Method for detecting weld root defects through ultrasonic waves

The invention relates to a method for detecting weld root defects through ultrasonic waves, in particular to a method for using a specially-developed tricrystal probe detector for detecting the defects of weld roots and positions near the roots manually. According to the method, due to the fact that the defects of the weld roots and the positions near the roots are detected manually through the tricrystal probe detector, the area defects of the roots can be detected, and the size defects of other parts in a weld joint can also be well detected.