Armco Steel Corporation

Armco Inc.

Thomas A Compton

Marvin B Pierson

Hart F Graff

Paul E Schnedler

William R Leasure

John A Thornton

Fred Byrd

Frank C Dunbar

Jerry L Arnold

Forrester Caudill

Steven L Boston

David S Mitch

Lloyd W Abrams

A process for controlling zinc vapor in a finishing process for a hot dip zinc based coating on a ferrous base metal strip in which the strip emerges from the coating bath into an enclosed chamber, by injecting high dew point gas into the chamber. The process is applicable on both a one side and two side coating process. Preferably the atmosphere has about 1-3% water vapor, by volume, for both one-sided and two-sided process.

Process for controlling zinc vapor in a finishing process for a hot dip

Improved means and method are provided for the guidance of metallic strip in a horizontal continuous furnace having hearth rolls and wherein the strip temperature and furnace atmosphere are such as to promote the transfer of metal, oxides, dirt and the like from the metallic strip to some at least of the hearth rolls. At least one lifting hearth roll is provided in an elevated position wherein it lifts the metallic strip from those critical hearth rolls subject to contamination transfer. The elevated position of the lifting roll and its diameter are so chosen to assure a wrap-around contact between the metallic strip and the lifting roll in its elevated position. In practice the metallic strip is fed through the furnace and continuous operation is begun. The lifting roll, in its elevated position, maintains the metallic strip out of contact with the critical hearth rolls.

Lift-off means and method for use with a horizontal continuous hearth

Apparatus for finishing a molten metallic coating on metallic strip and sheet comprising means for removing excess molten coating metal by impinging an elongated jet of gas under pressure on opposite sides of the strip and sheet substantially normal thereto. An improved nozzle of high efficiency is disclosed having an elongated plenum chamber communicating directly with a pair of elongated converging lips defining an orifice of about 0.03 to about 0.20 inch, the interior surface of the plenum chamber merging smoothly into each lip with a radius of curvature substantially equal to the orifice opening. The near-field region of the nozzle is about 8-10 times the orifice opening.

Apparatus for finishing molten metallic coatings

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

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

A method of finishing a molten metallic coating on metallic strip wherein an elongated subsonic fluid jet, preferably ambient air, is impinged across the molten coating on the upwardly moving strip, the narrow dimension of the jet being increased progressively from the center to each end thereof by contouring the nozzle orifice through which the jet is discharged, adjusting the distance from the nozzle orifice to the strip relative to the narrow dimension of the orifice adjacent the strip edge to satisfy the relation Z.sub.o = .phi.d where

Method and apparatus for finishing molten metallic coatings

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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Middletown, OH, United States of America

Thomas A Compton