Internal pressure creep behaviors for Hastelloy X cylinder with EB butt welded joint

Creep tests under internal-pressure on circumferentially EB-welded cylinders made of Hastelloy X were carried out for the investigation of structural behaviors of welded components in elevated temperature environment. Penetration cracks were not observed at base metal zone but at weld metal zone. EB welded zone of the cylinder showed the comparable creep ductility as compared with the non-welded cylinder. The creep rupture strength of EB-welded cylinders was lower than that of non-welded cylinders, but superior to TIG-welded cylinders. The rupture time ratio of EB-welded cylinders to non-welded cylinders was smaller than the ratio of EB weld metal to base metal obtained from uni-axial tests. The decrease in rupture strength under internal pressure is considered due to the difference in creep rates between EB weld metal and base metal. (author)