Ultrasonic impact treatment (UIT) is a method of metal improvement that uses ultrasonic energy. The physical characteristics: controlled residual compressive stress, grain refinement and grain size reduction. Low and high cycle fatigue are enhanced and have been documented to provide increases up to ten times greater than non-UIT specimens.
UIT improves the working life of welding joint effectively. It leads steel welding joint to increase fatigue strength by 60~180% and fatigue life by 10~135 times. It also leads Ti Al welding joint to increase fatigue strength by 26~48% and fatigue life by 5~54 times.