2009 Volume 49 Issue 8 Pages 1253-1258
The study of the initiation fracture toughness (JIC) and J–R curve of low carbon SA333 Gr. 6 steel by compact tension (CT) indicates that for thicker specimens, JIC decreases with the increasing ratio of crack depth (a) to specimen width (W), a/W, both for deep and shallow cracks. However, for thinner specimen, JIC decreases with a/W ratio for shallow cracks but for deep cracks, JIC is insensitive to a/W ratio. Initiation fracture toughness increases with decreasing thickness but at relatively lower thicknesses beyond plane strain condition, initiation fracture toughness increases significantly with increasing specimen thickness for different a/W ratio investigated.