EP3115482B1 - Tôle d'acier laminée à froid, procédé de fabrication s'y rapportant et pièce de voiture - Google Patents
Tôle d'acier laminée à froid, procédé de fabrication s'y rapportant et pièce de voiture Download PDFInfo
- Publication number
- EP3115482B1 EP3115482B1 EP15759246.0A EP15759246A EP3115482B1 EP 3115482 B1 EP3115482 B1 EP 3115482B1 EP 15759246 A EP15759246 A EP 15759246A EP 3115482 B1 EP3115482 B1 EP 3115482B1
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- EP
- European Patent Office
- Prior art keywords
- acid
- steel sheet
- cold
- concentration
- pickling
- 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.)
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- 239000010960 cold rolled steel Substances 0.000 title claims description 78
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 165
- 229910000831 Steel Inorganic materials 0.000 claims description 148
- 239000010959 steel Substances 0.000 claims description 148
- 229910052742 iron Inorganic materials 0.000 claims description 92
- 238000005554 pickling Methods 0.000 claims description 76
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 70
- 239000002253 acid Substances 0.000 claims description 67
- 239000007788 liquid Substances 0.000 claims description 51
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 45
- 229910017604 nitric acid Inorganic materials 0.000 claims description 45
- 238000000137 annealing Methods 0.000 claims description 32
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 28
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 26
- 230000003247 decreasing effect Effects 0.000 claims description 21
- -1 iron ions Chemical class 0.000 claims description 21
- 230000001590 oxidative effect Effects 0.000 claims description 15
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 11
- 238000005097 cold rolling Methods 0.000 claims description 11
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 6
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 4
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims description 4
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 claims description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 2
- 238000010790 dilution Methods 0.000 claims description 2
- 239000012895 dilution Substances 0.000 claims description 2
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 claims description 2
- 235000019253 formic acid Nutrition 0.000 claims description 2
- 235000006408 oxalic acid Nutrition 0.000 claims description 2
- 229940005657 pyrophosphoric acid Drugs 0.000 claims description 2
- 150000002500 ions Chemical class 0.000 claims 2
- 239000000126 substance Substances 0.000 description 89
- 238000005260 corrosion Methods 0.000 description 63
- 230000007797 corrosion Effects 0.000 description 63
- 238000006243 chemical reaction Methods 0.000 description 58
- 238000000034 method Methods 0.000 description 40
- 239000011248 coating agent Substances 0.000 description 33
- 238000000576 coating method Methods 0.000 description 33
- 150000003839 salts Chemical class 0.000 description 30
- 239000010410 layer Substances 0.000 description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 22
- 229910052710 silicon Inorganic materials 0.000 description 17
- 239000007921 spray Substances 0.000 description 17
- 230000008569 process Effects 0.000 description 16
- 125000004122 cyclic group Chemical group 0.000 description 14
- 230000000694 effects Effects 0.000 description 13
- 238000004070 electrodeposition Methods 0.000 description 13
- 238000007654 immersion Methods 0.000 description 13
- 229910052760 oxygen Inorganic materials 0.000 description 13
- 239000000243 solution Substances 0.000 description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 12
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 12
- 238000001816 cooling Methods 0.000 description 12
- 229910052748 manganese Inorganic materials 0.000 description 12
- 229910052814 silicon oxide Inorganic materials 0.000 description 12
- 239000000203 mixture Substances 0.000 description 11
- 238000010422 painting Methods 0.000 description 11
- 238000005098 hot rolling Methods 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 8
- 230000009257 reactivity Effects 0.000 description 8
- 229910006639 Si—Mn Inorganic materials 0.000 description 7
- 239000002131 composite material Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000011780 sodium chloride Substances 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 239000002344 surface layer Substances 0.000 description 6
- 230000002411 adverse Effects 0.000 description 5
- 239000012298 atmosphere Substances 0.000 description 5
- 230000015556 catabolic process Effects 0.000 description 5
- 238000006731 degradation reaction Methods 0.000 description 5
- LXEKPEMOWBOYRF-UHFFFAOYSA-N [2-[(1-azaniumyl-1-imino-2-methylpropan-2-yl)diazenyl]-2-methylpropanimidoyl]azanium;dichloride Chemical compound Cl.Cl.NC(=N)C(C)(C)N=NC(C)(C)C(N)=N LXEKPEMOWBOYRF-UHFFFAOYSA-N 0.000 description 4
- 239000002390 adhesive tape Substances 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000005238 degreasing Methods 0.000 description 4
- 238000004090 dissolution Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 150000002505 iron Chemical class 0.000 description 4
- 238000002791 soaking Methods 0.000 description 4
- 239000006104 solid solution Substances 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 229910000975 Carbon steel Inorganic materials 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 239000011247 coating layer Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000007739 conversion coating Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
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- 238000004611 spectroscopical analysis Methods 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- 238000009736 wetting Methods 0.000 description 3
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 3
- 229910000165 zinc phosphate Inorganic materials 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 229910001563 bainite Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 238000005237 degreasing agent Methods 0.000 description 2
- 239000013527 degreasing agent Substances 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 235000021110 pickles Nutrition 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000006061 abrasive grain Substances 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000002003 electron diffraction Methods 0.000 description 1
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
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- 239000002440 industrial waste Substances 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000005211 surface analysis Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/081—Iron or steel solutions containing H2SO4
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/085—Iron or steel solutions containing HNO3
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/086—Iron or steel solutions containing HF
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0478—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing involving a particular surface treatment
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
Definitions
- the present invention relates to a method for producing a cold-rolled steel sheet.
