Ultrasonic Examination
High-frequency sound waves go in, come back, and every echo tells a story. Where a discontinuity exists, the attenuation changes — and the flaw appears on the screen of the device, with its location.
What it is and how it works.
Ultrasonic inspection is a non-destructive testing method based on sending high-frequency sound waves into a material and reflecting them back. Waves are sent and received either with a single transceiver probe or with separate transmitting and receiving probes.
Because the dimensions of the part are known, the expected sound attenuation for a defect-free part can be calculated in advance. If a discontinuity exists inside the material, the attenuation increases — and the flaw shows up as an error echo on the screen of the device, revealing both its presence and its location.
The method at a glance.
Internal flaws — laminations, inclusions, voids and cracks hidden beneath the surface.
A transceiver probe or separate transmitter/receiver pair reads the echo pattern against the calculated, defect-free attenuation.
Thick sections, plates, welds and profiles where internal soundness matters.
A method with a long record.
The techniques behind this examination were earned over more than a century of engineering.
The physical foundations: James Prescott Joule establishes principles of ultrasound in 1847, and Pierre Curie discovers piezoelectricity in 1880.
After the Titanic sank, British inventor Richardson patented the first application of ultrasound — detection of icebergs.
During WWI, Chilowski and Langevin in France develop underwater detection of submarines.
Russian engineer Sergei Sokolov proposes testing castings with ultrasound, producing high-frequency vibrations in materials using a quartz crystal.
Detecting laminations in sheets and inclusions in hot-rolled profiles becomes mandatory — X-ray, MT, PT and ET could not solve the problem. Industrial ultrasonic inspection begins simultaneously in the USA, UK and Germany.
Floyd Firestone, Donald O. Sproule and Adolf Trost worked independently under secrecy. Sproule and Trost used a crossover technique with separate transmitter-receiver probes; Trost invented the two-probe “Trost-Tonge” method; Sproule placed both probes on the same side of the part, invented bi-crystalline probes — and was the first to recognise Firestone's echo technique.
Where this method earns its keep.
Typical components and industries we examine with this technique, across our country-wide network.