

[0183] The desired processing parameters for the elongated product 3 include the desired roughness for the elongated product 3 at the end of processing, and preferably include parameters relating to the thickness of the ablated oxide layer and / or the ablated metal layer on the surface of the elongated product 3.

[0184] The processing parameters are entered, for example, by an operator via an interface of the controller 9 and recorded in a memory device of the controller 9 .

[0185] The method then includes a step in which the control device 9 determines operating parameters to be given to the lasers of the laser groups 11, 11a, 11b so as to obtain etching of an oxide layer on the surface of the elongated product 3, so as to ablate a metal layer of a predetermined thickness on the surface of the elongated product 3 and so as to obtain a predetermined roughness on the surface of the elongated product 3.

[0186] Such operating parameters are determined from empirical reference data recorded in the memory of the controller 9.

[0187] The operating parameters include, for example, the radiation intensity of the laser 13, the mode of operation of the laser 13 (continuous beam or pulsed beam), and, where appropriate, the pulse duration and pulse frequency of a pulsed beam.

[0188] If the distribution system is an optical and mechanical scanning system, the operating parameters include, for each laser 13, the scanning parameters by said laser of the portion assigned to said laser 13, in particular the scanning speed and scanning pitch.

[0189] The controller 9 then transmits the operating parameters thus determined to the stripping assembly 7 .

[0190] The peeling assembly 7 then processes the surface of the elongated product 3 according to operating parameters.

[0191] More specifically, each laser 13 emits a laser beam in a selected mode of operation with an output power controlled by controller 9 .

[0192] When the operating mode of the lasers 13 of at least one group 11 , 11 a , 11 b is the pulsed mode, each laser 13 emits laser pulses whose duration and frequency are identically controlled by the controller 9 .

[0193] Furthermore, if at least one laser distribution system 13 of the groups 11, 11a, 11b is a scanning system, the scanning system produces a scan of the laser beam emitted by each laser according to a scanning speed and scanning pitch controlled by the control device 9.

[0194] During movement of the elongated product 3 through the peeling assembly 7, each laser 13 of each group 11, 11a, 11b emits a laser beam to treat a portion of the surface of the product assigned to that laser 13 in accordance with operating parameters provided by the controller 9.

[0195] As the elongated product 3 moves, at the end of processing the portion processed by each laser 13 extends over the entire length of the elongated product 3 in the direction of movement (different continuous sections of each portion moving in front of the peeling assembly).

[0196] When the stripping assembly comprises a first group of first lasers and a second group of second lasers, the surface is treated successively by the lasers of the first group and then by the lasers of the second group.

[0197] According to one embodiment, each group of lasers 11 treats the entire surface of the elongate product. In such an embodiment, the entire surface of the elongate product is successively treated by the lasers of the first group 11a, then by the lasers of the second group 11b and, if appropriate, by the lasers of each additional group.

[0198] In a variant, at least one group of lasers 11 treats only a portion of the surface of the elongate product. In such a variant, the groups of lasers 11 taken together treat the entire surface of the elongate product.

[0199] At the end of the treatment, the elongated product 3 is free of oxides on its surface, in particular the elongated product 3 is free of oxides resulting from the residence of the product at high temperature (in particular during annealing) in an oxidizing atmosphere.

[0200] Furthermore, the elongated product 3 has a characteristic roughness profile which differs from elongated products 3 obtained by chemical stripping.

[0201] The roughness profile refers to the profile obtained from the primary profile by suppressing the elongated wavelength components by applying a filter of profile λc so as to suppress wavelength components larger than λc (specifically ripple components), as described in standard NF EN ISO 4287:1998. In the present case, wavelength components smaller than λc=2.5 mm are considered.

[0202] More specifically, after stripping in the bath, the elongated product has a grainy surface, with irregular and non-periodic patterns on its surface.

[0203] On the other hand, the surface of the elongate product 3 treated according to the invention has a periodic roughness profile, ie a periodic roughness pattern on its surface.

