Abstract:
Stainless steel 316L, an austenitic stainless steel, is widely used as structural components in various industries because of its good strength, good corrosion and oxidation resistance at medium high temperatures. However, under more severe operating conditions, stainless steel needs higher oxidation resistance to reach longer service lifetime. Therefore, the present research had attempted to develop the new material to resist such conditions through modification of stainless steel 316L with nickel and/or chromium addition by powder metallurgy process. Nickel, chromium and nickel with chromium powders were added to 316L stainless steel powder with 1, 2, 3, 4 and 5 wt.%. After that, all mixed powders were compressed under pressure of 15 ton-force with 30-second hold duration. All compressed specimens were followed with sintering at 1300°C for 45 minutes under hydrogen atmosphere. From all results, it was found that specimens with chromium addition provide the highest oxidation resistance at 900°C tested up to 100 hours. The increasing of nickel and chromium content resulted in better oxidation resistance. The Oxides formed both on surface and inside the pores were similar types which were Cr2O3, Fe2O3, (Fe0.6Cr0.4)2O3, NiFe2O4 และ NiCr2O4 The effect of pure chromium addition on oxidation behavior is similar to both nickel and chromium addition and the effect of all element addition on hardness, almost all specimens, is also similar which their hardness is around 83 HRB.