US3616299A - Process for producing steel products having a hydrated chromium oxide film excellent in the surface appearance - Google Patents

Process for producing steel products having a hydrated chromium oxide film excellent in the surface appearance Download PDF

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Publication number
US3616299A
US3616299A US809891A US3616299DA US3616299A US 3616299 A US3616299 A US 3616299A US 809891 A US809891 A US 809891A US 3616299D A US3616299D A US 3616299DA US 3616299 A US3616299 A US 3616299A
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United States
Prior art keywords
steel plate
roll
film
plated steel
holddown
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Expired - Lifetime
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US809891A
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English (en)
Inventor
Akira Hata
Tamotu Hinami
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Nippon Steel Corp
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Nippon Steel Corp
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/38—Chromatising

Definitions

  • chromic acid series films especially the hydrated chromium oxide film obtained by the above-mentioned treatment, have a disadvantage that they are so soft as to be likely to be flawed particularly by rolls when they are still wet immediately after electrodeposition.
  • the drawing is a schematic view of an improved electrolysis treatment section for working the present invention.
  • This electrolysis treatment section is connected with degreasing, water-rinsing and pickling steps as the preliminary stage thereof and is followed by a heating and drying step as the latter stage thereof.
  • the improvement of the present invention is characterized only by providing a leveling roll 7 as an auxiliary holddown roll in such manner as shown in the drawing, but is quite the same as the former in other respects.
  • a steel plate is led with conductor rolls 4 and 4' which are provided with holddown rolls 3 and 3 respectively, and with sink rolls 5 which are installed as dipped in an electrolysis bathtub 2, in which there is held a treating solution containing water-soluble hexavalent chromium ions, and meanwhile a required film is formed on the surface of the steel plate.
  • 6 is an anode provided as dipped in the electrolyte and opposed to the surface of the passing plate.
  • These holddown rolls 3 and 3 are coated with material which has a high hardness above 90in the Shore Durometer hardness (A scale) and is difficult to elastically deform as, for example, a hard vinyl chloride, or may be coated with an elastic material ofa comparatively low hardness as of 40to 90in the Shore Durometer hardness (A scale) so that the pressing force may be elevated and the contact between the steel plate and conductor rolls may be improved to prevent the production of arc spots.
  • the surface layer of the anticorrosion film electrodeposited on the steel plate which is made a cathode, is made of hydrated chromium oxide in the form ofa sol, it is so soft that, if the surface of the contacting roll is defective, there is produced an unevenness in coloring, or else the electrodeposited film is easily scraped off and roll marks are left on the film surface while the steel plate is advancing.
  • the steel plate In the case of using the holddown rolls 3 and 3 made of a material having a high hardness the steel plate must suffer from a deterioration of the surface flatness as a result of the fluctuation of the tension of the steel plate during its passage at a high speed as, for example, about 200 to 290 m./min. That is, there appears a phenomenon of the steel plate being drawn by deformation, whereby the surface of the holddown rolls are flawed, again causing the soft electrodeposited film to scrape off by irregular flaws thus formed on the roll surface.
  • the treating solution was mainly composed of chromic acid series chemical having a strong oxidizing property. Consequently, a higher cost had to be paid for the lining materials.
  • the present inventors have made various investigations to eliminate such disadvantages and have confirmed as the result of the investigations that it is almost impossible to obtain the treated steel plate having a uniform film on its surface when selecting the elastic material for lining the surface of the holddown rollfrom those comparatively low in hardness to elevate the pressing force only, because in this case the holddown roll is largely elastically deformed and the contact area between the steel plate and the holddown roll surface expanded, whereby the formed corrosion-resisting film is often easily scraped off, but that the corrosion-resisting film on the side in contact with the conductor roll is substantially not flawed, irrespective of the hardness of the surface lining material of the holddown roll, because the conductor roll is plated on the surface with hard chromium.
  • the object of the present invention is to provide a method of continuously electrolytically treating steel plates to fonn thereon a surface layer of a hydrated chromium oxide film having a beautiful and uniform surface by erasing flaws or holddown roll marks unavoidably produced on the electrodeposited film surface owing to such flawed holddown rolls as is mentioned above.
  • flaws on the film surface may be erased by pressing the film surface on the side of the holddown roll 3' using a leveling roll (in the drawing this roll is indicated by a number 7), said leveling roll being lined with an elastic material having a surface hardness of 40to in the Shore Durometer (A scale) and being provided in the rear of the holddown roll 3 a hardness of more than 90or generally lOin the Shore Durometer (A scale), said holddown roll 3' being provided as attached to the final conductor roll 4' on the peripheral surface thereof, the steel plate 1 passing between said holddown roll 3' and the final conductor roll 4' after having finally left the electrolytic bath 2, or being provided as a roll separate from the above-mentioned conductor roll between said conductor roll 4 and a film heating and drying section (not illustrated).
  • a leveling roll in the drawing this roll is indicated by a number 7
  • said leveling roll being lined with an elastic material having a surface hardness of 40to in the Shore Durometer (A scale) and being provided in the rear of
  • the leveling roll 7 is provided on the final conductor roll 4 as is shown in the drawing or is provided in the part within drag-out tanks No. l, 2 ..arranged in connection with the latter part of the electrolytic treating section but so adjacent to the electrolytic treating section as possible, or a deflector roll of the said dragout tanks is utilized as a leveling roll, though not illustrated.
