Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
  • C21D9/562—Details
  • C21D9/564—Tension control
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
  • C21D8/1238—Flattening; Dressing; Flexing
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
  • C21D8/125—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest with application of tension
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
  • C21D8/1255—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest with diffusion of elements, e.g. decarburising, nitriding
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
  • C21D8/1261—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest following hot rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
  • C21D9/562—Details
  • C21D9/563—Rolls; Drums; Roll arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B17/00—Furnaces of a kind not covered by any preceding group
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
  • F27B9/28—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity for treating continuous lengths of work
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D2201/00—Treatment for obtaining particular effects
  • C21D2201/05—Grain orientation

Definitions

• the invention relates to the field of steel fabrication for electrotechnical applications, for example, but in a nonlimiting manner, used for producing magnetic circuits for transformers.
• the invention more particularly relates to a method for accentuating the orientation of the grains of a steel sheet in a process of manufacturing magnetic sheets, and a device for implementing such a method.
• the present invention further relates to a magnetic sheet production plant implementing this method and device.
• the efficiency of an electric machine is notably reduced by magnetic losses occurring in the magnetic circuits of such a machine.
• the optimization of the yield thus implies to manufacture magnetic circuits limiting as much as possible the losses that these circuits are likely to entail.
• the sheets are typically made of steel comprising silicon and whose grains, that is to say elements of its metallurgical structure, are oriented ("GO" type steel). Such sheets are designated by the terms “magnetic sheet” or “electrical steel”.
• FIGURES 1 and 2 each represent a 1x sample of steel sheet whose grains are represented in the schematic form of rectangular prisms 2a, 2b, 2c, 2d, 2e, 2f.
• the sample lx of FIG. 1 comprises grains 2a, 2b, 2c randomly oriented relative to each other, that is to say that their respective faces occupy random orientations in space with respect to a direction 3.
• the sample 1x is a sheet whose grains are said to be non-oriented ("NGO" type steel).
• the grains 2d, 2e, 2f are arranged in a substantially identical orientation, close to the direction 3 which is for example a rolling direction, that is to say a direction in which the sheet has undergone a stretching operation.
• FIG. 3 represents the crystallographic structure of a sample of steel sheet 1 with oriented gains (GO type steel) showing the grains in a plane parallel to a main face of the sheet. It shows grains 2g, 2h large and whose main orientations are substantially parallel to the direction 3, for example rolling.
• electrical steels typically contain 3.5% silicon, whereas traditional carbon steel contains about 0.3% to 0.6% silicon.
• the manufacture of electrical silicon steels typically aims to obtain a primary grain size as high as possible, for example 5- 15 pm for GO-type steels, and 20-200 ⁇ for NGO-type steels or steels. in which the grains are semi-oriented. It also aims to obtain a high secondary grain size, typically 1-5 mm for steels of the type "CRGB” ("Cold Rolled Grain-Oriented” in English), or even 5-30 mm for high-quality electrical steels such as than "HiB" type steels.
• CRGB Cold Rolled Grain-Oriented
• the average grain orientation of the GO steels must be achieved with an alignment tolerance of +/- 2 ° with respect to the Goss direction for the secondary grains, and an alignment tolerance of +/- 1, 5 ° for primary grains for an angle of these primary grains up to 10 ° with respect to the direction of Goss.
• at least two main processes are known for producing grain oriented magnetic sheets: a "hot” process and a "cold” process.
• the "hot” process consists of dissolving in a sheet of grain magnification inhibitors in undesired directions by heating to a temperature of 1300-1400 ° C.
• the formation of fine grains is then carried out in a hot rolling mill after which cold rolling is typically carried out and then a decarburization annealing to obtain the primary grains with deposition of magnesium oxide (mainly) on the surface of the sheet.
• the magnification of the grains in a preferred direction is obtained beforehand during an additional annealing at about 1200 ° C. in oven-type ovens.
• the "cold” process consists of the partial dissolution in the sheet of grain magnification inhibitors according to undesired orientations by its heating at a temperature of about 1200 ° C.
• Thin grain precipitation and grain orientation are performed in hot and cold mills followed by annealing, nitriding and (mainly) MgO deposition.
