Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
  • C23C2/06—Zinc or cadmium or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/003—Apparatus
  • C23C2/0034—Details related to elements immersed in bath
  • C23C2/00342—Moving elements, e.g. pumps or mixers
  • C23C2/00344—Means for moving substrates, e.g. immersed rollers or immersed bearings
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/003—Apparatus
  • C23C2/0035—Means for continuously moving substrate through, into or out of the bath
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/003—Apparatus
  • C23C2/0036—Crucibles
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
  • C23C2/12—Aluminium or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/50—Controlling or regulating the coating processes
  • C23C2/52—Controlling or regulating the coating processes with means for measuring or sensing
  • C23C2/521—Composition of the bath
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/50—Controlling or regulating the coating processes
  • C23C2/52—Controlling or regulating the coating processes with means for measuring or sensing
  • C23C2/523—Bath level or amount

Definitions

• the present invention relates to a method and a device for controlling an introduction of several metals into a cavity adapted to a melting of said metals according to the preambles of claims 1 and 9.
• the invention relates mainly to the metal coating by dipping rolled steel strips in continuous scrolling, and in particular to the control of the chemical analysis of the coating.
• the metal coating by dipping continuously rolled steel strips is a known technique which essentially comprises two variants, that in which the strip coming out of an annealing furnace slopes obliquely into a bath of liquid metal coating and is deflected vertically. upwards by a roll immersed in said liquid metal.
• the other variant is to deflect the strip vertically upwards at its outlet from the oven and then to scroll in a vertical channel containing magnetically levitated liquid metal.
• the purpose of the operation is to create on the surface of the steel strip a continuous and adherent deposit of metal coating.
• the strip drives on both sides a liquid film which is dewatered, by electromagnetic or gas-blowing devices, until it is reduced to the desired thickness.
• the wrung liquid film is then cooled until solidification.
• the consumption of coating metal by deposition on both sides of the strip is compensated by the addition of ingots in the bath of liquid metal.
• these ingots are brought to the liquid bath by chain conveying devices and are introduced into the liquid metal bath manually or automatically on a given instruction from a measurement of the bath level. More or less sophisticated devices, such as that described in WO2007137665, have been proposed to make the introduction of ingots in the bath more accurate, in particular to avoid their sudden drop.
• Metal coatings such as those used for example in galvanizing generally use an alloy of at least two different metals like zinc and aluminum.
• Document KR20020053126 describes such an ingot feeding system based on a calculation of daily consumption.
• the amount of a target alloy element in the coating may be different from that actually consumed. This is typically the case of galvanizing with aluminum alloy zinc. Indeed, in contact with the liquid mixture occurs a dissolution of the iron from the steel strip which, for one part, participates in the formation on the surface of the strip of a combination layer of about 0.1 ⁇ of compound Fe 2 Al 5 Zn x and, for another part, diffuses towards the bath of liquid mixture as long as the Fe 2 Al 5 Zn x layer is not formed in a continuous manner.
• the Fe 2 Al 5 Zn x layer serves as a support for the protective layer of zinc, whereas the dissolved iron will contribute to forming in the liquid mixture precipitates composed of Fe, Al and Zn called “mattes" or "dross".
• the steel elements immersed in the bath such as a stainless steel bottom roller and its support arms, also undergo a dissolution of the iron in the bath which also participates in the formation of dross.
• the aluminum content in these compounds is greater than that of the deposited alloy layer, the total consumption of aluminum is slightly greater than that which would be strictly necessary for the deposition of an alloy layer on both sides of the alloy. the band.
• the necessary aluminum content must therefore be determined from the sum of the aluminum consumptions in the coating, in the Fe 2 Al 5 Zn x combination layer formed on the surface of the strip and in the dross.
• many factors such as the immersion time (therefore, all things being equal the speed of travel of the band), the temperature of the bath, the amount of dross formed, etc. lead to more or less significant variations in the consumption of aluminum for the same content referred to in the deposit.
• document KR20040057746 suggests directly measuring the aluminum content of the bath "at regular intervals" in order to regulate a rate of introduction of ingots containing 20% of aluminum. alternatively with pure zinc ingots.
• This alternative remains however imperfect because the discontinuous measurement of the aluminum content associated with the response time required for the implementation, as a function of the measurement results, and the fusion of ingots without or with 20% of aluminum, besides its management difficulty over time, does not make the method more accurate than the theoretical calculation.
• a first device has two separate tanks respectively containing zinc and aluminum in liquid form, that is to say each of their liquid temperatures is above the melting temperature of zinc and aluminum, that is to say 420 0 C for zinc and -66O 0 C for aluminum. These two liquid metals are then introduced into the coating cavity (a temperature around 460 ° C.
