Radiographic inspection is based on the exposure by Either an X-ray machine or a radioactive source (Ir-192, Co-60, or in rare cases Cs-137) can be used as a source of photons. Since the amount of radiation emerging from the opposite side of the material can be detected and measured, variations in this amount (or intensity) of radiation are used to determine thickness or composition of material. Penetrating radiations are those restricted to that part of the electromagnetic spectrum of wavelength less than about 10 nanometers.The principle of Industrial Radiography Testing is Differential Absorption. This means that different materials absorb different amount of radiation based on the thickness difference, density and presence of defect.
Generally for detection medium is films which consist of an emulsion-gelatin containing radiation sensitive silver halide crystals, such as silver bromide or silver chloride, and a flexible, transparent, blue-tinted base. When x-rays, gamma rays, or light strike the grains of the sensitive silver halide in the emulsion, some of the Br- ions are liberated and captured by the Ag+ ions. This change is of such a small nature that it cannot be detected by ordinary physical methods and is called a “latent (hidden) image.” However, the exposed grains are now more sensitive to the reduction process when exposed to a chemical solution (developer), and the reaction results in the formation of black, metallic silver. It is this silver, suspended in the gelatin on both sides of the base, that creates an image. IRC has both Gamma Radiography source and X-Ray. In the recent past IRC has also carried out Closed Proximity system of Radiography using Se-75 Source. IRC is committed to provide on time services during shut-down and Erection Activities.
In-situ metallography is performed on actual site by team of metallographers and metallurgists. The technique is extensively used to assess in-service degradation of critical components operating under high temperature/ high pressure/ corrosive atmosphere. Micro structure survey is an important tool to evaluate real health status and residual life assessment of Boilers, Turbine, Pipelines, Reactors and Vessels. IRC believes in translating the latest technology into its real application at field to find better solutions for clients. To meet these challenges, IRC has team of highly qualified engineers and scientists in its fold to deliver technology driven services. The captive laboratory of IRC is equipped with an image analyzer software, to providecredible results of failure analysis, residual life assessment and condition assessmentof critical components.
Ultrasonic methods of NDT use beams of sound waves (vibrations) of a certain wavelength and frequency as per the requirements of the client, transmitted from a probe and after reflection detected by the same or other probes. Usually, pulsed beams of ultrasound are used and in the simplest instruments a single probe, hand held, is placed on the specimen surface. An oscilloscope display with a time base shows the time it takes for an ultrasonic pulse to travel to a reflector in terms of distance traveled across the oscilloscope screen. The y-axis of the oscilloscope screen depicts to the flaw size as seen from the transmitter probe. IRC has ASNT/ISNT level II and IIIexperts to interpret the results displayed on screen. It requires sufficient exposure and experience to determine the nature and severity of flaw .Ultrasonic examinations are performed for the detection of internal flaws or discontinuities in piping, castings, forgings, welds of fabricated items.An accurate sizing techniques have been developed to detect and monitor progressive cracking in a variety of equipment.
In case of Ultrasound Inspection IRC has made various advancements by adding up new technologies like Long Range Ultrasound Testing, Phased Array Ultrasound Testing, Time Of Flight Diffraction and Automated Ultrasound Testing
Dye Penetrant Test
The technique employs a penetrating liquid applied over the surface of the component . The dyewhich enters in to discontinuity or fine crack. After the excess penetrant is wiped off from the surface, developer is sprayed over the object ..The penetrant exudes or drawn out of the crack makes it more defined and visible . Liquid penetrant testcan be applied to detect surface flaws of non-porous clean , metallic or non-metallic material , however not suitable for un clean or very rough surfaces. Penetrants can contain a dye to make the indication visible under white light, or fluorescent material under ultra-violet light. Fluorescent penetrants are used when maximum flaw sensitivity is required. Through DPT ,micro cracks, as narrow as 150 nanometers can be detected. This method is only used for detection of surface cracks. Subsurface cracks cannot be detected by this method.
IRC is manned by ASNT Level-II and Level-III experts in Dye Penetrant Test to carry out the test . The experts also provide training to individuals in this particular discipline..
Magnetic Particle Testing
The Magnetic Particle Inspection method of Non-Destructive testing is a method for locating surface and sub-surface discontinuities in ferromagnetic material. Those defects can be detected upon magnetization of the part which are perpendicular to the flux lines, The flux leakage would be observed by the use of finely divided ferromagnetic particles applied on the part being magnetized. If there is a leakage in the field , ferromagnetic particles shall gather together and held by the leakage field. These ferromagnetic particles indicate size , location, shape and extent of the defect or discontinuity.
Dry magnetic particle examinations and wet fluorescent magnetic particle examinations are performed on ferromagnetic materials to detect surface and slight subsurface discontinuities. Specialized wet fluorescent magnetic particle techniques are available for black light internal examinations of equipment through bore scopes.
Certification of welding procedure, welds & Welders
IRCs team of Certified Welding Inspectors (CWI) can define the tests , necessary to qualify a weld, welding procedure, or individual welder. Each welding code follows three main criteria viz. Welding Procedure Specification (WPS), Welding Procedure Qualification Record (WPQR), and Welder Performance Qualification (WPQ). IRC team is well equipped to inspect, conduct requisite tests and certify all the aspects,of welding.
Visual Inspection Services (Boroscope)
Non-Destructive visual inspections can be preformed on-site or at the laboratory facility, and are based upon the requirements of the client or specification. Industries utilizing this service include Fabrication, Construction, Automotive, Power Generation and Transportation. Inspections can be performed at the laboratory facility or at site. These inspections are executed in accordance with the provisionsof BIS, BS, DIN, ASTM, AWS, ASME (American Society for Mechanical Engineers) and other standards.
We have carried out many Boroscope Services in India for Power Plants, Refineries, Fertiliser and Chemical units. IRC is also having one ASNT NDT LEVEL-III in Visual Inspection who can inspect such activities and give appropriate results.
It will be our pleasure to serve you in any of your future requirements.
In accordance with ASTM E110, this testing is normally required to be conducted for on-site applications or on very large objects / samples which can not be easily transported . IRC has number of portable hardness testing units to perform the se tests by application of 5 kg. Vickers load indenter that electronically converts the value in the preferred scale.