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US 4,365,136 AGranted
Zone refinement of inertia welded tubulars to impart improved corrosion resistance
AssigneeHydril Company
InventorTheodore Gottlieb
Life of this patent
Estimating the term…
Abstract
Corrosion resistance of tubular metal products is enhanced, and particularly to welds formed between metal tubes or pipes and threaded ends.
Claims20
In the method of fabricating an oil or gas well metallic tubular product, the steps that include,
- (a) providing a steel tube and a pre-fabricated thread end and welding said thread end to the tube to form a weld,
- (b) directing a laser beam at the surface of said weld to cause the beam to progressively and locally vaporize a thin film of the weld metal, and allowing the metal vapor to condense back onto the weld, thereby to form a corrosion resistant surface.
In the method of fabricating an oil or gas well metallic tubular product, the steps that include,
- (a) providing a steel tube and a pre-fabricated thread end and welding said thread end to the tube to define a weld,
- (b) effecting progressive and local vaporization of a thin film of the weld metal, and allowing the metal vapor to condense back onto the weld, thereby to form a corrosion resistant surface.
In apparatus for the fabrication of our oil or gas well metallic tubular product, the combination comprising
- (a) means to support a steel tube to which a threaded end has been welded, and
- (b) means for directing a laser beam at the surface of said weld to cause the beam to progressively and locally vaporize a thin film of the weld metal, and allowing the metal vapor to condense back onto the weld, thereby to form a corrosion resistant surface.
Dependencies are inferred from the claim text.