Hardness and Case Depth Analysis Through Optimization Techniques in Surface Hardening Processes

Abstract

Surface engineering and surface engineered materials find wide applications in engineering industries in recent years. Inconsistency in hardness and case depth has resulted in the further optimization of the process variables involved in surface hardening. In the present study, the following operating parameters viz. preheating, carbon potential, holding position, furnace temperature, carburising time, quenching medium, quenching temperature, quenching time, tempering temperature and tempering time were taken for optimization using the Taguchi and Factorial design of experiment concepts. From the experiments and optimization analysis conducted on EN29 and EN34 materials it was observed that furnace temperature and quenching time had equal influence in obtaining a better surface integrity of the case hardened components using gas carburizing. Preheating before gas carburizing further enhanced the surface hardness and the depth of hardness. In the case of induction hardening process, power potential played a vital role in optimizing the surface hardness and the depth of hardness.