- the present invention relates to a method for producing a cold-rolled steel sheet having excellent chemical convertibility and high corrosion resistance after coating, which is evaluated by a hot salt water immersion test or a combined cyclic corrosion test.
- Patent Literature 1 proposes a high-strength cold-rolled steel sheet in which the Si concentration on the surface of the steel sheet is decreased by heating a slab at a temperature of 1200°C or higher during hot-rolling, performing descaling at high pressure, grinding the surface of the resulting hot-rolled steel sheet using a nylon brush with abrasive grains before pickling, and immersing the steel sheet in a 9% hydrochloric acid tank twice to perform pickling.
- Patent Literature 2 proposes a high-strength cold-rolled steel sheet whose corrosion resistance is improved by controlling the line width of a Si-containing linear oxide observed at a depth of 1 to 10 ⁇ m from the steel sheet surface to 300 nm or less.
- Patent Literature 3 proposes a technique for improving the ability to remove oxides by controlling the concentration of iron ions (Fe(II)) in hydrochloric acid to 0.5% to 18%.
- Patent Literature 1 In the high-strength cold-rolled steel sheet described in Patent Literature 1, however, even when the Si concentration on the steel sheet surface is decreased before cold-rolling, a Si-containing oxide is formed on the steel sheet surface due to annealing performed after the cold-rolling. Therefore, the corrosion resistance after coating is not improved.
- the corrosion resistance is not problematic in a corrosive environment such as a salt spray test specified in JIS Z2371.
- a corrosive environment such as a salt spray test specified in JIS Z2371.
- sufficient corrosion resistance after coating is not achieved in a severe corrosive environment such as a hot salt water immersion test or a combined cyclic corrosion test.
- a high-strength cold-rolled steel sheet having excellent corrosion resistance after coating is not obtained only by decreasing the Si concentration on the steel sheet surface after hot-rolling or decreasing the amount of the Si-containing linear oxide.
- SiO 2 is insoluble in hydrochloric acid and cannot be removed even when the concentration of iron ions is controlled to 0.5% to 18%.
- Patent Literature 4 discloses a technique for improving the chemical convertibility by removing a Si-containing oxide concentrated on the steel sheet surface through an annealing process or the like by pickling and furthermore providing a S-based compound to the surface to improve the reactivity with a chemical conversion treatment liquid.
- Patent Literature 5 discloses a technique in which a P-based compound is provided instead of the S-based compound in Patent Literature 4.
- Patent Literature 6 discloses the following technique for improving the reactivity with a chemical conversion treatment liquid to improve the chemical convertibility.
- pickling is performed using an oxidizing acid to remove SiO 2 .
- pickling is performed using a non-oxidizing acid to remove an Fe-based oxide formed during the pickling at the first stage.
- the temperature of a chemical conversion treatment liquid has been decreased to reduce the amount of industrial waste (suppress the generation of sludge) and to reduce the operating cost.
- the reactivity of the chemical conversion treatment liquid with a steel sheet has been considerably decreased compared with previous chemical conversion conditions.
- the decrease in the temperature of the chemical conversion treatment liquid does not pose a problem for plain steel sheets, which have been conventionally used and contain only a small amount of alloy, by improving a surface control technique before the chemical conversion treatment, for example.
- the reactivity with the chemical conversion treatment liquid is considerably decreased because of the influence of a Si-containing oxide formed in a surface layer of the steel sheet in the annealing process.
- Patent Literature 4 and Patent Literature 5 are effective for conventional plain steel sheets, but do not provide a sufficient improvement effect on the decrease in the temperature of the chemical conversion treatment liquid for the high-strength cold-rolled steel sheet containing a large amount of Si. It has been found that, by applying the technique disclosed in Patent Literature 6 to the above techniques, the decrease in the temperature of the chemical conversion treatment liquid can be overcome even in the high-strength cold-rolled steel sheet containing a large amount of Si. In the technique disclosed in Patent Literature 6, however, when the Fe concentration is low, the pickling rate is low and thus the ability to remove a Si-containing oxide is insufficient. Furthermore, when the Fe concentration is high, an iron-based oxide is unfavorably formed, which degrades the chemical convertibility and also the corrosion resistance after coating.
