Isothermal Kinetic Analysis of Dissolution of The Retained Delta Ferrite in AISI ۳۰۴ Stainless Steel During Homogenization

In this investigation, the dissolution kinetics of delta ferrite in AISI-۳۰۴ austenitic stainless steel during homogenization was studied. The study encompasses a temperature range of ۱۰۵۰ to ۱۲۵۰ °C (۱۵۲۳ K) and a time span from ۱ to ۱۲ hours, with hourly intervals. Utilizing MIP software, the delta ferrite content in the homogenized steel was quantified. The findings demonstrate a reduction in delta ferrite content as both annealing temperature and duration increase. The presence of delta ferrite in AISI-۳۰۴ steel is undesirable, and homogenization proves effective in minimizing this phase, thereby enhancing mechanical properties. The dissolution of delta ferrite and chromium carbide, along with grain growth, contributes to a decrease in hardness throughout the homogenization process. Furthermore, kinetic analysis in isothermal conditions was performed to determine the parameters governing this phenomenon using the Arrhenius model. The activation energy (E) and pre-exponential factor (A) were determined to be ۲۴۶.۱۴ kJ/mol and ۸.۲۸×۱۰۷ hr-۱, respectively. Also, the results suggested that this process follows a two-dimensional reaction model (R۲).

کلیدواژه ها:

Retained Delta Ferrite ، Aisi۳۰۴ Austenitic Stainless Steel ، Homogenization ، Isothermal ، Kinetic analysis ، Fitting Models