CA2175105C - Process for improving the formability and weldability properties of zinc coated steel sheet - Google Patents
Process for improving the formability and weldability properties of zinc coated steel sheetInfo
- Publication number
- CA2175105C CA2175105C CA002175105A CA2175105A CA2175105C CA 2175105 C CA2175105 C CA 2175105C CA 002175105 A CA002175105 A CA 002175105A CA 2175105 A CA2175105 A CA 2175105A CA 2175105 C CA2175105 C CA 2175105C
- Authority
- CA
- Canada
- Prior art keywords
- zinc
- applying
- sheet
- layer
- alkaline solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 70
- 239000010959 steel Substances 0.000 title claims abstract description 70
- 238000000034 method Methods 0.000 title claims abstract description 62
- 239000011701 zinc Substances 0.000 title claims abstract description 62
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 229910052725 zinc Inorganic materials 0.000 title claims abstract description 61
- 239000010410 layer Substances 0.000 claims abstract description 82
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 76
- 239000011787 zinc oxide Substances 0.000 claims abstract description 38
- 239000012670 alkaline solution Substances 0.000 claims abstract description 37
- 238000000576 coating method Methods 0.000 claims abstract description 35
- 229910001297 Zn alloy Inorganic materials 0.000 claims abstract description 26
- 239000011241 protective layer Substances 0.000 claims abstract description 17
- 239000000243 solution Substances 0.000 claims description 42
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 33
- 239000011248 coating agent Substances 0.000 claims description 30
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 24
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical group OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 23
- 239000003792 electrolyte Substances 0.000 claims description 22
- 239000007800 oxidant agent Substances 0.000 claims description 21
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 claims description 16
- 239000002253 acid Substances 0.000 claims description 12
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 12
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 12
- 238000003618 dip coating Methods 0.000 claims description 10
- 238000009713 electroplating Methods 0.000 claims description 7
- 239000008366 buffered solution Substances 0.000 claims 1
- 239000000463 material Substances 0.000 claims 1
- 238000007747 plating Methods 0.000 abstract description 35
- 230000001681 protective effect Effects 0.000 abstract description 13
- 239000000047 product Substances 0.000 description 33
- 230000002378 acidificating effect Effects 0.000 description 8
- 239000008151 electrolyte solution Substances 0.000 description 8
- 239000007921 spray Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 239000000654 additive Substances 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000010008 shearing Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005246 galvanizing Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- GWUSZQUVEVMBPI-UHFFFAOYSA-N nimetazepam Chemical compound N=1CC(=O)N(C)C2=CC=C([N+]([O-])=O)C=C2C=1C1=CC=CC=C1 GWUSZQUVEVMBPI-UHFFFAOYSA-N 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000010955 niobium Substances 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 description 1
- 229940007718 zinc hydroxide Drugs 0.000 description 1
- 229910021511 zinc hydroxide Inorganic materials 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 239000011686 zinc sulphate Substances 0.000 description 1
- 235000009529 zinc sulphate Nutrition 0.000 description 1
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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
- C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
- C23C28/322—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only
- C23C28/3225—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only with at least one zinc-based layer
-
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- 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
- C23C22/60—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 alkaline aqueous solutions with pH greater than 8
-
- 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
-
- 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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
- C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
- C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/22—Electroplating: Baths therefor from solutions of zinc
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D7/00—Electroplating characterised by the article coated
- C25D7/06—Wires; Strips; Foils
- C25D7/0614—Strips or foils
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12583—Component contains compound of adjacent metal
- Y10T428/1259—Oxide
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12785—Group IIB metal-base component
- Y10T428/12792—Zn-base component
- Y10T428/12799—Next to Fe-base component [e.g., galvanized]
Abstract
A post plating or post coating method for improving formability and weldability properties in sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof. The steps of the method comprise immersing the sheet steel product into a bath containing at least zinc to apply the protective layer, removing the sheet steel product from the bath, the sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof, and applying an alkaline solution to the protective layer to form a zinc oxide layer thereon, the alkaline solution being applied at a location outside the bath.
Description
~ 1 75 1 C~
PROCESS FOR IMPROVING THE FORMABILITY AND WELDABILITY
PROPERTIES OF ZINC COATED ~ l STEEL
BACKGROUND OF THE INVENTION
s This invention is related to a process for improving the formability, weldability and surface appearance of zinc coated and zinc alloy coated sheet steel, and in particular, this invention is directed to improving the formability and weldability of electrogalvanized sheet steel. Zinc coated sheet steel is used for a variety of different automotive components. For example, hot-dip galvanized sheet steel is used in portions of the automobile where surface appearance is not important such as the underbody, door beams and trunk interiors. On the other hand, because of their high surface quality appearance, galvanneal, electrogalvanized and zinc alloy coated sheet steels tend to be used throughout the exterior portions of automobiles such as doors, hoods and deck lids, where a high gloss painted finish is important.
Zinc coated sheet steel products enjoy a major share of the automotive market because they have excellent resistance to corrosion and mechanical damage. However the protective zinc coatings are viewed, in some instances, as being unfavorable with respect to formability and weldability when compared to zinc alloy coatings.
Zinc coatings applied to sheet products tend to deform and gall during press forming operations. When the forming punch makes contact with the coated surface of the product, the coated surface galls and produces a buildup of zinc flakes within the die. The zinc flakes in turn cause defects in the surface appearance of the finished formed sheet product and, in order to overcome the problem, continuous downtime is required for maintenance and cleaning of the press forming dies.
Weldability of zinc coated sheet is also a problem. It is generally inferior to the weldability properties of zinc alloy coated or uncoated sheet steel. This is because the zinc 2~5lo5 coating melts during resistance welding and alloys with the copper in the electrode tip.
The chemical reaction causes poor quality weld joints and reduces weld tip life.
The forming and welding difficulties encountered with zinc coated sheet steel is well known within the steelm~king industry. In the past, there have been various ~lL~nlpl~ to improve both the formability and weldability. One of the more significant solutions to the problem is to provide a layer on the outer surface of the protective zinc or zinc alloy coating which will improve the forming and welding properties.
United States Patent No. 3,843,494 granted to Brown on October 22, 1974 shows one such improvement. Brown discloses a process comprising the steps of applying on a ferrous metal substrate separate layers of metallic zinc and metallic iron, the outermost layer being a metallic iron layer which promotes the ease with which a plurality of said zinc coated ferrous substrates may be welded by resistance spot welding.
A further improvement in the art, directed more to surface appearance than weldability, is shown in United States Patent No. 4,707,415. This patent teaches dipping zinc alloy coated sheet steel into an acidic oxidizing solution to electroch~mi~lly form a passive-state layer on the surface of the zinc alloy coating. The passive-state layer comprises at least one of oxides, hydroxides, and sulfides of zinc and nickel.
United States Patents No. 4,957,594 and 5,203,986 teach forming a zinc oxide layer on the surface of zinc and zinc alloy steels to improve weldability. The 594 patent teaches adding an oxidizer to an acidic plating bath to form a zinc oxide or zinc hydroxide layer during the electroplating operation. Similarly, the 986 patent also teaches forming an oxide layer by using an oxidizer in an acidic plating bath, but with the addition of introducing a burr~ling agent into the bath to control the pH level.
Introducing various oxidizers and buffers into plating and coating baths to improve formability and weldability properties is not desirable from an operational viewpoint.
