US3690940A - Preventing rusting of steel sheets coated with aqueous slurry of metal powder - Google Patents

Preventing rusting of steel sheets coated with aqueous slurry of metal powder Download PDF

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US3690940A
US3690940A US90379A US3690940DA US3690940A US 3690940 A US3690940 A US 3690940A US 90379 A US90379 A US 90379A US 3690940D A US3690940D A US 3690940DA US 3690940 A US3690940 A US 3690940A
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steel sheet
metal powder
mol
slurry
aqueous slurry
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US90379A
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Hidehisa Yamagishi
Fumitoshi Yokoi
Tadao Takahashi
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JFE Engineering Corp
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Nippon Kokan Ltd
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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
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent

Definitions

  • the slurry is added with corrosion inhibitor to prevent rusting of steel sheet at the time of drying the coating layer thereby improving the adhesion thereof to the steel surface
  • said corrosion inhibitor addition being a compound containing any one of such negative ions as N0 MoO or C H COO- in a concentration ranging from mol/l. to 10- mol/l.
  • the present invention relates to a metal coating method for steel sheets, and more particularly to a method of improving on the adhesion of metal coating layer to the surface of the steel sheet by restraining rusting of the steel sheet which is coated with metal powder in accordance with the water-slurry method at the stage of drying said metal coating layer.
  • the present invention has been developed to provide a novel and useful method in improving on the adhesion of a metal coating layer by modifying thejconventional water-slurry coating method in adding a corrosion inhibitor instead of organic solvent so as to prevent rusting of steel sheet. More particularly, it comprises coating steel sheet with a slurry of metal powder, drying, rolling and heat-treating the same. Said slurry contains one or more of the compounds which contain any one of such negative ions as N0 1 MoO.;-, C H COO in a concentration ranging from 10- mol/l. to 10 mol/l.
  • the curves show the effect of the corrosion inhibitors employed in the present invention.
  • Very small amount of said corrosion inhibitors is added to the waterslurry of metal powder in coating the same on steel sheet.
  • the amount to be added may vary in accordance with the types of inhibitors used, but is within the range of from 10- mol/l. to 10- mol/l.
  • the corrosion inhibitor is a compound containing any one of such negative ions as N0 Mo0 and C H COO, which is soluble in water and which would not chemically react with the particles of metal powder.
  • the concentration of the inhibitor to be added is specified as in the range from l0 mol/l. to 10- mol/l. because:
  • the addition may be carried out by adding any one or more of the corrosion inhibitors into water to dissolve therein, to which metal powder is introduced to prepare a slurry.
  • coating is not restricted to any particular method nor means, and can be done in accordance with the generally practiced ways such as curtain-flow method, spray method or methods using bar-coaters, roll-coaters or brushes.
  • the steel sheet After being coated with a slurry, the steel sheet will be heated to such an extent as to dry the coating layer or to have the metal particles sinter slightly. It is then subjected to rolling in order to improve on the adhesion of the coating layer to the steel sheet.
  • the coating layer after the rolling should show hardening due to the workings, and thus it becomes inferior in the drawability.
  • EXAMPLE 1 Slurry containing 1,500 g. of aluminum powder, 10- mol/l. of NaNO and 1,000 g. of water is coated on steel sheet with a reverse roll-coater to have the coating layer after drying weigh 80 g./m. After drying the coating layer, the steel sheet is rolled to elongate by 7%, and then subjected to heat-treatment in an oxidizing atmosphere of 600 C. for 2 minutes.
  • the resultant product has a gloss surface and is superior in anti-corrosiveness and workability.
  • EXAMPLE 2 Slurry containing 1,500 g. of aluminum powder, 10 mol/l. of Na MoO and 1,200 g. of Water is applied on a steel sheet with the use of a bar-coater.
  • the amount of coating is g./m. when weighed after drying.
  • the steel sheet thus coated is then subjected to heat-treatment in an oxidizing atmosphere for 30 seconds in a furnace temperature of 650 C. and to rolling to elongate by 5%. It is further treated for post-aging treatment in an electric furnace the temperature of which is maintained at 400 C. and rolled for temper regulation.
  • the resultant product is of the same properties as that of Example 1, and exhibits anti-corrosiveness for more than 1,200 hours when subjected to salt spray test (JIS Z2371).
  • EXAMPLE 3 Slurry containing 1,500 g. of aluminum powder, 10- mol/l. of C H COONa, l0- mol/l. of Na MoO and 1,000 g. of water is applied on steel sheet with the use of sprayer. It is subjected to succeeding procedures identical to those of Example 1 such as drying and rolling. The amount of coating weighed after drying is 75 g./m. The ratio of elongation at the time of rolling is 5%. The heattreatment is conducted in accordance with the induction heating system which is so controlled as to raise the temperature of the steel surface to 500 C., in two minutes.
  • the resultant product is of the same properties as those of Examples 1 and 2. It is superior in anti-corrosiveness, and peeling-01f of the coating layer is not observed when formed into sash .(window frame).
  • the present invention enables the improvement of the adhesion of coated layer to steel sheet since the rusting or corrosion at the time of drying is suppressed in steel sheet coated with water-soluble paint and water-slurry.
  • the employment of water in lieu of organic solvent as the dispersing agent in the present invention is economically advantageous.
  • the present invention eliminates danger of fire as compared with the conventional method, as well as it is harmless to bodies.
  • numerous advantages can be expected of the present invention.
  • it may well be applicable to all the corrosion preventive methods in the field wherein a coating is formed on steel sheet with the use of water as a medium such using water-soluble paint, water-slurry, water-soluble emulsion or the like.

