In the field of ultrasonic testing on in-cast bimetal turbine combined layer

due to the combining layer approximately perpendicular to the floor

and the low reflection waveform energy caused by internal high attenuation in turbine materials

bistatic phased array detection model becomes the desirable choice.For this kind of bistatic model adopted by bimetal combined layer defection

firstly

depthdelay fast table was established according to a two-dimensional acoustic line model based on the actual turbine structure

and then a method was put forward based on the OCOG algorithm after the adjustment of receiving data delay interception

which can orientate the defections precisely.The difference between direct wave equivalent frontier and gravity of defect wave was used to solve the corresponding defect depth fitting function in advance.Finally

all waveform data of the same depth was displayed according to the amplitude imaging.The experiment shows that the detection method by OCOG algorithm has high detection rate and accurate location of the defect.