Ultrasonic non-destructive testing

Before operation, metal products must receive a certificate of compliance with GOST, indicating the absence of internal defects. And if external damage can be detected by visual analysis, then various methods are used for hidden ones, including X-rays. However, the most common diagnosis is ultrasonic flaw detection due to its accuracy, speed and safety. Using devices that emit ultrasonic waves, the specialist receives a flaw diagram of the condition of the pipe or weld. This allows you to select a marriage at the verification stage or to identify premature wear before catastrophic breakdowns or accidents. Therefore, narrow is a necessary part of regular technical inspection in various industries.

Advantages of narrow

The principle of operation of ultrasonic testing is based on the radiation of waves passing through the thickness of the product. When faced with foreign inclusions, cracks, delaminations or foci of corrosion, they are reflected and change their indicators. The sensor picks them up at the output, interprets them with the help of a converter into a flaw diagram showing the coordinates. As a result, the specialist receives the exact localization and extent of the spread of the internal defect.

Among the advantages of ultrasound control , we highlight:

• speed. Ultrasound requires minimal preparation, reducing the procedure time in comparison with X-ray and other non-destructive testing methods. It is performed in the laboratory or portable, using automatic flaw detectors;
  
• accuracy. Modern flaw detectors have high accuracy, allowing you to determine the coordinates, depth of occurrence, type and breadth of the defect. This prevents accidents and accidents at work and helps to find the root cause of such a defect in the form of improper operation or environmental features.;
• versatility. UZK can be used in any conditions with appropriate device settings. Flaw detectors are used to control pipes, welds in laboratories or on the road. Special models are able to withstand aggressive environments of nuclear and chemical reactors, controlling the degree of their wear;
• economy. Non-destructive ultrasound is inexpensive due to the prevalence and accessibility of the procedure. The main condition is a certified specialist who is able to confirm the measurement results. Therefore, flaw detectors are widely used in production or in third-party companies.
• safety. X-ray control requires protection from radiation and the shutdown of all work processes. UZK allows you not to interrupt work and is completely safe for the operator and others.

Ultrasonic flaw detection has certain limitations. Difficulties arise when diagnosing objects of complex geometric shape or heterogeneous materials - in these cases, a special setting or model of the flaw detector is required. The experience of a specialist will help compensate for the shortcomings.

Types of ultrasonic non-destructive testing

There are several methods of narrowing for various purposes:

• passage - definition of deep violations like stratification;
  
• reflection - localization and construction of coordinates of defects, their sizes and nature;
• impedance - suitable for thin-walled pipes and similar products, allows you to sound adhesive joints; 
• forced oscillations are used to determine the thickness of the product, the so-called thickness measurement;
• acoustic emission - suitable for searching for cracks, developing and potential weak points.

Depending on the type of inspection, environmental features, GOST standards, one of the listed methods is used.

UZK is quite versatile - it is used in many industries. In transport and mechanical engineering, it helps to find defects in railway tracks, engines and components, in energy, flaw detectors monitor the condition of pipes, during construction they check the reliability of reinforced concrete structures. Despite its primary purpose of quality control of welds, today the ultrasonic testing system is used everywhere, and especially at high-risk facilities, such as nuclear or chemical reactors.

How is it conducted

The scheme of operation depends on the type of product and the method of ultrasound analysis. Most often, the object is divided into zones that are sequentially scanned with a flaw detector. To do this, the metal surface or seam is cleaned of grease and dirt, coated with technical oil and an emitter is installed. It sends ultrasonic waves to the receiver, then the device translates into electrical signals and creates a flaw pattern.