Abstract

IN COATING STEEL SHEET WITH AQUEOUS SLURRY OF METAL POWDER, THE SLURRY IS ADDED WITH CORROSION INHIBITOR TO PREVENT RUSTING OF STEEL SHEET AT THE TIME OF DRYING THE COATING LAYER THEREBY IMPROVING ADHESION THEREOF TO THE STEEL SURFACE, SAID CORROSION INHIBITOR ADDITING BEING A COMPOUND CONTAINING ANY ONE OF SUCH NEGATIVE IONS AS NO2-,MOO4--ORC6H5COO- IN A CONCENTRATION RANGING FROM 10**-5 MOL/L. TO 10**-1 MOL/L.

Description

Sept. 12, 1972 H YAMAGISHI ETAL 3,690,940
PREVENTING RUSTING OF STEEL SHEETS COATED WITH AQUEOUS SLURRY OF METAL POWDER Filed NOV. 1'7, 1970 MM 8 M my 6 L U\v SE55 mmim 20 who; 53 6 oz ION CONCENTRATION (MOLAR) United States Patent Int. Cl. B22f 7/04; C23c 17/00 US. Cl. 117-131 2 Claims ABSTRACT OF THE DISCLOSURE In coating steel sheet with aqueous slurry of metal powder, the slurry is added with corrosion inhibitor to prevent rusting of steel sheet at the time of drying the coating layer thereby improving the adhesion thereof to the steel surface, said corrosion inhibitor addition being a compound containing any one of such negative ions as N0 MoO or C H COO- in a concentration ranging from mol/l. to 10- mol/l.
The present invention relates to a metal coating method for steel sheets, and more particularly to a method of improving on the adhesion of metal coating layer to the surface of the steel sheet by restraining rusting of the steel sheet which is coated with metal powder in accordance with the water-slurry method at the stage of drying said metal coating layer.
As for the method of coating surface of steel sheets with a slurry which is prepared by admixing metal powder and a solution, there are one or two methods known in the prior art. However, there is yet no established technique relating to the use of corrosion inhibitor as an additive to suppress the rusting of steel sheet. Therefore, the adhesion of coating layers and steel sheets is always reduced in any of the conventional methods as the steel surface starts rusting at the stage of drying subsequent to coating. And it has been the common practice to use organic solvents in lieu of water in order to obviate such drawbacks. This is still defective in that it may very well lead to generation of poisonous gas and danger of fire as well as it is expensive, although the use of organic solvent may help restrain the rusting.
Under the afore-mentioned circumstances, the present invention has been developed to provide a novel and useful method in improving on the adhesion of a metal coating layer by modifying thejconventional water-slurry coating method in adding a corrosion inhibitor instead of organic solvent so as to prevent rusting of steel sheet. More particularly, it comprises coating steel sheet with a slurry of metal powder, drying, rolling and heat-treating the same. Said slurry contains one or more of the compounds which contain any one of such negative ions as N0 1 MoO.;-, C H COO in a concentration ranging from 10- mol/l. to 10 mol/l.
Reference is now made to the accompanying drawing in which the curves show the effect of the corrosion inhibitors employed in the present invention. Very small amount of said corrosion inhibitors is added to the waterslurry of metal powder in coating the same on steel sheet. As the curves indicate, the amount to be added may vary in accordance with the types of inhibitors used, but is within the range of from 10- mol/l. to 10- mol/l. It is desirable that the corrosion inhibitor is a compound containing any one of such negative ions as N0 Mo0 and C H COO, which is soluble in water and which would not chemically react with the particles of metal powder.
ice
As is evidently understood from the drawing, the concentration of the inhibitor to be added is specified as in the range from l0 mol/l. to 10- mol/l. because:
(1) no efiect thereof can be expected when said concentration is less than l0 mol/L, thereby it is determined that 10* mol/l. is the minimum required amount; on the other hand,
(2) the addition of the corrosion inhibitor exceeding 10- mol/l. may impair the adhesion of coating layer to steel sheet or the finish of the surface, thereby it is determined that 10- mol/l. is the upper limit of the range which will not deteriorate the coating layer.
The addition may be carried out by adding any one or more of the corrosion inhibitors into water to dissolve therein, to which metal powder is introduced to prepare a slurry.
Application of coating is not restricted to any particular method nor means, and can be done in accordance with the generally practiced ways such as curtain-flow method, spray method or methods using bar-coaters, roll-coaters or brushes.
After being coated with a slurry, the steel sheet will be heated to such an extent as to dry the coating layer or to have the metal particles sinter slightly. It is then subjected to rolling in order to improve on the adhesion of the coating layer to the steel sheet. The coating layer after the rolling should show hardening due to the workings, and thus it becomes inferior in the drawability. By removing the warping due to the workings under such heattreatment conditions as inhibit the formation of alloyed layer between the coating layer and the steel sheet, metal coated steel sheet having excellent adhesion and Workability may be obtained.
