7 Non-Destructive Testing Services

Non-Destructive Testing Services

Nondestructive testing (NDT) is a wide group of analysis techniques used in science, technology, and industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive examination (NDE), nondestructive inspection (NDI), and nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research.

The seven NDT methods provided by IQS are:

Radiographic Testing RT
Ultrasonic Testing UT
Magnetic Particle Testing MT
Dye Penetrant Testing PT
Leak Testing LT
Ground Penetrating Radar Guided Wave Testing GPR
Remote Visual Inspection RVI

Radiographic Testing RT

For Radiographic Testing (RT) the test-part is placed between the radiation source and film (or detector). The material density and thickness differences of the test-part will attenuate (i.e. reduce) the penetrating radiation through interaction processes involving scattering and/or absorption. The differences in absorption are then recorded on film(s) or through an electronic means. The amount of energy absorbed by the object depends on its thickness and density. Areas of the object where the thickness has been changed by discontinuities, such as porosity or cracks, will appear as dark outlines on the film. Inclusions of low density, such as slag, will appear as dark areas on the film while inclusions of high density, such as tungsten, will appear as light areas. The areas of increased density attributable to discontinuities within the test part can then be measured and directly referenced to a code or standard to determine acceptance or rejection of the part.

Radiographic Testing (RT) is defined as a volumetric examination, in that non-surface non-visible discontinuities can be revealed together with their approximate location, size, and orientation.

IQS can come to your facility to provide an onsite service or you may ship your part to us and we will examine it in our high density, lead lined vault. For larger parts, we offer a pick and return service.

Common Applications for RT

Ferrous and nonferrous castings and forgings
Weld Code Compliance
Measurement of wall thickness and evaluation of corrosion under insulation

CR – Computed Radiography – is the term given to the application of radiography where the radiographic film is replaced by a re-usable imaging plate.

CR imaging plate contains photo-stimulability storage phosphors. When radiation impinges on the plate, the phosphor crystals become trapped in a semi-stable higher energy state and the image is retained. The CR cassette is then removed from the inspection site and the plate placed in a CR reader. The CR reader scans a laser over the image, releasing the trapped electrons in the phosphor crystals and emitting visible light. This light is captured, digitized and stored as the radiographic image. The plate is then wiped clean for re-use.

CR has the following advantages:

The phosphors on the plate have an extremely wide dynamic range, giving a high tolerance for varying exposure conditions and the exposure dose. This reduces the need for re-takes.
The increased sensitivity of the plate allows for shorter exposure times or the use of a weaker radiation source, providing dose reduction over that required for film radiography.
No chemical developer is needed.

DR – Digital Radiography – is a term given to the application of radiography where the radiographic film is replaced by a sensor that provides an immediate digital image of the radiograph. However, DR is also sometimes used as a more generic term which relates to the use of digital technology in radiography inspection.

DR, a sensor digitizes the radiation passing through the component under inspection so that the radiographic image can be displayed immediately on a PC screen. There are three main digital sensors: CCD, CMOS and Amorphous Silicon. The DR sensors produce images in seconds, rather than the minutes required for the CR images, and are therefore particularly suited for real-time radiography. The digital sensors can also have a better resolution than CR plates and most film applications. However, the portability of CR cassettes makes them particularly suited for application in difficult access conditions.

Both CR and DR allow the benefits of digital technology to be applied to radiographic inspections: digital measurement can improve accuracy and reproducibility of results; the image can be digitally enhanced for better interpretation; and images can be easily archived and integrated into plant databases.

Open Vision for location Corrosion Under Insulation (CUI )

OpenVision is a lightweight live video X-ray imaging system specifically designed for hand-held inspection. The proprietary intensified video imaging system captures images and displays them on a handheld LCD viewer, head mounted display, or portable recorder with LCD display in real-time. This portable system is commonly used to locate welds under insulation, and corrosion under insulation captured on the monitor. Open vision with the use of guided wave ultrasonic used together are the most essential ndt applications used for identifying corrosion under insulation.

Ultrasonic Testing UT

Ultrasonic Testing (UT) is one of the more common non-destructive testing methods performed on materials. This method utilizes high frequency mechanical energy, i.e. sound waves, to conduct examinations and measurements on a test area.

The UT system consists of a transducer, pulsar/receiver, and display unit. A pulsar/receiver is an electronic device that can produce high voltage electrical pulses to the transducer. When driven by the pulsar, the transducer generates high frequency ultrasonic sound energy into the material in the form of sound waves. When there are discontinuities such as inclusions, porosity, cracks etc. present in the sound path, part of the mechanical energy will be reflected from the discontinuities’ (reflectors’) surface.