• the grain magnification in a preferred direction is achieved in an annealing of 1000-1200 ° C in kiln furnaces to obtain the secondary grains.
• the direction of Goss is parallel to the plane of the sheet and may correspond to the direction of rolling.
• the manufacturing steps according to such processes involve intermediate operations of storage and handling of sheets in order to transfer them from one station to another station, the thermal and mechanical operations being generally performed separately.
• Each processing operation and corresponding handling requires time and the setting up a production organization that is sufficiently precise to ensure the availability of equipment in due time.
• US3130088 discloses a solution for hot-rolling of metal strips. Rolling rollers of limited diameter, through which the band passes alternately, are placed in the oven. These small diameter planing rollers achieve a transverse homogeneity of stress in the strip by producing an elongation by surface bending of the sheet and secondly an elongation by a pure traction of this sheet, the latter being limited by the deformation already generated on the surface. . The total elongation obtained is limited, up to 3% maximum. This process generates an elongation heterogeneity in the thickness of the sheet and a heterogeneity in the grain orientation.
• US3130088 discloses powering the oven inlet and outlet strip by means of pinch rollers.
• the traction transmissible to the web by this device is limited because of the very small contact area between the web and the nip rolls. Therefore, a very high pressure force of the nip rolls is necessary to obtain a high level of traction having the effect of crushing the band and therefore an undesired thickness variation.
• An object of the present invention is to provide a device and a method making it possible to overcome all or some of the disadvantages mentioned above, in particular making it possible to accentuate the orientation of the grains of a grain-oriented steel sheet and of to lengthen these according to said orientation by reducing the total number of operations to obtain this orientation of the grains.
• An object of the present invention is to provide a device for overcoming all or part of the disadvantages mentioned above, in particular to improve the orientation accuracy of the grains of a silicon steel sheet by reducing the total number of operations to obtain this orientation of the grains.
• Another object of the present invention is to provide a device and a method for reducing the annealing temperature levels and / or the number and amount of inhibitors used in the methods known in the prior art.
• the invention proposes a method for modifying or accentuating the orientation of the grains of a steel sheet, preferably grains oriented and to lengthen them according to said orientation during an annealing operation of the steel sheet in a continuous heat treatment furnace, this operation being used in particular for the manufacture of magnetic sheet, this method comprising:
• the method according to the invention does not include elongation by bending the surface of the steel sheet.
• FIG. 9 An example of the result obtained by such stretching is presented in FIG. 9 on which are represented two grains gl, g2 of respective length Lgl, Lg2 and oriented at a respective angle ⁇ 1, ⁇ 2 with respect to the rolling direction 3.
• the grain g2 is obtained from the grain gl by the implementation of the method according to the invention. We see that after According to the invention, the grain has a length Lg2 and an angle ⁇ 2 such that Lg2> Lg1 and ⁇ 2 ⁇ 1.
• the above table shows that the step of stretching the sheet according to the method of the invention makes it possible to straighten in the direction of Goss the original orientation angle (that is to say the angle before stretching the sheet at said temperature according to the method of the invention) grains from 0.05 ° to 1.8 °.
• the following table shows a percentage of elongation of the length L of grain by the implementation of the invention, calculated according to the stretching of the steel sheet and the initial inclination of the grain.
• Stretching Percentage elongation of the length L of the sheet in the grain obtained by the elongation of the sheet according to the direction of the invention for an initial inclination of the rolling grain of:
• the increase in grain orientation accuracy, relative to a mean direction, results in an improvement of the magnetic properties of the steel, in particular its magnetic permeability. It is considered that the reduction of iron losses can reach 38% for average grain angles (between 5 ° and 10 °) whereas it is only 7% for smaller angles (between 0.5 ° and 4 °). °).
• the method according to the invention therefore makes it possible to grow the grains according to the rolling direction of the sheet and throughout the thickness thereof, while improving the angle formed by the grains with respect to this rolling direction, which improves the magnetic permeability of electrical steel throughout its thickness by reducing iron losses.
• the process according to the invention advantageously combines mechanical and thermal operations, making it possible to limit the disadvantages associated with the successive realization of mechanical and thermal operations which are separated in the processes known in the prior art.
