Research On Computed Radiography Detection Of Aero-engine Precision Castings

With the development of foundry technique and aircraft industry these years, the percent of castings in aero-engine production is increasing. Rough and processing parts require film radiography inspection technology in cast blade process period. The workload is very large, and inspection cycle is long, and expenditure is very high, and it is very difficulty to storage film. Computed radiography with flexible and reusable storage phosphor based luminescence imaging plate overcomes the lack of conventional film-based industrial radiography. Computed radiography is considered the best method to replace film to create the image in many radiographic methods. This paper focuses on the principle for industrial computed radiography testing of castings which made nicked-base cast supper alloy using X-rays in aircraft industry.Firstly, Based on the theory of X-ray imaging principle analyzes the process of CR image production. Studied the decay law of X-ray in steel by experiment, and establish the curve about the relation between radiography-attenuation and tube volte and current. This research prepared for selecting exposure parameter.Secondly, based on the duerr computed radiology system, research the character of imaging plate by experiment, which containing basic spatial resolution,energy and intensity response and so on. The result showed that some characters of imaging plate are different from film, so must establish CR exposure curve when carry our CR testing.Thirdly, making CR exposure curve on the X-ray equipment, and analyzing effect of tube volte and current to image quality. This research provide for selecting exposure parameters and parts of inspected object.Finally, according to the standard of CR testing and CR exposure curve, carry out CR inspect on one special blade of aviation engine, and obtain suitable exposure parameters. Compared the result of CR-testing with the result of conventional radiography. The result showed that the technology of CR-testing has its advantage such as high resolution and little radiation dosage, and image quality could be reached requirement if select proper exposure parameters.The results of this paper research provide theory and experiment for application of CR-testing in aero-engine.