Armco Steel Corporation

Armco Inc.

Jerry L Arnold

Frank C Dunbar

Forrester Caudill

Steven L Boston

Marvin B Pierson

Alan F Gibson

Joseph A Douthett

Thomas A Compton

David S Mitch

Lloyd W Abrams

A process for suppressing zinc vapor in the snout of a continuous line for hot dip coating one side or both sides of a ferrous base metal strip with a molten zinc or zinc based alloy by maintaining the atmosphere within the snout to include about 1-8% hydrogen by volume and about 300 ppm to 4500 ppm water vapor with the balance being one or more inert gases, such as nitrogen. The atmosphere has a hydrogen/water vapor ratio of at least 4 to 1, or higher. This atmosphere is oxidizing to zinc vapor but non-oxidizing to the ferrous strip.

Process for controlling snout zinc vapor in a hot dip zinc based coating

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

A method of surface treatment of aluminum-killed and low alloy steel strip and sheet for fluxless hot dip metallic coating which comprises heating the steel in a furnace atmosphere containing the hot gaseous combustion products of air with a sulfur bearing gaseous fuel including 5 to 1600 grains of sulfur per 100 cubic feet of fuel wherein the atmosphere includes sulfur compounds and from about 6% free oxygen to about 7% by volume excess combustibles whereby to form a sulfur and oxygen rich film on the steel surfaces, passing the steel into a further heating section wherein it is brought to a maximum temperature of about 593.degree. to about 927.degree. C. in a reducing atmosphere containing at least 10% hydrogen by volume, passing the steel into a cooling section having an atmosphere containing at least 10% hydrogen and the balance nitrogen whereby to reduce the sulfur and oxygen rich film to a metallic iron surface, and cooling the steel approximately to the temperature of the molten coating metal bath. Coke oven gas may be used as the fuel for the furnace.

Method of treating aluminum-killed and low alloy steel strip and sheet

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

Internally nitrided ferritic stainless steel cold reduced strip and sheet and products fabricated therefrom having an elevated temperature creep strength and oxidation resistance superior to AISI Type 316 austenitic stainless steel, and good room temperature formability. A non-hardenble AISI Type 400 series ferritic stainless steel containing a nitride former (titanium, zirconium, hafnium, columbium, vanadium, tantalum or rare earth metals) in excess of the amount required to react completely with residual nitrogen and carbon in the steel is reacted with nitrogen internally by heat treatment in a nitrogen-hydrogen atmosphere at a temperature of at least about 800.degree. C but below that at which austenite will form under conditions precluding formation of chromium nitrides, chromium oxides, and austenite.

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Franklin, OH, United States of America

Jerry L Arnold