Armco Steel Corporation

Armco Inc.

Marvin B Pierson

Frank C Dunbar

Thomas A Compton

Hart F Graff

Paul E Schnedler

Charles Flinchum

William R Leasure

Alan F Gibson

John R Newby

James A Elias, Deceased

Jerry L Arnold

Fred Byrd

John B Kohler

Noel W Parks

Richard E Strait

The application discloses a method of terne coating, and a terne coated product, wherein the tin content of the terne is substantially lower than in conventional terne, without the need for other alloying elements in substitution for tin, such as zinc, antimony, silver, and phosphorus. The tin content of the terne bath is lowered below conventional percentages, to between about 2% and about 6.5% and the terne coated product, upon emerging from the coating bath, is jet finished. Such a terne coat has improved solderability and appearance with no change in pinhole frequency. Coating weight control is easier than with a terne coat having 7% or more tin in the bath.

Low tin terne coating

A finishing method and apparatus for conventional continuous hot-dip coating of the type wherein a ferrous base metal strip is caused to pass beneath the surface of a coating bath of molten coating metal and is thereafter subjected to jet finishing, the ferrous base metal strip having been appropriately pretreated so as to be at the proper coating temperature and so as to have its surfaces oxide-free when passing through the bath of molten coating metal. The method comprises the steps of providing an enclosure for the two-side coated strip as it exits the coating bath, locating a finishing jet nozzle to either side of the coated strip within the enclosure, jet finishing the coated strip with a non-oxidizing or inert gas. The apparatus comprises the above mentioned enclosure with the jet finishing nozzles located therein and an appropriate system to provide a non-oxidizing or inert atmosphere within the enclosure.

Finishing method for conventional hot dip coating of a ferrous base

Low tin terne coated steel article

A method, and an apparatus for practicing the method, for producing heavy pure aluminum coatings on small diameter steel tubing are disclosed. The coating has an average thickness of 0.004 inch to 0.008 inch (100-200 .mu.m), to provide outstanding resistance to corrosion, and to maintain integrity in the face of abrasive action, and with coating ductility and adherence sufficient to permit double flaring. The method and apparatus are highly useful in the manufacture of Bundyweld tubing for automotive brake lines, and single wall tubing for refrigeration or air conditioner heat exchangers. Various surface preparations are disclosed; and after surface preparation the tube is uniformly heated to a carefully regulated peak temperature in a non-oxidizing high intensity direct fired furnace, followed by passing the tube vertically upward through a shallow pool of molten aluminum, whereby to cast on a thick coating, followed by 'free exit' finishing, air quenching, and, if desired, redrawing.

Production of heavy pure aluminum coatings on small diameter tubing

Method and means for continuously contact-coating one side only of a ferrous base metal strip with a molten coating metal. One or more roll means are provided to conduct the strip surface to be coated above the surface of a bath of the molten coating metal. The strip surface to be coated is caused to travel sufficiently close to the molten coating metal bath surface that the surface tension and wetting characteristics of the coating metal will permit the formation of a meniscus which will continuously contact and coat the strip surface. The coating is subjected to jet finishing. The strip is maintained in a protective non-oxidizing atmosphere at least until the one side thereof is coated. Alternatively, at least that side of the strip to be coated with the molten coating metal is coated with a flux which remains on the strip until contacted by the coating metal meniscus. The strip may be maintained in the protective non-oxidizing atmosphere until it is sufficiently cooled to prevent the formation of a visible oxide on the uncoated side thereof. When the strip is exposed to an oxidizing atmosphere after coating and while still sufficiently hot to form a visible oxide coating on the uncoated side thereof, the strip will thereafter be subjected to acid cleaning, rinsing and drying operations.

Method for continuously contact-coating one side only of a ferrous base

A method for finishing molten metallic coatings applied to iron and steel strip by the use of an elongate, laminar flow fluid jet, which jet is used to control thickness and quality of the finished coating. The narrow dimension of the fluid jet is contoured across the strip width to produce the desired coating weight at all parts of the strip and to produce a coated strip edge free from excessively heavy coatings and/or oxide 'berries.'