[0204] The roughness patterns form profile elements in a roughness profile (as defined in standard NF EN ISO 4287:1998).

[0205] As specified in NF EN ISO 4287:1998, the roughness profile is determined from the surface profile resulting from the intersection of the actual surface with a given cutting plane, the average of which is parallel to the actual surface and has the appropriate orientation.

[0206] The width of the periodic pattern is comprised between 5 μm and 1 mm, for example between 5 μm and 200 μm.

[0207] For example, the pattern is a periodic striation that includes a regular alternation of raised lines (or ridges) and grooves.

[0208] The grooves correspond to the areas of the surface of the elongated product 3 that have received the highest energy density of the laser 13 , whereas the protruding lines are the areas of the surface of the elongated product 3 that have received the lowest energy density of the laser 13 .

[0209] The grooves and lines extend, for example, along a direction parallel to the central axis of the elongated product 3, along a direction perpendicular to the central axis of the elongated product 3, or along a direction oblique to the central axis of the elongated product (specifically, forming an angle of 45° with the central axis).

[0210] For example, if the distribution system is an optical and mechanical scanning system, the direction of the orientation of the lines and grooves corresponds to the direction of scanning of the laser beam (i.e., the first direction of scanning as defined above), and therefore the direction between the grooves (i.e., the second direction of scanning) is equal to the scanning pitch.

[0211] Referring to the previous example, if the beam width is 75 μm and the scan pitch is equal to 100 μm, the grooves will have a width of approximately 75 μm and the protruding lines (or ridges) will have a width of approximately 25 μm.

[0212] Typically, the distance between the grooves (corresponding to the width of the periodic pattern) is comprised between 5 μm and 1 mm, for example between 5 μm and 200 μm. Naturally, the distance between the grooves refers to the distance between each groove and the adjacent groove.

[0213] In the variant, the periodic pattern is formed by a regular alternation of peaks and valleys along the first and second singular directions.

[0214] The first direction and the second direction are, for example, perpendicular to each other, and specifically, are parallel to the central axis of the elongated product 3 and perpendicular to the central axis, respectively.

[0215] According to other examples, at least one of the first and second directions is neither parallel nor orthogonal to the central axis of the elongate product 3. In all cases, periodic patterns are found in the roughness profile in the form of periodic profile elements, each pattern consisting of peaks and valleys.

[0216] The height of the profile elements, for example the average height between a ridge and a groove or the average height between a peak and a valley, is generally comprised between 0.2 μm and 500 μm.

[0217] To measure the distance between the profile elements and the height of the profile elements, a suitable cutting plane is selected, as described above, by first viewing the surface of the product, for example by imaging, in particular by optical microscopy, by scanning electron microscopy or using a profilometer.

[0218] For example, if the periodic patterns are grooves and protruding lines parallel to the central axis of the elongated product 3, a cutting plane perpendicular to the central axis will be selected, whereas if the lines and grooves are perpendicular to the central axis of the elongated product 3, a cutting plane parallel to the central axis will be selected.

[0219] If the periodic pattern is alternating peaks and valleys along a first direction and a second direction, then it is preferable to select two cutting planes parallel to the first direction and the second direction, respectively, and the average width and height in each of those directions are evaluated.

[0220] Preferably, waste materials generated by the oxide stripping and metal removal by the stripping assembly 7 are collected by a dust extraction system and a smoke extraction system.

[0221] Preferably, during processing, the operating parameters are recalculated by the control device 9 in the event of a change in the parameters relating to the elongated product when moving, or in the desired processing parameters.

[0222] For example, if the speed of movement is determined continuously or at a specific time by a system for determining the speed of movement and supplied to the control device 9, a change in the speed of movement results in the calculation of new operating parameters appropriate for the new speed of movement, and the new operating parameters are applied to the peeling assembly 7.

