CA1242669A - Chrome plated steel sheet with tin or tin-nickel and chromic oxide layers - Google Patents
Chrome plated steel sheet with tin or tin-nickel and chromic oxide layersInfo
- Publication number
- CA1242669A CA1242669A CA000454343A CA454343A CA1242669A CA 1242669 A CA1242669 A CA 1242669A CA 000454343 A CA000454343 A CA 000454343A CA 454343 A CA454343 A CA 454343A CA 1242669 A CA1242669 A CA 1242669A
- Authority
- CA
- Canada
- Prior art keywords
- tin
- chromium
- steel base
- nickel
- plating
- 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
Links
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims abstract description 181
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 133
- 239000010959 steel Substances 0.000 title claims abstract description 133
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 title claims abstract description 118
- CLDVQCMGOSGNIW-UHFFFAOYSA-N nickel tin Chemical compound [Ni].[Sn] CLDVQCMGOSGNIW-UHFFFAOYSA-N 0.000 title claims abstract description 69
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 title claims abstract description 51
- 239000011651 chromium Substances 0.000 claims abstract description 179
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 178
- 238000007747 plating Methods 0.000 claims abstract description 115
- 238000000034 method Methods 0.000 claims abstract description 53
- 229910000990 Ni alloy Inorganic materials 0.000 claims abstract description 51
- 229910000423 chromium oxide Inorganic materials 0.000 claims abstract description 32
- 239000000243 solution Substances 0.000 claims abstract description 24
- 230000002378 acidificating effect Effects 0.000 claims abstract description 15
- 239000003929 acidic solution Substances 0.000 claims abstract description 5
- 229940107218 chromium Drugs 0.000 claims description 169
- 235000012721 chromium Nutrition 0.000 claims description 169
- 239000003792 electrolyte Substances 0.000 claims description 86
- 239000002585 base Substances 0.000 claims description 85
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 84
- IUTCEZPPWBHGIX-UHFFFAOYSA-N tin(2+) Chemical compound [Sn+2] IUTCEZPPWBHGIX-UHFFFAOYSA-N 0.000 claims description 37
- 239000002253 acid Substances 0.000 claims description 33
- 229910052783 alkali metal Inorganic materials 0.000 claims description 32
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 claims description 32
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 claims description 32
- 229910052759 nickel Inorganic materials 0.000 claims description 32
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 23
- 229910001453 nickel ion Inorganic materials 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 150000001340 alkali metals Chemical class 0.000 claims description 19
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 18
- -1 alkali metal pyrophos-phate Chemical class 0.000 claims description 16
- 239000000654 additive Substances 0.000 claims description 12
- 150000002222 fluorine compounds Chemical class 0.000 claims description 11
- 235000011180 diphosphates Nutrition 0.000 claims description 10
- 229940048084 pyrophosphate Drugs 0.000 claims description 10
- 150000003464 sulfur compounds Chemical class 0.000 claims description 10
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 9
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 8
- WHOZNOZYMBRCBL-OUKQBFOZSA-N (2E)-2-Tetradecenal Chemical compound CCCCCCCCCCC\C=C\C=O WHOZNOZYMBRCBL-OUKQBFOZSA-N 0.000 claims description 7
- 229940044654 phenolsulfonic acid Drugs 0.000 claims description 7
- 230000005611 electricity Effects 0.000 claims description 6
- 229910001430 chromium ion Inorganic materials 0.000 claims description 4
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical compound N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 claims description 3
- PQUCIEFHOVEZAU-UHFFFAOYSA-N Diammonium sulfite Chemical compound [NH4+].[NH4+].[O-]S([O-])=O PQUCIEFHOVEZAU-UHFFFAOYSA-N 0.000 claims description 3
- 229910001515 alkali metal fluoride Inorganic materials 0.000 claims description 3
- 229910052936 alkali metal sulfate Inorganic materials 0.000 claims description 3
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 3
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 3
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 claims description 3
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 claims description 3
- 229940044652 phenolsulfonate Drugs 0.000 claims description 3
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 claims description 2
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 claims description 2
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 2
- 230000000996 additive effect Effects 0.000 claims 8
- 229940065278 sulfur compound Drugs 0.000 claims 6
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims 3
- PMJNEQWWZRSFCE-UHFFFAOYSA-N 3-ethoxy-3-oxo-2-(thiophen-2-ylmethyl)propanoic acid Chemical compound CCOC(=O)C(C(O)=O)CC1=CC=CS1 PMJNEQWWZRSFCE-UHFFFAOYSA-N 0.000 claims 2
- JXBUOZMYKQDZFY-UHFFFAOYSA-N 4-hydroxybenzene-1,3-disulfonic acid Chemical compound OC1=CC=C(S(O)(=O)=O)C=C1S(O)(=O)=O JXBUOZMYKQDZFY-UHFFFAOYSA-N 0.000 claims 2
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 claims 2
- JOSWYUNQBRPBDN-UHFFFAOYSA-P ammonium dichromate Chemical compound [NH4+].[NH4+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O JOSWYUNQBRPBDN-UHFFFAOYSA-P 0.000 claims 2
- UAHUSJDFWAEKNV-UHFFFAOYSA-N azanium;2-hydroxybenzenesulfonate Chemical compound [NH4+].OC1=CC=CC=C1S([O-])(=O)=O UAHUSJDFWAEKNV-UHFFFAOYSA-N 0.000 claims 2
- XYXNTHIYBIDHGM-UHFFFAOYSA-N ammonium thiosulfate Chemical compound [NH4+].[NH4+].[O-]S([O-])(=O)=S XYXNTHIYBIDHGM-UHFFFAOYSA-N 0.000 claims 1
- KXFWTZMGHPOWIB-UHFFFAOYSA-N diazanium oxidosulfonothioyl sulfate Chemical compound S(=S)(=O)([O-])OS(=O)(=O)[O-].[NH4+].[NH4+] KXFWTZMGHPOWIB-UHFFFAOYSA-N 0.000 claims 1
- 229910045601 alloy Inorganic materials 0.000 abstract description 12
- 239000000956 alloy Substances 0.000 abstract description 12
- 238000010924 continuous production Methods 0.000 abstract description 2
- 230000007423 decrease Effects 0.000 description 17
- 239000004922 lacquer Substances 0.000 description 17
- 238000000151 deposition Methods 0.000 description 15
- 150000002500 ions Chemical class 0.000 description 14
- 238000003466 welding Methods 0.000 description 12
- 230000008021 deposition Effects 0.000 description 11
- 239000005028 tinplate Substances 0.000 description 11
- 230000007797 corrosion Effects 0.000 description 10
- 238000005260 corrosion Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 9
- 238000000576 coating method Methods 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 8
- 238000005755 formation reaction Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000001035 drying Methods 0.000 description 6
- 238000004826 seaming Methods 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 235000013305 food Nutrition 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 4
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 239000001828 Gelatine Substances 0.000 description 3
- 229910008066 SnC12 Inorganic materials 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 229920000159 gelatin Polymers 0.000 description 3
- 235000019322 gelatine Nutrition 0.000 description 3
- 150000004820 halides Chemical class 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 238000005476 soldering Methods 0.000 description 3
- 229910000375 tin(II) sulfate Inorganic materials 0.000 description 3
- TXUICONDJPYNPY-UHFFFAOYSA-N (1,10,13-trimethyl-3-oxo-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-17-yl) heptanoate Chemical compound C1CC2CC(=O)C=C(C)C2(C)C2C1C1CCC(OC(=O)CCCCCC)C1(C)CC2 TXUICONDJPYNPY-UHFFFAOYSA-N 0.000 description 2
- 241001600451 Chromis Species 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- JQGGAELIYHNDQS-UHFFFAOYSA-N Nic 12 Natural products CC(C=CC(=O)C)c1ccc2C3C4OC4C5(O)CC=CC(=O)C5(C)C3CCc2c1 JQGGAELIYHNDQS-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 229910021626 Tin(II) chloride Inorganic materials 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 229910001514 alkali metal chloride Inorganic materials 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000005238 degreasing Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- NNIPDXPTJYIMKW-UHFFFAOYSA-N iron tin Chemical compound [Fe].[Sn] NNIPDXPTJYIMKW-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000001881 scanning electron acoustic microscopy Methods 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- KIEOKOFEPABQKJ-UHFFFAOYSA-N sodium dichromate Chemical compound [Na+].[Na+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KIEOKOFEPABQKJ-UHFFFAOYSA-N 0.000 description 2
- 239000001119 stannous chloride Substances 0.000 description 2
- 235000011150 stannous chloride Nutrition 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- DHCDFWKWKRSZHF-UHFFFAOYSA-L thiosulfate(2-) Chemical compound [O-]S([S-])(=O)=O DHCDFWKWKRSZHF-UHFFFAOYSA-L 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- KJCVRFUGPWSIIH-UHFFFAOYSA-N 1-naphthol Chemical compound C1=CC=C2C(O)=CC=CC2=C1 KJCVRFUGPWSIIH-UHFFFAOYSA-N 0.000 description 1
- 241000251468 Actinopterygii Species 0.000 description 1
- 101100177236 Bos taurus HBE4 gene Proteins 0.000 description 1
- 241000282326 Felis catus Species 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 239000004471 Glycine Substances 0.000 description 1
- 229910004039 HBF4 Inorganic materials 0.000 description 1
- 241000489861 Maximus Species 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 229910021333 Na2Si Inorganic materials 0.000 description 1
- 229910004883 Na2SiF6 Inorganic materials 0.000 description 1
- 229910005102 Ni3Sn Inorganic materials 0.000 description 1
- 229910005099 Ni3Sn2 Inorganic materials 0.000 description 1
- 229910003306 Ni3Sn4 Inorganic materials 0.000 description 1
- 229910005887 NiSn Inorganic materials 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- PYWICZIXLIWNGZ-UHFFFAOYSA-N [Sn].[Ni].[Fe] Chemical compound [Sn].[Ni].[Fe] PYWICZIXLIWNGZ-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000000443 aerosol Substances 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 235000011389 fruit/vegetable juice Nutrition 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 1
- 235000015250 liver sausages Nutrition 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- APVPOHHVBBYQAV-UHFFFAOYSA-N n-(4-aminophenyl)sulfonyloctadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(=O)NS(=O)(=O)C1=CC=C(N)C=C1 APVPOHHVBBYQAV-UHFFFAOYSA-N 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 229940005657 pyrophosphoric acid Drugs 0.000 description 1
- VMXUWOKSQNHOCA-UKTHLTGXSA-N ranitidine Chemical compound [O-][N+](=O)\C=C(/NC)NCCSCC1=CC=C(CN(C)C)O1 VMXUWOKSQNHOCA-UKTHLTGXSA-N 0.000 description 1
- IOVGROKTTNBUGK-SJCJKPOMSA-N ritodrine Chemical compound N([C@@H](C)[C@H](O)C=1C=CC(O)=CC=1)CCC1=CC=C(O)C=C1 IOVGROKTTNBUGK-SJCJKPOMSA-N 0.000 description 1
- 108010017584 romiplostim Proteins 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- RBWSWDPRDBEWCR-RKJRWTFHSA-N sodium;(2r)-2-[(2r)-3,4-dihydroxy-5-oxo-2h-furan-2-yl]-2-hydroxyethanolate Chemical compound [Na+].[O-]C[C@@H](O)[C@H]1OC(=O)C(O)=C1O RBWSWDPRDBEWCR-RKJRWTFHSA-N 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- ANOBYBYXJXCGBS-UHFFFAOYSA-L stannous fluoride Chemical compound F[Sn]F ANOBYBYXJXCGBS-UHFFFAOYSA-L 0.000 description 1
- 229960002799 stannous fluoride Drugs 0.000 description 1
- RCIVOBGSMSSVTR-UHFFFAOYSA-L stannous sulfate Chemical compound [SnH2+2].[O-]S([O-])(=O)=O RCIVOBGSMSSVTR-UHFFFAOYSA-L 0.000 description 1
- AVOWNHOMJQZECK-UHFFFAOYSA-N sulfuric acid hydrochloride hydrofluoride Chemical compound F.S(O)(O)(=O)=O.Cl AVOWNHOMJQZECK-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Electroplating Methods And Accessories (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a surface treated steel sheet having three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer of hydrated chromium oxide on a steel base, and to a method for the continuous production thereof which comprises chromium plating a steel base to form a layer of metallic chromium and a layer of hydrated chromium oxide thereon, tin or tin-nickel alloy plating the chromium plated steel base with a tin or tin-nickel alloy plating solution under acidic condi-tions sufficient to substantially dissolve the hydrat-ed chromium oxide in the solution, thereby removing the hydrated chromium oxide formed during chromium plating, and after rinsing, forming a layer of hydrat-ed chromium oxide on the tin or tin-nickel plated, chromium plated steel base. It is also possible to remove the hydrated chromium oxide formed during chromium plating by a cathodic treatment of the chromium plated steel base in an acidic solution having a pH of 0.5 to 2.0, and thereafter, tin or tin-nickel. alloy plating the chromium plated steel base. The surface treated steel sheet can be used to produce a welded can body at high speed without the removal. of the plated layer in the welded part since it has an excellent weldability.
The present invention relates to a surface treated steel sheet having three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer of hydrated chromium oxide on a steel base, and to a method for the continuous production thereof which comprises chromium plating a steel base to form a layer of metallic chromium and a layer of hydrated chromium oxide thereon, tin or tin-nickel alloy plating the chromium plated steel base with a tin or tin-nickel alloy plating solution under acidic condi-tions sufficient to substantially dissolve the hydrat-ed chromium oxide in the solution, thereby removing the hydrated chromium oxide formed during chromium plating, and after rinsing, forming a layer of hydrat-ed chromium oxide on the tin or tin-nickel plated, chromium plated steel base. It is also possible to remove the hydrated chromium oxide formed during chromium plating by a cathodic treatment of the chromium plated steel base in an acidic solution having a pH of 0.5 to 2.0, and thereafter, tin or tin-nickel. alloy plating the chromium plated steel base. The surface treated steel sheet can be used to produce a welded can body at high speed without the removal. of the plated layer in the welded part since it has an excellent weldability.
Description
-- ~IL2~2669 1 The present invention relates to a surEace treated steel sheet having an excellent weldabili-ty and an excell.ent corrosion resistance and a method for its production.
More par-ticularly, the invention relates -to a surface treated steel sheet having three layers consisting of a bottom layer (layer closest to the steel base) oE metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer (layer farthest from the steel base) of hydrated chromium ox.i.de on a steel base, and to a production method of this surface treated steel sheet which is character:ized by tin pla-ting by using a -tin plating electrolyte havlng a low concentration of s-tannous ion or t:in-rl.i.clcel alloy plating by using a known tin-nickeL al.l.oy pl.ating electrolyte which has a low current eff:ic:iency or by tin or tin-nickel alloy plat:iny by using a known tin or tin-nickel alloy pl.ating electro]yte after a removal of hydrated chromi.um oxide ~ormed during chromium pla-ting by using an acidic soluti.on having a pH of 0.5 -to 2Ø
~ y using this surface treated steel sheet, a welded can body can be produced at high speed without -the removal of the plated layer in -the welded part.
Recent].y the change from expensive electro-tinpl.ates to cheaper tin free s-teel (TFS-CT) having double :layers consisting of a lower layer of metallic chromium and an upper layer of hydra-ted chromium oxide ~", as well as a decrease in the weight of the tln coating in elec-trotinplates has rapidly taken place in the field of food cans.
This is because the tin used for the produc-tion of t~nplate is very expensive and there is concern over the exhaustion of tin resources.
An ordinary metal can consists of two can ends and a sinyle can body, except for drawn cans. In the case of tinplate, the seaming of the can body is generally carried out by soldering. In this soldering process, however, i-t is impossible to decrease the weight of tin coating on the tinplate to under 2.8 g/m , because it is difficult to stabilize the solder-ing process when the weight of the -tin coating is under 2.8 g/m2. From the regulation of lead content in the solder used for the seaming of -the tinplate can body in the field of food cans, -the seaming of the -tinplate can body is widely carried out by electric welding.
A Iap seam welding, for instance, SO~DRONIC
(trade mark) process has been recently used for the seaming of the tinpla-te can body.
In this process, it is desirable to decrease the tin coating weight in the tinplate, but the weldabilLty oE tinplate becomes poor wi-th a decrease of the tin coating weight.
~ ~2669 On the other hand, -the seaming of a TFS-CT
can body is general]y carried out with nylon adhesives by using the TOYO SEAM (trade mark) and MIRA SEAM
(trade mar]c) method.
Another me-thod of seaming a TFS-CT can body by electric wel.d:ing is also well known. In the case of the seaminCJ oE a TFS-CT can body by electronic weld-ing, however, the metallic chromium layer and -the hydrated chromlum oxide layer must be mechanically or chemically removed from the TFS-CT surface in order to easily we:Ld the TFS-CT can body at high speed. There-fore the corrosion resistance in the welded part of the TES-CT can body becomes remarkably poor, even if this wel.ded part is coated with lacquer after welding.
