《PHYSICS_AND_MECHANISM_OF_ULTRASONIC_IMPACT_TREATMENT_ABSTRACT》.pdf

International Institute of Welding RUSSIAN DELEGATION AMERICAN DELEGATION IIW Document XIII-2004-04 PHYSICS AND MECHANISM OF ULTRASONIC IMPACT TREATMENT Efim Statnikov Applied Ultrasonics, 2900 Crestwood Blvd., Alabama, 35210, USA Northern Scientific and Technology Company (NSTC), 6 Voronin St., Severodvinsk, 164500, Russia ABSTRACT It has been acknowledged that ultrasonic impact treatment (UIT) occupies a firm position among methods for improving the reliability of welded joints, particularly their fatigue strengths. Developed in Russia in the early 1970s, this process has aroused considerable interest among experts and researchers in the area of fatigue and fabrication of welded structures. This interest reflects the benefits of the treatment; the small dimensions, high power and ease-of-use of the tools; good control of the treatment parameters; consistency; economic feasibility and safety; the wide range of practical applications. This paper presents technical aspects of the process, including an experimental and theoretical description of the physics and the means of controlling the ultrasonic impact parameters. In addition, the efficiency of ultrasonic as compared to single impacts, such as obtained with peening processes, is assessed. Finally, it describes the mechanism of the effect on materials, feedback mode, in-process control of the treatment