Fateme Ghaderi - Iran University of Science and Technology, School of Material Science and Engineering, Tehran, Iran
Shahram Kheirandish - Iran University of Science and Technology, School of Material Science and Engineering, Tehran, Iran

ABSTRACTHNS (High Nitrogen Austenitic Stainless Steel) steels are attractive materials due to their unique combination of outstanding mechanical and corrosion resistance properties in medical and industrial applications. However, despite the excellent traits, brittle precipitates formation during aging would subvert the structure. Many studies performed on the aging reactions and the nature of deposits. This paper focuses on the effect of heat treatment and cold-work on precipitation and recrystallization behavior in the sensitive deposition zone of BioDur۱۰۸ HNS. For this purpose, Samples of high nitrogen austenitic stainless steel with cold-work values of ۰, ۴۰ and, ۶۰% were subjected to isothermal annealing at ۴ temperatures of ۸۵۰, ۹۰۰, ۹۵۰ and ۱۰۰۰ ° C, a constant time of ۳۰ minutes and, followed by water quenching. Microstructural characterization was carried out via optical microscopy and, EDS tests. Vickers Hardness was carried out. In all cold-worked samples, recrystallization occurs before deposition. Sensitive deposition temperature is ۹۵۰, ۹۰۰ and ۸۵۰°C, respectively for ۰, ۴۰, and ۶۰% amount of cold-work. Increasing the percentage of cold-work causes the transfer of sensitive deposition temperature to lower. No carbide is formed and, the precipitates, during annealing in cold-worked samples, are the predominant Cr۲N and Sigma phase. The main cause of the hardness increase is Cr۲N deposition.

HNS Steel, Precipitation, Sensitive Deposition Temperatures, Solution annealing, Cold- work, Cr۲N