The reflected sound waves signal received by the transducer is then transformed back into an electrical signal and its intensity is shown on the display unit.

The sound waves travel time can be directly related to the distance that the signal has travelled. From the signal, information about reflector location, size, orientation, and other features can be determined. UT is thus defined as a volumetric method

IQS can come to your facility and provide an onsite service with immediate results. For larger parts and /or multiple parts we offer a pick-up and delivery service

Common Applications for UT

Weld code compliance
Material thickness such as pressure vessel, storage tank and pressure piping. Interval thickness surveys and equipment retirement forecasting
Corrosion Evaluation
Bolt examination

Ultrasonic Shear wave

Shear wave testing, also known as angle beam inspection, is an ultrasonic testing technique used primarily for weld inspections.

sheerwave testing

A probe consisting of an ultrasonic transducer coupled with a plastic or epoxy wedge introduces an ultrasonic beam at an angle into a test area. As the probe is moved back and forth along the area, it can detect discontinuities in the weld based on the reflection and refraction of the ultrasonic beam.

Automated Ultrasonic

Automated Ultrasonic Testing (AUT) is any form of ultrasonic testing (Phased Array Ultrasonic Testing, Conventional Shear Wave Ultrasonic Testing, Corrosion Mapping, etc.) used to determine wall loss, crack detection, laminations, and other discontinuities that may exist in base materials or welds.

Corrosion Mapping ultrasonic testing maps the interior surface of pressure vessels, piping, heat exchangers, and more. It is often used for remaining life determinations as prescribed by the facility’s Mechanical Integrity program.

Encoded Weld Quality/Monitoring (ultrasonic testing) is best when the desire is to inspect new or existing welds for defects (critical defect sizing), crack monitoring, and more. We can fully meet the requirements laid out in ASME code case 2235-9. This case allows ultrasonic testing in lieu of radiography when dealing with certain sections of ASME fabrication

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. This technique can be used to inspect more complex geometries that are difficult and much slower to inspect with single probes. PAUT can be used to inspect almost any material where traditional UT methods have been utilized and is often used for weld inspections and crack detection.

Compared to other forms of UT, PAUT has several advantages. PAUT can be conducted more quickly than other forms of UT, often within a fraction of a second. It can easily be used for repeat scans because it has a high degree of repeatability. By emitting beams of multiple different angles sequentially, PAUT can create detailed and accurate cross-section of a part. It is also particularly useful in situations where there is less room for mechanical scanning because it’s able to sweep the beam without moving the probe.

Positive Material Identification ( PMI ) Vanta

XRF PMI

Vanta handheld XRF analyzers provide rapid, accurate elemental analysis when screening for lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), chromium (Cr), and other toxic metals in consumer products such as toys, apparel and footwear, and electronics to comply with RoHS regulations. Vanta analyzers are ideal tools for a reasonable testing program. With the optional 5-megapixel panoramic camera and Wireless LAN connectivity, Vanta handhelds make it easy to archive sample images and results. Olympus’ ultra-low-noise Axon technology built into every analyzer provides excellent sensitivity for low detection limits and accurate pass/fail results of regulated element

SciAps OES / LIB Carbon Analysis

SciAps OES / Libs

The traditional method to test carbon in alloys is spark optical emission spectroscopy (spark OES). Spark OES uses a high voltage spark source to continuously spark the alloy. The heat from the sparking vaporizes the surface of the metal, stripping the outer valence electrons from the atoms that comprise the alloy. These valence electrons form an electron plasma. As the plasma cools, the electrons recombine with the atoms, causing characteristic photons (light) to be emitted from the electrons at known wavelengths. SciAps allows for a hand held machine with data output with ergonomics in mind.

Safety and Compliance Certs

Magnetic Particle Testing MT

Magnetic Particle Testing (MT) is a non-destructive testing (NDT) process for detecting surface and slightly sub-surface discontinuities in ferroelectric materials such as: iron, steel, nickel, cobalt, and some of their alloys. The process introduces a magnetic field into the part to cause lines of flux between the magnetic poles. A medium consisting of iron oxide powder which can be either a dry product or a wet product in a suspension is distributed onto the part and into the magnetic field. Discontinuities that are perpendicular or close to perpendicular to the lines of flux cause flux leakage. This causes the iron oxide particles to be attracted to and clump at the flux leakage thus revealing what was a hidden discontinuity

A variety of MT materials are available, the selection of which is generally driven by the required sensitivity of the test.