Such additives tend to create complex, and sometimes unexpected, reactions which can lead to both environmental and product quality problems. For example, the addition of H2O2 in a zinc sulphate plating bath can adversely impact on the morphology of the zinc plating and produce a coating unsuitable for fini.~h~.d automotive surfaces. Such additives also tend to reduce the efficiency of the coating line. Additionally, when nitrate or nitrite oxidizers are added to a plating bath, they may precipitate into complex compounds which are environmentally unsound and must be treated for proper disposal.
It has been discovered that the above problems can be avoided by using a post plating, or post coating, alkaline solution treatment to form a zinc oxide layer on the outer surface of a zinc or zinc alloy layer formed on a sheet steel product. This can be accomplished by applying an ~lk~lin~ solution comprising an oxidizer to the surface of the zinc or zinc alloy layer, at a location separate from the plating or coating bath. The ~lk~line solution forms a suitable oxide layer on the surface of the zinc or zinc alloy layer, improves the formability and weldability, and avoids both environmental and product quality problems.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to improve the formability and weldability properties of a zinc or zinc alloy plated or coated steel sheet product.
It is a further object of this invention to provide a zinc or zinc alloy plated or coated steel sheet product having excellent surface quality and appearance while improving the formability and weldability properties of the sheet steel product.
2175~5 It is still a further object of this invention to form an oxide coating on the surface of a zinc or zinc alloy layer formed on a sheet steel product to improve the formability and weldability properties of the sheet steel product.
It is still a further object of this invention to form an oxide coating on the surface of a zinc or zinc alloy layer formed on a sheet steel product to improve the formability and weldability properties of the sheet steel product without introducing additives into a plating or coating bath.
And finally, it is still a further object of this invention to reduce environmental impact by applying an ~lk~lin~ solution COIllpliSillg an oxidizer to the surface of a zinc or zinc alloy layer formed on a sheet steel product to form an oxide layer on the surface thereof to improve the formability and weldability properties of the sheet steel product, the ~lk~lin~
solution being applied at a location separate from a plating or coating bath.
Still other objects and advantages of this invention will be obvious and apparell~ from the specification.
We have discovered that the foregoing objects can be attained by using a post plating or post coating method for improving the formability and weldability properties in sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof.
The steps of the method comprise immersing the sheet steel product into a bath cont~ining at least zinc to apply the protective layer, removing the sheet steel product from the bath, the sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof, and applying an ~lk~lin-- solution comprising an oxidizer to the protective layer to form a zinc oxide layer on at least one surface thereof, the ~lk~lin~ solution being applied at a location separate from the bath.
21 7~1 r~s BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows the preferred embodiment of the present invention in use on an electrogalvanized plating line.
Figure 2 is an alternate embodiment of the present invention similar to Figure 1.
Figure 3 is a still further alternate embodiment of the present invention similar to Figure 1.
Figure 4 shows the present invention in use on a plating line having a rinse immediately after the plating bath.
Figure 5 shows the present invention in use on a hot-dip galvanized coating line.
DESCRIPTION OF A PREFERRED EMBODIMENT
The pl~felled method for improving the formability and weldability properties of zinc or zinc alloy plated, or coated, sheet steel products comprises the post plating step of applying an ~lk~lin~ solution comprising an oxidizer to the protective plating or coating on the steel substrate to form a zinc oxide layer on at least one surface thereof, the ~lk~lin~
solution being applied at a location separate from the plating or coating bath. Referring to Figure 1 of the drawings, a continuous sheet steel strip lA is shown being electrochemically plated in the last plating cell 2 of an electrogalvanizing line "A". In the preferred embodiment, the sheet steel is shown being immersed in a zinc plating bath 3 and passing between spaced pairs of anodes 4 to plate two sides of the continuous sheet steel strip lA. It should be understood, however, that single anodes could be used to plate only one side of the steel strip without departing from the scope of this invention.
21 7~1 05 After completion of the final plating step, as illustrated by plating cell 2, the zinc plated sheet steel strip continues toward an :~lk~line treatment station 5 where an oxidizer is applied to the protective zinc layer to produce a zinc oxide layer on the surface thereof.
The zinc oxide layer is conducive to improving formability and weldability of such zinc plated sheet steel products. In the pr~fel.~d embodiment, strip lA is shown being sprayed with a buffered alkaline solution 6 cont~ining an oxidizer. The ~lk~line treatment station 5 includes spray headers 7 having a plurality of spray nozzles 8 for applying the ~lk~linP
solution 6 to the surface of strip lA.
The oxidizer in the ~lk~line solution reacts with the zinc plated layer on the steel strip to form an outer zinc oxide layer and the sheet steel strip lA advances toward a wash station 9 where a warm water rinse of about 120F is applied to the coated sheet product for up to about 20 seconds. The strip is then advanced to a drying station 10 where an air, or resistance, or other suitable means dryer is used to dry the sheet steel product, after which the sheet continues toward further processing such as oiling, shearing to length and wrapping or coiling for shipping.
Referring to Figure 2 of the drawings, a continuous sheet steel strip lA is shown being electrochemically plated in the last plating cell 2 of an electrogalvanizing line "A" similar to the line shown in Figure 1. After completion of the final plating step, the zinc plated sheet steel strip continues toward an ~lk~line treatment station 5 where an oxidizer is applied to the protective zinc layer to produce a zinc oxide layer on the surface thereof.
In this alternate embodiment, strip lA is shown being immersed in a buffered :~lk:~linP
solution 6a cont~ining an oxidizer. The alkaline treatment station 5 includes an immersion tank 7a having at least one sinker roll 8a for guiding strip lA into the ~lk~line solution.
Referring to Figure 3 of the drawings, a continuous sheet steel strip lA is shown being electrochemically plated in the last plating cell 2 of an electrogalvanizing line "A" also similar to the line shown in Figure 1. After completion of the final plating step, the zinc 2 1 1~ 1 05 plated sheet steel strip continues toward an ~lk~line treatment station 5 where an oxidizer is applied to the protective zinc layer to produce a zinc oxide layer on the surface thereof.
In this alternate embodiment, the ~lk:~lin~ treatment station 5 includes roll coating apparatus 7b for applying the alkaline solution to one or more surfaces of strip lA to form the zinc oxide layer.
It has been discovered that the prefell~d ~lk~lin~ solution 6 contained in immersion tank 7 of treatment station 5 should be an oxidizer in a buffered ~lk~line solution having a pH
range of about 7-11. Tests have also shown that in order to form a suitable zinc oxide layer of 20.15 g/m2, the alkaline solution should be applied to the protective zinc layer for a period of from 1-17 seconds at a temperature range of about between 20-50C. The preferred treatment method and alkaline solution is based upon the following research.
Laboratory test specimens were prepared by first cleaning the specimens in an ~lk~lin~
solution and then activated by immersing in an acid pickling bath and then electroplating the specimens under plating conditions shown in Table A. The specimens were thensprayed with various ~lk:~lin~ solutions as shown in Table B followed by a warm water rinse at a temperature of about 49C for 20 seconds, and then hot air dried. The oxidized specimens were finally tested for formability and weldability as well as inspected for surface quality and appearance.
From the group of alkaline solutions shown in Table B, it was discovered that the specimens prepared using a buffered alkaline solution comprising 30 g/l H2O2 exhibited the most favorable results. It was also discovered that H2O2 can be added to the ~lk~lin~
solution at a rate of from 10 g/l to 100 g/l of H2O2, with 30 g/l to 60 g/l of H2O2 being a pl~r~ d range, and with 30 g/l of H2O2 being the best formula for the :~lk~line solution.
