Effect of Ce on thermo-plasticity of lean duplex stainless steel

ABSTRACT

The effect of Ce on the hot-working ability of lean duplex stainless steel (LDSS) was investigated in this paper. A hot tensile test was performed by GLEEBLE 3500 to compare the high-temperature deformation behaviour of materials containing 0.01% Ce and no rare earth added. The results show that Ce significantly promoted LDSS recrystallization at a strain rate of $\dot{\epsilon }$ = 1 × 10⁻³ s⁻¹, softening austenite phase in the duplex material, reducing the strength difference between ferrite and austenite. With the strain rate increases, the ferrite phase recrystallized obviously and the recrystallization of ferrite enlarged the hardness difference between two phases aggravating the deformation incompatibility of the austenite and ferrite, which is not conducive to the high-temperature deformation performance of the material. Meanwhile, the increase of strain rate inhibited austenite recrystallization behaviour. Besides, LDSS containing Ce exhibits an improved deformation performance under high temperature due to the size and number of inclusions reducing significantly after the rare earth added.

KEYWORDS:

• Lean duplex stainless steel
• hot working
• rare earth
• inclusion
• recrystallization

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant No. U1806220]; The Science and Technology Major Project of Shanxi Province [20191102006].