Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2017 - September 06, 2017
Miniature creep specimens with 1mm diameter were machined from base metal, weld metal and heat affected zone(HAZ) of a long-term used welded pipe. Creep tests of these miniature specimens were performed in inert gas atmosphere. Creep strengths of the base metal and the HAZ in the long-term used welded pipe were similar to those in an undamaged welded joint. On the other hand, creep strain rate of the weld metal in used welded pipe is much faster than that in the undamaged welded joint. Standard size welded joint specimens were taken from near surface and X-shape regions of the welded pipe to understand creep rupture strength. Creep rupture time of the standard welded joint specimens taken from the used welded pipe was much shorter than that of the undamaged welded joint. It was suggested by finite element creep analyses that the highest axial stress occurred at HAZ in the specimen taken from X-region and that occurred at weld metal in the specimen taken from near surface region.
