# Ultrasonic Surface Rolling Process: Properties, Characterization, and Applications  
[PERSON]  
1 Department of Mechanical Engineering, University of Nevada, Reno, NV 89557, USA;  
[EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (A.M.R. );  
[EMAIL_ADDRESS] (C.C.D.) 1  
[PERSON]  
2 Quest-Global Engineering Services Pvt Ltd., Bengaluru 560103, Karnataka, India; [EMAIL_ADDRESS] 2  
[PERSON]  
3 Metal Welding and Joining, R&D Division, Tata Steel Ltd., Jamshedpur 831007, India; [EMAIL_ADDRESS] 3  
[PERSON]  
4 Department of Metallurgical and Materials Engineering, National Institute of Technology, Surathkal, Mangalore 575025, Karnataka, India; [EMAIL_ADDRESS] 4  
[PERSON]  
1 Department of Mechanical Engineering, University of Nevada, Reno, NV 89557, USA;  
[EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (A.M.R. );  
[EMAIL_ADDRESS] (C.C.D.) 1  
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rate [21; 22]. Bulk nanocrystallization is an alternative method to develop components with superior surface integrity and bulk mechanical properties. However, bulk nanostructuring is expensive [23]. To mitigate the issues associated with the mentioned SPD techniques and provide superior surface integrity, [PERSON] et al. [24] introduced a method in 2005 that integrates ultrasonic vibration into a DCR technique. The researchers named this integrated process as ultrasonic deep cold rolling (UDCR). Later in 2008, ultrasonic impact peening (UIP) and deep rolling (DR) were integrated, and the authors named the process USRP [22]. Scholars have adopted different nomenclatures for this process, such as ultrasonic surface rolling (USR) and surface ultrasonic rolling treatment (SURT). However, the most commonly used name is USRP. USRP is a novel surface SPD technique, and this combination could provide superior surface mechanical properties with reduced surface roughness. In addition, the high strain rate and SPD developed during the USRP generate GNS layers, which provide a uniform microstructure with superior surface integrity. The thickness of the affected surface layer during the USRP process is much higher than DR. This technique is an effective and economical method of SPD that can develop the GNS layer without affecting the chemistry of the substrate materials. Researchers have revealed that many materials that are successfully processed using USRP include but are not limited to different steel grades [25; 26; 27; 28; 29; 30], titanium alloys [31; 32; 33; 34; 35], aluminum alloys [36; 37], and magnesium alloys [38; 39; 40]. Scholars have experimentally demonstrated that USRP can provide superior enhancement in fatigue strength [25; 28; 29; 32], improved wear resistance [26; 30; 31], remarkable increases in hardness [25; 26; 27; 28; 31; 32], increases in yield strength [28; 34; 39; 40], enhanced corrosion resistance [41; 42], a reduction in surface roughness [25; 26; 27; 28; 31; 32], a significant amount of induced RCS [25; 28; 29] and superior grain refinement [38; 40; 39]. The beneficial properties of USRP compared to other methods of SPD have prompted researchers to utilize this process on various metals and alloys in diverse fields of applications in recent years, thus increasing the number of research papers. This trend has mainly been observed from the year 2018, which is illustrated in Figure 1.  
There are significant reviews on various surface SPD methods to enhance surface integrity and surface mechanical properties. [PERSON] et al. [10] comprehensively reviewed the three most commonly used peening techniques such as SP, UIP, and LSP for a broad range of engineering materials and elucidated the influence of various process parameters on surface mechanical properties. Their study revealed superior enhancement in surface mechanical properties and surface integrity.