Application and comparative study of the master curve methodology for fracture toughness characterization of 20MnMoNi55 steel

The master curve methodology proposed by Kim Wallin (ASTM E1921-02) has been used to evaluate master curve reference temperature (T0) from full compact tension (CT) and 1/2T-CT specimens for the material 20MnMoNi55 steel using single temperature and multi-temperature method. The effect of temperature range, number of test temperatures and initial crack length on the value of T0 are also studied. The correction proposed for thickness adjustment has been verified. Master curves are drawn using full and 1/2T-CT specimen separately and compared with best fit characteristic curve and found to be within 95% bound.

► Master curve method is used in ductile to brittle transition region.
► Fracture toughness of 20MnMoNi55 material is estimated.
► Reference temperature is evaluated for 1T-CT and 1/2T-CT specimens.
► Both single and multi-temperature test data are used.
► Effects of size, thickness and temperature range on T0 are studied.