An Application of Fracture Mechanics to Stress Corrosion Cracking in Austenitic Stainless Steels and their Welded Joints (Report 4)

Effects of Plate Thickness on Crack Propagation Feature

Abstract

The effects of plate thickness on crack propagation feature, particularly on crack branching, have been studied in stress corrosion cracking (SCC) of SUS 304 stainless steel in 42 % MgCl₂ solution (143°C). K_tr I II, stress intensity factor at which the transition from region I to II occurs, decrease with decreasing of the plate thickness. And K_tr I II is accorded with K_b, stress intensity factor at the start of crack branching.
The condition of start of crack branching is shown by the equation B-2ρ^H where B: Plate thickness, ρ^H: Radius of plastic zone at crack tip.
As mentioned above, the crack branching in SCC with depend on the variation of three dimensional plastic deformation mode at crack tip.