Eddy currents are created through a process called electromagnetic induction. When alternating current is applied to the conductor, such as copper wire, a magnetic field develops in and around the conductor. This magnetic field expands as the alternating current rises to maximum and collapses as the current is reduced to zero. If another electrical conductor is brought into close proximity with this changing magnetic field, current will be induced in this second conductor. Eddy currents are induced electrical currents that flow in a circular path. They get their name from Eddies, which are formed when a liquid or gas flows in a circular path around obstacles when conditions are right.

ID probes, which are also referred to as Bobbin probes or feed-through probes, are inserted into hollow products, such as pipes, to inspect from the inside out. ID probes have housing that keeps the probe centered in the product and the orientation of the coil(s) somewhat constant relative to the test surface. The coils are most commonly wound around the circumference of the probe so that the probe inspects an area around the entire circumference of the test object in one go.

Remote Field is a technique used for the inspection of tubes made of ferrous materials, like Carbon steel and Chrome-Molybdenum. RFT is only one of the techniques available for inspection of carbon steel tubes. Since al inspection techniques that are available for carbon steel have limitations compared to conventional eddy current, it is even more important to select the most suitable technique for each different situation. For the inspection of carbon steel tubes it is often recommended to use a combination of one or more techniques. Overall wall-loss can be easily detected and accurately quantified. Local defect scan be detected and quantified provided that they have some volume (diameter pit >5 mm). RFT can detect both in- and external defects but it is not possible to distinguish between them.

Widely used in Steel, Automotive and Aerospace industries, the eddy current method is one of many electromagnetic testing methods used in Non Destructive Testing (NDT). It making use of electromagnetic induction to detect and characterize surface and sub-surface flaws in conductive materials.

Phased Array Ultrasonic Testing (PAUT) is an advanced nondestructive examination technique that utilizes a set of ultrasonic testing (UT) probes made up of numerous small elements, each of which is pulsed individually with computer-calculated timing. more complex geometries that are difficult. PAUT can be used for more complex geometric weld inspections, high thick materials and crack detection. Advantages are, it can be conducted more quickly, used for repeat scans because it has a high degree of repeatability, it is able to create detailed and accurate cross-sections of a part, gives a permanent record, Gives information about lateral position of defect in weld (depth and height), No radiation, higher POD.

Although most ultrasonic flaw detection and thickness gauging is performed at ambient environmental temperatures, there are situations that require inspections be completed at elevated temperatures. This is a common requirement in process industries where high-temperature pipes or tanks are inspected while on-line. The system is specifically designed to operate at elevated temperatures and is used to evaluate the condition, particularly corrosion and weld inspections, of ferrous structures including storage tanks, pipelines, pressure vessels, Reactors and other critical equipment. The ThermalScan-700 is the best and the most cost effective solution for performing high temperature AUT/NDT scans on surfaces up to 700° F. This air cooled automated 2-axis scanner can scan at up to 30″ (760mm) per second on the arm and up to 5″ (125mm) per second on the wheels. It will scan on items ranging from 3 inch pipe to flat surfaces at temperatures up to 700°F (370°C) utilizing its compressed air cooling system.

Time of Flight Diffraction (TOFD) is a reliable and fastest method of nondestructive ultrasonic testing (UT) used to look for flaws in welds. TOFD uses the time of flight of an ultrasonic pulse to find the location of a reflector. It can also be used for weld overlays and the heat affected zones of other components as well such as piping, pressure vessels, clad material, storage tanks and structural steel. PAUT + TOFD combination is commonly used to inspect pipeline welds. To do this, TOFD uses a pair of ultrasonic transducers, one as a transmitter and the other as a receiver. The low frequency waves propagate at an angle and only diffract back to the receiver if they hit a defect. If this happens, the time it takes for both waves to make it to the receiver can be used to create a complete image of the weld and identify the size and location of the damage. Advantages are, high degree of repeatability, no radiation, higher POD, cost saving, more sensitive, Quick setup, precise sizing.

Electromagnetic acoustic transducer (EMAT) is a transducer for non-contact sound generation and reception using electromagnetic mechanisms. EMAT is an ultrasonic nondestructive testing (NDT) method which does not require contact or couplant, because the sound is directly generated within the material adjacent to the transducer. Due to this couplant-free feature, EMAT is particularly useful for automated inspection, and hot, cold, clean, or dry environments. EMAT is an ideal transducer to generate Shear Horizontal (SH) bulk wave mode, Surface Wave, Lamb waves and all sorts of other guided-wave modes in metallic and/or ferromagnetic materials. As an emerging ultrasonic testing (UT) technique, EMAT can be used for thickness measurement, flaw detection, and material property characterization. Advantages are, Dry Inspection, Easier sensor deployment, Ability to generate SH modes, less sensitive to surface conditions.

Short Range Ultrasonic testing (SRUT) is one of the Ultrasonic test methods wherein the ultrasonic waves are transmitted in the form of pulsed guided laminar waves using special purpose ultrasonic probes. When laminar waves hit discontinuities (corrosion, pitting & erosion) they are mode converted and the reflection of the waves are detected by the transducer. SRUT is a screening non-destructive test method to detect corrosion on the pipe wall or plates concealed under support structures or structural shell. SRUT is a screening technique used on wall thickness range of 6 to 25mm, this test method can locate the discontinuity location and size to an accuracy of ±10%. The special SRUT probe is placed away from the area of interest to scan up to 1metre of material length without losing adequate sensitivity. Advantages are, SRUT is a fast method, Recordable & Tracible, limited access.