• the stretching of a steel sheet in an oven is particularly advantageous because the temperature of the steel is stable there, so the metallurgical structure there is also homogeneous and stable. These conditions make it possible to apply stretching in a perfectly controlled manner to obtain the desired result.
• This stretching of the sheet may also be carried out, for example and without limitation, in a decarburization zone or a nitriding zone in which the temperature and metallurgical structure conditions of the sheet are also substantially constant.
• to stretch the steel sheet it is brought into drive engagement with two motorized tensioning units located in the oven.
• the tensioning units are located on either side of the stretching region, and define two different speeds of scrolling for the steel sheet respectively upstream and downstream of the region of the steel. stretching. Depending on the amount of tensile force to be applied to the sheet, these S blocks may comprise two or more rolls.
• the stretching of the steel sheet by motorized tensioning units thus arranged makes possible a localized treatment of the stretching region, in particular a controlled grain elongation.
• these tensioning units are advantageously installed at the end of the heating zone, in the temperature holding zone, or possibly in the decarburization zone or in the nitriding zone, so as to achieve controlled traction of the sheet metal. in an area in which the temperature and structure of the steel are stable. It ensures a perfect control of the setting in traction of the band to achieve the goals of elongation and grain orientation desired.
• the steel sheet has a thickness of less than or equal to about 0.5 mm, preferably about 0.3 mm.
• the elongation rate applied according to the invention to the steel sheet during the stretching step is well above the usual values obtained by planing. Indeed, the elongation rate obtained by planing is limited to 3% by design by combining winding around rollers of limited diameter and pure traction.
• the elongation rate applied to the steel sheet during the stretching step according to the invention may be less than or equal to 10 percent.
• This elongation rate can be achieved by setting the strip in the oven between two tensioning units equipped with large diameter rollers.
• a strip of a silicon steel having a thickness of 0.35 mm and a width of 1050 mm and at a temperature of 750 ° C. is energized in the zone of stretching.
• a tension on the band of 53 MPa makes it possible to obtain, with this steel grade, an elongation of this one of 10%.
• the device of the invention allows to exert the same level of tension over the entire width and over the entire thickness of the strip leading to a perfectly distributed elongation, avoiding any risk of rupture of the strip. For this steel grade, this occurs for a voltage of 58 Mpa at 750 ° C and 23.1 MPa at 900 ° C.
• the number and the diameter of the rolls of the tensioning units is determined so as to limit the plastic deformation of the band in the tensioning units.
• four roller tensioning units and a roll diameter of 800 mm are well suited. It can be seen in the table below, to a tape at 750 ° C, that the strip tension level is limited to 34.2 MPa between the 3 rd and the 4 th roll tensioner input block of where an elongation limited to 0.08% between these rolls and negligible before these.
• the diameter of the rollers is validated by the so-called "coil-break" calculations which define the minimum roll diameter to deviate from the plastic and permanent deformation which would limit the value of tension in the band and therefore the value of the elongation homogeneous in the thickness of it.
• Roll diameter values of at least 400 mm make it possible to move away from the negative deformation criteria, which depend on the strengths of the belts and the temperatures.
• Increasing the diameter of the rollers naturally gives more interesting results, the economic criterion being the only limitation.
• the number of rolls is a secondary criterion that allows for a more gradual increase in elongation as the number of rolls increases. Again, the economic criterion is the only limitation.
• the device according to the invention achieves a pure traction in the sheet which gives homogeneity of orientation of the grains in its thickness. minimizing the surface elongation by the use of rollers of large diameters defined for this purpose. It makes it possible to obtain greater pure traction by presenting a much lower surface deformation, thus more distant from the limit of rupture.
• the section variation resulting from the elongation of the strip is made by variation of its width and not by variation of its thickness, which remains constant: the stresses on the strip remain tangential to the strip and are not perpendicular to it so do not generate crushing. This situation of variation in hot width is moreover known in the field of sheet annealing furnaces.
• the continuous treatment of the sheet according to the invention greatly simplifies the production of oriented grain steels compared to the processes known in the prior art by producing in a single oven, and in a single pass of the sheet in this oven, simultaneously the metallurgical annealing operation of the steel and the step of elongation of the hot grain.
