OKOndt GROUP goes on operating for your non-destructive testing needs. Our team works for you to offer the best NDT solutions of top quality, and impeccable services. In September, the group of our experts attended InnoTrans 2024 and could showcase our latest developments to the visitors, as well as discuss current NDT issues and future partnership

Ultrasonic testing

UDS2-73 rail flaw detector

The flaw detector is intended for defects detection in both rails along the running surface and rail cross-section, except for the rail base blades using flaw detection trolley during complete testing, and for the confirmatory testing of separate rail cross-sections and welded joints by means of manual probes.

The ultrasonic rail flaw detector UDS2-73 RSUI is designed for continuous mechanized testing of the rail track including turnouts (crossings, frogs) at a speed of up to 5 km/h.

The ultrasonic rail flaw detector UDS2-73 RSUI is designed for continuous mechanized testing of the rail track including turnouts (crossings, frogs) at a speed of up to 5 km/h.

UDS2-77 Ultrasonic Single Rail Flaw Detectorem

UDS2-77 ultrasonic single rail flaw detector is a mechanized trolley intended for the inspection of one rail line.
The flaw detector utilizes a unique scanning scheme that allows testing the entire rail section, except for foot flanges, by pulse echo, echo-shadow and echo-image techniques.

USR-01 Set is intended for ultrasonic inspection of aluminothermic welded rail joints in accordance with EN14730-1 requirements. The USR-01 Set can be used for inspection of joints welded by the electrocontact method, for secondary rail track inspection based on the results of mechanized and quick systems of ultrasonic testing, as well as for pre-weld inspection of end sections of new and used rails before welding them at rail welding enterprises or in tracks.

ОKО-22М-UT ultrasonic flaw detector

The ОКО-22М-UT ultrasonic flaw detector is a standalone electronic unit and is intended for application in high-performance automated multi-channel NDT Systems, transportable systems (mechanized NDT systems) or for manual testing.

Available in several flaw detector models that are different in number of channels and in a volume of built-in functions for results processing.

Over few decades TOFD method is widely used for fast and reliable UT of welded joints. TOFD offers great accuracy for measuring the critical size of crack-like-defects. The accuracy of better than ±1mm can be obtained in a wide range of material thickness.

Ultrasonic non-destructive testing technique for flaw detection is based on propagation and reflection of high-frequency (0.5 to 24 MHz) UT waves in a test object (steel, plastic, composites, rubber, etc.), with their further processing and visualizing on a special-purpose NDT instrument (flaw detector).

This method is used to search for material defects (pores, hairlines, inclusions, inhomogeneities, etc.) and to control workmanship quality like welding, soldering, etc. Ultrasound examination is a mandatory procedure for manufacturing and operation of numerous critical parts, such as aircraft motor parts, main pipelines or rails.


Basic UT techniques are as follows:

  • Pulse echo technique is the most common: a single probe generates UT waves (i.e. acts as transmitter) and receives back the signals reflected from defects (receiver). This method has been widely practised due to its simplicity, since only one probe is required, which means that there is no need for special fixtures during manual testing (as compared to TOFD), or alignment of acoustic axes when two probes are used. Besides, it is one of the few ultrasonic NDE procedures that allow for quite accurate measurement of defect coordinates, such as depth and location in a test object (in relation to the probe).
  • Echo image technique (“Tandem”, “Duet”) utilizes two probes from one side of a test item, so generated waves are reflected from a flaw towards the receiver. In practice, it is used for recognizing defects that are located perpendicularly to the tested surface, e.g. cracks;
  • Time-of-flight diffraction technique (ToFD) utilizes two probes from one side of a test item which are placed opposite to each other. If a defect has sharp edges (for instance, cracks), UT waves are diffracted on the defect ends and reflected in all directions, also towards the receiver. The ultrasonic machine records the arrival time of both pulses at their sufficient amplitude. The instrument screen simultaneously displays both signals from upper and lower boundaries of the defect, thereby enabling to make a rather precise estimation of the conditional height of the defect. TOFD inspection is a sufficiently multipurpose technique that allows ultrasonic testing of welds of any complexity, but it requires specialized fixing devices for probes, as well as a tester capable of operating in such mode;
  • Echo shadow technique is used for examination of products having two parallel faces, whereas analysis is made for echoes reflected from the opposite side. Similarly to through-transmission technique, a defect is evidenced here by the loss of reflected waves. But in contrast to through-transmission technique, the echo shadow method is featured by easy access to the test object from one side only.