Common Applications for MT

Weld code compliance
Ferrous a castings and forgings
Fatigue cracks in in-service components

Penetrant testing (PT)

PT is also known as dye penetrant inspection was first developed in the early 1940s to detect flaws on the surface of materials. Although there are more options in the way the test is performed, the basic principles have not changed over the years.

Liquid penetrant inspection is a nondestructive test method which does not harm the samples or parts being inspected. PT may be used on both metallic and non-metallic parts. The test is very effective in detecting porosity, cracks, fractures, laps, seams, and other flaws that are open to the surface of the test piece and may be caused by welding, fatigue, impact, quenching, machining, grinding, casting, and forging etc.

This method derives its name from the liquid, called penetrant, that is applied to the sample during testing. The penetrant is drawn into open discontinuities by capillary action, after a suitable period the penetrant is drawn out of the open flaw to become visible on the surface of the part thus revealing what was a hidden discontinuity. A variety of penetrant materials are available and selection is often based on the required sensitivity level of the test.

Common Applications for PT

Weld code compliance
Ferrous and nonferrous castings and forgings
Ceramic machined components
Fatigue cracks in in-service components

Leak Testing LT

IQS provides the Bubble Leak Testing method (BLT). ASNT recognizes three variations for this process classified by the how the liquid used for detection is applied they are: Liquid Immersion, Liquid Film, and Foam application.

Bubble leak testing, it simple to use, rapid in application, and inexpensive. The technician can locate the exit point of leaks very accurately It is safe to apply BLT with proper inert gases, and testing liquids, in combustible areas.

While it is common to accomplish BLT with ordinary soap and water it is not a good practice, soap can form gummy deposits that can clog leaks. Soaps are alkaline (ph10.5 to 11.5) and can cause severe corrosion to aluminum alloys. Soaps contain chlorides and borates. These can cause stress corrosion cracking on stainless steels or titanium alloys. Many valves are stainless steel and titanium 22.

IQS only uses commercial BLT solutions that have a PH between 6 and 8, have low surface tension and have stabilized resistance to bacteria

Common Applications for BLT

All pressure retaining equipment and components both ferrous and non-ferrous

Ground Penetrating Radar Guided Wave Testing GPR

Ground Penetrating radar is a geophysical technique that employ radio waves to image the subsurface Although initially applied for ground (soils) applications, GPR can be used to identify features beneath other media such as concrete structures, pavement, rock and even ice. The GPR method is based on emission, reflection, and detection of electromagnetic waves. A short pulse of high frequency 1600 MHz of electromagnetic energy is produced and is transmitted into the medium being investigated. The pulse spreads into the subsurface materials and is affected by the properties of the surrounding materials. Some of the energy is attenuated and some is reflected at the interface between materials and different dielectric constants. The reflected energy is measured form the surface down using average wave velocity resulting in location accuracy within the 85 – 90% range.

IQS serves industry by supplying both Concrete scan GPR and Terrascan GPR.

Concrete Scan GPR

GPR is the NDT method of choice for concrete and structural examination where other methods are prohibited for example by being highly grained and unsuitable for UT, or ultra-thick and unsuitable for RT. IQS can verify and locate all sub surface indications such as rebar, conduit, piping and most importantly post tension cables. If you have ever drilled through a Post Tension Cable based upon the results obtained from a Ferro scan you know how expensive remediation can be! Consider allowing IQS to provide GPR reduce your risk.

Terrascan GPR

GPR technology can be employed to locate and determine the depth and position of metallic and non-metallic utilities and services. The wide scope of radar means we can also locate underground storage tanks and any associated ducting, sub surface concrete structures, voids and any other ground variations that may exist at your site. GPR is a viable method to employ prior to bore holing by performing a survey of the area to ensure there is clearance

Remote Visual Inspection RVI

RVI is an inspection technique that allows us to see inside small diameter openings often to 100feet from the opening. This is very useful in the internal examination of small diameter piping and tubing and may help the client avoid the cost of disassembly for conventional inspection. Detailed information can be obtained regarding the internal condition such as corrosion, erosion, and weld quality. Data is recorded and provided to the client in electronic media. IQS can help you ensure your equipment is free from foreign object debris. Foreign material can endanger plant/ equipment efficiency and operability and in some cases, such as the food industry can provide a significant health risk

Common applications for RVI

Piping systems
Pressure vessels
Boilers
Heat exchangers
Storage tanks
Weld code compliance, critical for autogenous welding processes

Contact IQS today

and allow us to develop an inspection program tailored to your specific requirements.