Hot Rolling vs. Forging: Newly Developed Fe-Al-O Based OPH Alloy

Abstract

Two oxide precipitation hardened (OPH) Fe-Al-O-based steels were prepared by mechanical alloying. In addition to the variant using yttria nano-precipitates to improve the mechanical properties, a variant using only alumina precipitates for strengthening was also prepared. Therefore, a more economically acceptable variant of these steels was developed. Hot consolidation is a significant production step for achieving the required mechanical properties. Hot consolidation was performed by either hot rolling or forging. The heat treatment was subsequently performed on both variants (0.85Fe–0.11Al–0.03Y2O3–0.01Y and 0.87Fe–0.11Al–0.02O2) of the alloys to support secondary recrystallization. The paper describes the influence of the consolidation method on grain size, material recrystallization, and mechanical properties. The difference in the consolidation method was reflected in the grain size after the heat treatment, where the material consolidated by hot rolling reached a grain size of almost 200 μm, while after forging the maximum grain size was around 30 μm. A higher ultimate tensile strength was achieved with forged states, both with and without the heat treatment.

Keywords

• oxide precipitation hardened (OPH)
• forging
• hot rolling
• mechanical properties
• microstructure
• Fe–Al–O