Non-Destructive Testing Services
Visual Methodology (VT)
All NDT methods are based on the ability to identify visual anomalies either from direct surface inspection or visualizing subsurface anomalies through some electronic medium. However, Visual Inspection or VT, principally refers to visual identification of surface conditions of a component or part. API 510, 570, and 653 rely heavily on the initial VT even though they may employ additional NDT methods in the inspection process. CWI (Certified Weld Inspector) inspections also rely on an initial visual inspection as a precursor to the use of additional NDE methods such as RT, MT, PT, or UT.
ITL technicians are trained in the importance of visual observations and how they may relate to other anomalies not visible on the surface of the part. In addition, recording the initial surface conditions before using any other inspection method is essential in the analysis of failure mechanisms that may be affecting a component or part. Photographic documentation (where permitted) is essential to reporting any VT activity.
Radiographic Inspection (RT)
Radiographic Inspection is a volumetric inspection method performed using a source of radiation that passes through an item producing an image on film or a detector placed on the opposing side of the item. Typically, two types of radiation can be used; radioactive isotopes (IR-192 and Co-60) or an x-ray tube/machine. Both options have advantages and disadvantages. The primary advantage for isotopes is portability. Isotopes are easily portable whereas an x-ray tubes of equivalent strength are somewhat less portable and they require power source. X-rays also produce a sharper image than isotopes.
Traditional or Film Radiography
Traditional Radiographic Inspections are performed using film to capture the desired image. Although technology has provided the industry with other options, traditional film is still utilized as the primary method. The advantages of this method are flexibility and it is easily customized to acquire the desired resolution and clarity. The disadvantage is radiation exposure and development time. Compared to other techniques, film generally takes longer to expose and develop, meaning more time waiting on results and more radiation exposure to the technician.
Computed Radiography (CR)
CR is very similar to Traditional film in the sense that it is flexible and customizable. The difference is the sensitivity, exposure, and development time. CR can achieve excellent sensitivity under specific circumstances however; the industry still prefers the traditional method to achieve higher quality images. With CR, exposure times are generally much less than that of traditional film. The main advantage of CR over film is the development process. An image can be scanned and imported into a computer program in approximately the same time it takes to scan a piece of paper. Because of this, CR is commonly used for large volume “Profile Radiography” projects.
ITL uses CR as its advanced RT method. We employ X units in our three operating locations all of which are the ALLPRO Imaging, SCANIX Discover Systems.
Digital Radiography (DR)
DR has many similarities to CR, the main difference being configuration of the image acquisition mechanism. Where CR requires a scanner to import the image from a plate, DR does not. DR is performed by exposing and rigid sensor panel that detects the radiation as it accumulates within its sensors. Because of this, results are nearly instant. As soon as the exposure is complete, a complete image can then be transferred to a computer monitor. The main disadvantage is that DR panels are large and awkward, making shot set-ups more difficult. Therefore, DR is typically reserved for easy access or stationary setups where the items can be brought to the panel.
The primary use for Real-time X-ray is to locate corrosion under insulation (CUI). By using a very low energy x-ray tube, inspections can be performed under insulation that would normally need costly removal and replacement of the insulation. When low intensity radiation is used, an image of the outer edge (profile view) of the pipe is created since the pipe wall blocks all but the radiation passing through the insulation, making areas of O.D. corrosion visible.
Digital archival of film
Film storage becomes a challenging issue when radiographic and x-ray film is required to be archived. Film comes in a variety of sizes, which itself can be challenging to filling and storing radiographs. Film, in large quantities, is heavy. Indexing large quantities of stored film further adds to burdens of maintain film in its physical state. Moreover, the environment of the storage area must be maintained under controlled temperature and humidity conditions in order to ensure it can be retrieved and read in the future.
The advantages of digitizing become very obvious considering the aspects of maintaining a physical film archive. The digital archive not only offers significant physical advantages to preserving the film images in a compact space not requiring rigid environmental controls, but also makes retrieval of a specific piece of film much faster and easier. Digital archives are searchable and therefore retrieval can be accomplished on system or part data, date, type of indication, or the radiographer that produced the shot. Digital film archives can be backed-up numerous times if needed for very little additional cost. This further ensures the longevity of the records.
Integrity Testlabs maintains the equipment and technical personnel that allow us to deliver Film Digitization and Archival Services with efficiency and competence.
Radiography serves venerated U.S. historical relic.
The setup for the shots shown on the right.
Inspection of the Liberty Bell
The Liberty Bell was radiographed to check for damage and potential growth of the famous crack after the bell was struck with a hammer by a tourist on April 6, 2001. Fortunately, the test results did not reveal any new cracks resulting from the incident. Copies of the radiographs shown were presented to our owner, who performed the radiographic work, at the completion of the project.
Ultrasonic Inspection (UT)
Ultrasonic thickness measurements (straight-beam, “L-wave”, etc.) are among most common form of ultrasonic testing that is performed. With this method, sound is introduced into the material perpendicular to the inspection surface. It is utilized to accurately collect remaining wall thickness measurements on in-service and out-of-service equipment. With this method, accurate wall thickness readings can be taken accurately to 1/1000 (0.001) of an inch. A significant advantage of ultrasound is its versatility. Readings can be taken through coatings, on hot items, and where access is limited. Ultrasonic units with data logging capabilities connected to automated scanners allow large volumes of data to be collected and imported into data management programs for analysis and follow-up. These applications are very effective when large, flat surfaces are being inspected for wall thinning. See C-Scan below.
Shear-wave ultrasonic inspection is a reliable and well-established NDT method. Manual ultrasonic methods have been used for decades to detect internal flaws. Manual ultrasonic equipment today is lightweight and compact. There are countless configurations of transducers that can be used to quickly evaluate internal material anomalies in materials and components throughout industry. Shear-wave refers to sound energy introduced at an angle. The type of anomaly and material dictate the specific angle used in the inspection process.
As with straight-beam inspection, manual shear-wave applications can be automated with the use of scanners that can collect a large volume of data quickly and store it for off-line analysis.
Penetrant Inspection (PT or LPI)
Liquid penetrant inspection (LPI) is an inspection performed to detect surface anomalies on cast, forged, and machined parts throughout all industries. In addition, it is also used on welds, and other surfaces subject to surface breaking anomalies. LPI is performed in many variations. The primary being visible dye and fluorescent dye that requiring a blacklight. Both can be performed in field and lab environments. The primary use of LPI is to make the location of surface breaking flaws, normally not visible, visible with the naked eye. Depending on the orientation of the part, surface condition, and material; most all items can be inspected with LPI. LPI provides benefits over other inspection techniques that are not designed to identify surface indications or are limited to carbon steel items only.
Magnetic Particle Inspection (MT)
Magnetic particle inspection utilizes a magnetic field and a magnetic medium consisting of very small iron particles. A magnetic field is induced into the area of inspection and the inspection medium (red, black, or fluorescent powder) applied simultaneously. The inspection medium will align the magnetic flux fields on the surface of the part. Anomalies and defects in the surface of the inspection area will be visible where magnetic flux lines are not contiguous or interrupted, thus making the surface defect visible.
This method is one of the most widely used methods in NDT where surface defects must be identified. It is widely used in the automotive, aerospace, petrochemical, power generation industries where fitness for service determinations are important.