- the present invention provides a method for producing a cold-rolled steel sheet as defined in the appended claims. According to the production method of the present invention, a cold-rolled steel sheet having excellent chemical convertibility and high corrosion resistance after coating can be easily and stably produced through a typical cold-rolling process and pickling process by simply adjusting the pickling conditions.
- a cold-rolled steel sheet can be provided which has excellent chemical convertibility even when 0.5% to 3.0% of Si is contained or even when the temperature of a chemical conversion treatment liquid is decreased and which has high corrosion resistance after coating even in a severe corrosive environment such as a hot salt water immersion test or a combined cyclic corrosion test. Accordingly, in the present invention, the chemical convertibility and the corrosion resistance after coating of a high-strength cold-rolled steel sheet having a tensile strength TS of 590 MPa or more and containing a large amount of Si can be considerably improved.
- the cold-rolled steel sheet according to the present invention can be suitably used for, for example, high-strength components of automotive bodies.
- a non-oxidizing gas or a reducing gas is normally used as an atmosphere gas, and the dew point is also strictly controlled. Therefore, in typical cold-rolled steel sheets containing only a small amount of alloy, the oxidation of the steel sheet surface is suppressed. In steel sheets containing 0.5% or more of Si or Mn, however, even when the components of the atmosphere gas and the dew point during annealing are strictly controlled, Si, Mn, or the like, which is more easily oxidized than Fe, is oxidized.
- silicon oxide (SiO 2 ) or a Si-containing oxide such as a Si-Mn composite oxide is formed on the steel sheet surface.
- the composition of such an oxide varies in accordance with the composition of the steel sheet, the annealing atmosphere, or the like, but often varies in accordance with mixed conditions of the composition of the steel sheet and the annealing atmosphere in general.
- the Si-containing oxide is formed not only on the steel sheet surface, but also in a steel substrate, which degrades the etching properties of the steel sheet surface in a chemical conversion treatment (zinc phosphate treatment) performed as an underlayer treatment for electrodeposition painting and thus adversely affects the steady formation of a chemical conversion coating.
- the temperature of the chemical conversion treatment liquid has been decreased in order to reduce the amount of sludge generated during the chemical conversion treatment and reduce the operating cost.
- the chemical conversion treatment is performed under conditions in which the reactivity of the chemical conversion treatment liquid with the steel sheet is considerably low.
- Such a change in chemical conversion conditions does not pose a problem for plain steel sheets, which have been conventionally used and contain only a small amount of alloy, by improving a surface control technique, for example.
- the change in the chemical conversion conditions that is, the decrease in the temperature of the chemical conversion treatment liquid has quite a large influence. Therefore, in cold-rolled steel sheets containing a large amount of Si, the reactivity with the chemical conversion treatment liquid needs to be improved by activating the surface of the steel sheet itself in order to overcome the degradation of chemical conversion conditions.
- the inventors have studied a method for improving the chemical convertibility of the steel sheet to overcome the degradation of chemical conversion conditions described above. As a result, they have found that it is effective to pickle the surface of a cold-rolled steel sheet subjected to continuous annealing using a strong acid such as nitric acid as a pickling solution to remove a Si-containing oxide layer formed in a surface layer of the steel sheet through continuous annealing or the like after cold-rolling.
- the Si-containing oxide refers to SiO 2 or a Si-Mn composite oxide formed along grain boundaries on the steel sheet surface or in the steel sheet during slab heating or during annealing after hot-rolling or cold-rolling.
- the thickness of a layer in which such a Si-containing oxide is present varies depending on the composition of the steel sheet and the annealing conditions (temperature, time, and atmosphere), and is normally about 1 ⁇ m from the steel sheet surface.
- the phrase "to remove a Si-containing oxide layer" in the present invention refers to the removal of a Si-containing oxide layer by performing pickling until peaks of Si and O do not appear when the steel sheet surface is analyzed by GDS (glow discharge spectroscopy) in the depth direction.
- the reason for which a strong acid such as nitric acid is used as the pickling solution is as follows.
- a Si-Mn composite oxide easily dissolves in an acid, but SiO 2 does not easily dissolve in an acid. Therefore, to remove SiO 2 , the Si-containing oxide on the steel sheet surface needs to be removed together with the steel substrate.
- the chemical convertibility is considerably improved by pickling a steel sheet with a strong acid such as nitric acid after continuous annealing to remove a Si-containing oxide layer present on the steel sheet surface, but the chemical convertibility is sometimes not sufficient.
- the cause thereof has been further studied. Consequently, the following has been additionally found. That is, the Si-based oxide layer is removed by performing pickling with a strong acid such as nitric acid, but Fe eluted from the steel sheet surface as a result of the pickling forms an iron-based oxide, which is different from the Si-based oxide layer. This iron-based oxide is precipitated on the steel sheet surface so as to cover the steel sheet surface, resulting in the degradation of the chemical convertibility.