Frorn the background described above, the development of a can material which is cheaper than tinplate and :is easily welded at high speed wi-thout the removal of the pla-ted layer, has been required in -the field of food cans.
Recentl~, ~arious surface treated steel sheets have been proposed as a can material which can be easily we]ded at high speed without the remo~al of the plated layer. For instance, the following surface treated steel sheets ha~e been proposed: (a)Lightl~ tin coated steel sheet (LTS) with below about 1.0 8/~ of tin which is reflowed or unreflowed after tin plating (Japanese Patent Publication Nos.Sho 56-3440, Sho 56-54070, Sho 57-55800, and Laid-Open Japanese Patent Application Nos. Sho 56-75589, Sho 56-130487, Sho 56-156788, Sho 57-101694, Sho 57-185997, Sho 57-192294, Sho 57-192295 and Sho 55-69297). (b)Nickel preplated LTS with below about 1.0 g/~ of tin (Laid-Open Japanese Patent Application Nos. Sho 57-23091, Sho 57-67196, Sho 57-110685, Sho 57-177991, Sho 57-200592 and Sho 57-203797). (c)Nickel plated steel sheet with chromate film or phosphate film (Laid-Open Japanese Patent Application Hos. Sho 56-116885, Sho 56-169788, Sho 57-2892, Sho 57-2895, Sho 57-2896, Sho 57-2897, Sho 57-35697 and Sho 57-35698). (d)TFS-CT ha~ing double layers ~onsisting of a lower layer of metallic chromium and an upper layer of hydrated chromium o~ide which is obtained bY some special methods such as cold rolling after TFS treatment ~Laid-Open Japanese Patent Application No. Sho 55-48406), porous chromium plating (Laid-Open Japanese Pate~t Application ~o. Sho 55-31124) and a cathodic treatment of a steel sheet in chromic acid electrol~te with ~3 3L2~2~
fluoride but without anions such as sulfate, nitrate and chloride iun (Laid-Open Japanese Patent Application No. Shu 55-185~2).
Howe7er, LTS and nickel preplated LTS abo~e~ide~tified as (a) and (b) are slightly more e~pensi~e than TFS-CT.
Furthermore, these ha~e nat only narrower a~ailable current range for sound welding than that in tinplate, but also E3oor lacquer ac~hesioll compaLed with that in TFS-CT, although these can be welded without the remo~al of the ~lated lager.The reason why the a~ailable current range far sound weldingin LTS and nickel preplated LTS is narrawer than that in tinplate is considered to be that the amount of free tin in these is smaller than that in tinplate and alsa further decreases because of changes oF free tin ta iron-tin alloy by heating For lacquer curing. Nickel plated steel sheet with chromate Film or phosphate film abo~e-identified as (c) also has a narrawer a~ailable current range for sou~d weIding than that of LTS or nickel preplated LTS.
Furthermore, the corrosion resistance of nickel plated steel sheet is paorer than that of TFS-CT, although the lacquer adhesion oF nickel pl.aced steel shee-c is good.
Particularly, pitting carrosion in the defecti7e part aF the lacquered nickel plated steel sheet may occur easily fro~
acidic foods such as tomata juice because the electrache~ical potential ~f nickel is more noble tha~ that af the steel .~..~, . ,~.~.~
- 12~6 base and metallic chrulnillln.
It is callsidered that the welding of TFS-CT shown aba~e in (d) without the removal of the TFS-CT film at high speed is ~ery diFficult ~1ecause the o~ide films haYing high electric resistance ale farmed by the 03idation oF metallic chromium and e3posed steel base through the plating pores by the dehYdratioll of hgdrated chr-omium o~ide during heating far cnring the lactruer coated on the T~S-CT can bod~
although TFS-CT showll in (d) ma7 be welded ~hen it is not heated before !ielding.
As described abo~e variaus surface treated steel sheets propased in (a) (b) (c) and (d) ha~e ~ariaus problems in their productiG~I cost and their characteristics as a can material which can be easily welded without the remo~al of the plated layer at high speed.
Accordingl~ it :is an object of -the presen-t in7ention ta proYi~e a surface treated steel sheet ha~ing an e~cellent weldability that is easily being ~elded without the remo~al af the plated la~er at high speed and ha7ing e~cellent corrusiull resistance aFter lacquering such as TFS-CT .
It is ano-the.r objec.. oE ~he present invention -to pro~ide a metholl Fur the continuous production oF a surFace treated s~eel sheet ha~ing an e3cellent weldability.
.'' ~ .~
~ ccor(lirlg to one aspect of the present :invention, I:here is provided a surface treated s-tee].
sheet consistirlg of a steel base having three layers thereon in t~le following order: a bo-ttom layer of 30 to 300 nng/m2 of metallic chromium, a middle layer of .10 to 500 mg/nl2 oE metallic tin or 10 to 500 mg/m2 of tin-nickel al.loy containing 20 to 60 weight ~ of nickel and a top :I.ayer of hydrated chromium oxide of 2 to 18 rng/m2 as chroinium.
'~'lle l:>resent invention also provides, in another aspect: thereof, a process for con-tinuously prepar:ing a sur.Eace treated steel sheet consisting of a steel. base hav;ng thereon three layers consisting of a bottom l.ayer o~ metallic chromium, a middle layer of meta.l.].:ic t:in or t:in-nickel alloy and a -top layer of hydrated chromiurn oxide, which process comprises:
a) chromium plating a steel base to form a layer oE me-tal:l.ic chromium and a layer of hydrated chrom:iurn oxi.de thereon;
b) tin plating -the chromium plated steel base with a tin pl.ating solution having a pH of 0.5 to 3.0 and containing 2 to 10 g/l of stannous ion at a temperature oE 30 to 60C or tin-nickel alloy plating the chromium plated steel base with a tin-nickel plat:ing solution having a pH of 8 to 10 and containi.ng
More par-ticularly, the invention relates -to a surface treated steel sheet having three layers consisting of a bottom layer (layer closest to the steel base) oE metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer (layer farthest from the steel base) of hydrated chromium ox.i.de on a steel base, and to a production method of this surface treated steel sheet which is character:ized by tin pla-ting by using a -tin plating electrolyte havlng a low concentration of s-tannous ion or t:in-rl.i.clcel alloy plating by using a known tin-nickeL al.l.oy pl.ating electrolyte which has a low current eff:ic:iency or by tin or tin-nickel alloy plat:iny by using a known tin or tin-nickel alloy pl.ating electro]yte after a removal of hydrated chromi.um oxide ~ormed during chromium pla-ting by using an acidic soluti.on having a pH of 0.5 -to 2Ø
~ y using this surface treated steel sheet, a welded can body can be produced at high speed without -the removal of the plated layer in -the welded part.
Recent].y the change from expensive electro-tinpl.ates to cheaper tin free s-teel (TFS-CT) having double :layers consisting of a lower layer of metallic chromium and an upper layer of hydra-ted chromium oxide ~", as well as a decrease in the weight of the tln coating in elec-trotinplates has rapidly taken place in the field of food cans.
This is because the tin used for the produc-tion of t~nplate is very expensive and there is concern over the exhaustion of tin resources.
An ordinary metal can consists of two can ends and a sinyle can body, except for drawn cans. In the case of tinplate, the seaming of the can body is generally carried out by soldering. In this soldering process, however, i-t is impossible to decrease the weight of tin coating on the tinplate to under 2.8 g/m , because it is difficult to stabilize the solder-ing process when the weight of the -tin coating is under 2.8 g/m2. From the regulation of lead content in the solder used for the seaming of -the tinplate can body in the field of food cans, -the seaming of the -tinplate can body is widely carried out by electric welding.
A Iap seam welding, for instance, SO~DRONIC
(trade mark) process has been recently used for the seaming of the tinpla-te can body.
In this process, it is desirable to decrease the tin coating weight in the tinplate, but the weldabilLty oE tinplate becomes poor wi-th a decrease of the tin coating weight.
~ ~2669 On the other hand, -the seaming of a TFS-CT
can body is general]y carried out with nylon adhesives by using the TOYO SEAM (trade mark) and MIRA SEAM
(trade mar]c) method.
Another me-thod of seaming a TFS-CT can body by electric wel.d:ing is also well known. In the case of the seaminCJ oE a TFS-CT can body by electronic weld-ing, however, the metallic chromium layer and -the hydrated chromlum oxide layer must be mechanically or chemically removed from the TFS-CT surface in order to easily we:Ld the TFS-CT can body at high speed. There-fore the corrosion resistance in the welded part of the TES-CT can body becomes remarkably poor, even if this wel.ded part is coated with lacquer after welding.
Frorn the background described above, the development of a can material which is cheaper than tinplate and :is easily welded at high speed wi-thout the removal of the pla-ted layer, has been required in -the field of food cans.
Recentl~, ~arious surface treated steel sheets have been proposed as a can material which can be easily we]ded at high speed without the remo~al of the plated layer. For instance, the following surface treated steel sheets ha~e been proposed: (a)Lightl~ tin coated steel sheet (LTS) with below about 1.0 8/~ of tin which is reflowed or unreflowed after tin plating (Japanese Patent Publication Nos.Sho 56-3440, Sho 56-54070, Sho 57-55800, and Laid-Open Japanese Patent Application Nos. Sho 56-75589, Sho 56-130487, Sho 56-156788, Sho 57-101694, Sho 57-185997, Sho 57-192294, Sho 57-192295 and Sho 55-69297). (b)Nickel preplated LTS with below about 1.0 g/~ of tin (Laid-Open Japanese Patent Application Nos. Sho 57-23091, Sho 57-67196, Sho 57-110685, Sho 57-177991, Sho 57-200592 and Sho 57-203797). (c)Nickel plated steel sheet with chromate film or phosphate film (Laid-Open Japanese Patent Application Hos. Sho 56-116885, Sho 56-169788, Sho 57-2892, Sho 57-2895, Sho 57-2896, Sho 57-2897, Sho 57-35697 and Sho 57-35698). (d)TFS-CT ha~ing double layers ~onsisting of a lower layer of metallic chromium and an upper layer of hydrated chromium o~ide which is obtained bY some special methods such as cold rolling after TFS treatment ~Laid-Open Japanese Patent Application No. Sho 55-48406), porous chromium plating (Laid-Open Japanese Pate~t Application ~o. Sho 55-31124) and a cathodic treatment of a steel sheet in chromic acid electrol~te with ~3 3L2~2~
fluoride but without anions such as sulfate, nitrate and chloride iun (Laid-Open Japanese Patent Application No. Shu 55-185~2).
Howe7er, LTS and nickel preplated LTS abo~e~ide~tified as (a) and (b) are slightly more e~pensi~e than TFS-CT.
Furthermore, these ha~e nat only narrower a~ailable current range for sound welding than that in tinplate, but also E3oor lacquer ac~hesioll compaLed with that in TFS-CT, although these can be welded without the remo~al of the ~lated lager.The reason why the a~ailable current range far sound weldingin LTS and nickel preplated LTS is narrawer than that in tinplate is considered to be that the amount of free tin in these is smaller than that in tinplate and alsa further decreases because of changes oF free tin ta iron-tin alloy by heating For lacquer curing. Nickel plated steel sheet with chromate Film or phosphate film abo~e-identified as (c) also has a narrawer a~ailable current range for sou~d weIding than that of LTS or nickel preplated LTS.
Furthermore, the corrosion resistance of nickel plated steel sheet is paorer than that of TFS-CT, although the lacquer adhesion oF nickel pl.aced steel shee-c is good.
Particularly, pitting carrosion in the defecti7e part aF the lacquered nickel plated steel sheet may occur easily fro~
acidic foods such as tomata juice because the electrache~ical potential ~f nickel is more noble tha~ that af the steel .~..~, . ,~.~.~
- 12~6 base and metallic chrulnillln.
It is callsidered that the welding of TFS-CT shown aba~e in (d) without the removal of the TFS-CT film at high speed is ~ery diFficult ~1ecause the o~ide films haYing high electric resistance ale farmed by the 03idation oF metallic chromium and e3posed steel base through the plating pores by the dehYdratioll of hgdrated chr-omium o~ide during heating far cnring the lactruer coated on the T~S-CT can bod~
although TFS-CT showll in (d) ma7 be welded ~hen it is not heated before !ielding.
As described abo~e variaus surface treated steel sheets propased in (a) (b) (c) and (d) ha~e ~ariaus problems in their productiG~I cost and their characteristics as a can material which can be easily welded without the remo~al of the plated layer at high speed.
Accordingl~ it :is an object of -the presen-t in7ention ta proYi~e a surface treated steel sheet ha~ing an e~cellent weldability that is easily being ~elded without the remo~al af the plated la~er at high speed and ha7ing e~cellent corrusiull resistance aFter lacquering such as TFS-CT .
It is ano-the.r objec.. oE ~he present invention -to pro~ide a metholl Fur the continuous production oF a surFace treated s~eel sheet ha~ing an e3cellent weldability.
.'' ~ .~
~ ccor(lirlg to one aspect of the present :invention, I:here is provided a surface treated s-tee].
sheet consistirlg of a steel base having three layers thereon in t~le following order: a bo-ttom layer of 30 to 300 nng/m2 of metallic chromium, a middle layer of .10 to 500 mg/nl2 oE metallic tin or 10 to 500 mg/m2 of tin-nickel al.loy containing 20 to 60 weight ~ of nickel and a top :I.ayer of hydrated chromium oxide of 2 to 18 rng/m2 as chroinium.
'~'lle l:>resent invention also provides, in another aspect: thereof, a process for con-tinuously prepar:ing a sur.Eace treated steel sheet consisting of a steel. base hav;ng thereon three layers consisting of a bottom l.ayer o~ metallic chromium, a middle layer of meta.l.].:ic t:in or t:in-nickel alloy and a -top layer of hydrated chromiurn oxide, which process comprises:
a) chromium plating a steel base to form a layer oE me-tal:l.ic chromium and a layer of hydrated chrom:iurn oxi.de thereon;
b) tin plating -the chromium plated steel base with a tin pl.ating solution having a pH of 0.5 to 3.0 and containing 2 to 10 g/l of stannous ion at a temperature oE 30 to 60C or tin-nickel alloy plating the chromium plated steel base with a tin-nickel plat:ing solution having a pH of 8 to 10 and containi.ng
2 to ~0 g/l of stannous ion, 4 to 20 g/l of nickel 6~
:ion, 0.1 to 3 concentra-tion ratio of s-tannous ion to nickel. ion, 8() to 300 g/1 oE an alkali metal pyrophos-phate at a -tennperature of 40 to 60C; and c~ formi.ng a layer of hydrated chromium oxide on the lin or -tin-nickel plated, chromium plated s-teel base o~ s-tep b) by a cathodic treatment in a hexavalent chroln:ium contai.ning solution at a tempera-ture of 30 to 70C.
AccordiJIg to another aspect of -the inven-tlon, there is provided a process for continuously preparing a surEace treated s-teel sheet consisting of a steel. base l~aviny thereon three layers consisting of a bottom layer of metallic chromium, a middle layer of metal].i.c tin or tin-nickel alloy and a top layer of hydrated chrc)tn.iulll oxide, which process comprises:
a) chromium plating a steel base to form a layer oE metal:lic chromium and a layer of hydrated chromium oxi.tle thereon;
b) EemOving the hydrated chromium oxide formecl on the cl~romium plated steel base by a cathodic treatment in an acidic soLution having a pH of 0.5 -to 2.0 at a temperature of 30 -to 70C;
c) tin plating the chromium plated steel base wi.th a t.:in pl.ating solution having a pH of 0.5 to
:ion, 0.1 to 3 concentra-tion ratio of s-tannous ion to nickel. ion, 8() to 300 g/1 oE an alkali metal pyrophos-phate at a -tennperature of 40 to 60C; and c~ formi.ng a layer of hydrated chromium oxide on the lin or -tin-nickel plated, chromium plated s-teel base o~ s-tep b) by a cathodic treatment in a hexavalent chroln:ium contai.ning solution at a tempera-ture of 30 to 70C.
AccordiJIg to another aspect of -the inven-tlon, there is provided a process for continuously preparing a surEace treated s-teel sheet consisting of a steel. base l~aviny thereon three layers consisting of a bottom layer of metallic chromium, a middle layer of metal].i.c tin or tin-nickel alloy and a top layer of hydrated chrc)tn.iulll oxide, which process comprises:
a) chromium plating a steel base to form a layer oE metal:lic chromium and a layer of hydrated chromium oxi.tle thereon;
b) EemOving the hydrated chromium oxide formecl on the cl~romium plated steel base by a cathodic treatment in an acidic soLution having a pH of 0.5 -to 2.0 at a temperature of 30 -to 70C;
c) tin plating the chromium plated steel base wi.th a t.:in pl.ating solution having a pH of 0.5 to
3.0 and containing 2 to 40 g/l of stannous ion at a temperature of 30 to 60C or -tin-nickel alloy plating sol.ution }~aving a pH of 8 to 10 and containing 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to ~2~2669 :~ concell~ra~ ratio of stannous ion to nickel ion, 8() to 3~0 q/l of an a:lkal.i metal pyrophosphate at a telnpe:rature oL~ 40 to 60C; and cl) rorllling a layer oE hydrated chromium oxide on the lin or tin-nickel plated, chromium plated slee:]. base o:r .sl-ep c) by a cathodic treaT..ment in a hexavalent cllrom;um containing solution at a tempera-ture o:E 30~ .o 70C.
