The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 01, 1980
Filed:
Jul. 11, 1977
Jimmie B Bolton, Houston, TX (US);
Smith International, Inc., Newport Beach, CA (US);
Abstract
An alloy steel tool joint connector is friction welded to one end of a seamless steel drill pipe tube. The weld area cools in the air as the pipe moves to a first tempering station. The weld area is brittle and too hard to machine. When the weld is below a temperature corresponding to 90% transformation from austenite to martensite, an infrared radiation responsive control viewing the weld causes an induction heating coil to be moved axially onto the end of the pipe. Energization of the coil reheats the weld area to a temperature below austenitizing but sufficient to temper the steel, and an infrared radiation responsive control viewing the pipe radially through a radial view passage in the coil deenergizes the induction heating coil and causes the coil to be withdrawn from the end of the pipe. The friction weld is then machined off inside and outside. The pipe is then moved to a rehardening station at which the weld area is heated to austenitize the steel following which it is fluid quenched to reharden it. The pipe is then moved to a second tempering station and its end is moved axially into an induction heating coil, whereupon the weld area is reheated. An infrared radiation responsive control viewing the weld obliquely through a slot in the coil's inner periphery deenergizes the coil when tempering temperature is reached. The pipe end is then withdrawn from the coil to cool in the air, such tempering toughening the weld area without unduly softening it.