- the concentration of iron ions in the present invention refers to the total concentration of Fe(II) ions and Fe(III) ions because, in the acid liquid containing nitric acid, which has a strong oxidation power, the eluted Fe(II) ions relatively quickly change to Fe(III) ions by the nitric acid.
- the inventors have also found that when the coverage of the iron-based oxide generated on the steel sheet surface is controlled to 40% or less by pickling and the maximum thickness of the iron-based oxide is controlled to 150 nm or less, the chemical convertibility is further improved and the corrosion resistance is also further improved. They have also found that the maximum thickness of the iron-based oxide is effectively controlled to 150 nm or less by appropriately setting pickling conditions (concentration, temperature, and time) and non-oxidative pickling conditions (acid concentration, temperature, and time).
- the iron-based oxide in the present invention refers to an oxide mainly containing iron at an atomic concentration ratio of 30% or more among elements other than oxygen constituting the oxide. This iron-based oxide is present with an uneven thickness on the steel sheet surface and is different from a natural oxide film present in the form of a layer with a uniform thickness of several nanometers.
- the iron-based oxide generated on the surface of the cold-rolled steel sheet is found to be amorphous from the observation with a transmission electron microscope (TEM) and the analysis result of a diffraction pattern obtained by electron diffraction analysis.
- TEM transmission electron microscope
- a steel sheet obtained by heating a steel material (slab) containing Si in an amount of 0.5% to 3.0% and performing hot-rolling, cold-rolling, and continuous annealing is subjected to first pickling using an acid liquid 1) or an acid liquid 2) below and then subjected to second pickling using an acid liquid made of a non-oxidizing acid.
- Fe eluted from the steel sheet surface by pickling forms an iron-based oxide, and this iron-based oxide is precipitated on the steel sheet surface so as to cover the steel sheet surface. Consequently, the chemical convertibility is sometimes degraded.
- the amount of the iron-based oxide generated on the steel sheet surface is preferably suppressed. For the above reasons, the following pickling conditions are specified.
- the concentration of the nitric acid is 50 g/L or less, a long time is required for pickling, which increases the facility length and thus increases the facility cost. If the concentration of the nitric acid is more than 200 g/L, the eluted iron is oxidized to generate an iron-based oxide. This iron-based oxide is precipitated on the steel sheet surface, which adversely affects the chemical convertibility and the corrosion resistance after coating. If R1 or R2 is more than 0.25 or the concentration of iron ions (total of Fe(II) and Fe(III)) is less than 3 g/L, a desired pickling rate is not achieved, and thus the Si-containing oxide cannot be efficiently removed.
- the maximum thickness of the iron-based oxide can be controlled to 150 nm or less by appropriately setting the pickling conditions (concentration, temperature, and time).
- the pickling conditions concentration, temperature, and time.
- the maximum thickness of the iron-based oxide is controlled to 150 nm or less. Consequently, the chemical convertibility is further improved, and the corrosion resistance is also further improved.
- the first pickling with a strong acid is not sufficient to stably control the surface coverage of the iron-based oxide generated on the steel sheet surface to 40% or less.
- second pickling is performed in order to decrease, with certainty, the amount of the iron-based oxide generated on the steel sheet surface as a result of the first pickling. That is, pickling is performed using an acid liquid made of a non-oxidizing acid to dissolve and remove the iron-based oxide.
- the second pickling is preferably performed at a temperature of the acid liquid of 20°C to 70°C for 1 to 30 seconds.
- the temperature of the pickling solution is 20°C or higher and the treatment time is 1 second or more, the iron-based oxide left on the steel sheet surface is sufficiently removed.
- the temperature of the pickling solution is 70°C or lower and the treatment time is 30 seconds or less, the steel sheet surface is not excessively dissolved and another surface oxide film is not formed.
- the maximum thickness of the iron-based oxide present on the steel sheet surface after the pickling is preferably decreased to 150 nm or less with certainty.
- the concentration of the acid liquid made of a non-oxidizing acid is preferably increased to an appropriate value.
- the concentration of the hydrochloric acid is preferably 3 to 50 g/L.
- sulfuric acid is used, the concentration of the sulfuric acid is preferably 8 to 150 g/L.
- the first pickling and the second pickling are performed. Subsequently, an ordinary process such as temper rolling is performed to obtain a product sheet (cold-rolled steel sheet).
- the Si content is preferably 0.5% to 3.0%.
- Si has a large effect (solid-solution strengthening ability) of increasing the strength of steel without considerably impairing the workability. Therefore, Si is an element effective for increasing the strength of steel, but is also an element that adversely affects the chemical convertibility and the corrosion resistance after coating. For the above reason, the Si content is preferably 0.5% or more. If the Si content is more than 3.0%, the hot rollability and the cold rollability are considerably degraded, which may adversely affect the productivity or degrade the ductility of the steel sheet itself. Accordingly, when Si is added, the Si content is preferably 0.5% to 3.0% and more preferably 0.8% to 2.5%.