Using this knowledge, further test specimens were prepared using both buffered and non-buffered alkaline solutions comprising 30 g/l H2O2, and these specimens were compared with test specimens prepared using other oxidation processes well known in the art. For example, the oxide layer for samples 3, 4 and 5 shown in Table C was formed using an electrochemical process using platinized niobium insoluble anodes. All the specimens were tested for both formability and weldability. The test results are shown in Table C.
As a result of this research work, it was discovered that the preferred post plating or post coating ;~lk~lin~. solution for forming a zinc oxide layer comprises NaOH+NaHCO3+ 30 g/l H2O2, a pH range of about 7.8-8.4, at a temperature range of about 20-50C.
Referring to Figure 4 of the drawings, an alternate embodiment of the post plating or post coating ~lk~lin~ treatment invention is shown in use on an electroplating line "B" having a rinse station immediately following the last plating bath 12. Electroplating line "B"
comprises a continuous sheet steel strip lB being electrochemically treated in a plating bath 11 cont~ining at least zinc ions in a plating cell 12 to form a protective coating of either zinc or zinc alloy on at least one surface of the sheet steel strip. The plating cell includes spaced pairs of anodes 13, and the sheet steel strip acts as a cathode in the acidic bath 11 cont~ining the ions. The plated sheet steel strip is removed from the plating cell and advanced to an optional rinse step shown as station 14.
2 1 7 5 1 li~
g TABLE A
Bath Type: Sulfate Zn++ 100 g/l pH 1.5-2.8 Temperature 49-60C
Coating Weight 60 g/m2 Current Density 60 A/dm2 TABLE B
Post Treatment Avg . Zn+ + Wt. in No.Chemical Solution pH Surface Film g/m2 NaOH + 30 g/l H2O2 10.03 0.195 2NaOH +NaHCO3 + 30 g/l H22 7.8 to 0.340 8.4 3 NaOH 10.03 0.071 4NaOH + 10 g/l NaHCO3 8.26 0.149 5NaOH + 3 g/l H2O2 10.00 0.165 6NaOH + 3 g/l H2O2+ 5 g/l NaHCO3 8.17 0.237 7NaOH + 3 g/l H2O2+ 10 g/l NaHCO38.18 0.164 8NaOH + 10g/lNaNO3 10.04 0.103 Table C
Chemistry ofMethod of Application Property Tested No.Solution Surface FilmWt.Zn++ in SurfaceLDHminCoefficient ofTip Life No.
g/m2 WSW Film g/m2 AA InchesFriction ,uof Welds NaOH + 30 g/l H2O2Alkaline Spray 0.465 0.195 1.240 0.111 4400 2NaOH+NaHCO3 + 30Buffered Alkaline 0.645 0.340 1.401 0.106 5600 g/l H22 (Preferred Sol.) Spray 3ZnSO47H2O + Acidic Immersion with 5.42 2.56 1.490 0.200 1600 18 g/l H2O2 Electrochemical Assist 10 A/dm2 4ZnSO47H2O + Acidic Immersionwith 1.14 0.58 1.395 0.119 50 g/l NaNO3 Electrochemical Assist r`) 10 A/dm2 - 1 5ZnSO47H2O + 10g/1ImmersionwithAnodic 5.38 2.65 1.518 0.095 3200 NaNO3 + 10 g/lElectrochemical Assist ZnNO3 GH20 10 A/dm2 6Untreated --- 0.154 0.081 1.215 0.120 4400 Electrogalvanized Rinse station 14 may include any rinse means suitable for rinsing or cleaning the surface of the plated steel. In this instance we have shown using a spray rinse. The rinse may comprise either a water rinse, a dilute acid rinse such as a dilute H2SO4 solution, or an acidic rinse cont~ining zinc ions.
After the rinse treatment at station 14, an electrolyte is applied to the protective zinc or zinc alloy layer at electrolyte station 16. In Figure 4 the sheet steel strip is shown being dipped into an electrolyte solution 15 contained in an immersion tank. This step is done prior to the ~lk;llin~ solution treatment to form a zinc electrolyte layer on the surface of the protective layer. The electrolyte may be applied to the plated surface of the sheet steel strip by any other suitable means known in the art such as spraying or roll coating or the like. However, it should be understood that the method of applying the electrolyte solution at station 16 is not an electrochemical assisted process. In addition, it should also be understood that if the acidic rinse of station 14 comprises a zinc ion concentration in a range of about 15-40 g/l, station 16 showing the application of an electrolyte solution to the sheet steel may be elimin~tc~l in the method taught in Figure 4.
Following the step of applying an electrolyte solution to the strip, the strip is advanced to an ~lk~lin-q solution treatment station 5 similar to any one of the treatment stations shown in Figures 1-3, or any like means known in the art suitable for applying the ~lk~lin~
solution to the surface of the strip. In this instance, treatment station 5 is shown comprising roll coating apparatus 17 to apply the ~lk~lin~ solution to the protective zinc or zinc alloy layer to form a zinc oxide layer on at least one surface thereof.
After the zinc oxide layer has been formed, the strip is advanced to wash station 18 where a warm water rinse of about 120F is applied to the coated sheet product for a period of about 20 seconds. The strip is then advanced to a drying station 19 where an air, or resistance, or other suitable means dryer is used to dry the rinsed sheet product, after 2 1 7 5 i 0~
which the sheet is advanced to move toward further processing such as oiling, shearing to length and wrapping or coiling for shipping.
Figure 5 shows the present invention being used on a hot-dip galvanizing line. Hot-dip galvanizing line "C" comprises a continuous sheet steel strip lC immersed into a hot-dip zinc or zinc alloy bath 20 contained in a tank 21. In some instances, the sheet steel strip may enter the hot-dip bath through a snorkel 22. The strip is immersed within the bath via a sinker roll 23 and exits the bath between gas wiping means 24 to remove excess coating from the surface of the steel sheet. At this point the sheet steel strip may either be annealed in ovens to produce an annealed product commonly known as galvanneal, or by-pass the :~nn~ling step to be sold as a hot-dip galvanized product. In either case, the hot-dip products have an electrolyte solution 25 applied to their coated surfaces in a step similar to the process shown in Figure 4.
Referring to Figure 5, the hot-dipped coated product is shown being immersed into tank 26 cont~ining an electrolyte solution 25, co~ ising zinc ions. This step is done prior to the application of the alkaline solution treatment to form a zinc oxide layer on the surface of the hot-dip coating. As heretofore described, the electrolyte may be applied to the hot-dipped coated surface of the sheet steel strip by any suitable means known in the art such as spraying or roll coating. However, it should again be understood that the step applying the electrolyte solution 25 is not an electrochemical assisted process.
Following the application of the electrolyte solution, the strip is advanced to an alk:llin~
solution treatment station 5 similar to the treatment stations shown in Figures 1 and 2.
Treatment station 5, shown in plating line "C", comprises a spray means 27 to apply the alkaline solution cont~ining an oxidizer to the surface of the hot-dipped coated sheet steel strip.
After the ~lk~lin~ solution has caused a zinc oxide layer to form on the surface of the strip, the strip is advanced to wash station 28 where a water rinse is applied to the coated sheet product. The strip is then advanced to a drying station 29 where an air, or resistance, or other suitable means dryer is used to dry the rinsed sheet product, after which the sheet continues to move toward further processing such as oiling, shearing to length and wrapping or coiling for shipping.
In any of the embodiments shown in Figures 1-5, either a buffered or non-buffered ~lk~lint~ solution comprising an oxidizer may be used to form an oxide layer on at least one surface of a plated or coated sheet steel product.
