METALLIC TUBULAR STRUCTURE HAVING IMPROVED COLLAPSE STRENGTH AND METHOD OF PRODUCING THE SAME

摘要

Abstract of the Disclosure:Disclosed is a metallic tubular structure having animproved collapse strength characterized in that thetubular structure has a circumferential residual tensilestress left in the inner peripheral surface thereof, saidresidual stress ranging between 0 and 15 % of the yieldstress of the tubular structure. The material of thestructure may be any one selected from a group consistingof plain steel, alloy steel, stainless steel and Fe-Ni-Cralloy. The tubular structure of the invention can suitablybe used as pipes under severe condition such as in deep oilwells.