- Components other than Si are allowable as long as the contents of the components are within the ranges of typical cold-rolled steel sheets.
- the suitable composition except for Si is preferably as follows.
- C is an element effective for increasing the strength of steel and also an element effective for generating retained austenite having a TRIP (transformation induced plasticity) effect, bainite, and martensite.
- TRIP transformation induced plasticity
- bainite bainite
- martensite martensite.
- the C content is 0.01% or more, the above effects are produced.
- the C content is 0.30% or less, the weldability does not degrade. Accordingly, the C content is preferably 0.01% to 0.30% and more preferably 0.10% to 0.20%.
- Mn is an element that increases the strength of steel through solid-solution strengthening, improves the hardenability, and facilitates the generation of retained austenite, bainite, and martensite.
- the Mn content is 1.0% or more, such effects are produced.
- the Mn content is 7.5% or less, the above effects are produced without increasing the cost. Accordingly, the Mn content is preferably 1.0% to 7.5% and more preferably 2.0% to 5.0%.
- the P content is preferably 0.005% or more.
- P is an element that degrades the spot weldability, no problem is posed when the P content is 0.05% or less. Accordingly, the P content is preferably 0.05% or less and more preferably 0.02% or less.
- S is an impurity element that unavoidably mixes and a harmful component that precipitates in steel in the form of MnS to degrade the stretch flangeability of the steel sheet.
- the S content is preferably 0.01% or less and more preferably 0.005% or less.
- the Al content is preferably 0.01% or more.
- the Al content is preferably 0.01% to 0.06% and more preferably 0.02% to 0.06%.
- the balance other than the above components is Fe and unavoidable impurities.
- the addition of other components is not necessarily denied as long as the advantageous effects of the present invention are not impaired.
- the cold-rolled steel sheet according to the present invention has a steel sheet surface from which the Si-containing oxide layer, such as SiO 2 and a Si-Mn composite oxide, formed in the surface layer of the steel sheet during annealing has been removed.
- the Si-containing oxide layer such as SiO 2 and a Si-Mn composite oxide
- the surface coverage of the iron-based oxide present on the steel sheet surface needs to be decreased to 40% or less. This is because if the surface coverage is more than 40%, the dissolution reaction of iron in the chemical conversion treatment is inhibited, which suppresses the growth of conversion crystals of zinc phosphate or the like.
- a coverage of 40% or less is insufficient for cold-rolled steel sheets used for parts, such as chassis parts of vehicles that severely corrode, required to have very high corrosion resistance after coating. Therefore, the surface coverage needs to be further decreased to 35% or less.
- the surface coverage is preferably 35% or less.
- the surface coverage of the iron-based oxide is determined by the following method.
- a steel sheet surface subjected to pickling is observed for about five fields at an acceleration voltage of 2 kV at a working distance of 3.0 mm with about 1000-fold magnification using an ultra-low-voltage scanning electron microscope (ULV-SEM) that can detect information regarding an outermost surface layer.
- UUV-SEM ultra-low-voltage scanning electron microscope
- Spectroscopic analysis is performed using an energy-dispersive X-ray diffractometer (EDX) to obtain a backscattered electron image.
- the backscattered electron image is processed using image analysis software such as Image J. Specifically, the backscattered electron image is converted into a binary representation to measure the area fraction of a black portion. By averaging the measured values in the fields, the surface coverage of the iron-based oxide can be obtained.
- UUV-SEM ultra-low-voltage scanning electron microscope
- EDX energy-dispersive X-ray diffractometer
- a steel slab shown in Table 1 is subjected to hot-rolling, cold-rolling, and continuous annealing under the conditions shown in Table 2 to obtain a cold-rolled steel sheet having a sheet thickness of 1.8 mm.
- the cold-rolled steel sheet after the continuous annealing is pickled under the conditions shown in Table 3, washed with water, dried, and then temper-rolled at an elongation percentage of 0.7% to obtain two cold-rolled steel sheets No. a and No. b containing different amounts of iron-based oxides on the steel sheet surfaces.
- a is defined as a standard sample containing a large amount of iron-based oxide
- the cold-rolled steel sheet No. b is defined as a standard sample containing a small amount of iron-based oxide.
- Fig. 1 illustrates photographs of the backscattered electron images of the steel sheets No. a and No. b.
- Fig. 2 illustrates a histogram showing the number of pixels plotted against gray values of the photographs of the backscattered electron images of the steel sheets No. a and No. b.
- the gray value (Y point) corresponding to an intersection point (X point) of the histogram No. a and the histogram No. b in Fig. 2 is defined as a threshold.
