US3379557A - Suppression of visible spangle - Google Patents

Suppression of visible spangle Download PDF

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Publication number
US3379557A
US3379557A US380533A US38053364A US3379557A US 3379557 A US3379557 A US 3379557A US 380533 A US380533 A US 380533A US 38053364 A US38053364 A US 38053364A US 3379557 A US3379557 A US 3379557A
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United States
Prior art keywords
coating
strip
temperature
spangle
salts
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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 - Lifetime
Application number
US380533A
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English (en)
Inventor
George R Hoover
Paul E Schnedler
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Armco Inc
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Armco Inc
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Filing date
Publication date
Application filed by Armco Inc filed Critical Armco Inc
Priority to US380533A priority Critical patent/US3379557A/en
Priority to GB28139/65A priority patent/GB1117323A/en
Priority to DE1521109A priority patent/DE1521109C3/de
Priority to AT612365A priority patent/AT268817B/de
Application granted granted Critical
Publication of US3379557A publication Critical patent/US3379557A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/50—Controlling or regulating the coating processes
    • C23C2/52—Controlling or regulating the coating processes with means for measuring or sensing

Definitions

  • ABSTRACT OF THE DISLOSURE A method of suppressing visible spangle in non-alloy coatings on metallic strips by inducing substantially submacroscopic spangling.
  • a water solution of an inorganic salt is applied to a freshly coated strip at a point where the temperature of the molten coating metal on the strip is above its solidification temperature.
  • the inorganic salt is selected from the class consisting of inorganic salts which decompose in the range of 175 to 550 F. and those salts which will hydrolize when added to water to form inorganic salts capable of decomposing in the above stated temperature range.
  • This invention relates to spangle metallic coatings wherein the amount of visible spangle is suppressed.
  • Spangle is the name given to the appearance of metallic coating on metal strip which is characterized by visible crystalline boundary outlines.
  • spangle has generally been considered a desirable characteristic because it gives an attractive appearance to the finished product.
  • a surface having such a sub-macroscopic spangle can be painted without the problem of the crystalline boun ary showing through.
  • a very important object of the invention is to provide solidification nuclei which greatly enhance the formation of the multitude of closely spaced, relatively minute, spangles which will give, to the naked eye, a coated strip with a substantially unspangled appearance.
  • a metallic strip is first coated in any desired manner.
  • a multitude of solidification nuclei are then applied to the molten coating when such coating is at a temperature very close to the solidification point (or freezing point) of the coating metal.
  • These nuclei are applied in a band transversely of the direction of strip travel, the band having such a width, having regard to the particular solidification nuclei being employed, that the coating metal is molten as it enters the band and solid as it leaves the band.
  • the solidification nuclei of this invention consist of that group of reactive inorganic salts which decompose in the range of to 550 F. Of this group di-basic ammonium phosphate (which decomposes at 180 to 210 F.) is preferred. It has been determined that the salts of this group, applied to the galvanized surface as taught herein, produce a highly satisfactory surface having an unspangled appearance. The use of these salts does not foul up the equipment and Work area; these salts and their decomposition products, do not promote corrosion or deterioration of equipment or buildings. They are safe to use-- they, their decomposition products, are non-toxic and will not harm the operator nor cause him unpleasantness. These salts are largely readily available and economical to use.
  • Salts that have decomposition temperatures much below 175 F. appear to be too fugitive to produce the desired results.
  • Ammonium bicarbonate for example, decomposes at 104 F. and has been found to be of little value. Salts having decomposition temperatures above 550 F. have little or no effect; their solutions are rated no better than Water.
  • Na- CO NaHCO Na- CO NaHCO
  • tri-sodium phosphate (not in the range as such) which reacts with water to form sodium phosphate (which is in the range) and sodium hydroxide.
  • Substances having the hydroxyl radical may, as indicated, form a non-desirable residue on the strip, but which residue is easily rinsed otf.
  • the designated solidification nuclei of this invention described as reactive inorganic salts which decompose in the range of 175 to 550 F., must be considered as including those salts which, although initially outside the designated range when considered alone, will hydrolize when added to water to form a salt within the range plus an hydroxide which can be rinsed off.
  • a coating pot is shown at containing a body of molten coating metal 11.
  • the pot is provided with the usual pot roll 12 and a strip of metal 13, which has been given any desired pretreatment, is led into the pot and around the roll 12 and exits vertically upward through an exit machine 14.
  • the coated strip 13a passes vertically upward to a turning roll 15 and thence to suitable coiling apparatus or the like.
  • the por tion of the apparatus heretofore described is in all respects conventional and will not be described in further detail. It is to be understood that the invention is applicable to galvanizing processes in general and is not restricted to any particular mode of applying the zinc coating.
  • the minimizing of spangle by inducing sub-macroscopic spangling is accomplished by applying a multitude of the designated solidification nuclei to the molten coating of the strip.
  • the process comprises spraying the strip or sheet while the zinc coating is still in the molten state as will be further described below, with a solution of the selected reactive inorganic salt in water.