'L'l-le su.rface -treated steel sheet according -to the present :invention can be used in application such as food can boclies, aerosol can bodies and miscella-neous carl i~od.ies which are lacquered, except for the part. to be weldecl, wherein excellent weldability, i.e.
being easil.y wel.ded without the removal of the plated 1ayer at hi CJh speed, is required.
The surface treated steel base according to the present invention can be also used in applieations wherein the lacquer coating is not carried out because it has exce]:lent weldability. Fur-therrnore this surface treated stee:l sheet can be used in applieations wherein exeellent eorrosion resistance after lacquer-ing are required, such as can ends, drawn cans and drawn and redrawn cans ~DR cans), besides ean bodies.
'l'ne steel base used for -the produc-tion of the surace treated steel sheet aceording to the present invention can be any cold rolled steel sheet customariLy used :in manufacturing electrotinplate and TE'S-CT. l'referably, a -type of steel base for electro-- ~2~ 9 tinpl.ate, as set ou-t in ASTM ~ 623-76 of 1977 (Stan-dard specifi.cat:ion for general requirements for tin mill produet), :i.s employed as the steel base. Prefer-abl.y, the th:icJcness of -the steel base is from about ().l to ahoul: 0.35 mrn.
'I`he su:rEace -treated s-teel sheet aeeording to the present invention is produeed by the following proeesses:
(.l) de~Jreasing with an alkali and piekling wi.th an a(id -_~ water rinsing -~ ehrom:ium plating wat.er .insirlg --~ tin or tin-nickel alloy plating wa'cer rinsing -~ ch.^o.nace 'creacment-~ wa'cer rinsing ~drying, or;
(2) degreasing with an allcali and pickling with an ac;d > water rinsing > chromium plating ->water :ri.ns-irlcl-->removal oE hydra-ted chromium oxide by eathodie l-reatment in an acid so`lution -~water rinsing _~ tin or tln-n.ickel alloy platiny -~ water rinsing >chromate -t.reaclrlenc -~ water rinsing~ dring.
By using the above processes (l) and (2), three l.ayers consisting of a bo-ttom layer oE metal.lic chromi.um, a middle layer of metallic tin or -tin-nickel alloy and a top layer of hydrated ehromium oxide are forrmed C)ll a stee:l base. In -the present invention, -the amount of each layer is very impor-tant in order -to obtain an e~cel.lent weldability, whieh is an objeetive of the present :invention.
~ 2~6~
At r irsl,, the amount of metallic chromium w11ich is t1~e i)c~ o111 layer in the surface treated steel sheet, accordir1g 1:~o the present invention, should be cor1l,ro'l1.ed i~ e range of 30 to 300 mg/m2, more preferabLy '1() l.o 150 mg/m . If the amount of metallic chromium :is bel,ow 30 mg/m2, the excellent weldabili-ty and excel.le11t corrosion resistance are not obtained because it is considered that the surface of the steel base is not suEficiently covered with the plated metal1,i.c chro1nililr1 and a greater part of the following plated 1-in or t:in-nickel alloy changes to iron-tin al:1.oy or iron-li.rl-nicke1 a]loy having high electric resistance duriny heating for lacquer curing. The arnount of meta'1.:1,ic chromium is ]imi-ted to 300 mg/m frorn an econol11ical and an industrial point of view, al.thou~h the oxi.dation of a steel base and the forma-tion of iron-ti.r1 alloy or iron-tin-nickel alloy during heating are prevented with an increasein the amount of metallic chrornium.
Secondly, the amount of metallic tin or tin-nic1~el alloy beiny a middle layer in the surface treated steel sheet according to the present invention shou1.d be controlled in the range of lO to 500 mg/m2, more preferably lO to 150 mg/m2. If -the amount of metal.]l,c tin or tin-nickel alloy plated on the metal-lic chrornium plated steel base is below lO mg/m2, excell.ent wel.dability is not obtained, because chro-rnium oxide having high electrical resistance is formed 66~3 by the oxida~-ion of metallic chromium during heating ror lacquer curing, even if the oxidation of a steel i)ase is prevenled by the sufficient amount of me-tal]ic chromium. ~rile amount of the plated -tin or tin-nickel a'l'loy is 'limil-e(l to 500 mg/m2 from an economical point of view, a~tho~lgh the effect of metallic tin or tin-nickel all,oy in the present invention does not chanye at, above 500 mg/m2.
In ~ e present invention, tin-nickel alloy does not, a:l,ways mean tin-nickel alloy having stoichio-metrical, cortlposil,ion with a cons-tant ra-tio of tin to nicke'l sucl~ a~ NiSn, Ni3Sn, Ni3Sn2 and Ni3Sn4, but mean.s -tl~e co-deposi-tion of tin and nickel having various rali()s Or tin l,o nickel. However, ,i-t is said that co-del)o~si~e(l tin and nickel Eorm tin-niclcel alloy at a room temE~erclture or during heating.
In the case of tin-nickel alloy plating on the chrotlliu~n pLated steel base, -the nickel content is preferably 20 to 60 weight % based on the total weight of plated tin and nickel. Although the weldability decreases slightl,y with an increase in the co-deposit-ed nic]cel, content in the pla-ted tin-nickel alloy, the surface treatecl steel sheet according to the present invention, wherein -tin-nickel alloy is plated on the chromium p,],ated steel base, also has an excellen-t weldabilily conlpared with that of TFS-CT. At above 60 weight % or below 20 weigh-t % of nickel in the tin-nickel alloy, the weldability and the corrosion ~' 12 : " ~2~26~
resistance ale exce].lent comparecl wi-th tha-t of TFS-CT.
Elowever, il is diEicult to stably plate tin-nickel alloy having bel.ow 20 weight % and above 60 weight %
of nickel. on the chromium plated steel base by using a ti.n-nickei alloy p1ating eleetrolyte, beeause niekel content or lin content in the tin-nickel alloy changes greatly wi.tl-l a sl.ight change in the plating condi-tions.
Particularly, the surface treated s-teel sheet accorcling to the present invention, wherein tin-nic1ce:1. alLoy is plated on the ehromium plated steel. base i.s charaeterized by exeellen-t corrosion resistance to sul.fide stains, which may often appear in the inside of the ean when some oods eontaining protein such as fish and mèat are paeked in the lacquered t:i.npl.ate can, unlaequered tinplate can and lacquered nickeL plated s-teel ean.
Various methods for making an alloy or eo~depos:itions layer such as the co-deposition of tin and z.inc, the co-deposition oE tin and eobalt, niekel pl.ating after tin pl.ating, tin plati.ng after niekel p].ating, zinc plating after tin plating and -tin platincJ after zinc pla-ting on the chromium plated steel. base have been considered in order to obtain a surEace treat.ed steel shee-t having an excellent wel.~abilily, blll- these methods are not suitab].e for the prc>ductic>rl of the surface treated s-teel sheet 66~
having excellerlt weldabili.-ty, because of the complexi-I:y of the process or because a special electrolyte is required.
As described above, the presences of me-tal-lic chrorni Ulll as a bottom layer and metallic tin or tin-ni.ckel. al.loy as a middle layer in the surface treated steel sheet according to -the present invention are indispellsable in order to realize excellent weldab;.l.ity aller heating.
13a ~2~6Çi9 Furthermore, in the present invention, the presence of a small amount o hydrated chromium oride as a top layer is indispensable in order to preYent the o~idation of the e~posed steel base and the e3posed metallic chromium after tin or tin-nickel alloy plating during heating for lacquer curing and to obtain e~cellent corrosion resistance and e~cellent lacquer adhesion.
The optimum range of hydrated chromium oxide is from 2 to 18 mg/~ , more preferably 4 to 12 mg~m2as chromium.
If the amount of hydrated chromium oside is belo~ 2 mg/m2 as chromium, the corrosion resistance and the lacquer adhesion become PoOr. If the amount of hydrated chromium o~ide is abo~e 18 mg/m2, the weldability becomes remarkably poor, because hydrated chromium o~ide changes to chromium o~ide having high electric resistance by deh~dration of it during heating for lacquer curing.
The conditions for each process in the production of the surface treated steel sheet accordin~ to the present invention are shown in detail.
At first, in order to form a metallic chromium layer as a bottom layer on the surface treated steel shéet according to the present invention, a known chromium plating electrolyte such as Sargent bath or a chromic acid electrolyte, containing additives such as fluorine compounds, which are used for ~he production of T~S-CT having 12~66~3 , a lower layer of metallic chromium and an upper la~er of hydrated chromium o~ide, may be employed.
In the present inYention, it is preferable to emplo~ the following electrolytic chromium plating conditions for the formation of a metallic chroDium la~er on a steel base:
Concentration of chromic acid: 30~ 300 g/l, more preferably 80~ 300 g/l Concentration of additi~e: 1.0~ 5.0, more preferably 1.0 ~ 3,0 weight % of concentration of chromic acid Additives: at least one compound selected from the group consisting of fluorine compounds and sulfur compounds Temperature of the electrolyte: 30~ 60 Cathodic current density: 10~ 100 A/d~
Generally, the amount of hYdrated chromium o~ide formed during chromium plating decreases with an increase in the concentration of chromic acid in the suitable weight ratio of additi~es to chromic acid. It is not preferable to use an electrolYte ha~ing below 30 g/l of chromic acid for the chromium plating, because the current efficiency for the deposition of metallic chromium decreases remarkabl7. The concentration of chromic acid abo~e 300 g/l is not also suitable from an econo~ical point of ~iew.
The presence of additives such as fluorine compounds and sulfur compounds in the chromium plating-electrolyte is indispensable for uniform chromiu~ depositiun. If the 6~
~eight % af additi~e.~ ta chromic acid is below 1.0 or abo~e 5.0, the CU rrent eFFiciellcy for the dePosition of metallic chromium remarkablY decreases, besides a decrease in unifarmity of the dePusited metallic chramium layer.
Particularly, at below 1.0 weight ~ of additi~es to chromic acid, the formed insoluble hydrated chromium o~ide remarkabl~
pre7ents the formatiall oF uniform metallic tin or tin-nickel alla7 la7er in the Fallo~itlg tin or tin-nickel plating.
[t is preferable that the additi~es be at least one compaund selected From the grouP consisting oF fluorine compound such as h~droFluoric acid, Fluaboric acid, fluosilicic acid, ammonium bifluoride, an alkali metal biFluoride, ammonium Fluorlde, an alkali metal fluoride.
ammunium Fluotarate, an alkali metal fluoborate, ammonium fluasilicate, an alkali metal fluosilicate, aluminum fluoride and sulFur compound such as sulfuric acid, ammonium sulFate, an alkali metal sulfate, chromium sulFate, aluminum sulFate, phenolsulFonic acid, ammonium phenalsulFonate, an alkali metal phenolsulfonate, phenoldisulfanic acid, ammoniut~
phenoldisulfonate, an al~ali metal phenoldisulfonate, ammonium sulfite, an alkali metal sulfite, ammanium thiosulfate and an all~ali metal thiosulfate.
The amount aF hydrated chromium o~ide Formed during chromium plating decreases with an increase in the temperature oF the electralyte. The temperature of the ~ ~266~
, . , electrolyte abo~e 60~ is not suitable from an industrial point of view, because the current efficienc~ for the dePosition of metallic chro~ium decreases remarkabl~. The tempeTatUTe of the electrolyte belo~ 30~ is not also suitable because a long time is necessary for the removal of the laTge amount of hydrated chromium o~ide formed during chromium plating.
With an increase in a cathodic cuTrent densitY, the curTent efficiency for the deposition of metallic chromium increases and the amount of hydrated chromium o~ide formed during chromium plating decreases. It is suitable in the present invention that the range of the cathodic current density for the dePosition of metallic chromium is 10 to 100 A/d~ , more preferably 40 to 80 A/d~ , because metallic chromium almost does not dePosit at below 10 A/d~ of the current densitY and the cuTrent efficiency for the deposition of metallic chromiu~ almost does not increase at above 100 A/d~ of the current density.
In the present invention, the conditions for chromium plating wherein a good CurTent efficiency for the dePosition of metallic chromiu~ is obtained and a small amount of h~drated chromium oxide is formed, should be seleted because the presence of hYdrated chromium o~ide prevents the formation of a uniform tin or tin-nickel alloy layer in the follo~ing tin or tin-nickel alloy plating.
~L2~266~3 ,, Howe~er, h~drated chromiu~ o~ide is always formed on a deposited metallic chromiu~ layer during chromium plating.
Under the conditions of higher concentration of chromic acid, higher current density and higher temperature of the electrol~te, the amount of h~drated chromium o~ide formed on the dePosited metallic chromium is about 3 to 10 mg/~ as chromium. On the contrar~, under the conditions of lower concentration of chromic acid, lower current densitY and lower temperature of the electrolyte, it is about 10 to 50 mg/~ as chromium.
When a large amount of hYdrated chromium 02ide is formed during chromium plating, it is possible to decrease it by lea~ing the chromium plated steel base in the chromium plating electrolyte for a few seconds. Howe~er, hgdrated chromium oxide of about 3 to 5 mg/~ as chromium remains on the surface of the chromium plated steel base, eYen if the chromium plated steel base covered with hydrated chromium o~ide is left in the the chromium plating electrolgte for a long ti~e.
In the present invention, such hydrated chromium oxide must be remo~ed before the subse~uent tin or tin-nickel alloy plating because the presence of hydrated chromium oside pre~ents the deposition of a uniform tin or tin-nickel alloy layer on a metallic chrowium la~er.
The follouing methods are considered suitable for the 2~669 removal of hydrated chromiu~ o~ide on the deposited metallic chromium la~er.
(A) An immersion of the chromium plated steel base, before drYing, into a high concentration of an alkaline solution such as an alkali metal hydroxide and an alkali metal carbonate at high temperature of 70 to 90 C. It is difficult to industrialize this method because the alkaline solution may be mi~ed into the following tin or tin-nicXel alloy plating electrolyte.
(8) An immersion of the chromium plated steel base before drYing, into an acid solution such as sulfuric acid and hydrochloric acid. This method is not suitable in the present inVentiDn, because hydrated chromium o~ide formed during chromium plating is nct sufficiently dissolYed by an immersion into acid solution for a short time.
(C)A mechanical remo~al of hydrated chromium o~ide by a brushing roll or wiper in an alkaline solutinn or an acid solution before drying the chromium plated steel base. The hydrated chromium o~ide formed on the chromium plated steel base is not uniformlY re~o~ed b~ this method.
Therefore these methods such as (A), (B) and (C) are not suitable for the remo~al of hydrated chromium o~ide before the following tin or tin-nickel alloy plating.
In the present in~ention, the following methods are preferable for the remo~al of hydrated chromium o~ide formed on the metallic chrumium layer. One is the method wherein the chr(]mium plated steel base is cathodicallY treated in an acid solution such as sulfuric acid and h~drochloric acid ha~ing a pH of U.5 ta 2.0 before tin or tin-nickel alloy plating. The other is the method wherein tin or tin-nickel alloy plating is carried aut at the same time as ~he remo7al of hYdrated chr(lmiu~ ozide Formed on the metallic chromium layer by using a tin plating electrolyte ha7ing a low c~ncentration oF stannous ion or a tin-nickel allo~
plating electrol~te l~ v i m~ a low curren. ef f iciency.
The conditiolls For the remo~al of hYdrated chromium o~ide by the former method are as follows:
Electrol~te: ~n acid solution containing at least one acid selected From the group consisting of sulfuric acid hydrochloric acid hydrofluoric acid fluoboric acid and fluosilicic acid ha~ing a pH of 0.5 ta ~.0 Temperature of the electrolyte: 30~ 70C
Cathadic current densit~: 2~ 50 AJdr~
Treatin8 time: 0.5 ~5.U seconds Although the main component in the elctrolYte is acid such as sulfuric acid and hydrochloric acid~ if the pH of the electrolyte is kept between 0.5 to 2.0 various ions which are not dePosited Oll the surface of the chramium plated steel base or do not o~idize the surface of the chromium ~ .
~ ~2 ~6 ~
plated steel base, can lle contairled in the electrolgte. It is nat necessar~ that the temperature af the electrol7te be strictlg contralle~ if it is kept betueen 'JO to 70~ .
If the temperature of the electrolgte is aba~e 70 ~ , the e~aporation of water is increased. At belnw 30 ~ a cathadic treatment far a long time is required far the sutficient remo~al of hgdrated chromium agide.
In below 2 A/dl~ of current densit~, hgdrated chromium a~ide is nat sufficientlg remoYed, e~en if the chromium plated steel base is cathodicallg treated for a long time.
upper limit of current densitg is limited to 50 A/d~
because the effect of the present in~entian is nat increased at a curreilt densitg abn7e 50 A~drr~.