- the maximum thickness of the iron-based oxide is determined as follows.
- the coating layer is found to be formed of an iron-based oxide.
- the distance between the line A that indicates a steel sheet substrate and the line B that indicates the thickest portion of the iron-based oxide layer in the cross-sectional photograph of Fig. 3 is measured for all the ten replicas. The largest distance is defined as the maximum thickness of the iron-based oxide. Note that the size and number of replicas, the measurement conditions with a TEM, and the like are merely examples, and may be obviously changed appropriately.
- the thus-obtained cold-rolled steel sheet has excellent chemical convertibility and high corrosion resistance after coating evaluated by a hot salt water immersion test or a combined cyclic corrosion test, and therefore can be suitably used for automotive components.
- the hot-rolled steel sheet was pickled to remove scales and then cold-rolled to obtain a cold-rolled steel sheet having a sheet thickness of 1.8 mm.
- the cold-rolled steel sheet was subjected to continuous annealing in which the steel sheet was heated to a soaking temperature of 750°C to 780°C and held for 40 to 50 seconds, then cooled from the soaking temperature to a cooling stop temperature of 350°C to 400°C at 20 to 30°C/s, and held in the cooling stop temperature range for 100 to 120 seconds.
- the steel sheet surface was pickled under the conditions shown in Table 4-1 and Table 4-2, washed with water, dried, and then temper-rolled at an elongation percentage of 0.7% to obtain cold-rolled steel sheets Nos. 2 to 80 in Table 4-1 and Table 4-2.
- a test specimen was collected from each of the cold-rolled steel sheets.
- the steel sheet surface was observed for five fields at an acceleration voltage of 2 kV at a working distance of 3.0 mm with 1000-fold magnification using an ultra-low-voltage scanning electron microscope (ULV-SEM, manufactured by SEISS, ULTRA 55).
- Spectroscopic analysis was performed using an energy-dispersive X-ray diffractometer (EDX, manufactured by Thermo Fisher, NSS312E) to obtain a backscattered electron image.
- EDX energy-dispersive X-ray diffractometer
- the backscattered electron image was processed using image analysis software (Image J).
- the gray value (Y point) corresponding to an intersection point (X point) of the histograms of the standard samples No. a and No. b described above was defined as a threshold.
- the backscattered electron image was converted into a binary representation to measure the area fraction of a black portion. The average of the measured values in the five
- test specimen was collected from each of the cold-rolled steel sheets.
- the test specimen was subjected to a chemical conversion treatment and a coating treatment under the conditions below and then subjected to three corrosion tests of a hot salt water immersion test, a salt spray test, and a combined cyclic corrosion test.
- the corrosion resistance after coating was evaluated.
- the depth profiles of O, Si, Mn, and Fe were measured by GDS for the surface of the test specimen collected from each of the cold-rolled steel sheets.
- Steels A to O having compositions shown in Table 5 were refined through typical refining processes such as a converter process and degassing and continuously cast to obtain steel slabs.
- Each of the steel slabs was hot-rolled under the hot-rolling conditions shown in Table 6 to obtain a hot-rolled steel sheet having a sheet thickness of 3 to 4 mm.
- the hot-rolled steel sheet was pickled to remove scales on the steel sheet surface and then cold-rolled to obtain a cold-rolled steel sheet having a sheet thickness of 1.8 mm.
- the cold-rolled steel sheet was subjected to continuous annealing and pickling under the conditions shown in Tables 6 and 7, then washed with water, dried, and temper-rolled at an elongation percentage of 0.7% to obtain each of cold-rolled steel sheets Nos. 81 to 111.
- test specimen was collected from each of the thus-obtained cold-rolled steel sheets.
- the surface coverage of the iron-based oxide on the steel sheet surface after pickling was measured in the same manner as in Example 1. Then, the test specimen was subjected to a tensile test and a test for corrosion resistance after coating described below. Furthermore, the depth profiles of O, Si, Mn, and Fe on the surface of the test specimen collected from each of the cold-rolled steel sheets were measured by GDS.
- Example 1 A test specimen collected from each of the cold-rolled steel sheets was subjected to a chemical conversion treatment and electrodeposition painting under the same conditions as in Example 1. The test specimen was subjected to three corrosion tests of a hot salt water immersion test, a salt spray test (SST), and a combined cyclic corrosion test (CCT) in the same manner as in Example 1. Thus, the corrosion resistance after coating was evaluated.
- SST salt spray test
- CCT combined cyclic corrosion test
- Table 7 shows the results of the tests (the tensile strength TS is shown in Table 6).
- the high-strength cold-rolled steel sheets of Invention Examples that contained 0.5% or more of Si and pickled under the conditions of the present invention to decrease the surface coverage of the iron-based oxide on the steel sheet surface to 40% or less had not only excellent chemical convertibility and high corrosion resistance after coating, but also high strength with a tensile strength TS of 590 MPa or more.