• a second device provides for the introduction of zinc and aluminum in the form of web-like solid metals which are unwound in the coating bath at controlled flow rates and grades at required levels and bath level. temperature gradients are unavoidable, since at least warm aluminum must be heated at least ⁇ 660 ° C just before its introduction in the coating bath so that it can mix in the bath in liquid form.
• a third device provides that the two separate tanks with respectively zinc and liquid aluminum flow into an intermediate reservoir where a large amount of dross is formed due to excessive temperature gradients.
• the present invention proscribes methods or devices involving high temperature gradients and should be based on a use of metal ingot or metal alloy to bring to fusion.
• an object of the present invention is to provide a method and a device for controlling an introduction of several metals in the form of ingots in a cavity adapted to a melting of said metals for which temperature gradients of the metals introduced and the content of the cavity are minimal.
• a set of subclaims also has advantages of the invention.
• a second metal is introduced in the form of at least one second ingot consisting of an alloy of the first metal and the second metal, the method according to the invention provides that: the content of the second metal of the second ingot is chosen in a range of significant grades to ensure an overall target flow of cumulative merger of ingots,
• the range of significant contents is chosen within a limited range of sequentially increasing values so as to minimize differences between ingots melting temperatures.
• the cavity here is a conventional or magnetic levitating coating crucible, or a melting crucible of said auxiliary ingots to the coating crucible.
• the first metal is zinc and the second metal is mainly aluminum.
• the present invention is however not limited to these two metals as well as to alloys of these unique metals depending on the type of coating chosen. More importantly, on the one hand, thanks to the use of alloy ingots where for example one of the two metals would have required a high melting temperature, the overall melting temperature of the ingot remains lower thanks to the presence on the other, metals of the alloy.
• At least a third ingot of the alloy type of the second ingot and having a significant content of second or other metal can of course be introduced into the cavity, its content being distinct from that of the second ingot in the selected range of significant grades.
• several distinct ranges of significant contents can be implemented in order to obtain a greater dynamic of variation of contents if need be. If large differences between the contents of several ranges are required, it is possible to arrange these ranges by using at least one ingot having an intermediate content between these ranges. Thus again, because of the differences in contents thus reduced, any sudden change in the required melting temperature will advantageously be damped.
• second metal content intervals are ideally frames in the ranges according to the invention around at least one eutectic point of an equilibrium diagram of the alloy of said ingots (said diagram representing the melting temperature of the alloy of each ingot as a function of the percentage of alloy metals of said ingot).
• the alloy firstly has a minimum required melting temperature lower than that of each metal component and therefore much closer to the bath temperature. It is thus possible to maintain the temperature differences in a minimal range while being able to modify the ranges of significant contents in a limited range framing the eutectic point.
• ingots corresponding to these sequentially increasing ranges are introduced or withdrawn from the bath.
• this ideal choice of ingots is intended to be permanent for the purpose of the invention, but the invention may be appended to provide that ingots in ranges of significant contents of second metal further apart from the limited range of the contents (and therefore of the eutectic point) are introduced temporarily.
• the first metal is zinc Zn and the second metal is Al aluminum and the significant range of contents is chosen in ranges of carbon content.
• aluminum around the eutectic point of the equilibrium diagram of the Zn-Al alloy corresponds to a minimum melting temperature for a Zn-Al alloy (for example: 4.5% Al allowing a melting point as early as 39O 0 C).
• Types of ingots at various levels used for the main types of galvanizing coatings such as for such a Zn-Al alloy are known and can be so calibrated according to the ranges of significant levels as the invention provides.
• a range named "Gl” provides an aluminum content in an interval of [0; 1%] (or more likely [0; 10%]).
• This meets a "ASTM B852-07" standard for which ranges of significant content can be selected by providing ingots having an aluminum content of 0.25, 0.35, 0.45, 0.55, 0.65, 0.75 or 1%.
• ASTM B860-07 presenting 4, 5, or 10% of aluminum or conversely to use a pure zinc ingot.
• the invention can provide intervals significant grades at limited intervals that meet other standards such as "ASTM B852-07".
• the invention can provide that at least one of the ingots may comprise pure zinc, such as an ingot known under the ASTM standard.
• Alloys for example under the trademark GALFAN®, also have higher aluminum content ranges [4.2-6.2%] (and sometimes [0; 10%]) which may be potentially exploitable within the meaning of the invention to define ranges of significant contents higher than usual contents, while remaining in a limited vicinity of the eutectic point of the Zn-Al equilibrium diagram.
• the significant range of contents is predominantly selected in aluminum content ranges of [0.10%]. and minor in higher grade intervals.