If the treating time is below 0.5 seconds~ hgdrated chramium ogide is not sufficientlg remo~ed fram the metallic chromium lager, e~en if the higher current densitg is applied.
The treating time abo7e 5 0 seconds is not suitable in the high speed productiall af the surface -~rea~ed s~eel s~eet according tu the present in~ention.
The conditians for the latter method wherein tin or till-; nickel allog plating is carried out at the same time as -~he remo~al of hydrated cilromium oxide formed an tbe metallic chramium lager is as follows:
In tin plating, the follouing conditians are preferable.
Cancentratian of stannaus ian: 2~ 10 g/l ..~ ~
~..~
.
~2~266~1 11 oF the ~ oL r nlyte: 0.5~ '1.0 I'emperature uF the electrolyte: 30~ 60~
- (;athadic lullellt densit~: 3 ~ 50 A/d~
Gellrrallg, a tin l~latillg electrol7te such as a etannous sul-fate n~lti~ and stamm(:~m.~ .ides ~ath ~laving abo~t 20 to 40 g/l of SCam(10m~ m iS mse-,l t()~ lf` iilclus~.-ial. p~o~uction of ~lectro~in-p~ . rt i~ a~ t~les(~ atillg eLectro:Ly-ces ~e used fol tin platin% on the chromium plated steel base without the remo7al oF h7dlal:e(1 :!lromium o~ide Formed during chromium platill~, iTI the lattel metllnd, because a uniForm tin layer is not Formed nn the chlomiu~ plated steel base and the coarselg antl deudritically plated tin mag be peeled off from the chromium plated steel tlase, although these tin plating elec.r.olyr~ can be use(l Fnr tin plating after the remo~al of hYdrated chrnmium o~i~le nll the chromium plated steel base by a cathodir, treatment in .arl acidic solution.
~ n latter m~tho(l, tin plating with the retroval of hsLllated chramillm ngi(le Formed during chromium plating is characterized hy the use oF tin plating electrolgte ha~ing a low concentratinll nF stannous ion such as 2 to 10 g/l.
namel7 ha~ing a low c~Lrrerlt efficiencg.
The reason whg a uniForm tin la~er is not Formed on the chromillm platell steel base b~ using a known tin plating electrolgte ha7ill2 a hi<~ll concentratian of stannous ion is ,,~i',, '.l 3 Z~ 69i `
that a greater part in Lhe quantit7 of electricity is cansumed for the dePosition nf tin, but a lesser ~art for the remo~al of h~drated chromium u~ide.
Therefore it is desirable to decrease the conce~tration of stannous ian to below 10 g/l in the present inPentiO~ in order to obtain an uniform ti~ laYer on the chromium plated steel base.
lluwe7er, the concentration of stannous ion belo~ 2 g/l is not suitable in the presrlt in~ention. because the curre~t efficiency For the deposition of tin decreases remarkablY and becomes unsuitable tlue to by the ~resence of a small amount of ions such as chromium ion a~d iron iOII which buiId up in the electrolyte by a dissolution of th.e hydrated chromium o~ide and the steel base.
Sta~nous iOII is maiml7 supplied by the addition of stan~olls sulfate, stannous chloride, stannous fluoride and sta~nous fluoborate or by the dissol~tion of a soluble ~i~
anode.
The p~ oF the electrolyte is also ~ery important for tin plating 011 the ch10mium plate~ steel base with the remo~al ot hydrated chromium 03ide formed duri~g chromium plating. The pH range of the electrolyte should be from O.S to 3.0, preferabl7 U.5 tu 1.5 in the stannous sulfate bath containing sulfuric acid or phenulsulfonic aci~ or preferablg 2 to 3 in the s~annol1s llalides bath containing scannous chloride, sodium 1~ ~2~6 ~
fluoride. ~utassium bifluoritle and sodium chloride.
At a low pll such as ().5 to 3.0, the surface of the chrornium plated steel base is uniFor~ls acti7ated because h~drated chromium o~ide Formed during chromium plating is easil.7 remo7ed Fram the chromium plated steel base with the eYolution of a large am o unt nF hy(Lrogell during dissolving by acid Therefole a uniform metallic tin layer is Farmed on the metallic chromium laser. The pH of belo~ 0.5 is not desirable in the present in7ention, because a part of metallic chrnmium ma7 be dissol7ed. ~ pH of abo7e 3.0 is not also desirable because a ul~iform tin layer is not formed on the metallic chromium la7er by the insufficient dissolution of h~drated chromium Far a short time. Furthermare it is difficult to stably produce the surface treated steel sheet accor~ing to the present in~ention because the pH of the ; elctrolyte changes greatl7 by a slight change in the concentration of stanllous ian and acid.
The pH of the electrolyte is mainly controlled by the addition of sulfuric acid, phenolsulfonic acid, hgdrochloric acid, hydrofluoric acid, fluoboric acid, fluosilicic acid a~d alkali metal salts thereoF. Variuos ions, ~hich do not gi~e bad effects in tin plating and in the dissolution of hYdrated chromium o~ide, mag be cosltained in the electrolgte, if the ~H
of the electrol~te is kept in the range of from 0.5 to 3Ø
AdditiYes such a etho~ylated a -naphthol sulFonic acid, 2 ~
.~
~2~L2~i69 ethog71ated ~-naphthol, ~ ~naphthol and gelatine ~hich are used in a knowll tin platiIlg electrolyte such as stannous sul-Eate ~atl-~ or s~annou~ hcll:icles ba-tn for the pro~uction of electro-~inpla~e Cdll ~e use-i ~or l:he improve.nent of the uniformity of ~he pldled rin ~ayer im t:~le present invention.
It is suitable i~l the present in~ention that the range of the cathodic current density is 3 to 50 A/d~ , core preferabl7 10 to 30 A/dnf. If the current densitg is belou 3 A/-lm~, the current efficiencg far ti~ plating becomes so low that a long time is necessarg for the dePosition of the required amuuItt of tin. If the current densitg is abo~e 50 A/dm', a tin laYer l~a7ing an e~cellent adhesio~ to the chromium plated steel base is not obtained.
The optimum range fur the temperature of the electrolgte is From 30 to 60~G, mcre preferabl7 30 to 50~ . At below 30 ~C, hydrated chromiuln o~ide is not dissol7ed sufficientl~, so that the uniform tin laYer is not plated on the chromium plated steel base. At abo~e 60C , a part of metallic chromium is dissol 7 ed with the dissolution of hgdrated chromium o~ide.
; In tin-nickel allog plating ~ith the remo~al of hgdrated chromium o~ide Eormed during chromium plating, the following two tgpes of the electrol~te are used. The first tgpe oF the electrolyte is pyrophosphate bath co~sisting of an alkali metal pyrophosphate, stannous chloride, nickel chloride and . :
~2~6~9 .
additi7es. The secolld type of the elctrolyte is a halide bath cullsisting of stanllalls t~alide, nickel halide, an alkali metal ~a~lcle .ll~d .-additives.
it is suitable to emplay the following eonditions for tin-t3 i c kel alloy plating W'lt?l~ usirlg the f i rs~ type of -the electrol7te:
Concentration oF stannous ion: 2~ 40 g/l Coneentration cf nickel ion: 4~ 20 g/l Coneentratian ratio af stannous ion to niekel ion:
0.1 ~ 3 Concentration of an alkali metal pYroPhosphate:
80~ 300 g/l pH of the electrol~te: 8~ 10 Temperature oF the electrolYte: 40~ 60 Cathodic current densitY: 1~ 30 A/dr~
It is suitable to e~ploy the following eonditions far tin-~iekel alloY plating wnen using the seeond cype o~ the eletrol~te:
Coneentration oF stannous ion: 2~ 70 g/l Cancentration oF nickel ion: 4~ 80 g/l Coneentration ratio oF stannous ion to nickel ion:
0.1~ 0.8 pH of the electrolYte: 0.5~ 3 Temperature oF the electrolYte: 30~ 60 Cathodic current densitY: I ~ 30 A/dr~
~ 2~66~3 In tin-nickel al luy plating on the chromium piated steel base with the remo~al of hydrated chromium 02ide bg using alkaline pyraphosphate bath or acidic halides bath, it is ~erY
important that the caucentration ratio of stannous ion to nickel ion be kept withill the range described abo~e in order ta abtain a uniform tin-llickel allay lager containin8 20 to 60 weight ~ af nickel on the chramium plated steel base.
~ rll tin-nickel al loy plating, generally the nickel content increases under the conditions of higher current de~sitY, lower temperature of the electrolYte, lower concentrations of stannous ion and nickel ion, lower corlcentration ratio of stannous ion and nickel ion, lower concentration ratio of stannous ion to nickel ion and higher p~l af the electrolYte.
~ t below the lower limit of the cancentration of stannous ian and nickel ion, the current eFficienc~ far the co-deposition af tin and nickel decreases remarkabl~. The concentration oF abo~e the upper limit of stannous ion and nickel ion is not suitabie frum an ecorsomical point of ~ie~, because the dray out loss af stannous ian and nickel ion increases. Furthermore, if the conceDtration ratio of stannaus lan to nickel ion is below the lower limit ar a'aa~e the upper limit, it is difficult to plate tin-nickel alloy ha~ing 20 to 60 weight % af nickel on the chromium plated steel base.
StannollS ion and nickel ian are mainly supplied by the ~ 26~i9 addition aF stanltulls chlaride and nickel chlaride or b~ the dissolution of a saluble tin anode and nickel anode, respecti~el,7.
The pll af the electr(ll7te is mainl7 controlled by the addition of h7drochlaric acid and alkali metal chloride in acidic llalogen bath anll by the addition of pyrophosphoric acid, alkali metal pyrophosphate, hYdrochloric acid, alkali metal chloride and alkali metal h7dro 3 ide in alkaline pyrophosphate bath.
Additi7es such as glYcine and ethglene glgcol which are used in a known tin-nickel alloy plating electrolyte can be also used for the impro7ement of the u~iformity of the plated tin-nickel allo7 layer in the present in~ention.
Cathodic treatment in an acidic salution ha~ing pH 0.5 to 2.0, tin or tin-nickel plating with the remo~al of hYdrated chromium 02ide ~ormed during chromium plating described abo~e are also applie~ for the dried chromium plated steel base under the same canditions described abo7e.
~ n the case uF tin ar tin-nickel allo.7 plating after the remo7al of hydrated chro~ium 02ide by a cathodic treatment i~
an acidic salution, tin or tin-nickel plating is also carried out by using the same electrolyte and the same plating cunditions ~escribed abo7e.
Tn this case, a knawn tin plating electrol7te such as a stannous sul.Ea~.e bal-h and stanrlous halides bath having high concentration of :~"~
~,..~
~2~L~6~9 stannuus il~1n, for ill;tallce, stamnous sulfa-te bath consis~ing oE
30 g/l o r ~ ,amllous ~m I f'.,li-e (as scannous ion), 30 g/l of pheno~
s~llfomi( m~-id (~ ?Iml~ lOn) dnd ~ g/L of e~hoxylate ~-naphtol sulf~ mi;l~)c stc~ m;ilalides ba-t~ consisting of 3~ g/l of stanntllls chloride (as stannaus ion), 30 g/l of sodiu~
fluori~le, 50 g/l of sullium chluride and 3 g/l af gelatine can be usell far tin plating after the remo~al of hydrated chrnmium o~ide nn the chromium plated steel base.
~ or the formation oF h7drated chromium o~ide layer being a top laler of the surface treated steel sheet according to the present in7entiou. a knnwll electralgte such as the acidic cllrumate electrol7te use(l For the past-treatment af electrotinplate ul a rllramic acid electralYte cantaini Dg a small amaullt nf additi~es such as Fluorine campollnd and sulfur campound which is use(i far the pra~uctian of rFS-CT ha~ing a Iower lager of metallic cllramium and an upper layer of llydrated chramium oxi(le, may be emplaYed.
in the present in7entian, t~a tgpes af the electrolgtes are used for the furmatiarl af hydrated chramiu~ a~ide. The first type af the electrolyte consists af an acidic chromate electralyte withaut a~ition of additi7es 5 uch as fluarine compaunds and sulfllr compounds. The second type of the electrol7te cnnsists of chrùmic acid electrolYte with additi7es such as flunrille compounds and sulfur ccmpaunds.
It is suitable to emplay the Following conditians for the ,. 3 ~
formatian af hYdrate(l chromium atide of 2 to 18 mgJ~ as chromium b7 using the first type of the electrolyte:
Cancentration of he2a7alent chramium ion: 5 ~ 30 g/l Temperature oF the electrolyte: 30~ 70 Cathudic current density: 1 ~ 20 A/dr~
Quantit7 of electricity: 1~ 40 coulombs/d~
~f the concentratian of hega7alent chromium ion is below S g/l, a waste af electric power occurs because af the higher electrical resistance af the electrolyte. The concentration of he3a7alent chromium ion is limited to 30 g/l fram the 7iewpoint of conser7ing resources, although the efFect of the present treatment is not decreased in a concentration abu7e 30 g/l.
It is an essential condition that the electrolyte should be acidiFied. ~n the case oF alkaline electrolYte, the efFiciency For the Formation of hydrated chromium oside is so lou that a long time is necessary for the farmation of satisfactory hydrated chromium n~ide. Therefore the electrolyte containing only a chromate of an alkali metal ~r ammanium is not used in the present in7ention.
In the abo7e case it should be acidified b-y the addition of chromic acid. it is also possible to add a hydro2ide of an alkali met~l or ammonium to chromic acid electrolYte within an acid range.
ThereFnre, at least one chromate selected From the group :
~ 66 ~
consisting oF chromic acid, a chromate and dichromate of an alkali metal, ammollium chrnmate ~nd ammonium dichrooate is used for the first t7~e of the electrol~te within an acid range in the present in~rerltion. It is ~ot necessarY that the temperatllre of the elertrolyte be strictl~ cantrolled if it is kept between 30 to 70 ~ .
Lf the temperature of the electrolyte is abo~e 70~', the e~aporation of uater i5 illCreaSed.
Under a current densitY below I A/dm~, a long time is necesszrg for the formation of a satisfactory hYdrated chromium o~ide. Under a current densit~ abo~e 20 A/d~ , the control in the amnunt of the formed hydrated chromium oxide may be difficult. although a saiisfactory hydrace~l chrom:i u~n ox.i rle i.s formed by a cathodic tLeal-.lnerlc :Eor ~ Si~ol-t: u ime.
Lf the quantity of electricitg is below 1 coulo~bs/d~ , it is difficult to form a suitable amount of hYdrated chro~ium o~ide. At abo~e 40 coulombs/d~ of electricitY, the weldability of the surface treated steel sheet accarding to the present in~ention becomes poor because of the formation af thicker hydrated chromiu~ o~ide.
[t is desirable to emplog the follo~ing conditions Far the Formatian of hydrated chromiur~ 03ide by using the second type of the electrulyte:
~ 2~266~
Concentration of cllromic acid: 10 ~ 50 g/l '~eight % of additi~es to chromic acid: 0.2~ 1.0 Additi~es: Sulfur compound and/or fluorine compound Temperature oF the electrolgte: 30~ 60 Cathadic current densit~: 1 ~ 1~ A~d~
Under the conditians described aboqe, ~eight X of additi~es to chromic acid and current densitg are ~er~
important in the present treatment, because at a higher weight percent of additi~es to chromic acid and higher curre~t densitY, metallic cllrumium, which imparts a bad effect to the weldability, is dePosited on the tin or tin-nickel allo~ plated steel base.
r herefcre the weight percent of additi~es to chromic acid is limited to 1.0 ~s a maximu~ and a cathodic curren-t densi--ty :iS .] imited ro :I.U ~/dnl2 . However, if -the weight percent of additi~es to chromic acid is below 0.2. the weldability becomes poor because thick hYdrated chromium 03ide is formed. Under current densitg below I A/d~ , a long time is ~ecessarY for the formation o~ Q satisfactorY hYdrated chromium 03ide.
Furthermare, the ranges in the concentration of chromic acid, the quantity of electricity and the temperature of the electrolyte are limited as in the first type o~ the electrolgte forthe same reason.
Additi7es are also selected from the same graup as in the chromium plating electralyte.
266~
In the treat~ent using the second type of the electrolyte, it is ~ery i~portant to select the conditiuns wherein ~etallic chromiu~ is not deposited on the tin or tin-nickel alloy plate surface. Howe~er, under so~e conditions wherein ~etallic chromium is dePosited, ma~i~u~ amount of metallic chro~îum should be limited to 10 mg/~ , although the amount of the dePosited metallic chromium should be ideall~ zero.
The present in~ention is illustrated by the following e~amples.
In E~ample 1 to E~ample 5, a cold rolled steel sheet ha~ing a thickness of 0.22 m~ was treated b~ the follo~ing process after electrolYticallY degreasing in a solution of 70 g/l of sodium hydro~ide, water rinsing and then pickling in a solutioD of 100 g/l of sulfuric acid, following b~ rinsing with water, Chromium plating ~water rinsing ~tin or tin-nickel alloy plating (with the re~o~al of h~drated chromium oside formed during chro~iu~ plating)~ water rinsing ~ chro~ate treatment >
water rinsi~g ~drYing.