• this operation and this step are performed successively with different equipment which requires the provision of these different equipment and the successive passage of the sheet in these equipment.
• This operation and this successive step involve intermediate handling of the sheet metal coils, the availability of several different equipment with their driving teams, energy consumption and possible emissions of corresponding pollutants.
• the present invention makes it possible to eliminate these disadvantages.
• the steel sheet passes continuously to a nitriding step.
• the invention also proposes a device comprising a traction apparatus, this traction apparatus comprising at least one tensioner block (or S block) upstream and a tensioner block (or S block). downstream, the upstream tensioning unit comprising a first group of traction rollers, the downstream tensioning unit comprising a second group of traction rollers, the traction rollers of the upstream tensioning unit and the downstream tensioning unit being arranged to tension the stretching region of the steel sheet, the furnace comprising heating means adapted to heat and maintain the stretching region of the steel sheet at the set temperature.
• the setting in traction of the sheet necessary to obtain the grain orientation of a high precision can be achieved by a controlled rotation of at least one traction roller in each tensioner block.
• an advantageous solution consists in subjecting the at least one roller of each tensioner unit to a specific speed or a specific torque, so that the speed of travel of the steel sheet is greater in the downstream tensioning unit. only in the upstream tensioner block.
• the traction rollers of the two tensioning units are driven at progressively increasing speeds from upstream to downstream along the path of travel of the steel sheet.
• the traction apparatus is arranged to allow the steel sheet to be moved along a linear displacement path in which the steel sheet is brought into contact with at most a part of the traction rollers without being put into position. in traction by the traction device.
• the traction device thus installed in an oven makes it possible to use the heat treatment line in a conventional manner because the traction device can be by-passed through the sheet which then follows a conventional treatment cycle according to the state of the process. 'art.
• the invention also relates to a magnetic sheet production plant, comprising a line comprising a rolling mill and on which the method or / and a device according to different combinations of the characteristics which have just been described is implemented downstream of the rolling mill.
• the line further comprises a planer comprising planing rollers. According to an advantageous characteristic, the line further comprises a decarburizing device upstream of said method and / or device.
• the line further comprises a nitriding device downstream of said method and / or device.
• the invention also makes it possible to reduce the number of operations for producing grain-oriented electrical steel, whether hot or cold, to increase the overall productivity gain of the installation, to reduce the amount of energy consumed, or to reduce reel handling, labor and pollutant emissions. The total cost of making steel is thus considerably reduced.
• the invention clearly differs from the planing system by producing a pure traction in the sheet which gives homogeneity of orientation of the grains in its thickness by minimizing the surface elongation by the use of rolls of large diameters defined for this purpose.
• the method makes it possible to obtain greater pure traction since it exhibits a much lower surface deformation, thus more distant from the rupture limit.
• the invention differs from the usual methods in particular by:
• FIG. 1 represents a sample of non-oriented grain steel sheet
• FIGURE 2 shows a sample of oriented grain steel sheet
• FIG. 3 illustrates the crystallography of a sample of steel sheet in a plane parallel to a main face of the sheet
• FIGURE 4 represents a steel sheet deformed by three leveling rollers
• FIGURE 5 shows a steel sheet circulating on transport rollers and traction rollers of a traction member according to a first embodiment
• FIGURE 6 shows a steel sheet circulating on transport rollers and traction rollers of the traction member according to a second embodiment
• FIGURE 7 shows the device of FIGURE 5 in which the steel sheet is not inserted into the traction member
• FIG. 8 represents the device of FIG. 5 comprising a planer installed upstream of the traction member
• FIGURE 9 represents two grains respectively before and after implementation of the method according to the invention.
• variants of the invention comprising only a selection of characteristics described, isolated from the other characteristics described (even if this selection is isolated within a sentence including these other characteristics), if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.
• This selection comprises at least one characteristic, preferably functional without structural details, or with only a part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention from the state of the art.
• the traction device 4 preferably comprises two tensioning units 41, 42.
• Each tensioner unit, or S block comprises at least one traction roller, for example as in FIGURES 5 to 8, four in number.