• a range with significant contents can therefore advantageously be chosen from at least one range of concentration values related to limited variations in the melting temperature of the equilibrium diagram of an ingot alloy, ideally by choosing the values of said staggered intervals in the vicinity of the eutectic point of the ingot alloy suitably serving the purpose of the invention.
• the method according to the invention also provides that:
• an active introduction of the first and at least one of the second ingots is controlled according to a measurement of each content of the metals, finally liquid in the cavity and / or solids on the coated strip,
• At least one second metal content of the second ingot is selected on the one hand within the range of significant contents to ensure an overall target flow rate of cumulative melting.
• an overall effective cumulative melting flow rate of the ingots in the cavity is measured and related to the measured contents of each metal in the cavity in order to determine an effective partial melting flow of each ingot
• At least one of the effective partial flows of each ingot is readapted to compensate for this difference by modifying a submerged depth of introduction of at least one of the ingots into the cavity.
• At least one third metal may also be introduced into the cavity in the form of an ingot alloy compound, of the type of the second or third ingot mentioned above.
• the previous equality can thus be applied to this third metal taking into account the flow rates / partial contents of said third metal. It would be the same for any other additive metal of the type of the second metal, like the aluminum stated above.
• at least one additional metal can be introduced into the cavity in the form of a high-grade ingot of said complementary metal.
• the invention also proposes a device for implementing the aforementioned method. This device is more particularly described with the aid of an exemplary embodiment and application provided using a figure described:!
• FIG. 1 thus presents a device for implementing the method described for the control of an introduction of several metals (Zn, Al, ...) in the form of ingots (10, 11) in a cavity (2, 3) adapted melting said metals to coat a steel strip (1) by dipping with said metals as a liquid metal, for which the cavity is a conventional coating crucible (2) (Including, for example, a deflector bottom roller (6) of intracavity strip and a vertical deflection roller (7) above the cavity) or a magnetically levitated crucible, or a melting auxiliary crucible (3) said slugs connected by a channel (8) to a coating tank (2), and comprising: - a measuring member (21) of the level (20) of liquid metal resulting from the melting of the ingots in the cavity,
• a calculator (4) receiving measurement values of levels and contents of the measuring elements (21, 22, 23), delivering effective values of overall and partial melting rates for each metal and adapting said actual values; at values corrected according to a predefined equilibrium equilibrium,
• a controller (5) to which the corrected flow rate values are provided and delivers correction instructions; - a variation member (9) with an introduction height of at least one and therefore of each of the ingots in the cavity; where the melting occurs, said dimming member being controlled by the controller correction instructions and the introduction or withdrawal of ingots under conditions that the bullion metals remain within a selected range of significant grades as framework of the method according to the invention.
• the ingots are thus arranged and driven by the variation member (9) in correlation with the significant ranges of contents in order to avoid any difference in the melting temperature of the ingots.
• the equal equilibrium (A) can therefore be taken into account in the controller (5) which, as a function of the correction setpoint, defines an appropriate sequence for introducing one or more ingots in compliance with the conditions imposed by a range chosen within a limited range of sequentially increasing values so as to minimize differences between ingot melting temperatures.
• the content measuring device (22, 23) may comprise a Laser Induced Breakdown Spectrocopy (LIBS) type laser spectrometer or at least one electrochemical sensor adapted to the measurement of one of the metals involved. It is possible to place at least one of these measuring members at the level of the liquid metal (case 22) and / or at the level of the coated strip (case 23) as a function of the desired liquid mixture contents or final coating properties.
• LIBS Laser Induced Breakdown Spectrocopy
• the level measuring member (21) may be a float on the surface of liquid metal for example at the liquid metal transfer channel from the auxiliary melting crucible (3) to the coating crucible ( 2), a radar or optical level measuring means of said liquid metal surface.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Coating With Molten Metal (AREA)
• Manufacture And Refinement Of Metals (AREA)

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• 2008
  • 2008-11-14 WO PCT/FR2008/001607 patent/WO2010055211A1/fr active Application Filing
  • 2008-11-14 US US13/129,432 patent/US8795408B2/en active Active
  • 2008-11-14 AU AU2008364126A patent/AU2008364126B2/en not_active Ceased
  • 2008-11-14 EP EP08875628.3A patent/EP2358919B1/de active Active
  • 2008-11-14 CN CN200880131967.6A patent/CN102216485B/zh active Active
  • 2008-11-14 RU RU2011123641/02A patent/RU2482214C2/ru active
  • 2008-11-14 CA CA2743554A patent/CA2743554C/en active Active
  • 2008-11-14 JP JP2011543786A patent/JP5791518B2/ja active Active
  • 2008-11-14 BR BRPI0823283-0A patent/BRPI0823283B1/pt active IP Right Grant
  • 2008-11-14 KR KR1020117010988A patent/KR101562085B1/ko active IP Right Grant

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