In E~ample 6 and E~ample 7, the same kind of steel sheet pretreated as in E~ample 1 to E~ample 5 was treated bY the following process.
Chromium plating~ water rinsing ~the re~o~al of h~drated chromium o~iùe for~ed during chromium plating by a cathodic treatment in an acidic solution ~water rinsing itin plating lZ~Z6~
water rinsing ~ chromate treat~ent ~water rinsin8 ~ drYing.
In each E~ample, the conditions were sho~n in detail.
E~ample 1 Conditions for chromiu~ plating Compo~ition of electrolyte Cr~3 120 g/l ;
HBE4 0.8g/l H2S04 0.5 g/l Temperature of electrol~te 60 Cathodic current densitg 50 AJd~
Conditons for tin plating Compositon of electrol~te SnS04 10 g/l as Sn2+
Phenolsulfonic acid (60 % solution) 20 g/l Etho~glated a -naphthol sulfonic acid 5 g/l pH 1.1 Temperature of electrolyte 40 ' Cathodic current densitY 5 A/dr~
Conditions for chromate treatment CrO3 50 g/l H 2sn 4 0 . 1 g/ I
Temperature of electrolyte 55 Cathodic current densitg 3 A/d~
~L242669 E~ample 2 Conditions for chromiu~ plating Composition of electrolyte CrO3 250 g/l H2S04 3 g/l Temperature of electrolyte 45 Cathodic current densitY 20 A/d~
Conditions for tin plating Compositon of electrolyte SnS0~ 3 g/l as Sn2+
Phenolsulfonic acid (60 % solution) 20 g/
Etho~lated a -naphthol sulfonic acid 3 g/l pH 0.9 Temperature of electrolyte 45C
Cathodic current densitY 8 A/d~
: Condition~ for chromate treatment Na2Cr207 2H2 60 g~l ~` Temperature of electrolyte 40~C
Cathodic current density 20 A/d~
E~ample 3 Conditions for chro~iu~ plating Composition of electrolyte CrO3 50 8/l NaF 2 g/l ~L2~Z669 Te~perature of eléctrolyte 55 Cathodic current densit~ 40 A/d~
Conditons for tin-nickel allo~ platin~
Compositon of electrol~te SnC12 50 g/l as S~2+
NiC12 . 6H20 75 8/1 as Ni2+
Ethylene glycol 80 g/l UCI 30 g/l Ratio of Sn2+ to Ni2+ 0.67 pH 0.5 Temperature of electrolyte45 Cathodic current densitY10 A/d~
Conditions fnr chromate treatment Composition of electrolyte Na2Cr2O7 2H2 30 g/l Temperature of electrolyte 40 Cathodic current densitY10 A/d~
E2ample 4 Conditions for chromiu~ plating Composition of electrolyte CrO3 100 g/l HF 3 g/l Te~perature of electrolyte60 Cathodic curreDt densit730 A/d~
Conditons for tin-nickel alloY plating ~2 ~66 Compositon of electrol~te SnC12 26 g/l as Sn2+
NiCI2 6H2 60 g~l as Ni2 NaH~2 35 g/l NaF 28 g/l Ratio of Sn2~ to Ni2+ 0 43 pH 2.9 Temperature of electrolyte 40 Cathodic current densit~ 2 A/d~
Conditions for chromate treatment Compositon of electrolyte K2Cr207 50 g/l Temperature of electrolyte 55 Cathodic current densitY S A/d~
; E~ample 5 Conditions for chromium plating Composition of electrolyte CrO3 200 g/l NaF 6 g/l Na2SiF6 1 g/l TempeTature of electrolyte S0 Cathodic cuTrent densit~ 40 A/d~
Conditons of tin-nickel alloy plating Co~positon of electrolyte SnC~2 15 8/l as Sn ~2 ~2~ ~
NiC12 . 6H20 7 g/l as Ni2+
Cl~cine 28 g/l K4P207 3H20 150 B/l Ratic of Sn2+ to Ni2~ 2.1 pH 8.1 Temperature of electrolyte 50 Cathodic current densitY 5 A/d~
Conditions for chromate treatment Composition of electrolyte CrO3 30 g/l Na2Si~6 0.3 g/l Temperature of electrolyte 55 Cathodic current densitY 10 A/d~
E~ample 6 Conditions_for chromium plating Composition of electrolyte CrO3 100 g/l HF 3 g/l Temperature of electrolyte 60 Cathodic current de.nsitY 80 A/d~
Conditons for the re~oval of h~drated chromiu~ o~ide Compositon of electrol~te H2SO4 pH 0.5 Temperature of electrolyte 60 Cathodic current densitY 20 A/d~
Treating time 0.5 seconds Conditons for tin_~latin~
_____ _ Compusiton of electrolyte SnS0~ 30 g/l as Sn2+
r'l~t?n~l~ulfo~ id ~60 ~ solution) 25 g/l Etho~ylated a -naphthol 6 g/l Temperature uf electrolyte. 40 Cathodic current de,nsit7 15 A/dr~
_onditions for chromate treatment Composition of electrol~,te K2Cr2~7 20 8/l Temperature of electral~te 40 Cathodic current densitY 5 A/d~
E~ample 7 Conditio~s for chromiun plating Compositinn o~ electr.olyte CrO3 40 g/l ~aF 1.5 g/l Temperature oF electrolyte 55 Cathodic current density 30 A/d~
Conditons For the remo7al of hydrated chromium o~ide Compositou of electrolyte ~lC I p~{ I . S
Temperature aF electrolyte 45~C
Catho(lic current densitY S A/d~
,, ~, , 2 ~ 6~9 ~ Treating time 3 seconds Conditons for tin platin~
Compositon of electrolyte SnC12 28 g/l as Sn2+
NaF 30 g/l ;~
NaCI 50 g~l Gelatine 3 g/l pH 2.5 Temperature of electrolyte 60 Cathodic current densit~ 15 A/d~
Conditions for chromate treatment Composition of electrol~te Na2Cr207 2H2O 30 g/l Temperature of electrolgte 60 Cathodic current densitY 3 A/d~
Comparati~e Exanple 1 The sa~e kind of steel sheet pletreated as in E~a~ple 1 was treated under the following conditions and ~as then rinsed ~ith water and dried.
_onditions of electrolytic chromic acid treat~ent Composition of electrolgte CrO3 80 g/l HBF4 O.S g/l H2SO4 0.5 g/l Teoperature of electrolyte 45 Cathodic current densitY 20 A/d~
'L'l-le su.rface -treated steel sheet according -to the present :invention can be used in application such as food can boclies, aerosol can bodies and miscella-neous carl i~od.ies which are lacquered, except for the part. to be weldecl, wherein excellent weldability, i.e.
being easil.y wel.ded without the removal of the plated 1ayer at hi CJh speed, is required.
The surface treated steel base according to the present invention can be also used in applieations wherein the lacquer coating is not carried out because it has exce]:lent weldability. Fur-therrnore this surface treated stee:l sheet can be used in applieations wherein exeellent eorrosion resistance after lacquer-ing are required, such as can ends, drawn cans and drawn and redrawn cans ~DR cans), besides ean bodies.
'l'ne steel base used for -the produc-tion of the surace treated steel sheet aceording to the present invention can be any cold rolled steel sheet customariLy used :in manufacturing electrotinplate and TE'S-CT. l'referably, a -type of steel base for electro-- ~2~ 9 tinpl.ate, as set ou-t in ASTM ~ 623-76 of 1977 (Stan-dard specifi.cat:ion for general requirements for tin mill produet), :i.s employed as the steel base. Prefer-abl.y, the th:icJcness of -the steel base is from about ().l to ahoul: 0.35 mrn.
'I`he su:rEace -treated s-teel sheet aeeording to the present invention is produeed by the following proeesses:
(.l) de~Jreasing with an alkali and piekling wi.th an a(id -_~ water rinsing -~ ehrom:ium plating wat.er .insirlg --~ tin or tin-nickel alloy plating wa'cer rinsing -~ ch.^o.nace 'creacment-~ wa'cer rinsing ~drying, or;
(2) degreasing with an allcali and pickling with an ac;d > water rinsing > chromium plating ->water :ri.ns-irlcl-->removal oE hydra-ted chromium oxide by eathodie l-reatment in an acid so`lution -~water rinsing _~ tin or tln-n.ickel alloy platiny -~ water rinsing >chromate -t.reaclrlenc -~ water rinsing~ dring.
By using the above processes (l) and (2), three l.ayers consisting of a bo-ttom layer oE metal.lic chromi.um, a middle layer of metallic tin or -tin-nickel alloy and a top layer of hydrated ehromium oxide are forrmed C)ll a stee:l base. In -the present invention, -the amount of each layer is very impor-tant in order -to obtain an e~cel.lent weldability, whieh is an objeetive of the present :invention.
~ 2~6~
At r irsl,, the amount of metallic chromium w11ich is t1~e i)c~ o111 layer in the surface treated steel sheet, accordir1g 1:~o the present invention, should be cor1l,ro'l1.ed i~ e range of 30 to 300 mg/m2, more preferabLy '1() l.o 150 mg/m . If the amount of metallic chromium :is bel,ow 30 mg/m2, the excellent weldabili-ty and excel.le11t corrosion resistance are not obtained because it is considered that the surface of the steel base is not suEficiently covered with the plated metal1,i.c chro1nililr1 and a greater part of the following plated 1-in or t:in-nickel alloy changes to iron-tin al:1.oy or iron-li.rl-nicke1 a]loy having high electric resistance duriny heating for lacquer curing. The arnount of meta'1.:1,ic chromium is ]imi-ted to 300 mg/m frorn an econol11ical and an industrial point of view, al.thou~h the oxi.dation of a steel base and the forma-tion of iron-ti.r1 alloy or iron-tin-nickel alloy during heating are prevented with an increasein the amount of metallic chrornium.
Secondly, the amount of metallic tin or tin-nic1~el alloy beiny a middle layer in the surface treated steel sheet according to the present invention shou1.d be controlled in the range of lO to 500 mg/m2, more preferably lO to 150 mg/m2. If -the amount of metal.]l,c tin or tin-nickel alloy plated on the metal-lic chrornium plated steel base is below lO mg/m2, excell.ent wel.dability is not obtained, because chro-rnium oxide having high electrical resistance is formed 66~3 by the oxida~-ion of metallic chromium during heating ror lacquer curing, even if the oxidation of a steel i)ase is prevenled by the sufficient amount of me-tal]ic chromium. ~rile amount of the plated -tin or tin-nickel a'l'loy is 'limil-e(l to 500 mg/m2 from an economical point of view, a~tho~lgh the effect of metallic tin or tin-nickel all,oy in the present invention does not chanye at, above 500 mg/m2.
In ~ e present invention, tin-nickel alloy does not, a:l,ways mean tin-nickel alloy having stoichio-metrical, cortlposil,ion with a cons-tant ra-tio of tin to nicke'l sucl~ a~ NiSn, Ni3Sn, Ni3Sn2 and Ni3Sn4, but mean.s -tl~e co-deposi-tion of tin and nickel having various rali()s Or tin l,o nickel. However, ,i-t is said that co-del)o~si~e(l tin and nickel Eorm tin-niclcel alloy at a room temE~erclture or during heating.
In the case of tin-nickel alloy plating on the chrotlliu~n pLated steel base, -the nickel content is preferably 20 to 60 weight % based on the total weight of plated tin and nickel. Although the weldability decreases slightl,y with an increase in the co-deposit-ed nic]cel, content in the pla-ted tin-nickel alloy, the surface treatecl steel sheet according to the present invention, wherein -tin-nickel alloy is plated on the chromium p,],ated steel base, also has an excellen-t weldabilily conlpared with that of TFS-CT. At above 60 weight % or below 20 weigh-t % of nickel in the tin-nickel alloy, the weldability and the corrosion ~' 12 : " ~2~26~
resistance ale exce].lent comparecl wi-th tha-t of TFS-CT.
Elowever, il is diEicult to stably plate tin-nickel alloy having bel.ow 20 weight % and above 60 weight %
of nickel. on the chromium plated steel base by using a ti.n-nickei alloy p1ating eleetrolyte, beeause niekel content or lin content in the tin-nickel alloy changes greatly wi.tl-l a sl.ight change in the plating condi-tions.
Particularly, the surface treated s-teel sheet accorcling to the present invention, wherein tin-nic1ce:1. alLoy is plated on the ehromium plated steel. base i.s charaeterized by exeellen-t corrosion resistance to sul.fide stains, which may often appear in the inside of the ean when some oods eontaining protein such as fish and mèat are paeked in the lacquered t:i.npl.ate can, unlaequered tinplate can and lacquered nickeL plated s-teel ean.
Various methods for making an alloy or eo~depos:itions layer such as the co-deposition of tin and z.inc, the co-deposition oE tin and eobalt, niekel pl.ating after tin pl.ating, tin plati.ng after niekel p].ating, zinc plating after tin plating and -tin platincJ after zinc pla-ting on the chromium plated steel. base have been considered in order to obtain a surEace treat.ed steel shee-t having an excellent wel.~abilily, blll- these methods are not suitab].e for the prc>ductic>rl of the surface treated s-teel sheet 66~
having excellerlt weldabili.-ty, because of the complexi-I:y of the process or because a special electrolyte is required.
As described above, the presences of me-tal-lic chrorni Ulll as a bottom layer and metallic tin or tin-ni.ckel. al.loy as a middle layer in the surface treated steel sheet according to -the present invention are indispellsable in order to realize excellent weldab;.l.ity aller heating.
13a ~2~6Çi9 Furthermore, in the present invention, the presence of a small amount o hydrated chromium oride as a top layer is indispensable in order to preYent the o~idation of the e~posed steel base and the e3posed metallic chromium after tin or tin-nickel alloy plating during heating for lacquer curing and to obtain e~cellent corrosion resistance and e~cellent lacquer adhesion.
The optimum range of hydrated chromium oxide is from 2 to 18 mg/~ , more preferably 4 to 12 mg~m2as chromium.
If the amount of hydrated chromium oside is belo~ 2 mg/m2 as chromium, the corrosion resistance and the lacquer adhesion become PoOr. If the amount of hydrated chromium o~ide is abo~e 18 mg/m2, the weldability becomes remarkably poor, because hydrated chromium o~ide changes to chromium o~ide having high electric resistance by deh~dration of it during heating for lacquer curing.
The conditions for each process in the production of the surface treated steel sheet accordin~ to the present invention are shown in detail.
At first, in order to form a metallic chromium layer as a bottom layer on the surface treated steel shéet according to the present invention, a known chromium plating electrolyte such as Sargent bath or a chromic acid electrolyte, containing additives such as fluorine compounds, which are used for ~he production of T~S-CT having 12~66~3 , a lower layer of metallic chromium and an upper la~er of hydrated chromium o~ide, may be employed.
In the present inYention, it is preferable to emplo~ the following electrolytic chromium plating conditions for the formation of a metallic chroDium la~er on a steel base:
Concentration of chromic acid: 30~ 300 g/l, more preferably 80~ 300 g/l Concentration of additi~e: 1.0~ 5.0, more preferably 1.0 ~ 3,0 weight % of concentration of chromic acid Additives: at least one compound selected from the group consisting of fluorine compounds and sulfur compounds Temperature of the electrolyte: 30~ 60 Cathodic current density: 10~ 100 A/d~
Generally, the amount of hYdrated chromium o~ide formed during chromium plating decreases with an increase in the concentration of chromic acid in the suitable weight ratio of additi~es to chromic acid. It is not preferable to use an electrolYte ha~ing below 30 g/l of chromic acid for the chromium plating, because the current efficiency for the deposition of metallic chromium decreases remarkabl7. The concentration of chromic acid abo~e 300 g/l is not also suitable from an econo~ical point of ~iew.
The presence of additives such as fluorine compounds and sulfur compounds in the chromium plating-electrolyte is indispensable for uniform chromiu~ depositiun. If the 6~
~eight % af additi~e.~ ta chromic acid is below 1.0 or abo~e 5.0, the CU rrent eFFiciellcy for the dePosition of metallic chromium remarkablY decreases, besides a decrease in unifarmity of the dePusited metallic chramium layer.
Particularly, at below 1.0 weight ~ of additi~es to chromic acid, the formed insoluble hydrated chromium o~ide remarkabl~
pre7ents the formatiall oF uniform metallic tin or tin-nickel alla7 la7er in the Fallo~itlg tin or tin-nickel plating.
[t is preferable that the additi~es be at least one compaund selected From the grouP consisting oF fluorine compound such as h~droFluoric acid, Fluaboric acid, fluosilicic acid, ammonium bifluoride, an alkali metal biFluoride, ammonium Fluorlde, an alkali metal fluoride.
ammunium Fluotarate, an alkali metal fluoborate, ammonium fluasilicate, an alkali metal fluosilicate, aluminum fluoride and sulFur compound such as sulfuric acid, ammonium sulFate, an alkali metal sulfate, chromium sulFate, aluminum sulFate, phenolsulFonic acid, ammonium phenalsulFonate, an alkali metal phenolsulfonate, phenoldisulfanic acid, ammoniut~
phenoldisulfonate, an al~ali metal phenoldisulfonate, ammonium sulfite, an alkali metal sulfite, ammanium thiosulfate and an all~ali metal thiosulfate.