While this invention has been described as having a pler~lled design, it is understood that it is capable of further modifications, uses and/or adaptations of the invention, following the general principle of the invention and including such departures from the present disclosure as have come within known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention of the limits of the appended claims.
PROCESS FOR IMPROVING THE FORMABILITY AND WELDABILITY
PROPERTIES OF ZINC COATED ~ l STEEL
BACKGROUND OF THE INVENTION
s This invention is related to a process for improving the formability, weldability and surface appearance of zinc coated and zinc alloy coated sheet steel, and in particular, this invention is directed to improving the formability and weldability of electrogalvanized sheet steel. Zinc coated sheet steel is used for a variety of different automotive components. For example, hot-dip galvanized sheet steel is used in portions of the automobile where surface appearance is not important such as the underbody, door beams and trunk interiors. On the other hand, because of their high surface quality appearance, galvanneal, electrogalvanized and zinc alloy coated sheet steels tend to be used throughout the exterior portions of automobiles such as doors, hoods and deck lids, where a high gloss painted finish is important.
Zinc coated sheet steel products enjoy a major share of the automotive market because they have excellent resistance to corrosion and mechanical damage. However the protective zinc coatings are viewed, in some instances, as being unfavorable with respect to formability and weldability when compared to zinc alloy coatings.
Zinc coatings applied to sheet products tend to deform and gall during press forming operations. When the forming punch makes contact with the coated surface of the product, the coated surface galls and produces a buildup of zinc flakes within the die. The zinc flakes in turn cause defects in the surface appearance of the finished formed sheet product and, in order to overcome the problem, continuous downtime is required for maintenance and cleaning of the press forming dies.
Weldability of zinc coated sheet is also a problem. It is generally inferior to the weldability properties of zinc alloy coated or uncoated sheet steel. This is because the zinc 2~5lo5 coating melts during resistance welding and alloys with the copper in the electrode tip.
The chemical reaction causes poor quality weld joints and reduces weld tip life.
The forming and welding difficulties encountered with zinc coated sheet steel is well known within the steelm~king industry. In the past, there have been various ~lL~nlpl~ to improve both the formability and weldability. One of the more significant solutions to the problem is to provide a layer on the outer surface of the protective zinc or zinc alloy coating which will improve the forming and welding properties.
United States Patent No. 3,843,494 granted to Brown on October 22, 1974 shows one such improvement. Brown discloses a process comprising the steps of applying on a ferrous metal substrate separate layers of metallic zinc and metallic iron, the outermost layer being a metallic iron layer which promotes the ease with which a plurality of said zinc coated ferrous substrates may be welded by resistance spot welding.
A further improvement in the art, directed more to surface appearance than weldability, is shown in United States Patent No. 4,707,415. This patent teaches dipping zinc alloy coated sheet steel into an acidic oxidizing solution to electroch~mi~lly form a passive-state layer on the surface of the zinc alloy coating. The passive-state layer comprises at least one of oxides, hydroxides, and sulfides of zinc and nickel.
United States Patents No. 4,957,594 and 5,203,986 teach forming a zinc oxide layer on the surface of zinc and zinc alloy steels to improve weldability. The 594 patent teaches adding an oxidizer to an acidic plating bath to form a zinc oxide or zinc hydroxide layer during the electroplating operation. Similarly, the 986 patent also teaches forming an oxide layer by using an oxidizer in an acidic plating bath, but with the addition of introducing a burr~ling agent into the bath to control the pH level.
Introducing various oxidizers and buffers into plating and coating baths to improve formability and weldability properties is not desirable from an operational viewpoint.
Such additives tend to create complex, and sometimes unexpected, reactions which can lead to both environmental and product quality problems. For example, the addition of H2O2 in a zinc sulphate plating bath can adversely impact on the morphology of the zinc plating and produce a coating unsuitable for fini.~h~.d automotive surfaces. Such additives also tend to reduce the efficiency of the coating line. Additionally, when nitrate or nitrite oxidizers are added to a plating bath, they may precipitate into complex compounds which are environmentally unsound and must be treated for proper disposal.
It has been discovered that the above problems can be avoided by using a post plating, or post coating, alkaline solution treatment to form a zinc oxide layer on the outer surface of a zinc or zinc alloy layer formed on a sheet steel product. This can be accomplished by applying an ~lk~lin~ solution comprising an oxidizer to the surface of the zinc or zinc alloy layer, at a location separate from the plating or coating bath. The ~lk~line solution forms a suitable oxide layer on the surface of the zinc or zinc alloy layer, improves the formability and weldability, and avoids both environmental and product quality problems.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to improve the formability and weldability properties of a zinc or zinc alloy plated or coated steel sheet product.
It is a further object of this invention to provide a zinc or zinc alloy plated or coated steel sheet product having excellent surface quality and appearance while improving the formability and weldability properties of the sheet steel product.
2175~5 It is still a further object of this invention to form an oxide coating on the surface of a zinc or zinc alloy layer formed on a sheet steel product to improve the formability and weldability properties of the sheet steel product.
It is still a further object of this invention to form an oxide coating on the surface of a zinc or zinc alloy layer formed on a sheet steel product to improve the formability and weldability properties of the sheet steel product without introducing additives into a plating or coating bath.
And finally, it is still a further object of this invention to reduce environmental impact by applying an ~lk~lin~ solution COIllpliSillg an oxidizer to the surface of a zinc or zinc alloy layer formed on a sheet steel product to form an oxide layer on the surface thereof to improve the formability and weldability properties of the sheet steel product, the ~lk~lin~
solution being applied at a location separate from a plating or coating bath.
Still other objects and advantages of this invention will be obvious and apparell~ from the specification.
We have discovered that the foregoing objects can be attained by using a post plating or post coating method for improving the formability and weldability properties in sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof.
The steps of the method comprise immersing the sheet steel product into a bath cont~ining at least zinc to apply the protective layer, removing the sheet steel product from the bath, the sheet steel product having a protective zinc or zinc alloy layer formed on at least one surface thereof, and applying an ~lk~lin-- solution comprising an oxidizer to the protective layer to form a zinc oxide layer on at least one surface thereof, the ~lk~lin~ solution being applied at a location separate from the bath.
21 7~1 r~s BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows the preferred embodiment of the present invention in use on an electrogalvanized plating line.
Figure 2 is an alternate embodiment of the present invention similar to Figure 1.
Figure 3 is a still further alternate embodiment of the present invention similar to Figure 1.
Figure 4 shows the present invention in use on a plating line having a rinse immediately after the plating bath.
Figure 5 shows the present invention in use on a hot-dip galvanized coating line.
DESCRIPTION OF A PREFERRED EMBODIMENT
The pl~felled method for improving the formability and weldability properties of zinc or zinc alloy plated, or coated, sheet steel products comprises the post plating step of applying an ~lk~lin~ solution comprising an oxidizer to the protective plating or coating on the steel substrate to form a zinc oxide layer on at least one surface thereof, the ~lk~lin~
solution being applied at a location separate from the plating or coating bath. Referring to Figure 1 of the drawings, a continuous sheet steel strip lA is shown being electrochemically plated in the last plating cell 2 of an electrogalvanizing line "A". In the preferred embodiment, the sheet steel is shown being immersed in a zinc plating bath 3 and passing between spaced pairs of anodes 4 to plate two sides of the continuous sheet steel strip lA. It should be understood, however, that single anodes could be used to plate only one side of the steel strip without departing from the scope of this invention.
