Abstract
The plane strain fracture toughness of 2.8%Ni-Cr-Mo-V steels was evaluated at the lowest service temperature (around room temperature) using huge size specimen with 345mm in thickness and 920mm in diameter, probably the largest fracture toughness specimen ever tested inthe world.
The validity criterion for KIC has been investigated by using various sizes of compact tension specimens.
It is proposed that KIC can be obtained when only the condition of Pmax=PO is satisfied, namely the linear relationship between load and displacement is maintained.
