Experimental Study of Ultrasonic Assisted Surface Rolling Process

Ultrasonic assisted surface rolling (UASR) process is one of the most prominent methods to create severe plastic deformation and fine-grained structures. The aim of this paper is to study the ultrasonic vibration effects in surface rolling process, experimentally. In this regard, the desired horn was designed and manufactured in order to vibrate at longitudinal mode, which the proposed horn is able to change the mechanical properties of the metal surface by applying static pressure and dynamic impacts. Experimental tests were performed for three samples: CK15, CK45 and CK60 (Low, medium and high carbon) with and without applying ultrasonic vibrations. Micro surface hardness tests of samples were compared before and after UASR. The results showed that the higher static pressure leads to the higher micro surface hardness of samples. In addition, the use of ultrasonic vibrations in UASR can cause considerable rise in micro surface hardness. Based on the experimental results, it was found that, applying ultrasonic vibrations in surface rolling process are more effectiveness specifically in high carbon samples. Fatigue life investigation in various amplitudes showed the relative fatigue life improved in UASR process, especially in high vibrations amplitudes.