Metal Magnetic Memory Method
Metal Magnetic Memory Method
October 30, 2017
Second International Conference on Diagnostics of Structures and Components Using Metal Magnetic Memory Method. April 24-25, 2018, Budapest, Hungary
July 01, 2017
More than 60 testimonials of organizations on the MMM method efficiency based on the results of practical diagnostics of equipment were presented at the workshop.
June 30, 2017
Energodiagnostika Co. Ltd took an active part in the work of the Congress, Exhibition and in the meetings of the International Society for Condition Monitoring, 13-16 June 2017 in London, UK.

Diagnostics of steam turbine rotor flushing holes

Inspection was carried out using the TSC-type instrument and the Type 16 scanning device or the Type 5 sensor.

Fig.1 shows the example of the turbine rotor flushing hole using the Type 16 scanning device connected to the TSC-type instrument. Inspection was performed without metal dressing or any other preparation of the flushing hole surface.

Fig.1. The example of the turbine rotor flushing hole inspection using the Type 16 scanning device connected to the TSC-type instrument.

The Type 16 scanning device consists of a casing, in which a card for processing of signals from flux-gate transducers and length-metering impulses, float sensors unit and support wheels unit is installed. A plastic ⌀12mm tube is connected to the casing. The plastic tube is stiff enough to control the SD movement inside the inspected tube. A connecting cable to the TSC-type instrument is inserted inside the plastic tube. The internal diameter of the inspected tubes is within the range from 70 mm to 120 mm, the tubes length is up to 12 meters. The characteristic feature of this scanning device consists in its versatility in the indicated range of internal tube diameters. The scanning device has twelve flux-gate transducers in their two-component arrangement for simultaneous measurement of the normal and the tangential component components of the magnetic field.

Upon completing the magnetic inspection of the rotor flush hole the visual examination using endoscopes is carried out. Here the attention should be focused on the detected stress concentration zones. In case of defects detection in SC zones metal sampling is performed in these zones of the rotor flushing holes. Then the magnetic and visual inspection is repeated in order to assess the state of the flushing hole.

Energodiagnostika Co. Ltd is the main developer of a principally new non-destructive testing method and inspection instruments based on application of the method of metal magnetic memory (MMM method).
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