Phase transformation and microstructure evolution of pearlite heat-resistant steel during heating

ABSTRACT

The phase transformation and microstructure evolution of pearlite heat-resistant steel during heating were observed with an ultra-high temperature confocal scanning laser microscope. The α-ferrite completely disappeared earlier than Fe₃C during the formation of γ-austenite, which is inconsistent with the fact that the Fe₃C should disappear completely earlier under equilibrium conditions. After the Fe₃C + α→γ transformation, static recrystallisation of γ-austenite occurred, accompanied by the dissolution of cementite. During the γ→δ transformation, the δ-cell first precipitated at the triple point of the γ-austenite grain boundaries, and then the δ-cell platelet with one tip appeared in the γ-austenite grain. The law of δ/γ inter-phase boundaries was analysed based on inter-phase boundary types and element diffusion.

KEYWORDS:

• Pearlite heat-resistant steel
• in-situ observation
• phase transformation
• grain boundary
• inter-phase boundary

Disclosure statement

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

ORCID

Heng Cui http://orcid.org/0000-0002-0645-7453

Additional information

Funding

The authors gratefully acknowledge the financial support of this research by the National Natural Science Foundation of China [grant number 51874028].