Corrosion Mapping is an ultrasonic technique which maps and identifies variations in material thickness due to corrosion. Corrosion is the deterioration of a metallic material by chemical (or electrochemical) attack. This is normally caused by the environment (most often water), and sometimes by another material. To perform corrosion mapping an automatic or semi-automatic scanner is used to scan an inspection surface, using various ultrasonic techniques including pulse echo, eddy current and phased array. The data is stored on a computer and may be color coded to show differences in thickness readings. Results for corrosion mapping provide a high degree of repeatability and the advantage of position and size data for every flaw which can be compared for repeat scans of the same area to track flaw growth or corrosion rates both generally and for individual pits.

Most ultrasonic flaw detection and thickness gauging is performed at ambient environmental temperatures, there are situations that require inspections be completed at elevated temperatures. High Temperature Corrosion Mapping(HTCM) is an advanced ultrasonic technique which maps and identifies variations in material thickness due to corrosion, Erosion at elevated temperatures up to 350°C. This is a common requirement in process industries where high-temperature pipes or tanks are inspected while on-line. The system is specifically designed to operate at elevated temperatures and is used to evaluate the condition, particularly corrosion and weld inspections, of ferrous structures including storage tanks, pipelines, pressure vessels, Reactors and other critical equipment. The data is stored on a computer and may be color coded to show differences in thickness readings.

Hydrogen Induced Cracking (HIC) is a common form of wet H2S cracking caused by the blistering of a metal due to a high concentration of hydrogen. The blistering damage tends to form parallel to the surface and to the direction of hoop stress. Hydrogen atoms are generated by corrosion reaction of H2S and Fe in present of free water. The hydrogen atoms, which have the smallest atomic elements are diffuses into steel and traps in mill laminations or voids. Then, every two atoms combine to form hydrogen molecular. The mechanism of HIC is similar to that for hydrogen blistering. If two or more adjacent blisters are close enough so that the crack tips are overlap, a series of stepwise cracks (SWC) will be developed. In this stage, a potential dangerous situation which could lead to rapture and gas leak.

Robotic Video Crawler is a advanced borescope method to assess the internal conditions of tubes, Pipes, vessels, etc., and record the observation in the movie format using remotely operated video Crawler equipment. The tubes and piping to be inspected shall have access to insert video Crawler and to carry out Visual inspection. By using this we can inspect piping greater than 10inch diameter. Visual examination is generally used to determine such things as the surface condition of the part, alignment of mating surfaces, corrosion, erosion, cracking, oxidization, distortion or evidence of leakage, bulging, sagging, etc. When Visual inspection is performed, the Video Crawler system shall have the same resolution as direct visual examination. The Video Crawler camera shall be articulated/focused, and the images shall be displayed as video or image formats. The results shall be recorded in the hard disk for future reference.

In non-destructive testing, a leak is defined as a hole, a porous area, a permeable area for gases or a different structure in the wall of a test specimen through which a gas can escape from one side of the wall to the other due to a difference in pressure or concentration. Expressed in simpler terms, leaks are small holes through which gases or liquids flow from the side of higher pressure to the side of lower pressure. A leak can be a harmless leak such as a dripping water faucet. Leaks involving the escape of aggressive media or toxic substances can have more serious consequences. Helium leak detectors are the ideal solution for leak detection and leak-tightness testing under vacuum. The test gas Helium is safe and a small, light molecule which is suitable for detecting micro leaks. The detection range of Helium in vacuum tests lies between 10-2 and 10-13 Pa · m3/s. Helium leak detection is extremely accurate, quantitative and repeatable. Fast cycle times are a further advantage. Manual sniffing or spraying is often the easiest way to detect a leak with Helium gas.

Pipelines perform a critical function in the global economy, transporting huge volumes of gas, oil, water, and other chemicals. Pipes are girth-welded on-site, typically using automated welding systems. For pipelines, welds are the “weak spot” as this is where defects tend to occur. Welds are nondestructively tested, coated, and buried or laid on the sea bed. Due to the demanding construction cycle, it is important that weld defects be detected and analyzed very quickly. Automated ultrasonic testing (AUT) has begun overtaking traditional radiography as the pipeline weld inspection method of choice throughout the world. Radiography has significant limitations: poor detection of planar defects, no vertical sizing capability, safety issues, and environmental concerns. The PipeWIZARD is an automated girth weld inspection system which is suitable for in-site weld-to-weld inspection in extreme environments. It uses conventional UT and phased array techniques. Electronic beamforming is used by phased arrays for producing and receiving ultrasound. The phased array systems are suitable for offshore and onshore pipeline construction projects. The PipeWIZARD system has resistance to electromagnetic interference, vibration and shock. Based on the pipe diameter, weld type, environment and location, the time of inspection cycle varies from 2 to 6 min. Defects detected by the PipeWIZARD system are incomplete penetration, burn through, porosity, lack of fusion, undercut, cold lap, hi-low, crack, inclusion, etc.