Effect of multifunction cavitation-treated carbon steel surface on fracture toughness

Abstract

Improving the strength of an object by surface treatment inevitably trades off strength and ductility, and also reduces toughness. In this study, carbon steel was treated by a surface modification technique, referred to as multifunction cavitation (MFC), and the improvement of strength and toughness was investigated. Peening marks, pits, and rust were observed in the MFC-treated carbon steel as the processing time increased. In addition, the surface roughness of MFC-treated carbon steel increased and the surface potential decreased. Hardness and compressive residual stress increased most under the condition of processing time of 5 min. Charpy impact tests were performed to evaluate toughness. The transition region between the untreated material and the MFC-treated material after the Charpy impact tests was 280–380 K. The MFC-treated material had a lower transition temperature and higher absorption energy than the untreated material, indicating that MFC treatment was effective in improving toughness.

Keywords

• Multifunction cavitation
• Transition temperature
• Absorbed energy
• Charpy impact test
• Toughness