Positioning And Software Realization Of Phased Array Detection Defects In Turbine Skew Joints

As a key component of an aero-engine,the turbine needs to carry very complicated cyclic thermal loads and powerful mechanical loads during the work process.In order to improve the overall performance of the turbine,in recent years,turbine blades have been used in one and the same manufacturing process.The nickel-based bimetal super alloy turbines involved in this project are made of turbine discs and turbine blades in a hot isotactic pressure(HIP)diffusion connection process.In the powder-solid diffusion connection process,the connection surface of the turbine disk and the turbine blade is prone to defects in connection.Through the analysis of domestic and foreign related literature in recent years,there is almost no involvement in the non-destructive testing method of the bimetal turbine interface,so It is necessary to detect the defect of the bimetal turbo-turbine layer prepared by this diffusion connection process.Due to the bimetal turbine produced by this diffusion connection process,its defects are located at the bimetal junction surface,and the geometry of the junction plane is relatively complex,and conventional nondestructive testing methods cannot effectively detect the bimetal turbine.In this study,a phased array ultrasonic detection method using a transceiver is used.The phased array probe is controlled by a time delay on the top of the turbine.The synthesized beam is focused on the joint surface and reflected to the bottom.After receiving by a conventional ultrasonic probe,The analysis of the received waveform realizes defect detection on the bimetal junction.The specific work is as follows:Firstly,the geometrical structure of the bonding layer of the bimetal turbine is analyzed,and the acoustic propagation characteristics of the ultrasonic wave near the turbine bonding layer are studied to study the feasibility of sending and receiving split phased array detection.Secondly,because of the conventional defect location method,it is no longer suitable for dual-metal turbine receive/distribution phased array inspection.Therefore,this paper describes a defect location method based on OCOG algorithm in detail,and experimentally verifies that this defect location method is fast and accurate.Again,on the QT development platform,a special bimetal turbine detection software module was developed using the PA22 X,a highly integrated phased array device that can be redeveloped.The system module can control the deflection of the phased-array synthesized beam to focus on any point of the bonding layer to complete the detection and imaging of the overall bonding layer.The defect location algorithm included can provide the defect position in real time.Finally,in order to verify the reliability of this special bimetal turbine detection system,the system was tested by terminal control and various imaging methods to study the practical application of the defect location method and to pass through the turbines with different depths of different embedded angles.The test block performs overall inspection and imaging display.The results show that the transceiver phased array detection method is suitable for the detection of defects on such bimetal turbine surface.Through the judgment of the amplitude of the reflected portion of the defect in the heterodyne receiving wave,the defect of the bonding layer can be 100% identified;The defect location method using OCOG algorithm can greatly improve the positioning accuracy of the bimetal turbine defect;the developed bimetal turbine detection module can meet the bimetal turbine's overall detection and defect location imaging.