Stainless steel, especially austenitic stainless steel, due to its high corrosion resistance and customizable mechanical properties has become an indispensable part of ever-evolving modern technology. Stainless steels of various qualities find applications in numerous fields from domestic to nuclear reactors; from food and drink cans to the construction of different car parts. The formation of a waterproof oxide layer on the surface makes it suitable for use in adverse environments such as seawater. The high temperature application of austenitic stainless steel is somewhat limited because at higher temperatures it undergoes a phenomenon called sensitization. According to Ghosh et al. [1], refers to the precipitation of carbides and nitrides at grain boundaries. Precipitation of chromium-rich carbides (Cr23C6) and nitrides at grain boundaries occurs when austenitic stainless steel is heated and held in the temperature range of 500 to 8500 C (773 K-1123 K). This precipitation of carbides that occurs at the grain boundary is due to their insolubility at these temperature ranges. This leads to devalued regions of chromium around the grain boundaries. Then the change in microstructure occurs and regions with low chromium content become susceptible to intergranular corrosion (IGC) and intergranular stress corrosion cracking (Alvarez et al.) [1, 2]. Together with carbides and nitrides, the chi phase is formed. The chi phase, which is a stable intermetallic compound, consists of M18C-type Fe, Cr, and Mo. Some studies reveal that sensitization can lead to the formation of Martensite. In addition to the altered microstructure, the mechanical properties of the austenitic stain...... half of the paper ......rminationTo obtain a detailed understanding of the effect of sensitization on the hardness of the samples, two types of hardness determination were performed the tests. (a) Microhardness(b) Macrohardness(a) MicrohardnessTo perform the microhardness test on the samples, they were first coarsely polished using a belt grinder. Subsequently they were polished with emery papers as described in the previous descriptions in order to obtain flat surfaces and avoid anomalies in the results. The microhardness of the prepared samples was obtained using a Vickers microhardness tester (model: Leco LV 700, USA). 5 readings were taken for each sample to calculate the average hardness. An indentation load of 5 gf was used. After calculating the average hardness for each sample, the average variance and standard deviation (SD) were calculated to check the consistency of the data.