[0223] In addition, the axis of movement A dWhen the position of is determined continuously or at a specific time by the system for determining said position and supplied to the control device 9, the control device 9 determines new operating parameters in the event of a change in the position and applies the new operating parameters to the peeling assembly 7.

[0224] According to another example, if the elongate product is pulled directly at the outlet of the peeling assembly 7 and if the pulling of the elongate product proves to be insufficient, the desired roughness can be changed in order to increase the pulling. The new roughness is fed to the control device 9, which results in the calculation of new operating parameters suitable for obtaining the new roughness, and the new operating parameters are applied to the peeling assembly 7.

[0225] According to yet another example, in the event of a failure of a laser in the group, the operating parameters are recalculated to take such failure into account.

[0226] The facility and method according to the invention therefore provide for efficient and rapid processing without the use of harmful products, ensuring both the stripping of the oxide layer present on the long product, removing surface defects, internal oxides, inclusions and / or areas of a chemical composition at the surface of the metal below the oxide layer that differ from the composition of the metal core, and imparting a roughness to the surface of the long product, without additional operations, which would allow the long product to be drawn.

[0227] Although the facility and method have been more particularly described with reference to wire rod, the facility and method are also suitable for processing other types of elongated products, such as strip rod.

[0228] For example, to process a strip having two major surfaces and two surfaces extending along the thickness of the strip, one or more groups of lasers can be used with at least one laser positioned opposite each of the major surfaces, at least one laser positioned opposite each of the surfaces extending along the thickness of the strip. [Explanation of symbols]

[0229] 1 Unwinding facility 2 crowns 3 Long products, wire rods, long metal products, long stainless steel products 5. Treatment facilities 6. Wire Drawing Facility 7 Peeling assembly 9. Control Device 11 Laser Group 11a First Group 11b Second Group 13 Lasers, laser distribution systems 15 Optical systems and devices 17 Enclosure A d Axis of movement D Main radiation direction α Spacing angle β angle

Claims

1. A facility (5) for the treatment of a metal elongate product (3) while in motion in preparation for a wire drawing step, said elongate product (3) having at least one surface covered with a layer of oxide, said facility (5) comprising: a peeling assembly (7) comprising at least one group (11, 11a, 11b) of a plurality of lasers (13) distributed around the moving elongated product (3), each laser (13) being configured to emit a beam onto the surface of the moving elongated product (3) in order to peel said surface, each laser (13) being intended for said treatment of an associated portion of the surface of the elongated product (3); A control device (9) configured to obtain information about the elongated product (3) when it is moving, said information being the speed of the movement of the elongated product (3) and the axis of movement of the elongated product (A d and at least one characteristic dimension of the elongated product (3) in a plane perpendicular to the plane of the control device (9). Equipped with The control device (9) determining the operating parameters to be applied to the stripping assembly (7) in order to obtain the stripping of the oxide layer on the surface of the elongated product (3) and to ablate a metal layer of a predetermined thickness on the surface of the elongated product (3) and to obtain a predetermined roughness on the surface of the elongated product (3) by comparing it with experimental results previously recorded in the control device (9); providing said operating parameters to said peeling assembly (7); A facility (5) configured to:

2. 2. A treatment facility (5) according to claim 1, characterized in that the lasers (13) of the or each laser group (11, 11a, 11b) are evenly distributed around the moving elongated product (3).

3. 3. A treatment facility (5) as claimed in claim 1 or 2, wherein the operating parameters comprise the radiation intensity of the laser (13) of the or each group (11, 11a, 11b) and / or the laser / material interaction time at each position on the surface of the elongated product (3).

4. 4. The treatment facility (5) according to any one of claims 1 to 3, wherein the peeling assembly (7) is configured to shape the laser beam emitted by the plurality of lasers (13) in the or each group (11, 11a, 11b) so as to cover the entire surface of the elongated product (3) during the movement of the elongated product (3) or comprises a distribution system configured to move the laser beam over the surface of the elongated product (3).

