Fracture behaviour of cruciform specimens under uni-axial and bi-axial bending at room and subzero temperature
Fracture studies were carried out on 135 mm thick notched cruciform specimens (20Mn 1Mo Ni55 steel) under uniaxial and biaxial bending at room and sub-zero temperature. In the case of specimens tested under sub-zero temperature, a low temperature chamber was fixed at the centre of the cruciform specimen. Liquid nitrogen was used to bring down the temperature to -70˚C at the core of the specimen and it was maintained throughout the test. The test was conducted under load control. Initial crack profile, profile after fatigue pre-cracking and final crack profile after fracture test were determined both by ultrasonic and Alternating Current Potential Difference (ACPD) techniques.