• These pull rollers may have an identical diameter to each other (FIGURES 5, 7 to 9) or different (FIGURE 6).
• a steel sheet 1 passes through a furnace 9, for example an annealing furnace, on support rollers 911, 912, 913, from an inlet (on the left in the figure) to an output (right in the figure) of this oven 9.
• the steel sheet 1 is not inserted into the traction rollers of the traction device 4, and this traction device 4 does not fill therefore not its stretching function of the steel sheet 1.
• This configuration allows for example to proceed with a heat treatment of the steel sheet 1 in the oven 9 without applying a stretching force on the sheet metal
• the traction device 4 may be installed in the oven 9 so that no traction roller is brought into contact with the steel sheet 1 when the latter is moved according to which to be described.
• the steel sheet 1 also rests on the support rollers 911, 912, 913.
• the sheet is wound on the rolls of the S blocks in such a way that the sufficient adhesion can be obtained between these rolls and the sheet to obtain the desired level of traction in a stretch region 1d of the sheet 1.
• the stretching force of the sheet in the stretching region 1d can be obtained and controlled by a speed differential or torque between different traction rollers.
• the arrangement of the traction rollers in the tensioning units 41, 42 or the relative positioning of the tensioning units 41, 42 in the traction apparatus makes it possible to control the dimension of the stretching region 1d, the 1 in the direction of movement of this sheet, which optimizes the stretching force applied as a function, for example, of the mechanical properties of the steel sheet 1 or the thermal conditions of the furnace 9.
• a stretching region 1a of larger size makes it possible to maintain the sheet in tension in this stretching region longer to obtain mechanical properties given at the end of this treatment.
• the optimization of this stretching effort, or the friction conditions of the steel sheet 1 on the traction rollers can also be controlled by the diameter of the traction rollers (eg multiple in the example of FIGURE 6) as well as by the choice of material in which these rolls are made or the surface condition of the roll table.
• the arrangement of the traction rollers can thus be chosen according to the nature of the treatment to be carried out or the type of material to be treated.
• FIG. 8 represents the device of FIG. 5 with a planer 7 installed upstream of the traction apparatus 4.
• This planer 7 comprises planing rollers 793, 794, 795 brought into contact, alternatively, with the upper surfaces 11 and lower section 12 of the sheet steel 1.
• FIG. 4 shows three planing rollers 791, 792, 793 and a steel sheet comprising four parts 1a, 1b, 1c, 1f located respectively upstream of the leveling roller 791, between the two planing rollers 791, 792, between the two planing rollers 792, 793 and downstream of the leveling roller 793.
• the spacing distance 79a of the leveling rollers 791, 792, 793 is preferably substantially equal to 70% of the diameter of these leveling rollers 791, 792, 793. When several leveling rollers are installed in the leveler 7, this spacing distance 79a may vary so as to avoid for example any residual camber of the steel sheet 1 at the output of the leveler 7.
• the planer 7 is arranged to reduce the shape defects of the sheet metal input of the traction member 4 to allow a uniform power of the sheet over its width.
• planer may be mounted downstream of the traction device 4 in order to obtain, for example, flatness characteristics suitable for processing steps of the steel sheet 1 made after the stretching method according to the invention. .

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
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• Crystallography & Structural Chemistry (AREA)
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• Organic Chemistry (AREA)
• Electromagnetism (AREA)
• Manufacturing & Machinery (AREA)
• General Engineering & Computer Science (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)
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• 2014
  • 2014-10-29 FR FR1460385A patent/FR3027920B1/fr not_active Expired - Fee Related
• 2015
  • 2015-10-28 EP EP15798564.9A patent/EP3212813B1/de active Active
  • 2015-10-28 CN CN201580070125.4A patent/CN107109510A/zh active Pending
  • 2015-10-28 WO PCT/IB2015/058308 patent/WO2016067214A1/fr active Application Filing
  • 2015-10-28 KR KR1020177013928A patent/KR102495407B1/ko active IP Right Grant
  • 2015-10-28 PL PL15798564T patent/PL3212813T3/pl unknown
  • 2015-10-28 US US15/523,450 patent/US11028459B2/en active Active

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