In case drawing is necessary, it is desirable to conduct temper rolling after the heat-treatment.
EXAMPLE 1 Slurry containing 1,500 g. of aluminum powder, 10- mol/l. of NaNO and 1,000 g. of water is coated on steel sheet with a reverse roll-coater to have the coating layer after drying weigh 80 g./m. After drying the coating layer, the steel sheet is rolled to elongate by 7%, and then subjected to heat-treatment in an oxidizing atmosphere of 600 C. for 2 minutes.
The resultant product has a gloss surface and is superior in anti-corrosiveness and workability.
EXAMPLE 2 Slurry containing 1,500 g. of aluminum powder, 10 mol/l. of Na MoO and 1,200 g. of Water is applied on a steel sheet with the use of a bar-coater.
The amount of coating is g./m. when weighed after drying. The steel sheet thus coated is then subjected to heat-treatment in an oxidizing atmosphere for 30 seconds in a furnace temperature of 650 C. and to rolling to elongate by 5%. It is further treated for post-aging treatment in an electric furnace the temperature of which is maintained at 400 C. and rolled for temper regulation.
The resultant product is of the same properties as that of Example 1, and exhibits anti-corrosiveness for more than 1,200 hours when subjected to salt spray test (JIS Z2371).
EXAMPLE 3 Slurry containing 1,500 g. of aluminum powder, 10- mol/l. of C H COONa, l0- mol/l. of Na MoO and 1,000 g. of water is applied on steel sheet with the use of sprayer. It is subjected to succeeding procedures identical to those of Example 1 such as drying and rolling. The amount of coating weighed after drying is 75 g./m. The ratio of elongation at the time of rolling is 5%. The heattreatment is conducted in accordance with the induction heating system which is so controlled as to raise the temperature of the steel surface to 500 C., in two minutes.
The resultant product is of the same properties as those of Examples 1 and 2. It is superior in anti-corrosiveness, and peeling-01f of the coating layer is not observed when formed into sash .(window frame).
As can be understood from the foregoing description, the present invention enables the improvement of the adhesion of coated layer to steel sheet since the rusting or corrosion at the time of drying is suppressed in steel sheet coated with water-soluble paint and water-slurry. The employment of water in lieu of organic solvent as the dispersing agent in the present invention is economically advantageous. The present invention eliminates danger of fire as compared with the conventional method, as well as it is harmless to bodies. Thus, numerous advantages can be expected of the present invention. Also, it may well be applicable to all the corrosion preventive methods in the field wherein a coating is formed on steel sheet with the use of water as a medium such using water-soluble paint, water-slurry, water-soluble emulsion or the like.
What is claimed is:
1. In the method of applying a metal coating layer on a steel sheet wherein a steel sheet is contacted with a slurry of a metal powder and water following by drying, rolling to improve adhesion of the coating layer to the steel sheet and heat-treating to improve workability thereof, the improvement which comprises so contacting said steel sheet with an aqueous slurry of metal powder containing a water-soluble compound containing an ion selected from the group consisting of N0 MoO and 4 C H COO in a concentration of from about 10- mol/l. to about 10- mol/l.
2. In the method of applying a metal coating layer on a steel sheet wherein a steel sheet is contacted with a slurry of a metal powder and water following by drying, rollling and heat-treating, the improvement which comprises so contacting said steel sheet with an aqueous slurry of metal powder containing an ion selected from the group consisting of N0 M005" and C H COO-, in a concentration of from about 10- mol/l. to about 10" mol/l.
References Cited UNITED STATES PATENTS DeHart 1466.l4 RX ALFRED L. LEAVITI, Primary Examiner J. R. BATTEN, JR., Assistant Examiner US. Cl. X.R.
Patent No.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3, 690,940 Dated September 12,1972
H'. YAMAGISHI et al Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 4 Claim 2 should be rewritten as follows:
"The method of Claim 1, wherein the metal powder is aluminum powder."
Signed and sealed this 16th day of April l97h.
(SEAL) Attesb:
" MARSHALL DANN EDWARD I-I.I"LETCHER,JR. v.
Commissioner of Patents Attes'bing Officer- UScOMM-DC 60376-P69 w u.s. GOVERNMENT mmnm; orrlc: "l9 o-up-au.
F ORM PO-105O (10-69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 690,940 Dated September 12,1972- H; YAMAGISHI et al Inventor(s) o It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 4 Claim 2 should be rewritten as follows:
"The method of Claim 1, wherein the metal powder is aluminum powder."
Signed and sealed this 16th, day of April 19%..
(SEAL) Attest:
EDT-{ARI I TJ LETCHEILJR. C. MARSHALL DANN Attestinp; Officer Commissioner of Patents FORM PO-1050 (10-69) uscoMM-Dc 60376-P69 1 Hi5. GOVERNMENT PRINTING OFHFE "l9 0-!!6-334,
US90379A 1969-11-21 1970-11-17 Preventing rusting of steel sheets coated with aqueous slurry of metal powder Expired - Lifetime US3690940A (en)

