Fracture Behaviour of 20MnMoNi55 Steel in DBT Region under Corrosive Environment

Different mechanical properties like strength, fracture toughness and fatigue life of structural components reduce due to corrosion of the material. In this paper the effect of corrosion on fracture toughness in ductile to brittle transition (DBT) region of 20MnMoNi55 steel is investigated. The corrosion properties of the material are measured by electrochemical impedance spectroscopy (EIS) test. The loss of ductility and fracture toughness due corrosion is measured by measuring master curve reference temperature in DBT region. Both single and multi–temperature method is used to measure the master curve reference temperature for both base material and corroded specimen. A comparative study is made to measure embrittlement that occurs due to corrosion in DBT region. From the EIS study it has been observed that the corrosion resistance properties decrease with time when the material corroded. Also the embrittlement occurring due to corrosion is reflected in the shift in master curve.