- the depth profiles of O, Si, Mn, and Fe were measured by GDS. It was confirmed that peaks of Si and O did not appear for all the steel sheets pickled under the conditions of the present invention, and thus the Si-containing oxide layer was sufficiently removed.
- the slab was reheated to a temperature of 1150°C to 1170°C, then hot-rolled at a finishing temperature of 850°C to 880°C, and coiled at a temperature of 500°C to 550°C to obtain a hot-rolled steel sheet having a sheet thickness of 3 to 4 mm.
- the hot-rolled steel sheet was pickled to remove scales and then cold-rolled to obtain a cold-rolled steel sheet having a sheet thickness of 1.8 mm.
- the cold-rolled steel sheet was subjected to continuous annealing in which the steel sheet was heated to a soaking temperature of 750°C to 780°C and held for 40 to 50 seconds, then cooled from the soaking temperature to a cooling stop temperature of 350°C to 400°C at 20 to 30°C/s, and held in the cooling stop temperature range for 100 to 120 seconds. Subsequently, the steel sheet surface was pickled under the conditions shown in Table 8, washed with water, dried, and then temper-rolled at an elongation percentage of 0.7% to obtain cold-rolled steel sheets Nos. 112 to 149 in Table 8.
- a test specimen was collected from each of the cold-rolled steel sheets.
- the surface coverage and maximum thickness of the iron-based oxide generated on the steel sheet surface as a result of the pickling were measured by the above-described methods.
- the test specimen collected from each of the cold-rolled steel sheets was subjected to a chemical conversion treatment so that the chemical conversion coating had a coating weight of 1.7 to 3.0 g/m 2 .
- the chemical conversion treatment was performed using a degreasing agent FC-E2011, a surface controlling agent PL-X, and a chemical conversion treatment agent Palbond PB-L3065 manufactured by Nihon Parkerizing Co., Ltd. under two conditions below which are standard conditions and comparative conditions in which the temperature of the chemical conversion treatment liquid was decreased.
- the temperature of the chemical conversion treatment liquid in the standard conditions was decreased to 33°C.
- Electrodeposition painting was performed on the surface of the test specimen subjected to the above chemical conversion treatment using an electrodeposition paint V-50 manufactured by NIPPONPAINT Co., Ltd. so that a layer having a thickness of 25 ⁇ m was formed.
- the test specimen was subjected to the three corrosion tests below under more strict conditions than those of Example 1.
- the test specimen was then immersed in a 5 mass% NaCl solution (60°C) for 480 hours, washed with water, and dried.
- a tape peel-off test was performed by attaching an adhesive tape to a cut mark portion and then peeling off the adhesive tape. The maximum total width of peeling on both left and right sides of the cut mark portion was measured. When the maximum total width of peeling is 5.0 mm or less, the corrosion resistance in the hot salt water immersion test is evaluated to be good.
- the test specimen was then subjected to a salt spray test for 1400 hours using a 5 mass% aqueous NaCl solution in conformity with a neutral salt spray test specified in JIS Z2371:2000. Subsequently, a tape peel-off test was performed on a crosscut mark portion. The maximum total width of peeling on both left and right sides of the cut mark portion was measured. When the maximum total width of peeling is 4.0 mm or less, the corrosion resistance in the salt spray test is evaluated to be good.
- the surface of the test specimen (n 1) subjected to the chemical conversion treatment and the electrodeposition painting was cut with a cutter to form a crosscut mark having a length of 45 mm.
- the test specimen was subjected to a corrosion test in which 150 cycles each including salt spraying (5 mass% aqueous NaCl solution: 35°C, relative humidity: 98%) ⁇ 2 hours ⁇ drying (60°C, relative humidity: 30%) ⁇ 2 hours ⁇ wetting (50°C, relative humidity: 95%) x 2 hours were repeatedly performed.
- the test specimen was washed with water and dried. Subsequently, a tape peel-off test was performed on a cut mark portion. The maximum total width of peeling on both left and right sides of the cut mark portion was measured. When the maximum total width of peeling is 6.0 mm or less, the corrosion resistance in the combined cyclic corrosion test is evaluated to be good.
- the steel sheets of Invention Examples had very high corrosion resistance after coating.
- the depth profiles of O, Si, Mn, and Fe were measured by GDS. It was confirmed that peaks of Si and O did not appear for all the steel sheets pickled under the conditions of the present invention, and thus the Si-containing oxide layer was sufficiently removed.
