On the Calibration of Design Collapse Strengths for Quenched and Tempered Pipe

Abstract

Summary The joint API/ISO Work Group 2b under Steering Committee 5 (SC5) for tubular goods is currently rewriting API Bull. 5C3/ISO 10400 for casing and tubing performance property equations. This paper describes the proposed new treatment for collapse of quenched and tempered (Q&T) pipe. The work is still in progress, and the final text has yet to be agreed upon, but the present results are considered reasonably mature and have been circulated as a committee draft for international comment. Committee work has shown that the current (sixth edition) rating equations give highly variable risk over the Do/t range for downhole well tubulars, whereas the proposed new equations give nearly uniform risk. Different ratings are proposed for cold- and hot-straightened pipe. Overall, they result in minor cost savings with respect to the sixth edition of API Bull. 5C3 collapse strengths.