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
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/68—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous solutions with pH between 6 and 8
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
• • 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
  • C23C2/26—After-treatment
• • 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
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
  • C23C22/53—Treatment of zinc or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/34—Anodisation of metals or alloys not provided for in groups C25D11/04 - C25D11/32
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D9/00—Electrolytic coating other than with metals
  • C25D9/04—Electrolytic coating other than with metals with inorganic materials
  • C25D9/06—Electrolytic coating other than with metals with inorganic materials by anodic processes

Definitions

• the present invention relates to the use of a treatment solution for treating the surface of a steel sheet coated with a metallic coating based on zinc or its alloys. It also relates to a method of lubricating such a coated sheet.
• Steel sheets coated with zinc or its alloys are commonly used in the automotive field and in industry in general, because they have excellent resistance to corrosion.
• these galvanized steel sheets present a certain number of difficulties when they are shaped, for example by stamping, to manufacture parts.
• a film of lubricating oil is applied to their surface which facilitates shaping.
• the very high friction exerted by the shaping tools on the surface of the sheet metal causes, on the surface of the sheet metal, powder or particles based on zinc or its alloys generated by degradation of the coating.
• the accumulation and / or agglomeration of these particles or of this powder in the shaping tools can cause damage to the formed parts, by the formation of spikes and / or necks.
• the sheet due to the high coefficient of friction which characterizes the sliding of a galvanized surface in contact with the surface of a forming tool, the sheet may break if there is insufficient sliding of the sheet in the grip of the formatting tool.
• the present invention therefore aims to provide a treatment solution which, applied to the surface of a steel sheet coated with a metallic layer based on zinc or its alloys, makes it possible to reduce the degradation of the zinc-plated surface. of this sheet during its shaping, to reduce the quantity of lubricating oil to deposit on the sheet before its shaping, and to improve the temporary protection against corrosion of the sheet.
• the subject of the invention is the use of an aqueous treatment solution containing sulphate ions SO 4 2 " at a concentration greater than or equal to 0.01 mol / l, for treating the surface of a sheet of steel coated on at least one of its faces with a metallic coating based on zinc or its alloys, in order to reduce the formation of powder or metallic particles based on zinc or its alloys generated by degradation of the coating during the shaping of said sheet.
• metallic coating based on zinc alloy means a zinc coating comprising one or more alloying elements, such as, for example and without limitation, iron, aluminum, silicon, magnesium, and nickel. According to the invention, the use of a steel sheet coated with an almost pure zinc coating is preferred.
• the treatment solution is applied in a conventional manner, for example by dipping, by sprinkling or by coating, both on electro-galvanized sheets and on galvanized sheets.
• the aqueous treatment solution also contains Zn 2+ ions at a concentration greater than or equal to 0.01 mol / l, which make it possible to obtain a more homogeneous deposit.
• the treatment solution is prepared, for example, by dissolving zinc sulfate in pure water; for example, zinc sulphate heptahydrate (ZnSO4, 7 H2O) is used; the concentration of Zn 2+ ions is then equal to that of the SO 4 2 7 anions.
• the pH of the treatment solution preferably corresponds to the natural pH of the solution, without the addition of base or acid; the value of this pH is generally between 5 and 7.
• concentration of SO4 2 " ions and Zn 2+ ions adjusted to form a layer based on zinc hydroxysulfate and zinc sulphate with a sulfur quantity greater than or equal to 0.5 mg / m 2.
• the contact time of the treatment solution with the galvanized surface is between 2 seconds and 2 minutes, and the temperature of the treatment solution is between 20 and 60 ° C.
• the solution of treatment used contains between 20 and 160 g / l of zinc sulfate heptahydrate, corresponding to a concentration of Zn 2+ ions and a concentration of SO 4 2 " ions between 0.07 and 0.55 mol / l. Indeed, it was found that, in this concentration range, the deposition rate was little influenced by the value of the concentration.
• the treatment solution is applied under conditions of temperature, time of contact with the galvanized surface, and concentrations of SO4 2 " ions and of Zn 2+ ions adjusted to form a layer based on hydroxysulphate and sulphate having a quantity of sulfur of between 3.7 and 27 mg / m 2.
• the treatment solution contains an oxidizing agent for zinc, such as hydrogen peroxide.
• This oxidizing agent can have an accelerating effect on hydroxysulfation and very marked sulfation at low concentration. It has been found that the addition of only 0.03% , that is to say 8.10 "3 mol / liter of hydrogen peroxide, or of 2.10 " 4 mole / liter of potassium permanganate in the solution made it possible to double (approximately) the rate of deposition. It was found, on the contrary, that concentrations 100 times higher no longer allowed this improvement in the deposition rate to be obtained.
