Phased Array Ultrasonic Testing Becoming Reliable across Industries

NDT or nondestructive testing describes a safe way to examine flaws in various products. The conventional ultrasonic transducers normally comprise of either a single active element that receives and sends out high-frequency sound waves or 2 paired elements- one for receiving and the other for generating. Phased Array Ultrasonic Testing in Singapore on the other hand consists of transducers ranging from 16 to 256 tiny individual elements that can be pulsed individually.

The arrangement of these can vary between being a strip (linear array), ring (annular array), circular matrix (circular array) and more complicated shape. With the conventional testing style, Phased Array Ultrasonic Testing or PAUT is devised for direct contact use which is a portion of angle beam assembly with a wedge. It can also be used for immersion with sound doubled through a water path. Transducers generally range within 2MHz to 10MHz. An advanced system will also incorporate a sophisticated automated instrument that drives multi-element testing receiving and digitizing the return of echoes and plotting that echo information in different formats.

PAUT sweeps a sound beam through a wide range of refracted angles which is dissimilar to that of conventional systems. It can also take linear path or dynamically focus at a number of depth ratios that increases the capacity and flexibility in inspection setups.

Usage of PAUT or Phased Array Ultrasonic Testing

NDT training services or nondestructive training services are for students who dream to become efficient technicians. The PAUT can be applied to practically any test where conventional flaw detectors are used. Crack detection and weld inspection are the commonest applications. However, it is practiced in various industries ranging from petrochemical to pipeline construction to aerospace. Sometimes, it is used even in structural metals and general manufacturing. It can also be used to effectively find out wall thickness in corrosion survey applications.

It generally uses multiple elements to steer, focus and scan beams with singular transducer assembly. This test can simplify the testing of components through complicated use of geometries. It also improves ability for sizing critical defects for volumetric inspections. With these advantages, this testing method can be used with great ease.

Time of Flight Diffraction - Most Effective Method of Ultrasonic Testing

Time of Flight Diffraction (ToFD) is a method of ultrasonic testing. It is a sensitive and genuine technique for welds. The method developed from tip diffraction techniques and was first used in 1975 by Silk and Liddington. Post development, it caught on very fast as a dependable method for nondestructive testing. This technique uses ultrasonic waves to arrive at the results. Therefore, it is a part of ultrasonic testing method. It functions properly wherein the tips of the fissure diffract signals back to the other spot on the surface when struck by an ultrasonic wave. The intensity of the concerned tips can be determined from the diffracted energy. Time of Flight Diffraction forms an important part of the NDT Level III training in Malaysia.

How Does ToFD Operate?

Determining the depth of a crack with the aid of reflected signal is not an accurate technique of nondestructive testing. The measurement is infested with defects because the depth depends on the orientation of the crack to a large extent. Thus, Time of Flight Diffraction uses the time of flight aspect of an ultrasonic pulse to determine the size and location of the reflector. In this mechanism, a pair of ultrasonic probes is positioned on the opposite sides of a weld along with a transmitter and a receiver. When the ultrasonic pulse is sent through the transmitter, the receiver catches it on the other end.

The receiver picks up 2 waves- one that reflects off the far wall and one that travels along the surface in a solid pipe without cracks. However, with the presence of a crack in the pipe, diffraction of the ultrasonic wave is detected from the tip giving out the size of the crack. Utilizing the measured time of flight of the pulse, the degree of cracks can be measured. Trigonometry is used to calculate the measurement of the crack. ToFD or Time of Flight Diffraction in Malaysia is applied to the manufacturing of pipeline welds. This industry utilizes this system optimally.

Is ToFD Dependable?

ToFD is largely dependable except for the fact that it has a “dead zone” created by lateral wave signal just below the inspection surface. The dead zone does not facilitate error detection and is around 5mm in measurement.

Features of Time of Flight Diffraction

• It features a computerized detection mechanism for automated weld testing.
• Investigates placed on a buggy traveling along a weld that records data on the move.
• ToFD measures the dimensions of cracks almost precisely.
• ToFD has a dead zone and in order to prevent flawed detection, it must be supplemented with the pulse-echo exam.
• It requires trained ultrasonic professionals to conduct the test.

Thus, ToFD or Time of Flight Diffraction is quite a successful technique but has its defects. The flaws can however, be covered up by supplementation. A majority of industries are depending on Time of Flight Diffraction technique to measure cracks.

