Mechanical Properties of Sub Zero Chilled Cast Iron useful for Wear Functional Requirements of Engineering Components

This paper highlights a surface modification technique to evaluate the mechanical properties like hardness and sliding wear resistance of cast Iron surface used in engineering. Basic sand casting mold was used and a portion of it was designed to accommodate the external mild steel chill (MSC). Chill accelerates the cooling rate of molten metal which leads to directional solidification. Cooling rate is directly proportional to formation of carbides in the form of iron carbide (Fe3C) near the chill end By controlling the flow of liquid nitrogen, the temperature of chills was reduced (upto -100 °C). Effect of using chills on mechanical properties like hardness and sliding wear resistance was evaluated and analyzed. The present work provides the effective chilling thickness, which gives higher hardness near the chilled surface and a fairly appreciable hardness conducive for a specific wear functional requirement. The mechanical properties of chilled cast iron (CCI) is compared with sub zero chilled cast iron (SZCCI) and normal cast iron without using chill. The present results clearly demonstrates that chilled cast iron has superior sliding wear resistance at the chilled surface, good machinibility away from the chilled end.