The amount aF hydrated chromium o~ide Formed during chromium plating decreases with an increase in the temperature oF the electralyte. The temperature of the ~ ~266~
, . , electrolyte abo~e 60~ is not suitable from an industrial point of view, because the current efficienc~ for the dePosition of metallic chro~ium decreases remarkabl~. The tempeTatUTe of the electrolyte belo~ 30~ is not also suitable because a long time is necessary for the removal of the laTge amount of hydrated chromium o~ide formed during chromium plating.
With an increase in a cathodic cuTrent densitY, the curTent efficiency for the deposition of metallic chromium increases and the amount of hydrated chromium o~ide formed during chromium plating decreases. It is suitable in the present invention that the range of the cathodic current density for the dePosition of metallic chromium is 10 to 100 A/d~ , more preferably 40 to 80 A/d~ , because metallic chromium almost does not dePosit at below 10 A/d~ of the current densitY and the cuTrent efficiency for the deposition of metallic chromiu~ almost does not increase at above 100 A/d~ of the current density.
In the present invention, the conditions for chromium plating wherein a good CurTent efficiency for the dePosition of metallic chromiu~ is obtained and a small amount of h~drated chromium oxide is formed, should be seleted because the presence of hYdrated chromium o~ide prevents the formation of a uniform tin or tin-nickel alloy layer in the follo~ing tin or tin-nickel alloy plating.
~L2~266~3 ,, Howe~er, h~drated chromiu~ o~ide is always formed on a deposited metallic chromiu~ layer during chromium plating.
Under the conditions of higher concentration of chromic acid, higher current density and higher temperature of the electrol~te, the amount of h~drated chromium o~ide formed on the dePosited metallic chromium is about 3 to 10 mg/~ as chromium. On the contrar~, under the conditions of lower concentration of chromic acid, lower current densitY and lower temperature of the electrolyte, it is about 10 to 50 mg/~ as chromium.
When a large amount of hYdrated chromium 02ide is formed during chromium plating, it is possible to decrease it by lea~ing the chromium plated steel base in the chromium plating electrolyte for a few seconds. Howe~er, hgdrated chromium oxide of about 3 to 5 mg/~ as chromium remains on the surface of the chromium plated steel base, eYen if the chromium plated steel base covered with hydrated chromium o~ide is left in the the chromium plating electrolgte for a long ti~e.
In the present invention, such hydrated chromium oxide must be remo~ed before the subse~uent tin or tin-nickel alloy plating because the presence of hydrated chromium oside pre~ents the deposition of a uniform tin or tin-nickel alloy layer on a metallic chrowium la~er.
The follouing methods are considered suitable for the 2~669 removal of hydrated chromiu~ o~ide on the deposited metallic chromium la~er.
(A) An immersion of the chromium plated steel base, before drYing, into a high concentration of an alkaline solution such as an alkali metal hydroxide and an alkali metal carbonate at high temperature of 70 to 90 C. It is difficult to industrialize this method because the alkaline solution may be mi~ed into the following tin or tin-nicXel alloy plating electrolyte.
(8) An immersion of the chromium plated steel base before drYing, into an acid solution such as sulfuric acid and hydrochloric acid. This method is not suitable in the present inVentiDn, because hydrated chromium o~ide formed during chromium plating is nct sufficiently dissolYed by an immersion into acid solution for a short time.
(C)A mechanical remo~al of hydrated chromium o~ide by a brushing roll or wiper in an alkaline solutinn or an acid solution before drying the chromium plated steel base. The hydrated chromium o~ide formed on the chromium plated steel base is not uniformlY re~o~ed b~ this method.
Therefore these methods such as (A), (B) and (C) are not suitable for the remo~al of hydrated chromium o~ide before the following tin or tin-nickel alloy plating.
In the present in~ention, the following methods are preferable for the remo~al of hydrated chromium o~ide formed on the metallic chrumium layer. One is the method wherein the chr(]mium plated steel base is cathodicallY treated in an acid solution such as sulfuric acid and h~drochloric acid ha~ing a pH of U.5 ta 2.0 before tin or tin-nickel alloy plating. The other is the method wherein tin or tin-nickel alloy plating is carried aut at the same time as ~he remo7al of hYdrated chr(lmiu~ ozide Formed on the metallic chromium layer by using a tin plating electrolyte ha7ing a low c~ncentration oF stannous ion or a tin-nickel allo~
plating electrol~te l~ v i m~ a low curren. ef f iciency.
The conditiolls For the remo~al of hYdrated chromium o~ide by the former method are as follows:
Electrol~te: ~n acid solution containing at least one acid selected From the group consisting of sulfuric acid hydrochloric acid hydrofluoric acid fluoboric acid and fluosilicic acid ha~ing a pH of 0.5 ta ~.0 Temperature of the electrolyte: 30~ 70C
Cathadic current densit~: 2~ 50 AJdr~
Treatin8 time: 0.5 ~5.U seconds Although the main component in the elctrolYte is acid such as sulfuric acid and hydrochloric acid~ if the pH of the electrolyte is kept between 0.5 to 2.0 various ions which are not dePosited Oll the surface of the chramium plated steel base or do not o~idize the surface of the chromium ~ .
~ ~2 ~6 ~
plated steel base, can lle contairled in the electrolgte. It is nat necessar~ that the temperature af the electrol7te be strictlg contralle~ if it is kept betueen 'JO to 70~ .
If the temperature of the electrolgte is aba~e 70 ~ , the e~aporation of water is increased. At belnw 30 ~ a cathadic treatment far a long time is required far the sutficient remo~al of hgdrated chromium agide.
In below 2 A/dl~ of current densit~, hgdrated chromium a~ide is nat sufficientlg remoYed, e~en if the chromium plated steel base is cathodicallg treated for a long time.
upper limit of current densitg is limited to 50 A/d~
because the effect of the present in~entian is nat increased at a curreilt densitg abn7e 50 A~drr~.
If the treating time is below 0.5 seconds~ hgdrated chramium ogide is not sufficientlg remo~ed fram the metallic chromium lager, e~en if the higher current densitg is applied.
The treating time abo7e 5 0 seconds is not suitable in the high speed productiall af the surface -~rea~ed s~eel s~eet according tu the present in~ention.
The conditians for the latter method wherein tin or till-; nickel allog plating is carried out at the same time as -~he remo~al of hydrated cilromium oxide formed an tbe metallic chramium lager is as follows:
In tin plating, the follouing conditians are preferable.
Cancentratian of stannaus ian: 2~ 10 g/l ..~ ~
~..~
.
~2~266~1 11 oF the ~ oL r nlyte: 0.5~ '1.0 I'emperature uF the electrolyte: 30~ 60~
- (;athadic lullellt densit~: 3 ~ 50 A/d~
Gellrrallg, a tin l~latillg electrol7te such as a etannous sul-fate n~lti~ and stamm(:~m.~ .ides ~ath ~laving abo~t 20 to 40 g/l of SCam(10m~ m iS mse-,l t()~ lf` iilclus~.-ial. p~o~uction of ~lectro~in-p~ . rt i~ a~ t~les(~ atillg eLectro:Ly-ces ~e used fol tin platin% on the chromium plated steel base without the remo7al oF h7dlal:e(1 :!lromium o~ide Formed during chromium platill~, iTI the lattel metllnd, because a uniForm tin layer is not Formed nn the chlomiu~ plated steel base and the coarselg antl deudritically plated tin mag be peeled off from the chromium plated steel tlase, although these tin plating elec.r.olyr~ can be use(l Fnr tin plating after the remo~al of hYdrated chrnmium o~i~le nll the chromium plated steel base by a cathodir, treatment in .arl acidic solution.
~ n latter m~tho(l, tin plating with the retroval of hsLllated chramillm ngi(le Formed during chromium plating is characterized hy the use oF tin plating electrolgte ha~ing a low concentratinll nF stannous ion such as 2 to 10 g/l.
namel7 ha~ing a low c~Lrrerlt efficiencg.
The reason whg a uniForm tin la~er is not Formed on the chromillm platell steel base b~ using a known tin plating electrolgte ha7ill2 a hi<~ll concentratian of stannous ion is ,,~i',, '.l 3 Z~ 69i `
that a greater part in Lhe quantit7 of electricity is cansumed for the dePosition nf tin, but a lesser ~art for the remo~al of h~drated chromium u~ide.
Therefore it is desirable to decrease the conce~tration of stannous ian to below 10 g/l in the present inPentiO~ in order to obtain an uniform ti~ laYer on the chromium plated steel base.
lluwe7er, the concentration of stannous ion belo~ 2 g/l is not suitable in the presrlt in~ention. because the curre~t efficiency For the deposition of tin decreases remarkablY and becomes unsuitable tlue to by the ~resence of a small amount of ions such as chromium ion a~d iron iOII which buiId up in the electrolyte by a dissolution of th.e hydrated chromium o~ide and the steel base.
Sta~nous iOII is maiml7 supplied by the addition of stan~olls sulfate, stannous chloride, stannous fluoride and sta~nous fluoborate or by the dissol~tion of a soluble ~i~
anode.
The p~ oF the electrolyte is also ~ery important for tin plating 011 the ch10mium plate~ steel base with the remo~al ot hydrated chromium 03ide formed duri~g chromium plating. The pH range of the electrolyte should be from O.S to 3.0, preferabl7 U.5 tu 1.5 in the stannous sulfate bath containing sulfuric acid or phenulsulfonic aci~ or preferablg 2 to 3 in the s~annol1s llalides bath containing scannous chloride, sodium 1~ ~2~6 ~
fluoride. ~utassium bifluoritle and sodium chloride.
At a low pll such as ().5 to 3.0, the surface of the chrornium plated steel base is uniFor~ls acti7ated because h~drated chromium o~ide Formed during chromium plating is easil.7 remo7ed Fram the chromium plated steel base with the eYolution of a large am o unt nF hy(Lrogell during dissolving by acid Therefole a uniform metallic tin layer is Farmed on the metallic chromium laser. The pH of belo~ 0.5 is not desirable in the present in7ention, because a part of metallic chrnmium ma7 be dissol7ed. ~ pH of abo7e 3.0 is not also desirable because a ul~iform tin layer is not formed on the metallic chromium la7er by the insufficient dissolution of h~drated chromium Far a short time. Furthermare it is difficult to stably produce the surface treated steel sheet accor~ing to the present in~ention because the pH of the ; elctrolyte changes greatl7 by a slight change in the concentration of stanllous ian and acid.
The pH of the electrolyte is mainly controlled by the addition of sulfuric acid, phenolsulfonic acid, hgdrochloric acid, hydrofluoric acid, fluoboric acid, fluosilicic acid a~d alkali metal salts thereoF. Variuos ions, ~hich do not gi~e bad effects in tin plating and in the dissolution of hYdrated chromium o~ide, mag be cosltained in the electrolgte, if the ~H
of the electrol~te is kept in the range of from 0.5 to 3Ø
AdditiYes such a etho~ylated a -naphthol sulFonic acid, 2 ~
.~
~2~L2~i69 ethog71ated ~-naphthol, ~ ~naphthol and gelatine ~hich are used in a knowll tin platiIlg electrolyte such as stannous sul-Eate ~atl-~ or s~annou~ hcll:icles ba-tn for the pro~uction of electro-~inpla~e Cdll ~e use-i ~or l:he improve.nent of the uniformity of ~he pldled rin ~ayer im t:~le present invention.
It is suitable i~l the present in~ention that the range of the cathodic current density is 3 to 50 A/d~ , core preferabl7 10 to 30 A/dnf. If the current densitg is belou 3 A/-lm~, the current efficiencg far ti~ plating becomes so low that a long time is necessarg for the dePosition of the required amuuItt of tin. If the current densitg is abo~e 50 A/dm', a tin laYer l~a7ing an e~cellent adhesio~ to the chromium plated steel base is not obtained.
The optimum range fur the temperature of the electrolgte is From 30 to 60~G, mcre preferabl7 30 to 50~ . At below 30 ~C, hydrated chromiuln o~ide is not dissol7ed sufficientl~, so that the uniform tin laYer is not plated on the chromium plated steel base. At abo~e 60C , a part of metallic chromium is dissol 7 ed with the dissolution of hgdrated chromium o~ide.
; In tin-nickel allog plating ~ith the remo~al of hgdrated chromium o~ide Eormed during chromium plating, the following two tgpes of the electrol~te are used. The first tgpe oF the electrolyte is pyrophosphate bath co~sisting of an alkali metal pyrophosphate, stannous chloride, nickel chloride and . :
~2~6~9 .
additi7es. The secolld type of the elctrolyte is a halide bath cullsisting of stanllalls t~alide, nickel halide, an alkali metal ~a~lcle .ll~d .-additives.
it is suitable to emplay the following eonditions for tin-t3 i c kel alloy plating W'lt?l~ usirlg the f i rs~ type of -the electrol7te:
Concentration oF stannous ion: 2~ 40 g/l Coneentration cf nickel ion: 4~ 20 g/l Coneentratian ratio af stannous ion to niekel ion:
0.1 ~ 3 Concentration of an alkali metal pYroPhosphate:
80~ 300 g/l pH of the electrol~te: 8~ 10 Temperature oF the electrolYte: 40~ 60 Cathodic current densitY: 1~ 30 A/dr~
It is suitable to e~ploy the following eonditions far tin-~iekel alloY plating wnen using the seeond cype o~ the eletrol~te:
Coneentration oF stannous ion: 2~ 70 g/l Cancentration oF nickel ion: 4~ 80 g/l Coneentration ratio oF stannous ion to nickel ion:
0.1~ 0.8 pH of the electrolYte: 0.5~ 3 Temperature oF the electrolYte: 30~ 60 Cathodic current densitY: I ~ 30 A/dr~
~ 2~66~3 In tin-nickel al luy plating on the chromium piated steel base with the remo~al of hydrated chromium 02ide bg using alkaline pyraphosphate bath or acidic halides bath, it is ~erY
important that the caucentration ratio of stannous ion to nickel ion be kept withill the range described abo~e in order ta abtain a uniform tin-llickel allay lager containin8 20 to 60 weight ~ af nickel on the chramium plated steel base.
~ rll tin-nickel al loy plating, generally the nickel content increases under the conditions of higher current de~sitY, lower temperature of the electrolYte, lower concentrations of stannous ion and nickel ion, lower corlcentration ratio of stannous ion and nickel ion, lower concentration ratio of stannous ion to nickel ion and higher p~l af the electrolYte.
~ t below the lower limit of the cancentration of stannous ian and nickel ion, the current eFficienc~ far the co-deposition af tin and nickel decreases remarkabl~. The concentration oF abo~e the upper limit of stannous ion and nickel ion is not suitabie frum an ecorsomical point of ~ie~, because the dray out loss af stannous ian and nickel ion increases. Furthermore, if the conceDtration ratio of stannaus lan to nickel ion is below the lower limit ar a'aa~e the upper limit, it is difficult to plate tin-nickel alloy ha~ing 20 to 60 weight % af nickel on the chromium plated steel base.
StannollS ion and nickel ian are mainly supplied by the ~ 26~i9 addition aF stanltulls chlaride and nickel chlaride or b~ the dissolution of a saluble tin anode and nickel anode, respecti~el,7.
The pll af the electr(ll7te is mainl7 controlled by the addition of h7drochlaric acid and alkali metal chloride in acidic llalogen bath anll by the addition of pyrophosphoric acid, alkali metal pyrophosphate, hYdrochloric acid, alkali metal chloride and alkali metal h7dro 3 ide in alkaline pyrophosphate bath.
Additi7es such as glYcine and ethglene glgcol which are used in a known tin-nickel alloy plating electrolyte can be also used for the impro7ement of the u~iformity of the plated tin-nickel allo7 layer in the present in~ention.
Cathodic treatment in an acidic salution ha~ing pH 0.5 to 2.0, tin or tin-nickel plating with the remo~al of hYdrated chromium 02ide ~ormed during chromium plating described abo~e are also applie~ for the dried chromium plated steel base under the same canditions described abo7e.
~ n the case uF tin ar tin-nickel allo.7 plating after the remo7al of hydrated chro~ium 02ide by a cathodic treatment i~
an acidic salution, tin or tin-nickel plating is also carried out by using the same electrolyte and the same plating cunditions ~escribed abo7e.
Tn this case, a knawn tin plating electrol7te such as a stannous sul.Ea~.e bal-h and stanrlous halides bath having high concentration of :~"~
~,..~
~2~L~6~9 stannuus il~1n, for ill;tallce, stamnous sulfa-te bath consis~ing oE
30 g/l o r ~ ,amllous ~m I f'.,li-e (as scannous ion), 30 g/l of pheno~
s~llfomi( m~-id (~ ?Iml~ lOn) dnd ~ g/L of e~hoxylate ~-naphtol sulf~ mi;l~)c stc~ m;ilalides ba-t~ consisting of 3~ g/l of stanntllls chloride (as stannaus ion), 30 g/l of sodiu~
fluori~le, 50 g/l of sullium chluride and 3 g/l af gelatine can be usell far tin plating after the remo~al of hydrated chrnmium o~ide nn the chromium plated steel base.
