In this study, Equal Channel Angular Pressing (ECAP) process on 316L stainless steel was done in this study using two different channel angles 120° and 126° after all samples were heat treated. There were three experiments ran in this study optical microscope analysis, hardness test and electrochemical measurement for three conditions samples which are before ECAP (BE), 120° ECAP and 126° ECAP. Metallurgical optical microscope was used to analyse the changing in grain size. The hardness test is examined using Wilson Vickers Hardness Test Machine with 100 gf load subjected on the samples about 10 seconds. Electrochemical measurements are done to observe the corrosion behaviour of the samples. Two electrolytes were used during the test which are 0.9%NaCl and E-MEM+10%NCS cell culture medium solution. As a result, optical analysis shows that the grain size for both 120° ECAP and 126° ECAP samples had refined compared to BE for both materials. However, 120° ECAP shows a slightly better refinement grain size than 126° ECAP. Therefore, in hardness test results, the 120° ECAP shows the increment 45.06% of hardness while 126° ECAP gained 40.35% hardness increment compare to BE sample. Meanwhile, for electrochemical tests show that ECAP influences the corrosion properties of 316L stainless steel. Icorr is reduced by 120° ECAP (24.6±4.9 nA/cm2 and 37.6±24.3 nA/cm2) and 126° ECAP (107.0±82.0 nA/cm2 and 56.6±27.2 nA/cm2) in both conditions tested (0.9%NaCl and E-MEM+10%NCS) , but 120° ECAP improves better than 126° ECAP for both conditions. The reduction of Icorr by ECAP process is smaller in cell culture medium than 0.9% NaCl. As a conclusion, 120° ECAP shows the best performance in these three testing but almost to 126° ECAP results.

Keywords: Stainless steel 316L; Bulk nanostructured materials; Severe Plastic Deformation; Equal channel angular pressing; Channel angle.