understand and analyse the failures often associated with this material. Ultrasonic attenuation measurements were made using both conventional and signal analysis techniques. Microstructural changes were characterised using optical microscope (OM) and scanning electron microscope (SEM). The increase in the attenuation is attributed to precipitation of carbides. There is good correlation between microstructures and attenuation coefficients. Ultrasonic velocity measurements were made using pulse-echo overlap technique. Impact analysis was carried out using subsize charpy V-notch specimens. It is interesting to note that there is very good correlation between the ultrasonic velocity and impact energy data. There are two stages of decomposition during embrittlement. These results suggests that ultrasonic attenuation and velocity measurements could be used for detection of possible embrittlement in this steel during inservice microstructural and mechanical property degradation if any.