Critical ausforming temperature to promote isothermal bainitic transformation in prior-deformed austenite

ABSTRACT

The effects of deformation temperature on phase transformation and microstructure in nanostructured bainite steel were studied. The results indicate that the deformed austenite with a strain of 0.3 at 300°C presents accelerated kinetics of bainitic transformation. However, the amount of bainite in ausformed austenite then reduces with the increase in deformation temperature. A critical deformation temperature, determining whether the bainitic transformation can be promoted, was found in deformed austenite. In addition, the thickness of bainite plate in deformed austenite reduces with the decrease in ausforming temperature. The adjacent bainite ferrite plates grow up interactively, and the intersection angle is about 60–73°. A lower ausforming temperature contributes to a more serious cross-growth phenomenon of bainite plates.

KEYWORDS:

• Bainitic transformation
• microstructure
• ausforming
• deformation temperature

Acknowledgements

The authors gratefully acknowledge the financial supports from the National Nature Science Foundation of China (Nos.51704217, 51874216), China Postdoctoral Science Foundation (2017M622533), the Major Projects of Technological Innovation in Hubei (No.2017AAA116), Hebei Joint Research Fund for Iron and Steel (E2018318013).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge the financial supports from the National Nature Science Foundation of China [grant numbers 51704217, 51874216], China Postdoctoral Science Foundation [grant number 2017M622533], the Major Projects of Technological Innovation in Hubei [grant number 2017AAA116], Hebei Joint Research Fund  for Iron and Steel [grant number E2018318013].