Circumferential notched tensile (CNT) tests for generating KIscc data for cast iron vessels used in hot caustic solutions

The paper discusses a novel technique for rapid and cost-effective determination of stress intensity factor (KI) and fracture toughness (KIc) using small circumferential notch tensile (CNT) specimens, and highlights the scope and advantages of extending this for developing a fracture mechanics technique for assessing susceptibility to stress corrosion cracking (SCC). The paper presents modification of the CNT testing rig for mechanical testing into an SCC testing rig that simplifies and speeds up the testing procedure as well as provides considerable cost advantage over the conventional fracture mechanics techniques. The paper also presents results of the SCC tests carried out on a cast iron using this modified CNT set-up.