Non-destructive Inspections: Phased Array Ultrasonic Method

High-level visual diagnosis to provide more visible and more accurate inspection services

This technology is an improvement on the pulse-echo method of ultrasonic flaw detection. The method entails the use of probes with numerous arrays of microscopic transducers, which emit ultrasonic beams in a specific direction and are focused at an arbitrary depth of the test subject to improve flaw detection and sizing capacity. This technology makes it possible to obtain highly accurate inspection results in comparison with conventional ultrasonic flaw detection. The improvements are in terms of the identification of object shapes or flaw echoes, as well as flaw sizes (lengths and heights), as evaluations are conducted with scanned images and damage conditions are easier to imagine intuitively.


The following applications that use the phased array ultrasonic method are being developed for users in fields as diverse as steel production, machinery, petroleum, and chemical plants, both in Japan and in other countries.

Ultrasonic beams can be focused at an arbitrary depth

Basic concept of phased array

Ultrasonic beams can be focused to an arbitrary depth by controlling the transmission timing of each transducer, arranged in a linear form. Adding delay time for each transducer to the signal received by each transducer makes it possible to raise the directivity of wave reception from any arbitrary position.

Electronic scanning of ultrasonic beam is possible

Electronic scanning of ultrasonic beam

Electronic scans can be performed with transducers, but without any mechanical scanning sweeps, by electronically controlling the transmission and reception angles, as well as the focus distance of the ultrasonic wave.

Weld line inspection

When inspecting a weld line, by running electronic scans in an orthogonal direction with respect to the weld line and manually scanning with transducers in parallel with the weld line, users can digitize and upload waveforms for the segment equal to (pitch of electronic scan) × (pitch of scan in X-axis direction) to the system. The recorded waveform data can be processed to obtain scan images of an arbitrary cross section or projection (B-Scope, C-Scope, or D-Scope), so that flaw echoes and shape echo coordinates can be read directly.

Materials with significant attenuation

The technology can be applied even to sections where it has been difficult to perform inspections due to the attenuation of the ultrasonic beam with conventional ultrasonic flaw detection methods, such as welding sections of austenite stainless piping or large cast items, such as press components.

Deep surface flaws

The technology enables inspection of corrosion thinning for pressure vessels or steel structures. Also possible are inspections for flaws, such as hydrogen-induced cracking (HIC) resulting in parallel cracks in the metal rolling direction caused by the coagulation of hydrogen molecules on the boundaries of uneven structures, such as intruding objects. Scan data for the overall area within a specified range can be recorded and evaluated in a short time.

Case example of hydrogen induced cracking (HIC) detection
Left: Flaw distribution diagram;
Right: Two-tone graduated image with only flaw section enhanced

Shaft inspection

Shafts of reduction gears on cranes or the wheel shafts of trains, as well as drive train shafts that are used in large quantities in facilities at manufacturing plants, are periodically overhauled due to threat of destruction from fatigue. By implementing the phased array ultrasonic inspection from the ends of the shafts, users can evaluate the soundness of shafts without any disassembly.

Complex shapes

Case example of detecting a crack on a wheel shaft

For objects with complex shapes, applying or evaluating with the conventional ultrasonic scanning method has traditionally been difficult. The phased array ultrasonic method can be used to easily identify flaws and shape echoes, as the shape of the cross-sectional area of the object prepared by CAD can be displayed in the software window.

Other inspection items

  • General non-destructive inspections
  • Investigative diagnostic services for steel and concrete structures
  • Inspections, trial operations, performance verification tests, and facility maintenance
  • Stress measurements
  • Analysis services
  • Coke drum deformation measurements

This is a system for taking measurements on the extent of deformation of coke drums, which are easily deformed, because the plates are thin compared to the diameter of the drums.
A sensor unit comprising a laser instrument and a video camera is moved along the wire suspended between the upper and lower nozzles to take measurements of deformation in the body section of the container.

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