• the layer deposited on the sheet is adherent;
• the drying is adjusted to remove the residual liquid water between the application step and the drying step, the sheet is preferably rinsed so as to remove the soluble part of the deposit obtained; the absence of rinsing and obtaining a deposit which is partially soluble in water which results therefrom are not very detrimental to the reduction of the degradation of the zinc-plated coating during the shaping of the sheet, as long as the deposit obtained includes a layer based on zinc hydroxysulfate and zinc sulfate insoluble in water in contact with the sheet.
• the aqueous treatment solution comprising a concentration of SO 2 " ions greater than or equal to 0.01 mol / l is applied under anodic polarization, and the pH of the treatment solution is higher or equal to 12, and less than 13. If the pH of the solution is less than 12, no adherent hydroxysulfates are formed on the surface to be treated. If the pH of the solution is greater than or equal to 13, the hydroxysulfate redissolves and / or decomposes into zinc hydroxides.
• the concentration of SO 4 2 " ions be greater than or equal to 0.01 moles per liter, and preferably greater than or equal to 0.07 mol / l.
• the ion concentration sulfates is preferably less than or equal to 1 mole / liter; in the case of the use of sodium sulfate, at concentrations greater than 142 g / l (equivalent to 1 mole SO 4 2 " / liter), for example 180 g / l, there is a decrease in the yield of formation of the layer based on zinc hydroxysulfate and zinc sulfate.
• the total amount of hydroxysulphates and sulphates deposited should be greater than or equal to 0.5 mg / m 2 and less than or equal to 30 mg / m 2 in sulfur equivalent, preferably between 3.5 and 27 mg / m 2 in sulfur equivalent.
• the zinc necessary for the formation of the deposit based on zinc hydroxysulphate and zinc sulphate comes from the anodic dissolution of zinc under the effect of the polarization of the zinc-plated surface. It is therefore appropriate that the density of electrical charges, circulating during the treatment through the surface of the sheet, be adjusted so as to form a layer based on zinc hydroxysulfate and on zinc sulfate with a higher sulfur content.
• the charge density applied is preferably between 10 and 100 C / dm 2 of surface to be treated. If the charge density exceeds 100 C / dm 2 , it can be seen that the quantity of sulfur deposited on the surface no longer increases and even decreases. Thanks to the anodic polarization of the zinc-plated surface to be treated, there is a rapid dissolution of the zinc in the immediate vicinity of the zinc-plated surface, which promotes the precipitation of zinc salts on this surface. Thus, to carry out this treatment as productively as possible with a satisfactory faradic yield, it is advisable to deposit the layer based on zinc hydroxysulfate and zinc sulfate under a high bias current density, in particular greater than 20
• the deposition efficiency is very low and the amount of sulfur in the deposited layer does not make it possible to obtain a significant reduction in the degradation of the zinc coating of the sheet. during its shaping.
• a titanium cathode can be used as a counter electrode.
• the temperature of the treatment solution is generally between 20 ° C and 60 ° C. Preferably, the temperature is greater than or equal to 40 ° C., so as to increase the conductivity of the solution and to reduce the ohmic losses.
• the speed of circulation of the solution on the surface of the sheet does not, here, have a decisive effect on the treatment according to the invention.
• the treated surface is thoroughly rinsed with demineralized water. This rinsing step is important to remove alkaline reagents from the surface of the deposit, which would cause corrosion problems.
• the invention also relates to a method of lubricating a steel sheet coated with a layer consisting of a metallic coating based on zinc or its alloys, and in which: - said sheet is coated with a layer upper based on zinc hydroxysulphate and zinc sulphate, said upper layer having been obtained by the use of a treatment solution according to the invention, then - a film of lubricating oil is applied to the upper layer with a grammage of less than 1 g / m 2 .
• the film of lubricating oil is applied with a grammage preferably less than 0.9 g / m 2 , and more preferably between 0.2 and 0.5 g / m 2 , because these grammages are sufficient to obtain excellent protection temporary against corrosion and avoid any risk of pollution of workshops and shaping tools.
• the subject of the invention is the use of an aqueous treatment solution comprising sulphate ions at a concentration greater than or equal to 0.01 mol / l, to improve the temporary protection against corrosion of a sheet of steel coated with a metallic layer based on zinc or its alloys.
• this aqueous treatment solution to the steel sheet is carried out according to the embodiments described in the paragraphs concerning the use of an aqueous treatment solution containing sulphate ions to treat a galvanized steel sheet. to reduce the degradation of the zinc coating during its shaping.
• an aqueous treatment solution containing sulphate ions to treat a galvanized steel sheet. to reduce the degradation of the zinc coating during its shaping.
• the inventors have shown that temporary protection against corrosion of a galvanized steel sheet first treated with a treatment solution according to the invention, then coated with a film of oil was much superior to that of a galvanized steel sheet not previously treated.
