| This study aims to investigate the effects of vanadium(V) and titanium(Ti) alloying elements additions and cooling rate on the morphologies of eutectic carbide, secondary carbide, the austenite retention in the matrix, and heat treatment characteristics for hypoeutectic chromium cast iron with 2.5% C, 14% Cr, 0% to 2.2% V, or 0% to 0.6% Ti alloying elements. The specimens for unidirectional solidification were melted at 1500℃ and casted into an exothermic furan mold(30㎜×70㎜) placed on the water cooled copper chill, and were solidified unidirectionally. Also, the specimens for study of heat treatment characteristics were casted into the furan mold and were treated by different heat treatments (cyclic heat treatment, destabilization heat treatment). The eutectic and eutectoid transformation temperature rise both with the increase of Ti and V contents in the specimen. With the increase in Ti and V contents, the eutectic carbide is decreased, the second carbide is increased. The morpholigies shape of second carbide is changed from the bar to the finer granular type as increase in both(Ti,V) contents. For cyclic heat treatment, the hardness is improved with the increase of number of cycles, because hardness depend on the fine matrix as well as the amount of carbide and martensite. |
|