  • the hardness of the elastic member applied to line the surface of the leveling roll is 40to 90in the Shore Durometer (A scale), that is, lower than that of the above-described holddown roll.
  • the position of fitting the leveling roll is not limited to only those mentioned above, but any effective position may be found within the range covering from the final conductor roll to the heating and drying section. Further, it is to be noted, that at least either one of the leveling rolls, when they are arranged in a pair, must have a surface of an elastic member.
  • the steel plate means a cold-rolled steel sheet, chromium-plated steel plate, zinc-plated steel plate, tin-plated steel plate or any other iron or steel product, a continuous steel strip of a thickness of about'O. l 2 to 1.2 mm. being preferred.
  • the leveling roll 7 in the rear of the holddown roll 3' so as to be opposed to the surface of the conductor roll 4' where the film on the steel plate 1 is still wet just after it is electrodeposited until it is heated and dried.
  • the leveling roll need not always be opposed to the conductor roll 4' and can be provided independently in the rear of the conductor roll 4' together with an opposed roll (not illustrated).
  • the leveling roll 7 is made to act on the electrodeposited film while it is still wet. Once the film dries, it becomes very difficult to erase the flaws made on the film surface.
  • the effect of leveling the film surface with the leveling roll 7 can also be adjusted by regulating the wet state of the film surface by applying such means as spraying the electrolyte onto the film surface between the holddown roll 3' and leveling roll 7.
  • the leveling roll 7 is desirably to be of a hardness of 40 to 90 or preferably 60 to 75 in the Shore Durometer hardness on the A scale.
  • the elastic material is selected from a group consisting of a chromic acidproof rubber, chloroprene rubber, polypropylene, vinylidene chloride, chlorinated polyethylenevinyl chloride and chlorosulfonated polyethylene resin which will not deteriorate in contact with said solution.
  • a roll lined with a rubber material made mainly of a chlorinated polyethylene resin is most preferable.
  • the surface hardness of the leveling roll is limited to within the range of 40 to 90 in the Shore Durometer hardness on the A scale. This is because, when the hardness is more than the roll surface will be too hard and will be likely to be flawed and when the hardness is less than 40 it will be difficult to erase flaws on the film surface.
  • this leveling roll 7 is arranged in the rear of the holddown roll 3 or 3 so that it may work together with said'holddown roll 3 or 3 lined for example, with a hard vinyl chloride resin of a high hardness of more than 90 in the Shore Durometer hardness on the A scale, it is possible to obtain a steel plate having a uniform smooth anticorrosion film free from are spots and roll marks or scratches.
  • the surfaces of the rolls located in the plate passing section from the final conductor roll to the heating and drying step should have a hardness which is the same as or lower than the hardness of the above-described leveling roll. But their pressing force can be higher than that of said leveling roll in some cases.
  • the object of the present invention is not limited to the hydrated chromium oxide coated steel plate as shown in the following example, but also includes chromic acid coated materials made with any other bath composition, and the means of erasing roll marks in the chromium oxide coating, and in addition thereto the position of setting the leveling roll, the material for lining the leveling roll, the pressing force and others may be altered freely within the scope of the claims.
  • the electrolytic treating solution was an aqueous solution of 45g./l. of chromic anhydride and 0.4g./l. of sulfuric acid at a bath temperature of 55C.
  • the above-mentioned steel strip was electrolytically treated as a cathode at a current density of 30 amp./dm. for 3seconds and was advanced at a high speed through the above-mentioned final conductor roll, drag-out tanks and wringer rolls to the heating and drying step.
  • the steel plate was water-washed and was then dried to obtain a product having a uniform electrodeposited film rich in luster and having no color irregularity, roll mark or coating defect.
  • a process for producing steel products having a hydrated chromium oxide film excellent in the surface appearance by electrodepositing an anticorrosion film by electrolytically treating an iron or steel product as a cathode in an electrolyte containing hexavalent chromium ions comprising a step of pressing the electrodeposited film surface with a leveling roll of a surface hardness of 40 to 90 in the Shore Durometer hardness (A Scale) while said electrodeposited film is still wet after the steel product coated with the electrodeposited film has passed a holddown roll provided on a final conductor roll.
  • said iron or steel product is a continuous cold-rolled steel sheet, steel plate, chromium-plated steel plate, zinc-plated steel plate or tinplated steel plate.
  • said iron or steel product is a continuous cold rolled steel sheet, steel plate. chromium-plated steel plate, zinc-plated steel plate or tinplated steel plate.
  • a process for producing steel products having a hydrated chromium oxide film excellent in the surface appearance by electrodepositing an anticorrosion film by electrolytically treating an iron or steel product as a cathode in an electrolyte containing hexavalent chromium ions comprising a step of pressing the electrodeposited film surface with a leveling roll of a surface hardness of 40 to 90 in the Shore Durometer hardness (A scale) under a maximum pressure of 30kg./cm.” while said electrodeposited film is still wet after the steel product coated with the electrodeposited film has passed a 5 holddown roll provided on a final conductor roll.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Chemical Treatment Of Metals (AREA)
US809891A 1968-03-28 1969-03-24 Process for producing steel products having a hydrated chromium oxide film excellent in the surface appearance Expired - Lifetime US3616299A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1971768 1968-03-28
NL6908669.A NL162974C (nl) 1968-03-28 1969-06-06 Werkwijze voor het aanbrengen van een tegen corrosie bestand zijnde bekledingslaag op banden of platen van ijzer of staal.

