Tests for chemical composition

micro-structure

tensile behavior and impact toughness of SA299 steel plate matrix and its weld-seam material possessing different carbon contents have been carried out

the fragility appearance transform temperature（FATT） of said steel plates has been measured

the investigation of low-cycle fatigue property having been emphasized. The obtained results indicate that the microstructure

grain-size and inclusion level of said steel plates were normal

hardened structure induced from quench had not been found; longitudinal and horizontal tensile strength as well as plasticity index of the said steel plates had no remarkable difference; their impact toughness could meet the requirements of related standards; the FATT of steel plates possessing higher carbon content was lower than that of steel plates possessing normal carbon content; their low-cycle fatigue lifes at room temperature were approximately the same

but the low-cycle fatigue life of weld-seam material at 370℃ was higher than that at room temperature.