Ultrasonic testing of soldered joints in fuel manifolds of gas turbine engines

Abstract

The X-ray technique used in the quality control of soldered joints of injectors with fuel manifold tubes of gas turbine engines (GTE) has a number of limitations and drawbacks. The detectability of flat flaws, e.g., dry solders, strongly depends on their orientation with respect to the direction of X-ray beam propagation. An ultrasonic method which provides increased efficiency of controlling soldered joints of modern gas turbine engines, the manifolds of which usually contain two rows of tubes is presented. A focused high-frequency pencil-type transducer has been used in the study. Samples with artificial reflectors in the form of flat-bottomed holes located in the soldering zone were analyzed. Special delay lines provided the transmission of ultrasonic waves at the angles close to the normal to the surface of the soldered joint. The results of the control obtained using the developed procedure were compared with the data of X-ray method. It is shown that ultrasonic technique provides detection of the flaws not detected by radiographic control. The sensitivity, minimal width of the flaw (dry solder) and possible completeness of the control were determined for the developed technique. The results obtained could be used to improve the method of control of soldered joints of GTE fuel manifolds.