Effect of Stem Concentricity on Unconfined Pinch Welds

摘要

Welds made on stems exceeding the 0.005 in. maximum lack of concentricity met unconfined pinch weld specifications SS452907 and SB452907. Stems with up to 0.009 in. lack of concentricity were welded. A principal concern was the possibility of welds not meeting the minimum wall thickness due to excessive thinning during the welding process. This concern proved unfounded as all welds easily met the minimum wall thickness requirement. The hydrostatic burst testing of three welds yielded stem wall failures at a mean pressure of 51.4 Kpsi, typical for the material used. (ERA citation 12:004295)