21 7~1 05 After completion of the final plating step, as illustrated by plating cell 2, the zinc plated sheet steel strip continues toward an :~lk~line treatment station 5 where an oxidizer is applied to the protective zinc layer to produce a zinc oxide layer on the surface thereof.
The zinc oxide layer is conducive to improving formability and weldability of such zinc plated sheet steel products. In the pr~fel.~d embodiment, strip lA is shown being sprayed with a buffered alkaline solution 6 cont~ining an oxidizer. The ~lk~line treatment station 5 includes spray headers 7 having a plurality of spray nozzles 8 for applying the ~lk~linP
solution 6 to the surface of strip lA.
The oxidizer in the ~lk~line solution reacts with the zinc plated layer on the steel strip to form an outer zinc oxide layer and the sheet steel strip lA advances toward a wash station 9 where a warm water rinse of about 120F is applied to the coated sheet product for up to about 20 seconds. The strip is then advanced to a drying station 10 where an air, or resistance, or other suitable means dryer is used to dry the sheet steel product, after which the sheet continues toward further processing such as oiling, shearing to length and wrapping or coiling for shipping.
Referring to Figure 2 of the drawings, a continuous sheet steel strip lA is shown being electrochemically plated in the last plating cell 2 of an electrogalvanizing line "A" similar to the line shown in Figure 1. After completion of the final plating step, the zinc plated sheet steel strip continues toward an ~lk~line treatment station 5 where an oxidizer is applied to the protective zinc layer to produce a zinc oxide layer on the surface thereof.
In this alternate embodiment, strip lA is shown being immersed in a buffered :~lk:~linP
solution 6a cont~ining an oxidizer. The alkaline treatment station 5 includes an immersion tank 7a having at least one sinker roll 8a for guiding strip lA into the ~lk~line solution.
Referring to Figure 3 of the drawings, a continuous sheet steel strip lA is shown being electrochemically plated in the last plating cell 2 of an electrogalvanizing line "A" also similar to the line shown in Figure 1. After completion of the final plating step, the zinc 2 1 1~ 1 05 plated sheet steel strip continues toward an ~lk~line treatment station 5 where an oxidizer is applied to the protective zinc layer to produce a zinc oxide layer on the surface thereof.
In this alternate embodiment, the ~lk:~lin~ treatment station 5 includes roll coating apparatus 7b for applying the alkaline solution to one or more surfaces of strip lA to form the zinc oxide layer.
It has been discovered that the prefell~d ~lk~lin~ solution 6 contained in immersion tank 7 of treatment station 5 should be an oxidizer in a buffered ~lk~line solution having a pH
range of about 7-11. Tests have also shown that in order to form a suitable zinc oxide layer of 20.15 g/m2, the alkaline solution should be applied to the protective zinc layer for a period of from 1-17 seconds at a temperature range of about between 20-50C. The preferred treatment method and alkaline solution is based upon the following research.
Laboratory test specimens were prepared by first cleaning the specimens in an ~lk~lin~
solution and then activated by immersing in an acid pickling bath and then electroplating the specimens under plating conditions shown in Table A. The specimens were thensprayed with various ~lk:~lin~ solutions as shown in Table B followed by a warm water rinse at a temperature of about 49C for 20 seconds, and then hot air dried. The oxidized specimens were finally tested for formability and weldability as well as inspected for surface quality and appearance.
From the group of alkaline solutions shown in Table B, it was discovered that the specimens prepared using a buffered alkaline solution comprising 30 g/l H2O2 exhibited the most favorable results. It was also discovered that H2O2 can be added to the ~lk~lin~
solution at a rate of from 10 g/l to 100 g/l of H2O2, with 30 g/l to 60 g/l of H2O2 being a pl~r~ d range, and with 30 g/l of H2O2 being the best formula for the :~lk~line solution.
Using this knowledge, further test specimens were prepared using both buffered and non-buffered alkaline solutions comprising 30 g/l H2O2, and these specimens were compared with test specimens prepared using other oxidation processes well known in the art. For example, the oxide layer for samples 3, 4 and 5 shown in Table C was formed using an electrochemical process using platinized niobium insoluble anodes. All the specimens were tested for both formability and weldability. The test results are shown in Table C.
As a result of this research work, it was discovered that the preferred post plating or post coating ;~lk~lin~. solution for forming a zinc oxide layer comprises NaOH+NaHCO3+ 30 g/l H2O2, a pH range of about 7.8-8.4, at a temperature range of about 20-50C.
Referring to Figure 4 of the drawings, an alternate embodiment of the post plating or post coating ~lk~lin~ treatment invention is shown in use on an electroplating line "B" having a rinse station immediately following the last plating bath 12. Electroplating line "B"
comprises a continuous sheet steel strip lB being electrochemically treated in a plating bath 11 cont~ining at least zinc ions in a plating cell 12 to form a protective coating of either zinc or zinc alloy on at least one surface of the sheet steel strip. The plating cell includes spaced pairs of anodes 13, and the sheet steel strip acts as a cathode in the acidic bath 11 cont~ining the ions. The plated sheet steel strip is removed from the plating cell and advanced to an optional rinse step shown as station 14.
2 1 7 5 1 li~
g TABLE A
Bath Type: Sulfate Zn++ 100 g/l pH 1.5-2.8 Temperature 49-60C
Coating Weight 60 g/m2 Current Density 60 A/dm2 TABLE B
Post Treatment Avg . Zn+ + Wt. in No.Chemical Solution pH Surface Film g/m2 NaOH + 30 g/l H2O2 10.03 0.195 2NaOH +NaHCO3 + 30 g/l H22 7.8 to 0.340 8.4 3 NaOH 10.03 0.071 4NaOH + 10 g/l NaHCO3 8.26 0.149 5NaOH + 3 g/l H2O2 10.00 0.165 6NaOH + 3 g/l H2O2+ 5 g/l NaHCO3 8.17 0.237 7NaOH + 3 g/l H2O2+ 10 g/l NaHCO38.18 0.164 8NaOH + 10g/lNaNO3 10.04 0.103 Table C
Chemistry ofMethod of Application Property Tested No.Solution Surface FilmWt.Zn++ in SurfaceLDHminCoefficient ofTip Life No.
g/m2 WSW Film g/m2 AA InchesFriction ,uof Welds NaOH + 30 g/l H2O2Alkaline Spray 0.465 0.195 1.240 0.111 4400 2NaOH+NaHCO3 + 30Buffered Alkaline 0.645 0.340 1.401 0.106 5600 g/l H22 (Preferred Sol.) Spray 3ZnSO47H2O + Acidic Immersion with 5.42 2.56 1.490 0.200 1600 18 g/l H2O2 Electrochemical Assist 10 A/dm2 4ZnSO47H2O + Acidic Immersionwith 1.14 0.58 1.395 0.119 50 g/l NaNO3 Electrochemical Assist r`) 10 A/dm2 - 1 5ZnSO47H2O + 10g/1ImmersionwithAnodic 5.38 2.65 1.518 0.095 3200 NaNO3 + 10 g/lElectrochemical Assist ZnNO3 GH20 10 A/dm2 6Untreated --- 0.154 0.081 1.215 0.120 4400 Electrogalvanized Rinse station 14 may include any rinse means suitable for rinsing or cleaning the surface of the plated steel. In this instance we have shown using a spray rinse. The rinse may comprise either a water rinse, a dilute acid rinse such as a dilute H2SO4 solution, or an acidic rinse cont~ining zinc ions.