• An aqueous treatment solution was prepared in accordance with the invention, prepared with 125 g / l zinc sulfate heptahydrate ZnS ⁇ 4 , 7 H 2 O. This treatment solution was then applied to part of the test pieces by spraying the solution treatment, at a temperature of 40 ° C. After a contact time of the solution with the sheet of 3 to 4 s, the treated sheet is wrung and then dried. Then was applied to the layer based on zinc hydroxysulphate and zinc sulphate formed on the surface of the test pieces of galvanized steel sheet, a film of lubricating oil which may be either QUAKER 6130 oil (from Quaker company), i.e.
• FUCHS 4107S oil (from Fuchs company), with a grammage of 1.5 g / m 2 .
• Another part of the test pieces which had not been previously treated with the treatment solution according to the invention was oiled either with QUAKER 6130 oil or with FUCHS 4107S oil also with a grammage of 1.5 g / m 2 .
• the two series of test pieces were then subjected to a deformation test controlled by means of a press comprising a punch, a matrix and a blank holder, recreating in the laboratory the stresses undergone by the sheet during the stamping operation, in particular in the matrix radii and / or in the retaining rods which equip the stamping tools. Different clamping forces of the blank holder were applied to the test pieces tested.
• test pieces of the two series were weighed before the oiling operation, then at the end of the test after oil removal, using a balance accurate to 0.0001 grams.
• the difference in measured mass was reduced to a loss of mass per square meter, taking into account the surface affected by friction during the simulation of the stamping of the test piece, identical for each of the test pieces.
• the press was wiped so as to identify the powder or particles of zinc coating lost by the test piece in the press.
• Table 1 The results of loss of mass of the test pieces after stamping, as well as the identification of the powder and / or of the zinc particles resulting from the coating are grouped in Table 1.
• test pieces Part of these test pieces is treated with a treatment solution according to the invention, under the same conditions as those indicated in Example 1, so as to form a layer based on zinc hydroxysulfate and zinc sulfate. Then a film of lubricating oil (QUAKER 6130 oil) is applied to this layer with quantities of between 0.25 and 2.5 g / m 2 . Another part of the test pieces was oiled in the same way as above, but was not previously treated with the treatment solution according to the invention. Then the friction characterization of each of the test pieces is carried out using a tribology test apparatus, in the following manner: The test apparatus is a plane-plane tribometer known in itself.
• the test pieces to be tested are clamped according to a clamping force Fs between two high-speed steel plates providing a bearing (or sliding) surface on the test pieces.
• the coefficient of friction N is measured, while moving the test piece relative to the pads over a total stroke D of 180 mm and at the speed of 10 mm / Fs by gradually increasing the clamping force Fs.
• test pieces Part of these test pieces is treated with a treatment solution according to the invention, under the same conditions as those indicated in Example 1, so as to form a layer based on zinc hydroxysulfate and zinc sulfate. Then a film of lubricating oil (QUAKER 6130 oil) is applied to this layer with grammages between 0.25 and 1.0 g / m 2 . Another part of the test pieces was oiled in the same way as above, but was not previously treated with the treatment solution according to the invention.
• the lubricating oils applied to steel sheets coated with a zinc-based metal layer guarantee protection against corrosion during the period of time between the manufacture of the sheets and their implementation, for example by stamping.
• test specimens are placed in a climatic chamber corresponding to the DIN 50017 standard, which simulates the corrosion conditions of an outer coil of sheet metal coil or of a sheet metal cut into sheets during storage.
• the test pieces are individually hung vertically.
• the test result, shown in table 3 is obtained by recording the number of successive cycles before the corrosion traces appear on the test piece.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
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• General Chemical & Material Sciences (AREA)
• Electrochemistry (AREA)
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• Other Surface Treatments For Metallic Materials (AREA)
• Coating With Molten Metal (AREA)
• Electroplating Methods And Accessories (AREA)
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• 2003
  • 2003-12-24 FR FR0315381A patent/FR2864552B1/fr not_active Expired - Fee Related
• 2004
  • 2004-12-14 UA UAA200608324A patent/UA89368C2/ru unknown
  • 2004-12-14 EP EP12000368A patent/EP2450470A1/fr not_active Ceased
  • 2004-12-14 JP JP2006546227A patent/JP2007517135A/ja active Pending
  • 2004-12-14 US US10/583,765 patent/US20080308192A1/en not_active Abandoned
  • 2004-12-14 BR BRPI0418188-3A patent/BRPI0418188B1/pt active IP Right Grant
  • 2004-12-14 RU RU2006126698/02A patent/RU2371516C2/ru not_active IP Right Cessation
  • 2004-12-14 CA CA002551492A patent/CA2551492A1/en not_active Abandoned
  • 2004-12-14 WO PCT/FR2004/003208 patent/WO2005071140A1/fr active Application Filing
  • 2004-12-14 KR KR1020067014952A patent/KR101022683B1/ko not_active IP Right Cessation
  • 2004-12-14 CN CNA2004800406185A patent/CN1914354A/zh active Pending
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• 2006
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