High-strength Fe-Cr-Ni-Al multiplex stainless steel and manufacturing method therefor

Abstract

The present invention relates to a high-strength Fe-Cr-Al-Ni multi-phase stainless steel and a method for producing the same. The multi-phase stainless steel includes 35 to 67 wt% of iron (Fe), 13 to 30 wt% of chromium (Cr), 15 to 30 wt% of nickel (Ni), and 5 to 15 wt% of aluminum (Al), and has a multi-phase structure in which an austenite phase resulting in high ductility, a ferrite phase resulting in high strength, and NiAl (B2) providing strength and high temperature steam oxidation resistance are present in combination. The multi-phase stainless steel can ensure necessary workability and mechanical toughness even in a thin state, can maintain the integrity as a structural member under normal operating conditions of a light water reactor due to a chromium oxide film formed thereon, and can form a stable oxide film containing alumina under a high-temperature steam environment, which is reasonable in a high-temperature nuclear accident, thereby providing particularly improved resistance to a severe accident.