  • the spray may be in the form of a moderately fine mist aspirated by means of air or steam, or it may be produced by pressure of the solution through properly designed nozzles.
  • Preferably standard paint spray guns may be employed to apply the treating solution.
  • di-basic ammonium phosphate is used as the reactive inorganic salt and steam as the aspirating media.
  • the point in the travel of the coated strip at which the solidification nuclei are applied is quite critical. If the temperature of the coating is too high when the nuclei are projected onto the coating, the action of inducing submacroscopic spangling is ineffective. If the temperature is too low, then of course solidification with normal spangle formation has already occurred. Generally speakin g, therefore, the particles must contact the surface of the molten coating while the temperature of that surface is just above the freezing point of the coating metal. Zinc, for example, is considered as having a freezing point of 787 F. and the particles should contact this coating metal at a temperature just above the freezing point, preferably up to about 10 F, or even up to 25 to 40 F., thereabove, depending on the quenching qualities of the cooling media.
  • the coating temperature at which the spray of solidification nuclei must contact it will depend also upon the cooling or quenching qualities of the spray. If a spray of a high volume of water is used, there will be a greater quenching action and therefore the coating could be hotter at the point where it is sprayed. If a fine spray of these particles is used, the temperature of the coating should be only very slightly above the solidification temperature. If an aqueous solution is used, the volume of the solvent must be considered with respect to its quenching action and it must be insured that the solvent does not quench the coating to a temperature below its freezing point before the solute particles can serve their function as solidi fication nuclei. Furthermore, the use of large quantities of water is to be avoided because there is the problem of disposing of that portion which is not converted to steam and because such a volume will disrupt the smoothness of the surface.
  • the spray heads or other projecting apparatus should also move up and down to compensate for this.
  • pure zinc is not the only galvanizing coating that may be used; the galvanizing spelter commonly includes additives and even impurities which will change the freezing point, and there fore the spangle forming point,.of.the bath material.
  • the point at which the application of the solidification nuclei is most effective is in the previously designated range of say up to 10 F., or even up to 25 to 40 F., above the freezing point of the particular bath employed.
  • a vertical guide 16 disposed adjacent the vertically moving coated strip 13a.
  • An element 17 is movable vertically along the guide 16 and carries the spray heads 18 and a sensing device 19.
  • the sensing device 19 is a radiation pyrometer or infrared pyrometer. Such devices are available commercially and have the advantage that they can measure temperature in the ranges here under consideration quite accurately without contacting the strip.
  • a signal from the radiation pyrometer 19 actuates a.
  • the sprays from the spray head 18 extend entirely transversely across the strip and that the width of the spray in the direction of strip travel will be such, having due regard to the material being sprayed, that the coating which enters the band in a molten condition will leave the band in a solid condition.
  • Cook et al. 2,126,244 and Coifman 2,764,808 disclose the spraying of galvanized ware with a water mist or a water solution of copper sulphate, sodium nitrate, sodium chloride, potassium chromate or potassium permanaganate in an efiort to produce Ware having an unspangled appearance.
  • Cotfman discloses the concept of automatic mechanism controlled by the temperature of the coating bath for automatically adjusting the vertical position of bonding rolls in a system wherein layers of fibrous material are secured to an iron or steel sheet.
  • the method of suppressing visible spangle by inducing substantially submacroscopic spangling including the step of applying to the freshly coated strip, at a point where the temperature of said molten coating metal on said strip is above its solidification temperature, a water solution of a salt selected from the class consisting of reactive inorganic salts which decompose in the range of 175 to 550 F. and release radicals reactive with metallic zinc and those salts which will hydrolize when added to Water to form a reactive inorganic salt decomposable in said range, said salts and their decomposition products being non-toxic and leaving no harmful, difiiculty removable residues on said coated strip.
  • a salt selected from the class consisting of reactive inorganic salts which decompose in the range of 175 to 550 F. and release radicals reactive with metallic zinc and those salts which will hydrolize when added to Water to form a reactive inorganic salt decomposable in said range, said salts and their decomposition products being non-toxic and leaving no harmful,
  • said salt is chosen from the class consisting of di-basic ammonium phosphate, sodium bicarbonate, sodium phosphate, ammonium borate, ammonium molybdate, ammonium sulfate, sodium carbonate and tri-sodium phosphate.
  • the method of claim 1 including the step of subjecting the strip to a water rinse after the substantially submacroscopic spangling has been induced.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Coating With Molten Metal (AREA)
  • Chemical Treatment Of Metals (AREA)
US380533A 1964-07-06 1964-07-06 Suppression of visible spangle Expired - Lifetime US3379557A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US380533A US3379557A (en) 1964-07-06 1964-07-06 Suppression of visible spangle
GB28139/65A GB1117323A (en) 1964-07-06 1965-07-02 Suppression of visible spangle in the hot dip coating of ferrous metal strip with zinc
DE1521109A DE1521109C3 (de) 1964-07-06 1965-07-03 Verfahren zur Vermeidung einer sichtbaren Blumenbildung beim Überziehen von Metallband durch Feuerverzinken
AT612365A AT268817B (de) 1964-07-06 1965-07-06 Verfahren zur Herabsetzung des sichtbaren Glanzes metallischer Überzüge

