The effect of induction heating power on the microstructural and physical properties of investment cast ASTM-F75 CoCrMo alloy

Abstract

Investment cast ASTM F-75 Cobalt Chromium Molybdenum (CoCrMo) alloy is commonly used for orthopaedic implants due to its biocompatibility and wear characteristics. Apart from the values listed in the standard, the relationship between individual processing parameters and the resulting physio-mechanical properties are not well documented. This study characterises the effect of induction heating power on the microstructural and physical properties of investment cast CoCrMo alloy. Furnace loads ranging from 30 kg to 45 kg of alloy were inductively melted using 75 kW and 125 kW of power and cast into tensile test bars. The bars were ground to create samples conforming to ASTM E8M and tested per ISO 6892-1. It was found the mean ultimate tensile strength, yield strength and % elongation increased when the material was melted at 125 kW. There may be scope to improve the mean mechanical properties of F75 by using higher induction melting power whilst reducing cycle time and cost.