Material Properties of High Cr-Mo Steel (V) Mechanical properties of SUS410J3 Welded joint and base metal aged for 12000h

Onizawa, Takashi  ; Ando, Masanori ; Kato, Shoichi ; Yoshida, Eiichi

The high chromium (Cr) ferritic steels have both excellent thermal and mechanical properties at elevated temperature. Therefore, the applicability of high Cr ferritic steels for structural material of the future advanced Fast Breeder Reactor (FBR) is investigated. In this study, creep tests and metallurgical observations are conduced in order to investigate mechanical properties on SUS410J3 weld joint at FBR's temperature region. And tensile, impact tests and metallurgical observations after thermal aging for 12000 hours are conduced in order to evaluate mechanical properties and stability of microstructures on SUS410J3 material. As a result, following conclusions are obtained;Creep rupture properties up to about 3000 hours are obtained in weld metal zone at 823K and 873K. In this study, creep rupture strength show that the tendency of weld joint base metal (SR treatment) base metalweld metal. Then the remarkable decreasing of creep fracture ductility was recognized at 873K for about 2000 hours. The possibilities of Type 4 damage are suggested because of the fracture position is fine HAZ region near the base metal from results of microstructure investigation etc. Therefore about the creep properties of a weld joint, long term creep dates are intend to expansion for evaluation. On the other hand dates of impact, tensile properties on high temperature and microstructure of stability about 350000 hours at 827K calculated by LMP are obtained. The decreasing of the impact properties by aging are saturated in 3000-6000 hours at 873K. And that decreasing rate is about 0.6-0.7 times at upper shelf energy (USE). Ultimate tensile strength and 0.2% proof stress are slightly decreases with time of aging. It is thought that reasons are inference of deposits, such as MC etc.