Corrosion Monitoring - Preserving the Critical Components of Industrial Objects

Corrosion Monitoring program is an effective part of NDT testing techniques. It is quite a popular monitoring system which is used to monitor critical components of industrial objects, assets, facilities and plants for signs of corrosion. For dependable operation, it is of immense importance to recognize the location, rate and underlying causes of corrosion. A corrosion identifying system identifies any sort of non-conforming alloy components as these are usually susceptible to increased level of corrosion. These can also provide relatively significant cause for catastrophic failure.

This particular type of NDT Inspection technique in Malaysia can offer various benefits when integrated into preventive maintenance and the processes ingrained in safety management programs. Based on the accurate results provided by the program, informed decisions can be made by the management. Decisions not only regarding the remaining life of the manufactured product affected by corrosion but also regarding life extension strategies, prospective material selection and cost-effective techniques as an answer of corrosion issues and problems.

Activities Related to NDT Inspection

• Identifying all critical components
• identifying component alloy composition
• Measuring the location and degree of corrosion
• Predicting remaining life
• Identifying failure system
• Determining fitness for service condition
• Inspection scheduling
• Developing recommendations for redressal and rectifying issues
• Developing Corrosion preventive strategies

Why Should Corrosion be Monitored?

Corrosion is a major issue in various industries, specifically in the petrochemical industry. Corrosion is one of the major serious decay mechanisms influencing the life and quality of equipment and assets of plants and refineries. If corrosion is not controlled, it can cause leaks and component failure inducing reduction in both the performance and reliability of significant equipment. In extreme cases, corrosion can lead to devastating failures that can be really expensive in terms of repair costs, environmental damage and potential harm to humans.

Methods for Monitoring Corrosion

There are a couple of mechanisms monitoring corrosion. It actually utilizes a large number measurement techniques the NDT techniques are the most cost-effective and widely applied testing techniques. The methods include:

• Ultrasonic Testing
• Radiographic Testing
• Guided Wave Testing
• Electromagnetic Testing

The selection of apt method as well as the detection and monitoring of corrosion needs knowledgeable and experienced personnel. Some techniques can be used online while others are used offline to provide the measurement. The measurements are highly sensitive as well.

LT of NDT Technology - A Conventional, Versatile and Cost-Effective Testing Mode

NDT or nondestructive testing is safe and also cost-effective. Due to these reasons they are being used by different industries in a rapid manner. Particularly, manufacturing industries are actually taking it up on themselves to use NDT technology in Malaysia and other countries. These can be divided into traditional and non-traditional ones and both these are still very much in vogue. There are several techniques used for detecting flaws in metallic components. One such method is the Liquid Penetrant testing or LT. This method is employed to detect flaws like cracks on the surface of any kind of non-porous material like plastics, ceramics and metals.

More about Liquid Testing

Liquid Penetrant Testing is also referred to as Dye Penetrant Testing or Penetrant Inspection method. This particular method is used in the industrial sector by people who are experienced and qualified to conduct such tests. This is particularly very effective in detecting cracks in pipelines of course made from various metals and machine components. Detecting and rectifying those cracks can help in avoiding accidents and preventing failures. Different kinds of defects can be detected using this process and it includes fatigue cracks, hairline cracks and porosity. Some more industries being served with Dye Penetrant testing include aerospace, petrochemical, engineering and automotive companies.

Although it is a widely used nondestructive testing technique, it is still considered to be the least technologically sound testing method compared to others like ultrasonic testing and radiography. There are reasons to believe this. It is definitely a cost-effective, versatile and easy to perform test which requires relatively less trained technicians to be completed. The process of work for LT is quite simple but a little lengthy.

The Process of Liquid Penetrant Testing

The process of LT continues in the following manner:

• The material to be tested needs to be cleaned using a spray cleaner that is easily wiped off with a cloth. Wire brushing and grinding might be required.
• A Dye Penetrant is applied to the surface with the help of aerosol spray.
• The liquid is left on the surface for sometime so that the liquid penetrates into the cracks and fissures making them visible to the technicians.
• After this process is done and the cracks are visible, you have to remove the liquid with a cloth.
• The developer then acts to draw out the excess liquid that may have seeped into a crack making it highly visible and providing an indication of the defects on the surface of the object.

LT of NDT Technology in Malaysia depends on only visual inspection thus making it a little weaker method than others. The color indication is important and hence many technicians prefer using fluorescent dye. This is a conventional technique. However, its versatility is a big point why it is so popular. This is quite easy to manipulate through the cracks and thus is a viable nondestructive technique to be used. It still continues to be the preferred technique of many.