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US380533A US3379557A (en) 1964-07-06 1964-07-06 Suppression of visible spangle

Publications (1)

Publication Number Publication Date
US3379557A true US3379557A (en) 1968-04-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
US380533A Expired - Lifetime US3379557A (en) 1964-07-06 1964-07-06 Suppression of visible spangle

Country Status (4)

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US (1) US3379557A (de)
AT (1) AT268817B (de)
DE (1) DE1521109C3 (de)
GB (1) GB1117323A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523036A (en) * 1966-03-09 1970-08-04 Chiers Hauts Fourneaux Method of preventing spangle formation on hot-dip galvanized steel strip
AU579376B2 (en) * 1984-06-22 1988-11-24 Union Siderurgique Du Nord Et De L'est De La France (Usinor) S.A. Optimizing process and device in a process for reducing the size of the flowering of a galvanized steel strip
WO2003048403A1 (fr) * 2001-12-04 2003-06-12 Centre De Recherches Metallurgiques Asbl - Centrum Voor Research In De Metallurgie Vzw Procede de revetement de surface metallique
US20080206592A1 (en) * 2004-12-28 2008-08-28 Posco Galvanized Stell-Sheet Without Spangle, Manufacturing Method Thereof and Device Used Therefor
EP2964805A4 (de) * 2013-03-06 2016-10-12 Quaker Chem Corp Hochtemperaturwandlungsbeschichtung auf stahl- und eisensubstraten
CN116219346A (zh) * 2023-02-24 2023-06-06 鞍钢股份有限公司 一种无锌花热镀铝锌镀层钢板的制造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2126244A (en) * 1935-12-13 1938-08-09 Wheeling Steel Corp Metal coated product
US2764808A (en) * 1949-06-04 1956-10-02 Robertson Co H H Method of producing a protected metal article
US2950991A (en) * 1959-04-30 1960-08-30 American Chain & Cable Co Method and apparatus for coating ferrous metal with aluminum

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2126244A (en) * 1935-12-13 1938-08-09 Wheeling Steel Corp Metal coated product
US2764808A (en) * 1949-06-04 1956-10-02 Robertson Co H H Method of producing a protected metal article
US2950991A (en) * 1959-04-30 1960-08-30 American Chain & Cable Co Method and apparatus for coating ferrous metal with aluminum

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3523036A (en) * 1966-03-09 1970-08-04 Chiers Hauts Fourneaux Method of preventing spangle formation on hot-dip galvanized steel strip
AU579376B2 (en) * 1984-06-22 1988-11-24 Union Siderurgique Du Nord Et De L'est De La France (Usinor) S.A. Optimizing process and device in a process for reducing the size of the flowering of a galvanized steel strip
WO2003048403A1 (fr) * 2001-12-04 2003-06-12 Centre De Recherches Metallurgiques Asbl - Centrum Voor Research In De Metallurgie Vzw Procede de revetement de surface metallique
BE1014525A3 (fr) * 2001-12-04 2003-12-02 Ct Rech Metallurgiques Asbl Procede de revetement de surface metallique.
US20080206592A1 (en) * 2004-12-28 2008-08-28 Posco Galvanized Stell-Sheet Without Spangle, Manufacturing Method Thereof and Device Used Therefor
US7914851B2 (en) * 2004-12-28 2011-03-29 Posco Method of manufacturing hot-dipped galvanized steel sheet
EP2964805A4 (de) * 2013-03-06 2016-10-12 Quaker Chem Corp Hochtemperaturwandlungsbeschichtung auf stahl- und eisensubstraten
US9926628B2 (en) 2013-03-06 2018-03-27 Quaker Chemical Corporation High temperature conversion coating on steel and iron substrates
CN116219346A (zh) * 2023-02-24 2023-06-06 鞍钢股份有限公司 一种无锌花热镀铝锌镀层钢板的制造方法

Also Published As

Publication number Publication date
DE1521109B2 (de) 1973-07-19
GB1117323A (en) 1968-06-19
DE1521109A1 (de) 1969-08-07
DE1521109C3 (de) 1974-03-07
AT268817B (de) 1969-02-25

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