After the rinse treatment at station 14, an electrolyte is applied to the protective zinc or zinc alloy layer at electrolyte station 16. In Figure 4 the sheet steel strip is shown being dipped into an electrolyte solution 15 contained in an immersion tank. This step is done prior to the ~lk;llin~ solution treatment to form a zinc electrolyte layer on the surface of the protective layer. The electrolyte may be applied to the plated surface of the sheet steel strip by any other suitable means known in the art such as spraying or roll coating or the like. However, it should be understood that the method of applying the electrolyte solution at station 16 is not an electrochemical assisted process. In addition, it should also be understood that if the acidic rinse of station 14 comprises a zinc ion concentration in a range of about 15-40 g/l, station 16 showing the application of an electrolyte solution to the sheet steel may be elimin~tc~l in the method taught in Figure 4.
Following the step of applying an electrolyte solution to the strip, the strip is advanced to an ~lk~lin-q solution treatment station 5 similar to any one of the treatment stations shown in Figures 1-3, or any like means known in the art suitable for applying the ~lk~lin~
solution to the surface of the strip. In this instance, treatment station 5 is shown comprising roll coating apparatus 17 to apply the ~lk~lin~ solution to the protective zinc or zinc alloy layer to form a zinc oxide layer on at least one surface thereof.
After the zinc oxide layer has been formed, the strip is advanced to wash station 18 where a warm water rinse of about 120F is applied to the coated sheet product for a period of about 20 seconds. The strip is then advanced to a drying station 19 where an air, or resistance, or other suitable means dryer is used to dry the rinsed sheet product, after 2 1 7 5 i 0~
which the sheet is advanced to move toward further processing such as oiling, shearing to length and wrapping or coiling for shipping.
Figure 5 shows the present invention being used on a hot-dip galvanizing line. Hot-dip galvanizing line "C" comprises a continuous sheet steel strip lC immersed into a hot-dip zinc or zinc alloy bath 20 contained in a tank 21. In some instances, the sheet steel strip may enter the hot-dip bath through a snorkel 22. The strip is immersed within the bath via a sinker roll 23 and exits the bath between gas wiping means 24 to remove excess coating from the surface of the steel sheet. At this point the sheet steel strip may either be annealed in ovens to produce an annealed product commonly known as galvanneal, or by-pass the :~nn~ling step to be sold as a hot-dip galvanized product. In either case, the hot-dip products have an electrolyte solution 25 applied to their coated surfaces in a step similar to the process shown in Figure 4.
Referring to Figure 5, the hot-dipped coated product is shown being immersed into tank 26 cont~ining an electrolyte solution 25, co~ ising zinc ions. This step is done prior to the application of the alkaline solution treatment to form a zinc oxide layer on the surface of the hot-dip coating. As heretofore described, the electrolyte may be applied to the hot-dipped coated surface of the sheet steel strip by any suitable means known in the art such as spraying or roll coating. However, it should again be understood that the step applying the electrolyte solution 25 is not an electrochemical assisted process.
Following the application of the electrolyte solution, the strip is advanced to an alk:llin~
solution treatment station 5 similar to the treatment stations shown in Figures 1 and 2.
Treatment station 5, shown in plating line "C", comprises a spray means 27 to apply the alkaline solution cont~ining an oxidizer to the surface of the hot-dipped coated sheet steel strip.
After the ~lk~lin~ solution has caused a zinc oxide layer to form on the surface of the strip, the strip is advanced to wash station 28 where a water rinse is applied to the coated sheet product. The strip is then advanced to a drying station 29 where an air, or resistance, or other suitable means dryer is used to dry the rinsed sheet product, after which the sheet continues to move toward further processing such as oiling, shearing to length and wrapping or coiling for shipping.
In any of the embodiments shown in Figures 1-5, either a buffered or non-buffered ~lk~lint~ solution comprising an oxidizer may be used to form an oxide layer on at least one surface of a plated or coated sheet steel product.
While this invention has been described as having a pler~lled design, it is understood that it is capable of further modifications, uses and/or adaptations of the invention, following the general principle of the invention and including such departures from the present disclosure as have come within known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention of the limits of the appended claims.
Claims (53)
1. A method for improving formability and weldability properties in sheet steel product on which a protective layer is formed on at least one surface thereof, the protective layer being an electroplated or hot dip coated protective layer and comprising at least zinc, the steps of the method comprising:
a) immersing the steel sheet product into a bath containing at least zinc material to apply the protective layer;
b) removing the sheet steel product from the bath, the sheet steel product having the protective layer formed on at least one surface thereof; and c) chemically applying an alkaline buffered solution comprising an oxidizer to the protective layer to form a zinc oxide layer thereon, said alkaline solution having a pH range of about 7 to <11.
a) immersing the steel sheet product into a bath containing at least zinc material to apply the protective layer;
b) removing the sheet steel product from the bath, the sheet steel product having the protective layer formed on at least one surface thereof; and c) chemically applying an alkaline buffered solution comprising an oxidizer to the protective layer to form a zinc oxide layer thereon, said alkaline solution having a pH range of about 7 to <11.
2. The method of claim 1 wherein:
a) the bath is an electrogalvanized bath containing zinc ions, and b) the protective layer is an electrogalvanized layer.
a) the bath is an electrogalvanized bath containing zinc ions, and b) the protective layer is an electrogalvanized layer.
3. The method of claim 2 wherein said oxidizer is H2O2
4. The method of claim 2 wherein said alkaline solution has a pH range of about 7.8 - 8.4.
5. The method of claim 4 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and H2O2.
6. The method of claim 4 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and 30 g/l H2O2.
7. The method of claim 2 including a further step of applying a rinse to the sheet steel product being removed from the electrogalvanized bath, said rinse being applied prior to said step of applying said alkaline solution to the electrogalvanized layer to form said zinc oxide layer thereon.
8. The method of claim 7 wherein said rinse comprises an acid solution.
9. The method of claim 7 wherein said rinse comprises an acid solution containing zinc ions.
10. The method of claim 7 including a further step of applying an electrolyte to the electrogalvanized layer prior to said step of applying said alkaline solution to the electrogalvanized layer to form said zinc oxide layer thereon.
11. The method of claim 10 wherein said electrolyte is applied by a means other than electrochemical means.
12. The method of claim 2 including a further step of applying a rinse to the sheet steel product being removed from the electrogalvanizing bath followed by a further step of applying an electrolyte to the electrogalvanized layer prior to said step of applying said alkaline solution to the electrogalvanized layer to form said zinc oxide layer thereon.
13. The method of claim 12 wherein said rinse comprises an acid solution and said electrolyte is applied by a means other than electrochemical means.
14. The method of claim 12 wherein said rinse comprises an acid solution containing zinc ions and said electrolyte is applied by a means other than electrochemical means.
15. The method of claim 1 wherein:
a) the bath is an electroplating bath containing at least zinc ions, and b) the protective layer is an electroplated zinc alloy layer
a) the bath is an electroplating bath containing at least zinc ions, and b) the protective layer is an electroplated zinc alloy layer
16. The method of claim 15 wherein said oxidizer is H2O2.
17. The method of claim 15 wherein said alkaline solution has a pH range of about 7.8 - 8.4.
18. The method of claim 17 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and H2O2.
19. The method of claim 17 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and 30 g/l H2O2.
20. The method of claim 15 including a further step of applying a rinse to the sheet steel product being removed from the electroplating bath, said rinse being applied prior to said step of applying said alkaline solution to the electroplated layer to form said zinc oxide layer thereon.
