Civil Aviation Technology CollegeIRAN

Examination of component surfaces, using special equipmentsuch as Borescopes, and magnifying glasses.

The application of a coloured or fluorescentdye to detect surface breaking defects onnon-porous materials.

Detection of flaws on or just underneath the surface offerromagnetic materials, using fluorescent, black, or drymagnetic particles.

ProdsDC or

AC

Electro-magnet(yolk) DC or AC

Crack like

indication

Crack like

indication

This method uses the transmission of high-frequencysound waves through a material to detect internaldefects. The pulse-echo method is the most commonlyused ultrasonic testing technique. Automated andadvanced ultrasonic testing methods, such as phasedarray and time of flight diffraction, are also used.

This technique generates eddy currents up to a few millimeters below the surface of a conductive material through an induced alternating magnetic field.Material defects will disturb the flow of eddy currents and generate a traceable signal.

Replication is used to evaluate microstructures andother surface features.

Radiography uses an x-ray device or radioactive isotope as a source of radiation which passes through the material and is captured on film or digital device.After processing the film an image of varying density is obtained. Possible imperfections are identified through density changes.

One of many advantages of cast steel for complex designed structures such as turbine components is, that defects can be repaired by welding .

A large variety of NDT methods are available for the condition assessment of gas turbine components.

Selecting the most appropriate one depends upon:

The type of component

The type of defect

The specific situation, such as the accessibility or cleanliness of the part

Images for surfaces of gas turbine blades made of the ŻS6-K alloy, ordered according to the criterion of the increasing degree of the material overheating

General Electric MS7001FA

Impact damage on the leading edge S-5 stator vane

White deposits on all of the effusion plates

mid-span sidewall cracking on first stage nozzle 1, segment 24.

trailing edge of the first stage nozzles and the leading edge of the first stage buckets.

Manual Ultrasonic Inspection

UT for discs

UT for Shafts

www.Rolls-royce.comwww.Mtu.dewww.Saarschmiede.com

SDF) (fahr.com-www.Samedeutzwww.Bohler-forging.comwww.FAA.gov

Józef BŁACHNIO : EXAMINATION OF CHANGES IN MICROSTRUCTURE OF TURBINE VANES WITH THE USE OF NON-DESTRUCTIVE METHODS