Session: MF-16-01 Creep and Creep-Fatigue Interaction-1

Paper Number: 122116

122116 - Long-Term Creep Strength Evaluation of Welded Joint of Asme Grade 91 Type Steel 

Creep rupture data of welded joint of ASME Grade 91 type steel were collected by the Assessment Committee on Creep Data of High Chromium Steels, which consists of the Federation of Electric Power Companies of Japan, materials producers, power plant manufacturers and institutes in Japan, and the creep rupture life curve of the material was evaluated using the latest data set to examine the validity of the long-term creep rupture life curves determined by the Assessment Committee in 2015. The evaluation for the welded joint of Grade 91 type steel is the fourth time in Japan as similar studies were conducted in 2004, 2010 and 2015. The re-evaluation of the creep rupture strength was conducted with emphasis on the long-term creep rupture data obtained after the 2015 study, where rupture time of the new data were in the range of up to about 100,000 h. It was found that the evaluation formula of the welded joint of Grade 91 type steel proposed in 2015 can appropriately evaluate the new long-term data of the material. The creep curves calculated using the 2015 evaluation formula were also compared with analysis results on creep strength under actual service conditions obtained using creep data of the long-term used material, and it was shown that they were in agreement with reasonable precision. Therefore, it was suggested that the 2015 evaluation formula for the welded joint of Grade 91 type steel is valid in a long-term range; thus, there is no need to revise it.

Presenting Author: Masatsugu Yaguchi Central Research Institute of Electric Power Industry

Presenting Author Biography: Educational Background:Doctor in Mechanical Engineering in 1995 , University of Tokyo
Organization :Central Research Institute of Electric Power Industry since 1995
Division/Dept.:Materials Science Division, Energy Transformation Research Laboratory
Position :Associate Vice President

Authors:

Masatsugu Yaguchi Central Research Institute of Electric Power Industry