1997 年 15 巻 2 号 p. 365-369
Fatigue crack propagation rates of SB450 steel plate were measured at a stress ratio of 0. The fatigue crack propagated through the weld metal or the base metal at room temperature and 300°C in air. In order to perform the high temperature test, a special furnace was made. The furnace achieved the proper distrbution of temperature, which reduced the compressive thermal sterss near the center portion of specimen below 1 MPa. The low thermal stress condition avoided the enhancement of fatigue crack closure. Finally, the same fatigue crack propagation properties were obtained at room temperature and 300°C.