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Claims (6)
- Procédé de production d'une tôle d'acier laminée à froid, comprenant :la réalisation d'un premier décapage avec un liquide acide 1) ou un liquide acide 2) ci-après sur une tôle d'acier soumise à un recuit continu après laminage à froid ; etla réalisation d'un second décapage avec un liquide acide constitué d'un acide non oxydant sur la tôle d'acier,le liquide acide 1) contenant de l'acide nitrique et de l'acide chlorhydrique, l'acide nitrique ayant une concentration supérieure à 50 g/L jusqu'à 200 g/L ou moins, un rapport R1 (acide chlorhydrique/acide nitrique) d'une concentration de l'acide chlorhydrique à la concentration de l'acide nitrique allant de 0,01 à 0,25, et une concentration en ions fer qui est la concentration totale en ions Fe(II) et Fe(III) allant de 3 à 50 g/L, etle liquide acide 2) contenant de l'acide nitrique et de l'acide fluorhydrique, l'acide nitrique ayant une concentration supérieure à 50 g/L jusqu'à 200 g/L ou moins, un rapport R2 (acide fluorhydrique/acide nitrique) d'une concentration de l'acide fluorhydrique à la concentration de l'acide nitrique allant de 0,01 à 0,25, et une concentration en ions fer qui est la concentration totale en ions Fe(II) et Fe(III) allant de 3 à 50 g/L, etle maintien de la concentration en ions fer de 3 à 50 g/L en effectuant une dilution par ajout d'acide nitrique et d'acide chlorhydrique ou en réduisant la quantité de fer dans un acide au moyen d'un appareil d'élimination du fer,le premier décapage et le second décapage étant effectués en continu.
- Procédé de production d'une tôle d'acier laminée à froid selon la revendication 1, dans lequel le premier décapage est effectué à une température de liquide acide de 20 °C à 70 °C pendant 3 à 30 secondes.
- Procédé de production d'une tôle d'acier laminée à froid selon la revendication 1 ou 2, dans lequel l'acide non oxydant est l'un au moins parmi l'acide chlorhydrique, l'acide sulfurique, l'acide phosphorique, l'acide pyrophosphorique, l'acide formique, l'acide acétique, l'acide citrique, l'acide fluorhydrique et l'acide oxalique.
- Procédé de production d'une tôle d'acier laminée à froid selon l'une quelconque des revendications 1 à 3, dans lequel l'acide non oxydant est l'un au moins parmi de l'acide chlorhydrique ayant une concentration de 0,1 à 50 g/L, de l'acide sulfurique ayant une concentration de 0,1 à 50 g/L et un acide mixte contenant de l'acide chlorhydrique ayant une concentration de 0,1 à 20 g/L et de l'acide sulfurique ayant une concentration de 0,1 à 60 g/L.
- Procédé de production d'une tôle d'acier laminée à froid selon l'une quelconque des revendications 1 à 4, dans lequel le second décapage est effectué à une température de liquide acide de 20 °C à 70 °C pendant 1 à 30 secondes.
- Procédé de production d'une tôle d'acier laminée à froid selon l'une quelconque des revendications 1 à 5, dans lequel la tôle d'acier laminée à froid contient du Si à hauteur de 0,5 à 3,0 % en masse.
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JPH0328386A (ja) * | 1989-06-23 | 1991-02-06 | Daido Steel Co Ltd | 金属の酸洗処理方法 |
JP3021164B2 (ja) * | 1992-02-14 | 2000-03-15 | 川崎製鉄株式会社 | 表面光沢の優れるオーステナイト系ステンレス鋼の製造方法 |
JP3059376B2 (ja) * | 1996-03-22 | 2000-07-04 | 川崎製鉄株式会社 | 光沢性および耐食性に優れるオーステナイト系ステンレス鋼板およびその製造方法 |
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US20150013716A1 (en) * | 2012-01-18 | 2015-01-15 | Jfe Steel Corporation | Method for prevention of yellowing on surface of steel sheet after pickling |
JP2013173976A (ja) * | 2012-02-24 | 2013-09-05 | Jfe Steel Corp | 冷延鋼板の製造方法およびその製造設備 |
JP6137089B2 (ja) * | 2014-09-02 | 2017-05-31 | Jfeスチール株式会社 | 冷延鋼板の製造方法および冷延鋼板の製造設備 |
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Publication number | Priority date | Publication date | Assignee | Title |
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JPH0328386A (ja) * | 1989-06-23 | 1991-02-06 | Daido Steel Co Ltd | 金属の酸洗処理方法 |
JP3021164B2 (ja) * | 1992-02-14 | 2000-03-15 | 川崎製鉄株式会社 | 表面光沢の優れるオーステナイト系ステンレス鋼の製造方法 |
JP3059376B2 (ja) * | 1996-03-22 | 2000-07-04 | 川崎製鉄株式会社 | 光沢性および耐食性に優れるオーステナイト系ステンレス鋼板およびその製造方法 |
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WO2015133077A1 (fr) | 2015-09-11 |
EP3115482A1 (fr) | 2017-01-11 |
CN106062253A (zh) | 2016-10-26 |
CN106062253B (zh) | 2019-10-18 |
JP6108028B2 (ja) | 2017-04-05 |
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