Method for producing tubing of varying wall thickness
AssigneeGeorge A. Mitchell Company
InventorRandall L. Alexoff
Life of this patent
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Abstract
A method for producing tubing of variable wall thickness, and particularly for producing double-butted tubing, wherein the wall thickness or gage at the ends of the tube is greater than that in the intermediate portion of the tube. This is accomplished by threading the tube over a mandrel, usually having a removable plug at one end thereof, until a portion of the plug passes through a necked-down end of the tube, pushing the tube and the mandrel through a die, and thereafter pulling the removable plug and the tube from the mandrel while causing the outer periphery of the tube to pass through a die.
Claims13
A method for producing tubing having a variable wall thickness along its length which comprises nosing-down one end of a tube of constant wall thickness, threading the tube over a mandrel until it contacts the nosed-down end, extending the nosed-down end through a die and thereafter passing the tube and the mandrel through the die to cause the tube to extrude while reducing its outer periphery and while causing the inner periphery of the tube to conform to the periphery of the mandrel due to the plasticity of the material from Cwhich the tube is formed, and pulling said tube from the remainder of the mandrel while causing the outer periphery of the tube to pass through a die.
A method for producing tubing having a variable wall thickness along its length which comprises nosing-down one end of a tube of constant wall thickness to produce an opening in said one end which is of smaller cross section than the remainder of the tube, threading the tube over a mandrel having a removable plug at one end thereof until a portion of said plug extends through the opening in said nosed-down end, pushing the tube and the mandrel through a die to cause the tube to extrude while reducing its outer periphery and while causing the inner periphery of the tube to conform to the periphery of the mandrel due to the plasticity of the material from which the tube is formed, and pulling said removable plug and said tube from the remainder of the mandrel while causing the outer periphery of the tube to pass through a die.
Dependencies are inferred from the claim text.