Study on properties and kinetics of carburizing superplastic duplex stainless steel

In this study, a new type of surface carburizing process was introduced using superplastic duplex stainless steel (DSS). The superplastic DSS was carburized at temperatures ranging from 1123 K to 1223 K for Various durations. Initial pressures of 25 MPa, 49 MPa and 74 MPa were applied to give the superplastic deformation effect oil the carburized specimens. SEM studies revealed a thick, uniform, smooth and dense hard carbon layer was formed on the Surface of the superplastic DSS. By using metallographic technique and SEM. the resulting case depth of carbon layer was between 15 pin to 76 mu m. The kinetics of this process in terms of carbon diffusion and its variation with processing time and temperature was determined using Arrhenius equation. Activation energy (Q) was determined as 152 kJ/mol.