~ or the formation oF h7drated chromium o~ide layer being a top laler of the surface treated steel sheet according to the present in7entiou. a knnwll electralgte such as the acidic cllrumate electrol7te use(l For the past-treatment af electrotinplate ul a rllramic acid electralYte cantaini Dg a small amaullt nf additi~es such as Fluorine campollnd and sulfur campound which is use(i far the pra~uctian of rFS-CT ha~ing a Iower lager of metallic cllramium and an upper layer of llydrated chramium oxi(le, may be emplaYed.
in the present in7entian, t~a tgpes af the electrolgtes are used for the furmatiarl af hydrated chramiu~ a~ide. The first type af the electrolyte consists af an acidic chromate electralyte withaut a~ition of additi7es 5 uch as fluarine compaunds and sulfllr compounds. The second type of the electrol7te cnnsists of chrùmic acid electrolYte with additi7es such as flunrille compounds and sulfur ccmpaunds.
It is suitable to emplay the Following conditians for the ,. 3 ~
formatian af hYdrate(l chromium atide of 2 to 18 mgJ~ as chromium b7 using the first type of the electrolyte:
Cancentration of he2a7alent chramium ion: 5 ~ 30 g/l Temperature oF the electrolyte: 30~ 70 Cathudic current density: 1 ~ 20 A/dr~
Quantit7 of electricity: 1~ 40 coulombs/d~
~f the concentratian of hega7alent chromium ion is below S g/l, a waste af electric power occurs because af the higher electrical resistance af the electrolyte. The concentration of he3a7alent chromium ion is limited to 30 g/l fram the 7iewpoint of conser7ing resources, although the efFect of the present treatment is not decreased in a concentration abu7e 30 g/l.
It is an essential condition that the electrolyte should be acidiFied. ~n the case oF alkaline electrolYte, the efFiciency For the Formation of hydrated chromium oside is so lou that a long time is necessary for the farmation of satisfactory hydrated chromium n~ide. Therefore the electrolyte containing only a chromate of an alkali metal ~r ammanium is not used in the present in7ention.
In the abo7e case it should be acidified b-y the addition of chromic acid. it is also possible to add a hydro2ide of an alkali met~l or ammonium to chromic acid electrolYte within an acid range.
ThereFnre, at least one chromate selected From the group :
~ 66 ~
consisting oF chromic acid, a chromate and dichromate of an alkali metal, ammollium chrnmate ~nd ammonium dichrooate is used for the first t7~e of the electrol~te within an acid range in the present in~rerltion. It is ~ot necessarY that the temperatllre of the elertrolyte be strictl~ cantrolled if it is kept between 30 to 70 ~ .
Lf the temperature of the electrolyte is abo~e 70~', the e~aporation of uater i5 illCreaSed.
Under a current densitY below I A/dm~, a long time is necesszrg for the formation of a satisfactory hYdrated chromium o~ide. Under a current densit~ abo~e 20 A/d~ , the control in the amnunt of the formed hydrated chromium oxide may be difficult. although a saiisfactory hydrace~l chrom:i u~n ox.i rle i.s formed by a cathodic tLeal-.lnerlc :Eor ~ Si~ol-t: u ime.
Lf the quantity of electricitg is below 1 coulo~bs/d~ , it is difficult to form a suitable amount of hYdrated chro~ium o~ide. At abo~e 40 coulombs/d~ of electricitY, the weldability of the surface treated steel sheet accarding to the present in~ention becomes poor because of the formation af thicker hydrated chromiu~ o~ide.
[t is desirable to emplog the follo~ing conditions Far the Formatian of hydrated chromiur~ 03ide by using the second type of the electrulyte:
~ 2~266~
Concentration of cllromic acid: 10 ~ 50 g/l '~eight % of additi~es to chromic acid: 0.2~ 1.0 Additi~es: Sulfur compound and/or fluorine compound Temperature oF the electrolgte: 30~ 60 Cathadic current densit~: 1 ~ 1~ A~d~
Under the conditians described aboqe, ~eight X of additi~es to chromic acid and current densitg are ~er~
important in the present treatment, because at a higher weight percent of additi~es to chromic acid and higher curre~t densitY, metallic cllrumium, which imparts a bad effect to the weldability, is dePosited on the tin or tin-nickel allo~ plated steel base.
r herefcre the weight percent of additi~es to chromic acid is limited to 1.0 ~s a maximu~ and a cathodic curren-t densi--ty :iS .] imited ro :I.U ~/dnl2 . However, if -the weight percent of additi~es to chromic acid is below 0.2. the weldability becomes poor because thick hYdrated chromium 03ide is formed. Under current densitg below I A/d~ , a long time is ~ecessarY for the formation o~ Q satisfactorY hYdrated chromium 03ide.
Furthermare, the ranges in the concentration of chromic acid, the quantity of electricity and the temperature of the electrolyte are limited as in the first type o~ the electrolgte forthe same reason.
Additi7es are also selected from the same graup as in the chromium plating electralyte.
266~
In the treat~ent using the second type of the electrolyte, it is ~ery i~portant to select the conditiuns wherein ~etallic chromiu~ is not deposited on the tin or tin-nickel alloy plate surface. Howe~er, under so~e conditions wherein ~etallic chromium is dePosited, ma~i~u~ amount of metallic chro~îum should be limited to 10 mg/~ , although the amount of the dePosited metallic chromium should be ideall~ zero.
The present in~ention is illustrated by the following e~amples.
In E~ample 1 to E~ample 5, a cold rolled steel sheet ha~ing a thickness of 0.22 m~ was treated b~ the follo~ing process after electrolYticallY degreasing in a solution of 70 g/l of sodium hydro~ide, water rinsing and then pickling in a solutioD of 100 g/l of sulfuric acid, following b~ rinsing with water, Chromium plating ~water rinsing ~tin or tin-nickel alloy plating (with the re~o~al of h~drated chromium oside formed during chro~iu~ plating)~ water rinsing ~ chro~ate treatment >
water rinsi~g ~drYing.
In E~ample 6 and E~ample 7, the same kind of steel sheet pretreated as in E~ample 1 to E~ample 5 was treated bY the following process.
Chromium plating~ water rinsing ~the re~o~al of h~drated chromium o~iùe for~ed during chromium plating by a cathodic treatment in an acidic solution ~water rinsing itin plating lZ~Z6~
water rinsing ~ chromate treat~ent ~water rinsin8 ~ drYing.
In each E~ample, the conditions were sho~n in detail.
E~ample 1 Conditions for chromiu~ plating Compo~ition of electrolyte Cr~3 120 g/l ;
HBE4 0.8g/l H2S04 0.5 g/l Temperature of electrol~te 60 Cathodic current densitg 50 AJd~
Conditons for tin plating Compositon of electrol~te SnS04 10 g/l as Sn2+
Phenolsulfonic acid (60 % solution) 20 g/l Etho~glated a -naphthol sulfonic acid 5 g/l pH 1.1 Temperature of electrolyte 40 ' Cathodic current densitY 5 A/dr~
Conditions for chromate treatment CrO3 50 g/l H 2sn 4 0 . 1 g/ I
Temperature of electrolyte 55 Cathodic current densitg 3 A/d~
~L242669 E~ample 2 Conditions for chromiu~ plating Composition of electrolyte CrO3 250 g/l H2S04 3 g/l Temperature of electrolyte 45 Cathodic current densitY 20 A/d~
Conditions for tin plating Compositon of electrolyte SnS0~ 3 g/l as Sn2+
Phenolsulfonic acid (60 % solution) 20 g/
Etho~lated a -naphthol sulfonic acid 3 g/l pH 0.9 Temperature of electrolyte 45C
Cathodic current densitY 8 A/d~
: Condition~ for chromate treatment Na2Cr207 2H2 60 g~l ~` Temperature of electrolyte 40~C
Cathodic current density 20 A/d~
E~ample 3 Conditions for chro~iu~ plating Composition of electrolyte CrO3 50 8/l NaF 2 g/l ~L2~Z669 Te~perature of eléctrolyte 55 Cathodic current densit~ 40 A/d~
Conditons for tin-nickel allo~ platin~
Compositon of electrol~te SnC12 50 g/l as S~2+
NiC12 . 6H20 75 8/1 as Ni2+
Ethylene glycol 80 g/l UCI 30 g/l Ratio of Sn2+ to Ni2+ 0.67 pH 0.5 Temperature of electrolyte45 Cathodic current densitY10 A/d~
Conditions fnr chromate treatment Composition of electrolyte Na2Cr2O7 2H2 30 g/l Temperature of electrolyte 40 Cathodic current densitY10 A/d~
E2ample 4 Conditions for chromiu~ plating Composition of electrolyte CrO3 100 g/l HF 3 g/l Te~perature of electrolyte60 Cathodic curreDt densit730 A/d~
Conditons for tin-nickel alloY plating ~2 ~66 Compositon of electrol~te SnC12 26 g/l as Sn2+
NiCI2 6H2 60 g~l as Ni2 NaH~2 35 g/l NaF 28 g/l Ratio of Sn2~ to Ni2+ 0 43 pH 2.9 Temperature of electrolyte 40 Cathodic current densit~ 2 A/d~
Conditions for chromate treatment Compositon of electrolyte K2Cr207 50 g/l Temperature of electrolyte 55 Cathodic current densitY S A/d~
; E~ample 5 Conditions for chromium plating Composition of electrolyte CrO3 200 g/l NaF 6 g/l Na2SiF6 1 g/l TempeTature of electrolyte S0 Cathodic cuTrent densit~ 40 A/d~
Conditons of tin-nickel alloy plating Co~positon of electrolyte SnC~2 15 8/l as Sn ~2 ~2~ ~
NiC12 . 6H20 7 g/l as Ni2+
Cl~cine 28 g/l K4P207 3H20 150 B/l Ratic of Sn2+ to Ni2~ 2.1 pH 8.1 Temperature of electrolyte 50 Cathodic current densitY 5 A/d~
Conditions for chromate treatment Composition of electrolyte CrO3 30 g/l Na2Si~6 0.3 g/l Temperature of electrolyte 55 Cathodic current densitY 10 A/d~
E~ample 6 Conditions_for chromium plating Composition of electrolyte CrO3 100 g/l HF 3 g/l Temperature of electrolyte 60 Cathodic current de.nsitY 80 A/d~
Conditons for the re~oval of h~drated chromiu~ o~ide Compositon of electrol~te H2SO4 pH 0.5 Temperature of electrolyte 60 Cathodic current densitY 20 A/d~
Treating time 0.5 seconds Conditons for tin_~latin~
_____ _ Compusiton of electrolyte SnS0~ 30 g/l as Sn2+
r'l~t?n~l~ulfo~ id ~60 ~ solution) 25 g/l Etho~ylated a -naphthol 6 g/l Temperature uf electrolyte. 40 Cathodic current de,nsit7 15 A/dr~
_onditions for chromate treatment Composition of electrol~,te K2Cr2~7 20 8/l Temperature of electral~te 40 Cathodic current densitY 5 A/d~
E~ample 7 Conditio~s for chromiun plating Compositinn o~ electr.olyte CrO3 40 g/l ~aF 1.5 g/l Temperature oF electrolyte 55 Cathodic current density 30 A/d~
Conditons For the remo7al of hydrated chromium o~ide Compositou of electrolyte ~lC I p~{ I . S
Temperature aF electrolyte 45~C
Catho(lic current densitY S A/d~
,, ~, , 2 ~ 6~9 ~ Treating time 3 seconds Conditons for tin platin~
Compositon of electrolyte SnC12 28 g/l as Sn2+
NaF 30 g/l ;~
NaCI 50 g~l Gelatine 3 g/l pH 2.5 Temperature of electrolyte 60 Cathodic current densit~ 15 A/d~
Conditions for chromate treatment Composition of electrol~te Na2Cr207 2H2O 30 g/l Temperature of electrolgte 60 Cathodic current densitY 3 A/d~
Comparati~e Exanple 1 The sa~e kind of steel sheet pletreated as in E~a~ple 1 was treated under the following conditions and ~as then rinsed ~ith water and dried.
_onditions of electrolytic chromic acid treat~ent Composition of electrolgte CrO3 80 g/l HBF4 O.S g/l H2SO4 0.5 g/l Teoperature of electrolyte 45 Cathodic current densitY 20 A/d~
4 O
ComparatiYe e3ample 2 The same kind of steel sheet pretreated as in E2a~ple 1 was plated with tin under the follawing conditions.
; Canditions For tin plating Compasitiaa of electraIyte SnSO4 30 g/l as Sn2~
Phenolsulfonic acid ~60 ~ solution) 20 g/l Etho3~1ate[1 ~ -naphthol 5 g~t pH 0.8 Temperature of electrol~te 40 Cathodic current densitY 8 A/d~
After rinsing with water, the tin plated steel sheet was treated under the follawing conditions and was then rinsed and d:ried.
Conditions for chromate trea ment Compasiton aF electralyte Na2Cr2O7 2 li2 Temperature af electrol~te 60 Cathodic current densit~ 10 A~d~
Comparati7e esa~ple 3 The same kind of steel sheet pretreated as in E~ample 1 was plated with tin under the same canditions as in Comparati~e E~ample 2. After rinsing with water, the tin plated steel sheet ~as treated under the sa~e cunditiaus as in Comparati~e E3ample 1 and was then rinsed with iater and dried.
The weldabilit~, lac(lller adhesion and corrosion resistance of the thtls treated steel sheet in the above described E~arrples and Comparati~e E3aples were e~aluated by the f~llowing testing methods after the measurements of the amounts of metallic chrnmiu~t, metallic tin, metallic nickel and chro~iu~t in the hydrated chro~iu~ o~ide by the fluorescent X-rag method.
The results are shown in the attached Table.
~ I)Weldabilit~
The weldabilit7 is usuallg e~aluated by an a~ailable range of secondarg current in welding as shown in the .e~ort bg N.T.
'~ilZiams ~Metal Construction, April 1977, page 157~ 160), that is to sag, the wider the secondarg current range in welding, the better the weldabilit~. The uPper limit in the a~ailable secondarg current range corresponds to the welding conditions ilt which some defect such as splashing is found and the lot~er limit corresponds to the uelding cDnditions in which the breakage occurs in the welded part bY tearing tests.
Howe~er, in arder to determine the a~ailable range oF
sec~ndarg current in welding to be used in each sample, a large number oF samples are necessary.
rherefore, the weldabilit7 was e~aluated b~ the electric contact resistance according to the fallo~iLtg rtethods, because the electricul cDutact resistance has an apparent correlat ian tD the a~ailable range of secondarg current in welding as shown in the report by T.l~uJi~ura (Journal of The iron and ~ 2 ~Z669 " . ~
Steel Institute of Japan, Yol.69, No. 13, Septe~ber 1983, page 181), that is, the loNer the electric contact resistance, the wider the secondarg current range in welding. Accordingly, if the electric contact resistance is lower, the weldability is better.
At first, the sa~ple ~as cut to a size of 20~ X 100~-after baking at 210 ~ for Z0 ~inutes.
The electric contact resistance of the sa~ple was calculated from the chan$e of ~oltage between a pair of copper disk electrodes (dia~eter: 65~3, thickness 2~o) wherein 5 amperes of direct current was e~plo~ed and 50 kg of load was added, when a pair of samples were inserted into between a pair of the copper disk electrodes rotating at 5 mJmin.
(2) Lacquer adhesion The sa~ple was baked at 210 ~ for 12 ~inutes after coating with 60 mgtd~ of an epo~y-phenolic type of lacquer.
The coated sample was cut into a circular blan~ ha~ing a dia~eter of 80 m3 by a punch press, and the blank was deeplY
drawn to form a cup.
The lacquer film in the side wall of a cup ~as peeled off b~ an adhesiYe tape. The adhesion of the lacquer fil~ was di~ided into 5 ranks, naDely, 5 ffas e~cellent, 4 was good, 3 was fair, 2 was poor and 1 was bad.
(3) Corrosion resistance after lacquer coating The saople ~as baked at 210 ~ for 12 oinutes after ~ 9 ,...~
coating with 60 ~g/d~ of an epo~-phenolic t~pe of lacquer.
The coated sa~ple was i~ersed into the solution containing--1.5 g of citric acid and 1.5 % of sodiu3 chloride for 7 days at 50 ~ , after the surface of the coated sa~ple Nas cross-hatched by a razor.
The corrosian in the scratched part of the coated sa~ple was di~ided into 5 ranks, na~el~, 5 was e2cellent, 4 was good, 3 was fair, 2 was poor and 1 was bad.
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ComparatiYe e3ample 2 The same kind of steel sheet pretreated as in E2a~ple 1 was plated with tin under the follawing conditions.