21. The method of claim 20 wherein said rinse comprises an acid solution.
22. The method of claim 20 wherein said rinse comprises an acid solution containing zinc ions.
23. The method of claim 15 including the further step of applying an electrolyte to the electroplated layer prior to said step of applying said alkaline solution to the electroplated layer to form said zinc oxide layer thereon.
24. The method of claim 23 wherein said electrolyte is applied by a means other than electrochemical means.
25. The method of claim 15 including a further step of applying a rinse to the sheet steel product being removed from the electroplating bath followed by a further step of applying an electrolyte to the electroplated layer prior to said step of applying said alkaline solution to the electroplated layer to form said zinc oxide layer thereon.
26. The method of claim 25 wherein said rinse comprises an acid solution and said electrolyte is applied by a means other than electrochemical means.
27. The method of claim 25 wherein said rinse comprises an acid solution containing zinc ions and said electrolyte is applied by a means other than electrochemical means.
28. The method of claim 1 wherein:
a) the bath is a hot-dip coating bath containing at least zinc, and b) the protective layer is a hot-dip coating containing at least zinc.
a) the bath is a hot-dip coating bath containing at least zinc, and b) the protective layer is a hot-dip coating containing at least zinc.
29. The method of claim 28 wherein said oxidizer is H2O2.
30. The method of claim 28 wherein said alkaline solution has a range of about 7.8 - 8.4.
31. The method of claim 30 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and H2O2.
32. The method of claim 30 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and 30 g/l H2O2.
33. The method of claim 28 including a further step of applying an electrolyte to the hot-dip coating prior to said step of applying said alkaline solution to the hot-dip coating to form said zinc oxide layer thereon.
34. The method of claim 33 wherein said electrolyte is applied by a means other than electrochemical means.
35. The method of claim 33 wherein the hot-dip zinc coating is annealed prior to said further step of applying said electrolyte to the hot-dip coating.
36. The method of claim 28 including a further step of applying a rinse to the sheet steel product being removed from the hot-dip coating bath followed by a further step of applying an electrolyte to the hot-dip coating prior to said step of applying said alkaline solution to the hot-dip coating to form said zinc oxide layer thereon.
37. The method of claim 36 wherein said rinse comprises an acid solution and said electrolyte is applied by a means other than electrochemical means.
38. The method of claim 36 wherein said rinse comprises an acid solution containing zinc ions and said electrolyte is applied by a means other than electrochemical means.
39. The method of claim 36 wherein the hot-dip zinc coating is annealed prior to said further step of applying said electrolyte to the hot-dip coating.
40. The method of claim 28 wherein the hot-dip zinc coating is a galvannealed coating.
41. The method of claim 1 wherein said zinc oxide layer formed on the protective layer comprises a thickness by weight ~0.15 g/m2.
42. The method of claim 41 wherein said alkaline solution is applied to the protective layer for 1-17 seconds to form said zinc oxide layer.
43. The method of claim 42 wherein said alkaline solution has a pH range of about 7.8 to 8.4.
44. The method of claim 1. wherein said alkaline solution has a pH range of about 7.8 - 8.4.
45. The method of claim 1 wherein said buffered alkaline solution comprises NaOH, NaHCO3 and H2O2.
46. An electrogalvanized sheet or strip having improved formability and weldability, the sheet or strip produced by the steps of:
a) providing an electrogalvanized sheet or strip;
b) chemically applying to the electrogalvanized sheet or strip abuffered alkaline solution comprising an oxidizer having a pH of from about 7.8 to 8.4; and c) applying the buffered alkaline solution for a period sufficient to form a zinc oxide layer on the electrogalvanized sheet or strip layer having a Zn++
concentration of at least 0.340 g/m2, said sheet or strip with the formed zinc oxide layer having improved formability as measured by a limited dome height of at least 1.401 inches and a coefficient of friction of at least 0.106, and having improved weldability as measured by a tip life of at least 4400 welds.
a) providing an electrogalvanized sheet or strip;
b) chemically applying to the electrogalvanized sheet or strip abuffered alkaline solution comprising an oxidizer having a pH of from about 7.8 to 8.4; and c) applying the buffered alkaline solution for a period sufficient to form a zinc oxide layer on the electrogalvanized sheet or strip layer having a Zn++
concentration of at least 0.340 g/m2, said sheet or strip with the formed zinc oxide layer having improved formability as measured by a limited dome height of at least 1.401 inches and a coefficient of friction of at least 0.106, and having improved weldability as measured by a tip life of at least 4400 welds.
47. The sheet or strip of claim 46 wherein:
a) said zinc oxide layer has a coating weight in excess of 0.15 g/m2.
a) said zinc oxide layer has a coating weight in excess of 0.15 g/m2.
48. A zinc coated sheet or strip having improved formability and weldability, the sheet or strip produced by the steps of:
a) providing a zinc coated sheet or strip;
b) chemically applying to the zinc coated sheet or strip a buffered alkaline solution comprising an oxidizer having a pH of from about 7.8 to about 8.4;
and c) applying the solution for a period sufficient to form a zinc oxide layer on the zinc coated sheet or strip said layer having a Zn++ concentration of at least 0.340 g/m2, said sheet or strip with the formed zinc oxide layer having improved formability as measured by a limited dome height of at least 1.401 inches and a coefficient of friction of at least 0.106, and having improved weldability as measured by a tip life of at least 4400 welds.
a) providing a zinc coated sheet or strip;
b) chemically applying to the zinc coated sheet or strip a buffered alkaline solution comprising an oxidizer having a pH of from about 7.8 to about 8.4;
and c) applying the solution for a period sufficient to form a zinc oxide layer on the zinc coated sheet or strip said layer having a Zn++ concentration of at least 0.340 g/m2, said sheet or strip with the formed zinc oxide layer having improved formability as measured by a limited dome height of at least 1.401 inches and a coefficient of friction of at least 0.106, and having improved weldability as measured by a tip life of at least 4400 welds.
49. The sheet or strip of claim 48 wherein:
a) said zinc oxide layer has a coating weight in excess of 0.15 g/m2.
a) said zinc oxide layer has a coating weight in excess of 0.15 g/m2.
50. A zinc coated sheet or strip having improved formability and weldability, comprising:
a) zinc oxide layer formed on at least one surface of a zinc coated sheet or strip, said layer having a Zn++ concentration of at least 0.340 g/m2, the sheet or strip with the formed zinc oxide layer having improved formability as measured by a limited dome height of at least 1.401 inches, and a coefficient of friction of at least 0.106, and having improved weldability as measured by a tip life of at least 4400 welds.
a) zinc oxide layer formed on at least one surface of a zinc coated sheet or strip, said layer having a Zn++ concentration of at least 0.340 g/m2, the sheet or strip with the formed zinc oxide layer having improved formability as measured by a limited dome height of at least 1.401 inches, and a coefficient of friction of at least 0.106, and having improved weldability as measured by a tip life of at least 4400 welds.
51. The sheet or strip of claim 50 wherein said zinc oxide layer having a coating weight in excess of 0.15 g/m2.
52. The sheet or strip of claim 50 wherein:
a) the sheet or strip is electrogalvanized.
a) the sheet or strip is electrogalvanized.
