Eddy current flaw detector VD3-71.

The usage of VD3-71 eddy current flaw detector for welds in railway cars bearing structures testing at Kiev Electric Locomotive Repair Plant.
The magnetic-particle, ultrasonic and eddy current methods of nondestructive testing are currently used for estimation and control of domestic parts and units quality of multiple-unit train  (MUT) at Kiev Electric Locomotive Repair Plant while electric trains major repair. The main methods of NDT are magnetic-particle and ultrasonic methods. The enterprise is provided with standing magnetic flaw detectors and with portable ultrasonic flaw detectors (UD2-70), which fulfil the requirements of industrial institutions in magnetic (ZT-0066) and ultrasonic (ZT-0069) testing.
The problems in prolongation of a service term of electric trains are set due to the economic situation in Ukraine. These trains have used up their boundary service life by mastering overhaul with service term prolongation. The special emphasis lays on the estimation and control of bearing welds quality, e.g. bogie frames and car trucks, for which UST and MPT are limited for a number of reasons:
•    Testing surface preparation (roughness RZ320, presence of dirt, oil, lacquer coating);
•    Big range of throats and types of welds (end joints, fillet welds, lap joints);
•    Difficult configuration and complicated access;
•    Absence of industrial normative-technical documentation with specific methodical recommendations in choice of equipment, testing, testing object quality estimation.
All these factors effect on the cost increase maintenance and create certain requirements for qualification of a defectoscopist.
The application of eddy-current testing with use of portative new age eddy-current flaw detector the VD3-71 is the most optimal for screening, identification and classification of fatigue defects.
The main advantage of the flaw detector VD3-71, in comparison with the old type eddy-current flaw detectors, is the improve of testing reliability via the possibility of automatic adjustment against influence of such external factors as irregularity of testing object electromagnetic properties, “end effect” and the influence of the operating clearance. The testing reliability improves by such flaw detector functions as signal rotation and signal filtering, creation of two channels mix.
Such flaw detector functions as evaluation of the length and depth of fatigue defects location play a significant role in object maintainability measurement.
Broad frequency of operation, possibility of control range setting of actuating signal voltage of the transducer, coefficient of amplification setting – all these solve problems not only in welds testing and bearing constructions of MUT, but in fulfillment of such tasks as testing of critical parts, which have processed surface RA2,5 (axles, shafting, bearings parts etc.). That is important for a final decision making on their culling. That means that the eddy-current method can be used as a confirmation testing (in case when one of the UST or MPT methods have limited application or can not be used at all).
The portability of the flaw detector and its built-in rechargeable battery allow to make express-testing in hard-to-reach places of the bearing constructions of bogie frame and bodies direct under the car without bringing it to the repair depot and rolling out the truck. It is the most optimal variant for testing in depot conditions.
Flaw detector VD3-71 is irreplaceable in testing of such parts as solid-rolled wheels of trailing wheel pairs, arms of wheel center of driving wheel pairs, body of traction gear boxes, compressors parts, air reservoir welds and others.
The aspect that the developer of the flaw detector Ltd. SPC “Promprylad” does the repair, support manning, inspection and also carries out the licensed training of personnel and provides documents for testing promotion.
We hope for further cooperation with SPC “Promprylad” in such spheres as learning and automation of new flaw detectors installations and operators training.

Musienko E.V.
Head of OAO ND department
Kiev Electric Locomotive Repair Plant
II level specialist in magnetic testing