Ultrasonic testing method used for large-sized complex forging

The invention belongs to the nondestructive testing field and relates to an ultrasonic testing method used for a large-sized complex forging. The method combines the testing mode of the contact process and the testing mode of the water-soaking process. By utilizing the characteristic of the contact process that the detection sensitivity for the interior of the material is high, the part of the forging that is deeper from the surface is detected; by utilizing the characteristic of the water-soaking process that the blind zone on the surface is small, the defect of the near surface detectability of the contact process is made up, the effective supplement detection can be carried out on the near surface of the forging; particularly, by utilizing the characteristic of the water-soaking process that the curvature of the molded surface is insensitive, the zone (including a corner part and other big-curvature parts) of the near surface that is not effectively covered by the contact process at the complex part of the molded surface of the forging is detected. The method can be used for the large-sized complex forging with the shape complex coefficient being the S4 level, the detection sensitivity for the near surface and the interior of the material can reach more than Phi1.2-6dB, the detection depth can be 400mm, and the blind zone on the surface is 5-8mm.