Method for nondestructive evaluation of residual stress levels in aluminum alloy forged piece through ultrasonic waves

The invention belongs to the field of nondestructive detection and relates to a method for nondestructive evaluation of residual stress levels in an aluminum alloy forged piece through ultrasonic waves. According to the method, the phenomenon that the propagation speed of the ultrasonic waves in materials can be affected by stress in the materials to a certain extent is used, and the difference of residual stress levels among different positions in the large size aluminum alloy forged piece is reflected through changes of sound speeds. The method has the advantages of being high in detection speed, large in measuring depth, good in economy and the like. The residual stress in the large size aluminum alloy forged piece is measured through the sound elastic effect of the ultrasonic waves in the method, and the method has the advantages of being high in measuring speed, convenient to use, flexible in measuring range, good in economy and the like. The single-time measuring time of the method is about five minutes and is shorter that the single-time measuring time of a neutron diffraction residual stress measuring method, the detection speed is high, the maximum measuring depth of the method can reach 400 mm, is larger that the measuring depth of the neutron diffraction method, and is much larger that the measuring depth of an X-ray method or a Barkhausen noise method.