Metallic coating method

A method of preparing the surfaces of steel strip and sheet stock for fluxless hot dip metallic coating, comprising the steps of passing the stock through a first heating section under conditions which form a visible iron oxide layer on the stock surfaces within the color range of dark straw through blue, continuing the heating of the stock in a second heating section isolated from the first heating section in an atmosphere containing less than 5% hydrogen by volume, thereby preserving the oxide layer, and cooling the stock approximately to the temperature of the molten coating metal in a cooling zone containing a reducing atmosphere comprising at least 10% hydrogen by volume, whereby to reduce the oxide layer completely to a metallic iron surface wettable by the coating metal. The radiant energy absorptivity of the steel stock is increased by the formation and preservation of the iron oxide layer in the first and second heating sections.

Method of treating steel strip and sheet surfaces for metallic coating

A method of preparing the surfaces of steel strip and sheet stock for fluxless hot dip coating with molten metal by passing the stock through a first heating zone containing the hot gaseous products of combustion of a sulfur-bearing gaseous fuel with air, continuing the heating in a further heating zone, and cooling the stock approximately to the temperature of the molten coating metal in a reducing atmosphere. The radiant energy absorptivity of the stock is increased by forming a visible sulfur and oxygen rich layer thereon in the first heating zone and preserving the layer throughout the further heating zone. Coke oven gas may be used as fuel in the first heating zone.

Method of treating steel strip and sheet surfaces, in sulfur-bearing

Method and means for continuously contact-coating one side only of a ferrous base metal strip with a molten coating metal. One or more roll means are provided to conduct the strip surface to be coated above the surface of a bath of the molten coating metal. The strip surface to be coated is caused to travel sufficiently close to the molten coating metal bath surface that the surface tension and wetting characteristics of the coating metal will permit the formation of a meniscus which will continuously contact and coat the strip surface. The coating is subjected to jet finishing. The strip is maintained in a protective non-oxidizing atmosphere at least until the one side thereof is coated. The strip may be maintained in the protective non-oxidizing atmosphere until it is sufficiently cooled to prevent the formation of a visible oxide on the uncoated side thereof. When the strip is exposed to an oxidizing atmosphere after coating and while still sufficiently hot to form a visible oxide coating on the uncoated side thereof, the strip will thereafter be subjected to acid cleaning, rinsing and drying operations.

Apparatus for continuously contact-coating one side only of a ferrous

Cold reduced, annealed steel strip and sheet stock having 0.2% yield strength of 45 to 65 ksi with an elongation of at least 25%, or having a yield strength of at least 90 ksi with an elongation of at least 10%. A low carbon steel (0.02-0.10% C) typical of rimmed or drawing steel analysis is preferably vacuum degassed, and 0.02% to 0.18% columbium is added. The casting is hot rolled, coiled not higher than 1300.degree. F, cold reduced 40% to 70%, and annealed at low temperature for a time sufficient to restore desired ductility without substantially decreasing yield strength.

Cold rolled, ductile, high strength steel strip and sheet and method

Application of a graphite film to at least the first roll contacted by a metal strip to which a coating metal has been applied. The roll may be scraped clean and the graphite film applied immediately after scraping. The graphite film may be applied by wiping the roll with a solid graphite block or by wiping the roll with a graphite colloidal suspension in a suitable carrier. In the latter event, the roll temperature must be high enough to vaporize the carrier so that strip contamination is avoided. The graphite film prevents adherence of coating metal particles to the roll surface whereby damage to the coated surface on the metal strip is prevented.

Method for preventing coating metal pickup on hot-dip coating line rolls

Cold reduced, annealed steel strip and sheet stock having 0.2% yield strength of 45 to 65 ksi with an elongation of at least 25%, or having a yield strength of at least 90 ksi with an elongation of at least 10%. A low carbon steel (0.02-0.10% C) typical of rimmed or drawing steel analysis is preferably vacuum degassed, and 0.02% to 0.18% columbium is added. The casting is hot rolled, coiled not higher than 1300.degree.F, cold reduced 40% to 70%, and annealed at low temperature for a time sufficient to restore desired ductility without substantially decreasing yield strength.

A method of preparing carbon steel strip and sheet for hot dip metallic coating in a Selas-type direct-fired furnace, wherein the atmosphere in the furnace is controlled to contain from about 3% oxygen to about 2% excess combustibles by volume, thereby forming a thin iron oxide film on the carbon steel surfaces. The strip and sheet is then heated in a subsequent furnace containing at least 5% hydrogen by volume at a temperature sufficient to reduce the oxide film, viz., at least about 675.degree.C. The direct-fired furnace is preferably operated at stoichiometrically equivalent fuel:air ratios.

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Franklin, OH, United States of America

Marvin B Pierson