Comparative Study of Effects of Power Ultrasonic Impact Treatment (UIT) and Other Fatigue Life Improvement Methods for Welded Joints in High Strength Steel and Aluminium Alloys

E.Statnikov, V.O.Muktepavel (Northern Scientific & Technology Company, Severodvinsk, Russia); P.J.Haagensen (Norwegian University of Science and Technology, NTNU, Norway); L.Lopez-Martinez (Swedish Steel AB (currently with TWI, UK))

e-mail: nstc@uit.atnet.ru

This paper summarises fatigue test on high strength steel specimens in the as-welded condition and specimens treated by ultrasonic impact treatment, TIG dressing and a combination of TIG dressing and ultrasonic impact treatment. Single lap joint specimens in 6 mm aluminium plate material were tested in the as-welded, hammer peened, needle peened and ground condition. Aluminium joints with longitudinal stiffeners in 8 mm plate were tested in the as-welded condition improved by ultrasonic impact treatment (UIT). Increases in fatigue strength at a life of 2 million cycles ranged from a negative influence for hammer peening of 6 mm aluminium lap joints to approximately 135 % for high strength steel specimens treated by TIG dressing plus UIT.  In accordance with the official document of the International Institute of Welding XIII-1748-98, the study presented in this work is approved on the IIW Annual Assembly held in 1998 (Commission XIII).


Section : 11