5. 5. The treatment facility (5) of claim 4, wherein the distribution system comprises, for each laser (13) of at least one group (11, 11a, 11b), an optical device (15) configured to convert each beam emitted by the associated laser (13) into a band affecting a portion of the surface of the elongated product (3).

6. 6. A treatment facility (5) as claimed in claim 4 or 5, wherein the distribution system comprises, for each laser (13) of at least one group (11, 11a, 11b), a scanning device configured to move the beam generated by the associated laser (13) over the surface of the elongated product (3) according to a predetermined scanning speed and scanning pitch, such that the beam emitted by each laser (13) affects a portion of the surface of the elongated product (3).

7. 7. The treatment facility (5) according to claim 6, wherein the operational parameters include the scanning speed and the scanning pitch of the scanning device.

8. 8. A treatment facility (5) according to any one of claims 5 to 7, wherein the portion of the surface of the elongated product (3) is defined by two straight lines parallel to each other on the surface of the elongated product (3).

9. The peeling assembly (7) comprises a first group (11a) of a plurality of first lasers distributed around the moving elongated product (3) and a second group (11b) of a plurality of second lasers distributed around the moving elongated product (3), each second laser being aligned along the axis of movement (A d 9. The treatment facility (5) according to claim 1, wherein the first laser of each of the first groups (11a) is downstream with respect to the first laser of the first group (11b).

10. 10. The treatment facility (5) of claim 9, wherein the first laser is configured to ablate a metal layer of a predetermined thickness on the surface of the elongated product (3) to remove the oxide layer on the surface of the elongated product (3), and the second laser is configured to impart the predetermined roughness to the surface of the elongated product (3).

11. 11. The treatment facility (5) according to claim 9 or 10, wherein the first laser is a continuous emission laser and the second laser is a continuous emission laser or a laser configured to emit a pulsed beam, in particular a nanosecond laser.

12. A treatment method for a moving metal long product (3) in preparation for a wire drawing step, using a facility (5) according to any one of claims 1 to 11, the long product (3) having at least one surface covered with a layer of oxide, A step of obtaining information about the elongated product (3) when it is moving, by the control device (9), said information being the speed of the movement of the elongated product (3) and the axis (A d at least one characteristic dimension of said elongated product (3) in a plane transverse to said elongated product (3); a step of determination by the control device (9) according to the information on the elongated product (3) when it is moving of the operating parameters to be applied to the stripping assembly (7) for obtaining a stripping of the oxide layer on the surface of the elongated product (3) and for ablating a metal layer of a predetermined thickness on the surface of the elongated product (3) and for obtaining a predetermined roughness on the surface of the elongated product (3) by comparison with experimental results previously recorded in the control device (9); controlling said stripping assembly (7) by said control device (9) to provide said operating parameters to said stripping assembly (7); emitting, by the peeling assembly (7), a laser beam onto the surface of the moving elongated product (3) using a laser (13) in accordance with the operating parameters determined by the control device (9); A method comprising:

13. A long metal product (3) for wire drawing, the long metal product (3) having a periodic roughness pattern on its surface, the width of the periodic pattern being comprised between 5 μm and 1 mm.

14. 14. The metal elongate product (3) according to claim 13, wherein the width of the periodic pattern is comprised between 5 μm and 200 μm.

15. 15. The metal elongate product (3) according to claim 13 or 14, wherein the periodic pattern is comprised of periodic striations including a regular alternation of protruding lines and grooves, or in a pattern including a regular alternation of peaks and valleys along the first and second singular directions.

16. 16. The elongated metal product (3) according to claim 15, wherein the average height between the ridges and the grooves or the average height between the peaks and the valleys is comprised between 0.2 μm and 500 μm.

17. The elongated product (3) according to any one of claims 13 to 16, characterized in that the elongated product (3) is a wire or a strip.

18. 18. A metal elongate product (3) according to any one of claims 13 to 17, characterized in that the elongate product (3) is to be drawn without being subjected to a surface preparation treatment by chemical or mechanical stripping.

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