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JP (1) JPS4843533B1 (en)
DE (1) DE2057175C3 (en)
FR (1) FR2069766A5 (en)
GB (1) GB1309580A (en)
NL (1) NL150520B (en)
SE (1) SE362268B (en)
ZA (1) ZA707822B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3769068A (en) * 1971-08-09 1973-10-30 Nippon Kokan Kk Method for manufacturing steel plates coated with aluminum powder
US3827140A (en) * 1968-10-17 1974-08-06 Nippon Kokan Kk Method of surface treating steel products with metal powder
US4119763A (en) * 1974-09-27 1978-10-10 Hooker Chemicals & Plastics Corp. Anti-corrosion weldable coatings

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3827140A (en) * 1968-10-17 1974-08-06 Nippon Kokan Kk Method of surface treating steel products with metal powder
US3769068A (en) * 1971-08-09 1973-10-30 Nippon Kokan Kk Method for manufacturing steel plates coated with aluminum powder
US4119763A (en) * 1974-09-27 1978-10-10 Hooker Chemicals & Plastics Corp. Anti-corrosion weldable coatings

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Publication number Publication date
DE2057175C3 (en) 1975-01-23
JPS4843533B1 (en) 1973-12-19
GB1309580A (en) 1973-03-14
NL150520B (en) 1976-08-16
DE2057175B2 (en) 1974-06-06
ZA707822B (en) 1971-08-25
SE362268B (en) 1973-12-03
FR2069766A5 (en) 1971-09-03
DE2057175A1 (en) 1971-06-03
NL7016983A (en) 1971-05-25

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