Correlation of delta-ferrite precipitation with austenite grain growth during annealing of steels

Abstract

Grain-boundary migration can be retarded by the presence of particles via the so-called Zenner pinning effect. This originates from the pinning of inclusions or solute drag on the grain boundary. In this study on two steels, delta-ferrite precipitation along an austenite grain-boundary suppressed grain growth at high temperatures. The inhibiting effect is very strong, with the inclusions and solute losing their efficiency for grain-boundary pinning.

Keywords:

• time-resolved X-ray diffraction
• synchrotron radiation
• grain growth
• Zenner pinning
• inclusions
• steel

Acknowledgements

The synchrotron radiation experiments were performed at the BL46XU station at the Spring-8 synchrotron with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal no. 2010B1886). The authors are grateful to Dr Sato, JASRI, for their experimental assistance. The authors appreciate assistance with the experiments and also helpful discussions from Dr Yasuda and Dr Murakami at the JFE Steel Corporation.