53. A sheet steel product with a protective layer made by the method in any of the claims 1 - 45.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US44765695A | 1995-05-23 | 1995-05-23 | |
| US08/447,656 | 1995-05-23 |
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| CA2175105A1 CA2175105A1 (en) | 1996-11-24 |
| CA2175105C true CA2175105C (en) | 1999-09-21 |
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| CA002175105A Expired - Fee Related CA2175105C (en) | 1995-05-23 | 1996-04-26 | Process for improving the formability and weldability properties of zinc coated steel sheet |
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| EP (1) | EP0744475B1 (en) |
| JP (1) | JPH08325791A (en) |
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| AT (1) | ATE175730T1 (en) |
| BR (1) | BR9602406A (en) |
| CA (1) | CA2175105C (en) |
| DE (1) | DE69601323T2 (en) |
| TW (2) | TW419534B (en) |
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| JP3435255B2 (en) * | 1995-05-30 | 2003-08-11 | 新日本製鐵株式会社 | Manufacturing equipment for electro-galvanized steel sheet with excellent lubricity |
| JPH08325790A (en) * | 1995-05-31 | 1996-12-10 | Nippon Steel Corp | Equipment for production of electrogalvanized hot rolled sheet having excellent lubricity |
| US6599643B2 (en) | 1997-01-31 | 2003-07-29 | Elisha Holding Llc | Energy enhanced process for treating a conductive surface and products formed thereby |
| US6149794A (en) * | 1997-01-31 | 2000-11-21 | Elisha Technologies Co Llc | Method for cathodically treating an electrically conductive zinc surface |
| US6322687B1 (en) | 1997-01-31 | 2001-11-27 | Elisha Technologies Co Llc | Electrolytic process for forming a mineral |
| US6592738B2 (en) | 1997-01-31 | 2003-07-15 | Elisha Holding Llc | Electrolytic process for treating a conductive surface and products formed thereby |
| US6231686B1 (en) | 1997-11-10 | 2001-05-15 | Ltv Steel Company, Inc. | Formability of metal having a zinc layer |
| WO2003035922A1 (en) * | 2001-10-23 | 2003-05-01 | Sumitomo Metal Industries, Ltd. | Method for press working, plated steel product for use therein and method for producing the steel product |
| US20040188262A1 (en) * | 2002-02-05 | 2004-09-30 | Heimann Robert L. | Method for treating metallic surfaces and products formed thereby |
| CN1692178A (en) * | 2002-02-05 | 2005-11-02 | 以利沙控股有限公司 | Method for treating metallic surfaces and products formed thereby |
| JP4617826B2 (en) * | 2004-10-26 | 2011-01-26 | 凸版印刷株式会社 | Blackening device |
| JP5354166B2 (en) * | 2007-12-27 | 2013-11-27 | Ｊｆｅスチール株式会社 | Method for producing galvanized steel sheet |
| KR101360802B1 (en) | 2008-12-16 | 2014-02-10 | 제이에프이 스틸 가부시키가이샤 | Method for manufacturing galvanized steel sheet |
| DE102009053368A1 (en) * | 2009-11-14 | 2011-05-19 | Bayerische Motoren Werke Aktiengesellschaft | Process and manufacturing plant for producing a sheet metal part with a corrosion protection coating |
| WO2013010968A1 (en) * | 2011-07-15 | 2013-01-24 | Tata Steel Ijmuiden Bv | Apparatus for producing annealed steels and process for producing said steels |
| MX365287B (en) | 2012-11-19 | 2019-05-29 | Chemetall Gmbh | Method for coating metallic surfaces with nanocrystalline zinc oxide layers, aqueous compositions therefor and use of the surfaces coated in this way. |
| PL2851452T3 (en) * | 2013-09-19 | 2019-10-31 | Fuchs Petrolub Se | Inorganic functional coating on hot-dip galvanised steel |
| CA2953199A1 (en) | 2014-06-27 | 2015-12-30 | Henkel Ag & Co. Kgaa | Dry lubricant for zinc coated steel |
| EP3470553A4 (en) * | 2016-06-09 | 2019-08-21 | JFE Steel Corporation | Method for producing electroplated steel sheet and production device therefor |
| CN107739809B (en) * | 2017-10-24 | 2019-03-08 | 浙江博星工贸有限公司 | A kind of solid solution treatment method of austenitic stainless steel strip |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3415692A (en) * | 1965-03-12 | 1968-12-10 | Combustion Eng | Method of passivating metal surfaces |
| GB1281872A (en) * | 1969-07-02 | 1972-07-19 | British Steel Corp | Improvements in or relating to the formation of zinc-iron-coatings |
| JPS5413858B2 (en) * | 1974-05-20 | 1979-06-02 | ||
| US4707415A (en) * | 1985-03-30 | 1987-11-17 | Sumitomo Metal Industries, Ltd. | Steel strips with corrosion resistant surface layers having good appearance |
| JPH01149996A (en) * | 1987-12-08 | 1989-06-13 | Nippon Steel Corp | Production of plated steel sheet having superior spot weldability |
| DE68917332T2 (en) * | 1988-02-19 | 1994-12-08 | Nippon Steel Corp | Using a zinc or zinc alloy clad steel sheet with excellent spot welding properties. |
| DE69027428T2 (en) * | 1989-12-12 | 1997-02-13 | Nippon Steel Corp | GALVANIZED STEEL SHEET WITH EXCELLENT PRESS FORMING, CHEMICAL SURFACE CONVERSION AND SIMILAR PROPERTIES AND THE PRODUCTION OF SUCH A SHEET |
| US5203986A (en) * | 1990-03-08 | 1993-04-20 | Nkk Corporation | Method for manufacturing electrogalvanized steel sheet excellent in spot weldability |
| JPH0421751A (en) * | 1990-05-16 | 1992-01-24 | Kawasaki Steel Corp | Production of hot-dip galvanized steel sheet excellent in spot weldability, chemical conversion treating property, and sliding characteristic at the time of press-working |
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1996
- 1996-04-26 CA CA002175105A patent/CA2175105C/en not_active Expired - Fee Related
- 1996-05-03 TW TW088117729A patent/TW419534B/en active
- 1996-05-03 TW TW085105315A patent/TW401468B/en not_active IP Right Cessation
- 1996-05-09 KR KR1019960015162A patent/KR100292229B1/en not_active IP Right Cessation
- 1996-05-14 AT AT96107647T patent/ATE175730T1/en not_active IP Right Cessation
- 1996-05-14 DE DE69601323T patent/DE69601323T2/en not_active Expired - Fee Related
- 1996-05-14 EP EP96107647A patent/EP0744475B1/en not_active Expired - Lifetime
- 1996-05-17 JP JP8171687A patent/JPH08325791A/en active Pending
- 1996-05-23 BR BR9602406A patent/BR9602406A/en not_active IP Right Cessation
- 1996-12-16 US US08/767,379 patent/US5660707A/en not_active Expired - Fee Related
- 1996-12-16 US US08/767,378 patent/US5714049A/en not_active Expired - Fee Related
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| TW401468B (en) | 2000-08-11 |
| US5660707A (en) | 1997-08-26 |
| EP0744475A1 (en) | 1996-11-27 |
| KR100292229B1 (en) | 2001-06-01 |
| DE69601323T2 (en) | 1999-09-09 |
| ATE175730T1 (en) | 1999-01-15 |
| EP0744475B1 (en) | 1999-01-13 |
| US5714049A (en) | 1998-02-03 |
| TW419534B (en) | 2001-01-21 |
| BR9602406A (en) | 1998-10-06 |
| KR960041398A (en) | 1996-12-19 |
| DE69601323D1 (en) | 1999-02-25 |
| CA2175105A1 (en) | 1996-11-24 |
| JPH08325791A (en) | 1996-12-10 |
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