Improvement of high-temperature oxidation resistance and strength in alumina-forming austenitic stainless steels

摘要

A new alumina-forming austenitic stainless steel with greatly improved high-temperature oxidation resistance and strength was developed via alloying 3.0 wt.% Al in the Fe-25Ni-18Cr based alloy. Continuous, stable and exclusive alumina scale was formed in either dry air or air with 10% water vapor mixed environment at 800 ℃. The long-term high-temperature oxidation performance is appreciably enhanced which is associated with the high density of the B2-NiAl precipitation phase maintaining the Al_2O_3 surface layer. Moreover, when tested at 750 ℃ in dry air environment, the new steel showed high yield and fracture tensile strength of 310-335 and 480-500 MPa, respectively.