Method for forming well drill tubing

Abstract

Seamless well drill tubes are formed by extruding seamed tube blanks through a die throat by pushing the tube blank through the die throat with a pusher rod having a portion located internally of the tube and die throat. The pusher rod has a narrow lead portion so that as the lead end of the tube length is forced through the die throat, its material flows inwardly to form an inwardly thickened annulus and therefore, the remainder of the pusher rod is located within the die throat and blank so that the blank material flows into the desired wall thickness. Before the tube is completely pushed through the die throat, the pusher rod is removed and the second tube blank is inserted in end to end contact with the trailing end of the first blank. Thereafter, the pusher rod is reinserted into the tube of blanks and advanced so that the force of the pusher rod causes the second tube to push the first tube completely through the die throat while the lead end of the pusher rod is positioned within the die throat so as to form the inwardly thickened end portions on the trailing end of the first blank and the lead end of the second blank. Thereafter, the cycle is completed to successively produce drill tubes having inwardly thickened flange-like ends. These ends may be converted into outwardly extending flanges by forcing a punch into each end to flow the thickened end annulus radially outwardly.