@Article{, title={Study the Microstructure and Mechanical Properties of High Chromium White Cast Iron (HCWCI) under Different Martempering Quenching Mediums.}, author={Zainab A. Betti and Ali H. Ataiwi}, journal={Engineering and Technology Journal مجلة الهندسة والتكنولوجيا}, volume={37}, number={4part (A) Engineering}, pages={112-119}, year={2019}, abstract={This study aims to find the effect of hydroxide mixture as a quenchingmedium in martempering heat treatment on microstructure and mechanicalproperties of high chromium white cast iron. This mixture is cheaper and moreavailable than the ordinary nitrate mixture in Iraqi markets. High chromiumwhite cast iron is used in mining, crushing and cement plants as mill liners andit is subjected to extreme conditions of wear and impact that cause failure,reduction in life and raise the cost of repairing. Hence it is important toimprove its mechanical properties. In this study, two types of quenchingmediums were used:(50% NaOH: 50% KOH ) mixture and (50% NaNO3 + 50% KNO3) mixture. The specimens were austenitized at 950°C for 1 hr then thefirst group was quenched in nitrate mixture, and the other was quenched inhydroxide mixture both at about 350°C for (1/2, 2,4,6,8) hr. The results showedan increase in hardness and decrease in toughness for both mixtures, and thehigher hardness value was found for both of the mixtures at martemperingtemperature 350°C for 4hr quenching time.

} }