; Canditions For tin plating Compasitiaa of electraIyte SnSO4 30 g/l as Sn2~
Phenolsulfonic acid ~60 ~ solution) 20 g/l Etho3~1ate[1 ~ -naphthol 5 g~t pH 0.8 Temperature of electrol~te 40 Cathodic current densitY 8 A/d~
After rinsing with water, the tin plated steel sheet was treated under the follawing conditions and was then rinsed and d:ried.
Conditions for chromate trea ment Compasiton aF electralyte Na2Cr2O7 2 li2 Temperature af electrol~te 60 Cathodic current densit~ 10 A~d~
Comparati7e esa~ple 3 The same kind of steel sheet pretreated as in E~ample 1 was plated with tin under the same canditions as in Comparati~e E~ample 2. After rinsing with water, the tin plated steel sheet ~as treated under the sa~e cunditiaus as in Comparati~e E3ample 1 and was then rinsed with iater and dried.
The weldabilit~, lac(lller adhesion and corrosion resistance of the thtls treated steel sheet in the above described E~arrples and Comparati~e E3aples were e~aluated by the f~llowing testing methods after the measurements of the amounts of metallic chrnmiu~t, metallic tin, metallic nickel and chro~iu~t in the hydrated chro~iu~ o~ide by the fluorescent X-rag method.
The results are shown in the attached Table.
~ I)Weldabilit~
The weldabilit7 is usuallg e~aluated by an a~ailable range of secondarg current in welding as shown in the .e~ort bg N.T.
'~ilZiams ~Metal Construction, April 1977, page 157~ 160), that is to sag, the wider the secondarg current range in welding, the better the weldabilit~. The uPper limit in the a~ailable secondarg current range corresponds to the welding conditions ilt which some defect such as splashing is found and the lot~er limit corresponds to the uelding cDnditions in which the breakage occurs in the welded part bY tearing tests.
Howe~er, in arder to determine the a~ailable range oF
sec~ndarg current in welding to be used in each sample, a large number oF samples are necessary.
rherefore, the weldabilit7 was e~aluated b~ the electric contact resistance according to the fallo~iLtg rtethods, because the electricul cDutact resistance has an apparent correlat ian tD the a~ailable range of secondarg current in welding as shown in the report by T.l~uJi~ura (Journal of The iron and ~ 2 ~Z669 " . ~
Steel Institute of Japan, Yol.69, No. 13, Septe~ber 1983, page 181), that is, the loNer the electric contact resistance, the wider the secondarg current range in welding. Accordingly, if the electric contact resistance is lower, the weldability is better.
At first, the sa~ple ~as cut to a size of 20~ X 100~-after baking at 210 ~ for Z0 ~inutes.
The electric contact resistance of the sa~ple was calculated from the chan$e of ~oltage between a pair of copper disk electrodes (dia~eter: 65~3, thickness 2~o) wherein 5 amperes of direct current was e~plo~ed and 50 kg of load was added, when a pair of samples were inserted into between a pair of the copper disk electrodes rotating at 5 mJmin.
(2) Lacquer adhesion The sa~ple was baked at 210 ~ for 12 ~inutes after coating with 60 mgtd~ of an epo~y-phenolic type of lacquer.
The coated sample was cut into a circular blan~ ha~ing a dia~eter of 80 m3 by a punch press, and the blank was deeplY
drawn to form a cup.
The lacquer film in the side wall of a cup ~as peeled off b~ an adhesiYe tape. The adhesion of the lacquer fil~ was di~ided into 5 ranks, naDely, 5 ffas e~cellent, 4 was good, 3 was fair, 2 was poor and 1 was bad.
(3) Corrosion resistance after lacquer coating The saople ~as baked at 210 ~ for 12 oinutes after ~ 9 ,...~
coating with 60 ~g/d~ of an epo~-phenolic t~pe of lacquer.
The coated sa~ple was i~ersed into the solution containing--1.5 g of citric acid and 1.5 % of sodiu3 chloride for 7 days at 50 ~ , after the surface of the coated sa~ple Nas cross-hatched by a razor.
The corrosian in the scratched part of the coated sa~ple was di~ided into 5 ranks, na~el~, 5 was e2cellent, 4 was good, 3 was fair, 2 was poor and 1 was bad.
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Claims (23)
1. A surface treated steel sheet consisting of a steel base having three layers thereon in the following order: a bottom layer of 30 to 300 mg/m2 of metallic chromium, a middle layer of 10 to 500 mg/m2 of metallic tin or 10 to 500 mg/m2 of tin-nickel alloy containing 20 to 60 weight % of nickel and a top layer of hydrated chromium oxide of 2 to 18 mg/m2 as chro-mium.
2. The surface treated steel sheet according to claim 1, wherein the amount of metallic chromium in said bottom layer is from 70 to 150 mg/m2, the amount of metallic tin or tin-nickel alloy being from 50 to 300 mg/m2 and the amount of hydrated chromium oxide in said top layer being from 4 to 12 mg/m2 as chromium.
3. A process for continuously preparing a surface treated steel sheet consisting of a steel base having thereon three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer of hydrated chromium oxide, which process comprises:
a) chromium plating a steel base to form a layer of metallic chromium and a layer of hydrated chromium oxide thereon;
b) tin plating the chromium plated steel base with a tin plating solution having a pH of 0.5 to 3.0 and containing 2 to 10 g/l of stannous ion at a temperature of 30° to 60°C or tin-nickel alloy plating the chromium plated steel base with a tin-nickel plating solution having a pH of 8 to 10 and containing 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to 3 concentration ratio of stannous ion to nickel ion, 80 to 300 g/l of an alkali metal pyrophos-phate at a temperature of 40° to 60°C; and c) forming a layer of hydrated chromium oxide on the tin or tin-nickel plated, chromium plated steel base of step b) by a cathodic treatment in a hexavalent chromium containing solution at a tempera-ture of 30° to 70°C.
a) chromium plating a steel base to form a layer of metallic chromium and a layer of hydrated chromium oxide thereon;
b) tin plating the chromium plated steel base with a tin plating solution having a pH of 0.5 to 3.0 and containing 2 to 10 g/l of stannous ion at a temperature of 30° to 60°C or tin-nickel alloy plating the chromium plated steel base with a tin-nickel plating solution having a pH of 8 to 10 and containing 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to 3 concentration ratio of stannous ion to nickel ion, 80 to 300 g/l of an alkali metal pyrophos-phate at a temperature of 40° to 60°C; and c) forming a layer of hydrated chromium oxide on the tin or tin-nickel plated, chromium plated steel base of step b) by a cathodic treatment in a hexavalent chromium containing solution at a tempera-ture of 30° to 70°C.
4. A process for continuously preparing a surface treated steel sheet consisting of a steel base having thereon three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer of hydrated chromium oxide, which process comprises:
a) chromium plating a steel base to form a layer of metallic chromium and a layer of hydrated chromium oxide thereon;
b) removing the hydrated chromium oxide formed on the chromium plated steel base by a cathodic treatment in an acidic solution having a pH of 0.5 to 2.0 at a temperature of 30° to 70°C;
c) tin plating the chromium plated steel base with a tin plating solution having a pH of 0.5 to 3.0 and containing 2 to 40 g/l of stannous ion at a temperature of 30° to 60°C or tin-nickel alloy plating solution having a pH of 8 to 10 and containing 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to 3 concentration ratio of stannous ion to nickel ion, 80 to 300 g/l of an alkali metal pyrophosphate at a temperature of 40° to 60°C; and d) forming a layer of hydrated chromium oxide on the tin or tin-nickel plated, chromium plated steel base of step c) by a cathodic treatment in a hexavalent chromium containing solution at a tempera-ture of 30° to 70°C.
a) chromium plating a steel base to form a layer of metallic chromium and a layer of hydrated chromium oxide thereon;
b) removing the hydrated chromium oxide formed on the chromium plated steel base by a cathodic treatment in an acidic solution having a pH of 0.5 to 2.0 at a temperature of 30° to 70°C;
c) tin plating the chromium plated steel base with a tin plating solution having a pH of 0.5 to 3.0 and containing 2 to 40 g/l of stannous ion at a temperature of 30° to 60°C or tin-nickel alloy plating solution having a pH of 8 to 10 and containing 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to 3 concentration ratio of stannous ion to nickel ion, 80 to 300 g/l of an alkali metal pyrophosphate at a temperature of 40° to 60°C; and d) forming a layer of hydrated chromium oxide on the tin or tin-nickel plated, chromium plated steel base of step c) by a cathodic treatment in a hexavalent chromium containing solution at a tempera-ture of 30° to 70°C.
5. The process according to claim 3, wherein said chromium plating onto a steel base is carried out at a temperature of 30 to 60°C and under a cathodic current density of 10 to 100 A/dm2 in an electrolyte containing 30 to 300 g/l of chromic acid and at least one additive 47a selected from the group consisting of a fluorine com-pound and a sulfur compound wherein the amount of said additive is 1 to 5 weight percent of chromic acid.
6. The process according to claim 4, wherein said chromium plating onto a steel base is carried out at a temperature of 30 to 60°C and under a cathodic current density of 10 to 100 A/dm2 in an electrolyte containing 30 to 300g/l of chromic acid and at least one additive selected from the group consisting of a fluorine com-pound and a sulfur compound wherein the amount of said additive is 1 to 5 weight percent of chromic acid.
7. The process according to claims 5 or 6, wherein said fluorine compound is at least one compound selected from the group consisting of hydrofluoric acid, fluoboric acid, fluosilicic acid, ammonium bifluoride, an alkali metal bifluoride, ammonium fluoride, an alkali metal fluoride, ammonium fluoborate, an alkali metal fluoborate, ammonium fluosilicate, an alkali metal fluosilicate and aluminum fluoride.
8. The process according to claims 5 or 6, wherein said sulfur compound is at least one compound selected from the group consisting of sulfuric acid, ammonium sulfate, an alkali metal sulfate, phenolsulfonic acid, ammonium phenolsulfonate, an alkali metal phenolsulfonate, phenoldisulfonic acid, ammonium phenoldisulfonate, an alkali metal phenoldisulfonate, ammonium sulfite, an alkali metal sulfite, ammonium thiodisulfate, an alkali metal thiosulfate, aluminum sulfate and chromium sulfate.
9. The process according to claim 3, wherein said tin plating onto the chromium plated steel base with the removal of hydrated chromium oxide formed on the chromium plated steel base is carried out at a temperature of 30 to 60°C and under a cathodic current density of 3 to 50 A/dm2 in a tin plating electrolyte having a pH of 0.5 to 3.0 and containing 2 to 10 g/l of stannous ion.
10. The process according to claim 4, wherein said removal of hydrated chromium oxide formed on the chromium plated steel base is carried out at a temperature of 30 to 70°C and under a cathodic current density of 2 to 50 A/dm2 and a treating time of 0.5 to 5 seconds in an acidic electrolyte containing at least one acid selected from the group consisting of sulfuric acid, hydrochloric acid, hydrofluoric acid, fluoboric acid and fluosilicic acid having a pH of 0.5 to 2Ø
11. The process according to claims 3 or 4, wherein said tin-nickel alloy plating on the chromium plated steel base is carried out at a temperature of 40 to 60°C
and under a cathodic current density of 1 to 30 A/dm2 in a tin-nickel alloy plating electrolyte having 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to 3 con-centration ratio of stannous ion to nickel ion, 80 to 300 g/l of an alkali metal pyrophosphate and pH of 8 to 10.
and under a cathodic current density of 1 to 30 A/dm2 in a tin-nickel alloy plating electrolyte having 2 to 40 g/l of stannous ion, 4 to 20 g/l of nickel ion, 0.1 to 3 con-centration ratio of stannous ion to nickel ion, 80 to 300 g/l of an alkali metal pyrophosphate and pH of 8 to 10.
12. The process according to claims 3 or 4, wherein said tin-nickel alloy plating on the chromium plated steel base is carried out at a temperature of 30 to 60°C
and under a cathodic current density of 1 to 30 A/dm2 in a tin-nickel alloy plating electrolyte having 2 to 70 g/l of stannous ion, 4 to 80 g/l of nickel ion, 0.1 to 0.8 concentration ratio of stannous ion to nickel ion and pH of 0.5 to 3.
and under a cathodic current density of 1 to 30 A/dm2 in a tin-nickel alloy plating electrolyte having 2 to 70 g/l of stannous ion, 4 to 80 g/l of nickel ion, 0.1 to 0.8 concentration ratio of stannous ion to nickel ion and pH of 0.5 to 3.
13. The process according to claim 4, wherein said tin plating on the chromium plated steel base is carried out at a temperature of 30 to 60°C and under a cathodic current density of 3 to 50 A/dm2 in a tin plating elec-trolyte having a pH of 0.5 to 3.0 and containing 2 to 40 g/1 of stannous ion.
14. The process according to claim 3, wherein said hydrated chromium oxide is formed on the tin or tin-nickel alloy plated steel base by a cathodic treatment in an acidic electrolyte containing at least one com-pound selected from the group consisting of chromic acid, a chromate and a dichromate of an alkali metal, ammonium chromate and ammonium dichromate.
15. The process according to claim 4, wherein said hydrated chromium oxide is formed on the tin or tin-nickel alloy plated steel base by a cathodic treatment in an acidic electrolyte containing at least one com-pound selected from the group consisting of chromic acid, a chromate and a dichromate of an alkali metal, ammonium chromate and ammonium dichromate.
16. The process according to claims 14 or 15, where-in said cathodic treatment is carried out at a tempera-ture of 30 to 70°C and under a cathodic current density of 1 to 20 A/dm2 , a quantity of electricity of 1 to 40 coulombs/dm2 in an acidic electrolyte containing 5 to 30 g/l of hexavalent chromium ion.
17. A process according to claim 3, wherein said hydrated chromium oxide is formed on the tin or tin-nickel alloy plated steel base by a cathodic treatment in an acidic electrolyte containing 10 to 50 g/l of chromic acid and at least one additive selected from the group consisting of a fluorine compound and a sulfur com-pound wherein the amount of said additive being 0.2 to 1.0 weight percent of chromic acid.
18. The process according to claim 4, wherein said hydrated chromium oxide is formed on the tin or tin-nickel alloy plated steel base by a cathodic treatment in an acidic electrolyte containing 10 to 50 g/l of chromic acid and at least one additive selected from the group consisting of a fluorine compound and a sulfur com-pound wherein the amount of said additive being 0.2 to 1.0 weight percent of chromic acid.
19. The process according to claims 17 or 18, wherein said cathodic treatment is carried out at a temperature of 30 to 60°C and under a cathodic current density of 1 to 10 A/dm2 with a quantity of electricity of 1 to 20 coulombs/dm2.
20. The process according to claims 17 or 18, where-in said fluorine compound is at least one compound selected from the group consisting of hydrofluoric acid, fluoboric acid, fluosilicic acid, ammonium bifluoride, an alkali metal bifluoride, ammonium fluoride, an alkali metal fluoride, ammonium fluoborate and an alkali metal fluoborate.
21. The process according to claims 17 or 18, where-in said sulfur compound is at least one compound selected from the group consisting of sulfuric acid, ammonium sulfate, an alkali metal sulfate, phenolsulfonic acid, ammonium phenolsulfonate, an alkali metal phenolsulfonate, phenoldisulfonic acid, ammonium phenoldisulfonate, an alkali metal phenoldisulfonate, ammonium sulfite, an alkali metal sulfite, ammonium thiosulfate, an alkali metal thiosulfate and chromium sulfate.
22. The process of claim 3, wherein water rinsing of the plated steel base is performed after step a) but before step b) and after step b) but before step c).
23. The process of claim 4, wherein water rinsing of the plated steel base is performed after step a) but before step b), after step b) but before step c) and after step c) but before step d).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000454343A CA1242669A (en) | 1984-05-15 | 1984-05-15 | Chrome plated steel sheet with tin or tin-nickel and chromic oxide layers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000454343A CA1242669A (en) | 1984-05-15 | 1984-05-15 | Chrome plated steel sheet with tin or tin-nickel and chromic oxide layers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1242669A true CA1242669A (en) | 1988-10-04 |
Family
ID=4127869
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000454343A Expired CA1242669A (en) | 1984-05-15 | 1984-05-15 | Chrome plated steel sheet with tin or tin-nickel and chromic oxide layers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1242669A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102369310A (en) * | 2009-03-24 | 2012-03-07 | Mtv金属精制有限两合公司 | Layer system with improved corrosion resistance |
| EP2857557A4 (en) * | 2012-05-29 | 2016-04-06 | Toyo Kohan Co Ltd | Surface-treated steel sheet for container having excellent processing adhesion to resin, method for manufacturing same, and can |
-
1984
- 1984-05-15 CA CA000454343A patent/CA1242669A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102369310A (en) * | 2009-03-24 | 2012-03-07 | Mtv金属精制有限两合公司 | Layer system with improved corrosion resistance |
| EP2857557A4 (en) * | 2012-05-29 | 2016-04-06 | Toyo Kohan Co Ltd | Surface-treated steel sheet for container having excellent processing adhesion to resin, method for manufacturing same, and can |
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