Effective Case Depth and Wear Resistance of Pack Carburized SCM 420 Steel Processed Using Different Concentrations of Natural Shell Waste Powders and Carburizing Duration

The efficacy of using coconut shell powder (CSP) and dog conch shell powder (DCSP) as an alternative carburizing media for SCM 420 steel pack carburization was investigated. The effective case depth and wear resistance of quenched specimens prepared using various CSP–DCSP ratios and carburizing times were determined and compared. The effective case depth was measured from the microhardness profile obtained using a Vickers hardness testing machine. A CSP–DCSP ratio of 60%:40% and carburization time of 12 h were found to increase the effective case depth of SCM 420 quenched specimens to 2340 µm. The results clearly showed that the effective case depth increased by increasing carburization time and DCSP concentrations from 0% to 40% as a carburizing media and decreased by further increasing DCSP concentrations to 50%. Moreover, the wear resistance of quenched specimens increased approximately two times as DCSP concentrations were increased from 0% to 40% for a carburization time of 12 h.