Study on carbide-bearing and carbide-free bainitic steels and their wear resistance

Abstract

Carbide-free and carbide-bearing bainitic steels have been obtained. The relationship between the bainitic microstructure and wear resistance has been studied. Results show that carbide-free upper and lower bainitic microstructures obtained in the steel with Si + Al mainly consist of bainitic ferrite and retained austenite. Carbide-bearing upper and lower bainitic microstructures obtained in the steel without Si + Al consist of bainitic ferrite, carbide and trace amounts of retained austenite. The carbide-free bainite exhibits higher strength and toughness than carbide-bearing bainite, especially the toughness. Under lower wear loading, carbide-bearing lower bainite (LB) exhibits higher wear resistance. Under higher wear loading, carbide-free LB exhibits higher wear resistance, which results from the improved surface hardness due to strain-induced martensitic transformation from the retained austenite.

Keywords:

• Bainite
• Carbide
• Mechanical property
• Abrasive wear resistance

Acknowledgements

This work was supported by the < No. 51471146 > under Natural Science Foundation of China < No. 2016SJBS004 > under the Graduate Student Innovation Fund Project of Hebei Province of China; and < No. E2013203258 > under the Natural Science Foundation of Hebei Province of China; National Natural Science Foundation of China (CN).