Developing high-strength, ductile Ni-free Fe–Cr–Mn–C–N stainless steels by interstitial-alloying and thermomechanical processing

摘要

Microstructures and mechanical properties of a new grade of Fe–18Cr–12Mn–CN (wt%) austenitic stainless steels interstitial-alloyed with 0.3–0.48 wt% C+N at 0.22–1.06 C/N ratios were investigated after thermomechanical processing. Appropriate thermomechanical treatment was designed to obtain good combination of strength and elongation. The developed steel possessed ultimate tensile strength of 1GPa, yield strength of 450MPa, and elongation up to 83%. It was found that strength and ductility of the studied steels were affected by strain-hardening behavior and decreasing the strain-hardening rate resulted in lower ultimate tensile strength. Addition of C to N-containing Ni-free steels deteriorated mechanical properties. The best combination of strength and elongation was obtained in steel with lowest C+N (0.3wt%) and C/N ratio (0.22).