Publications (1)

Publication Number Publication Date
US3616299A true US3616299A (en) 1971-10-26

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US809891A Expired - Lifetime US3616299A (en) 1968-03-28 1969-03-24 Process for producing steel products having a hydrated chromium oxide film excellent in the surface appearance

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US (1) US3616299A (enrdf_load_stackoverflow)
BE (1) BE730531A (enrdf_load_stackoverflow)
FR (1) FR2004968A1 (enrdf_load_stackoverflow)
GB (1) GB1253422A (enrdf_load_stackoverflow)
NL (1) NL162974C (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090250136A1 (en) * 2008-04-07 2009-10-08 Illinois Tool Works Inc. Corrosion resistant sheet metal jacketing
CN104878332A (zh) * 2015-06-03 2015-09-02 河北钢铁股份有限公司邯郸分公司 一种提高热基镀锌板带产品耐腐蚀性能的生产方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4296182A (en) * 1978-05-08 1981-10-20 Toyo Seikan Kaisha Limited Can composed of electrolytically chromated steel

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1488553A (en) * 1923-01-26 1924-04-01 Willis G Waldo Process of coating sheet steel with aluminum
FR1080914A (fr) * 1953-06-16 1954-12-14 United States Steel Corp Procédé électrochimique de revêtement des surfaces en acier, produits destinés à sa mise en oeuvre et produits en résultant
FR1309576A (fr) * 1961-12-21 1962-11-16 Fuji Iron & Steel Co Ltd Tôle d'acier chromé destinée à recevoir une peinture ou un autre revêtement ou enduit

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090250136A1 (en) * 2008-04-07 2009-10-08 Illinois Tool Works Inc. Corrosion resistant sheet metal jacketing
US10208885B2 (en) * 2008-04-07 2019-02-19 Illinois Tool Works Inc. Corrosion resistant sheet metal jacketing
CN104878332A (zh) * 2015-06-03 2015-09-02 河北钢铁股份有限公司邯郸分公司 一种提高热基镀锌板带产品耐腐蚀性能的生产方法

Also Published As

Publication number Publication date
NL6908669A (enrdf_load_stackoverflow) 1970-12-08
NL162974C (nl) 1980-07-15
FR2004968A1 (enrdf_load_stackoverflow) 1969-12-05
DE1916049A1 (de) 1969-10-02
DE1916049B2 (de) 1976-10-28
BE730531A (enrdf_load_stackoverflow) 1969-09-01
NL162974B (nl) 1980-07-15
GB1253422A (en) 1971-11-10

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