The creep and creep-rupture strength behavior of the low-activated martensitic F82H-mod. steel. Final report

Low-activated F82H-mod. steel plate material was made available by the Japanese side to the European laboratories, where various tests are performed within the framework of the Fusion Technology Research Program. The activities of the FZK-IMF I focused among others on the investigation of the creep and creep-rupture strength behavior. The tests were performed on three plates in the reference state (as received = 1040 38'+750 1 h) at temperatures of 450-700 C for a period of up to 30000 h. Furthermore, the aging behavior following stabilization annealing (550/600 -5000 h) and the influence of reduced hardening temperatures (950 or 1000 C) were examined. On the basis of the experimental data and in accordance with the design criteria for 400-650 C/20000 h, minimum values could be indicated for the 1% time yield limit and the creep-rupture strength. In addition, specimens were tested at 875 C hardening temperature and tests were performed with a preliminary temperature transient to 875 C, during which a two-phase structure of martensite+ferrite was formed. The associated decrease in strength could be quantified. (orig.)