Mechanized ultrasonic inspection

Metallic and non-metallic products may contain hidden defects that cannot be determined visually. Hidden defects can be detected using ultrasonic non-destructive testing systems. In this article we will look at the features of these systems and what techniques are used in this case.

What is a mechanized ultrasonic inspection

The main task of ultrasound control is to identify hidden defects inside the object of study, usually metal. To do this, ultrasonic vibrations are used, which, penetrating into the thickness of the material, are reflected back from voids, cracks and inhomogeneities. Returning in the opposite direction, they are detected by a flaw detector device, which interprets the signals in a way understandable to humans, making a defect map. Thus, it is possible to determine with high accuracy:

• the depth of the defect occurrence;
  
• its localization by coordinates;
• type and dimensions;
• a potential hazard
• is a residual resource.

Ultrasonic inspection is used when checking welds and the base metal. It is also used for the analysis of concrete, plastics, polymers, composite and other similar materials with high uniformity.

When using a mechanized narrow

Ultrasonic testing is widely used in the production and operation of products with a high degree of strength and reliability. With the help of ultrasonic inspection techniques, non-destructive testing is carried out for hidden defects in such control objects as aircraft engines, aircraft parts, railway rails, pipelines, reactor installations. Objects whose failure can lead to enormous emergency consequences are checked using ultrasound.

Ultrasonic inspection is not the only method of non-destructive testing, but it is the most reliable and accurate method of all existing today. The main advantages of ultrasound control include:

• high sensitivity - ultrasound subtly reacts to defects of any size and depth of occurrence, accurately giving out the coordinates of all non-provenance cracks, foreign inclusions and detachments;
  
• safety for the operator - the use of an ultrasonic device does not require protective measures, as in the case of flaw detection using X-rays;
• economy - flaw detectors and the measurement process are relatively inexpensive;
• convenience - the control of the device is carried out without the need to prepare separate procedures. It is carried out right at the workplace, without interrupting other processes;
• reliability - unlike other methods of flaw detection, when scanning with ultrasound, the object is not damaged and remains intact;
• versatility - ultrasonic inspection shows itself well when working with various materials, both metal and polymers.

However, mechanized ultrasound control has a number of limitations. For example, this method is not effective enough for non-destructive testing of materials with a granular structure. Voids and inhomogeneous formations in the metal scatter the waves, leading to their rapid attenuation. The level of roughness of the surface of the object of control also affects the effectiveness of control.

Mechanized non-destructive testing is carried out using a flaw detector, which displays the results of the control. Further, these results are deciphered by a flaw detection engineer. This approach requires high qualification, since any error in calculations will lead to disastrous consequences.

What equipment is used

A flaw detector is a portable device that is used to conduct ultrasound using the technique of pulses of ultrasonic vibrations and recording the intensity and time of arrival of echo signals reflected from discontinuities (defects). Mechanized models perform this in an automated mode, leaving the operator with the need to calculate coordinates through special software.

There are two types of ultrasonic flaw detectors - single and multi-channel. The former are more common, easier to handle and have a built-in scanner that picks up signals. Multi-channel ones are more productive - several scanners are connected to them at once. Thus, the device covers a large area in one cycle of operation, significantly speeding up the process.

Where it is used

Ultrasonic flaw detection is a universal procedure that is used in many industries:

• construction - for the control of reinforced concrete products, beams, bridges, joints;
  
• petrochemical and gas industry - quality control of pipes, their supporting structures and storage tanks;
• mechanical engineering - scanning of bodies, machine elements,
• nuclear power engineering - non-destructive testing of nuclear reactors.

The main field of application of the ultrasonic inspection is non-destructive testing of welding seams and base metal.

How is the mechanized ultrasonic inspection carried out

Ultrasonic monitoring is carried out using several blocks - a signal generator and receiver, a recording and display device, as well as a converter.

The algorithm of operation is as follows:

1. An ultrasonic signal is introduced into the object in the form of a full, spreading through its structure until it meets with a crack or other dislodging defect.
   
2. Crack, layering, non-metallic inclusion and other defects reflect the wave that the receiver picks up and transmits to the converter.
3. The transducer converts ultrasound into an electrical signal, which is transmitted to the screen in the form of an echo pulse.
4. From the data obtained, the specialist receives all the information about the structure of the object, the depth and width of the defect.

Ultrasonic inspection is the most effective and easiest way of non-destructive testing of objects of various types.