Nondestructive Testing (NDT) Material Testers Specifications

Help with Nondestructive Testing (NDT) Material Testers specifications:

Instrument Type / Technology

	Technology:
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	Acoustic Emission		Acoustic emission instruments monitor conditions and detect changes in mechanical, electrical and process systems. In electrical power distribution systems, they detect shorting or arcing. In mechanical systems, flaws also provide specific acoustic or vibrational responses. For example, if a break, deformation or other failure occurs, acoustic emission (AE) sensors can detect the burst of high frequency caused by the event. Continuous acoustic emissions are associated with dislocation movement and the resulting strain or deformation. Bursts or short pulses of acoustic emissions signals are produced by micro-yielding, twinning, and crack formation. Melting, phase transformation, thermal stresses, fiber breakage and fiber-matrix debonding in composites also result in acoustic emissions.    Monitoring acoustic emissions can also access the location and severity. This NDT technique is particularly useful in determining the structural adequacy of tanks and pressure vessels.  AE is also used for the detection of faults or leakage in pressure vessels, tanks, and piping systems. Welds and stress corrosion cracking can be monitored on-line with AE techniques.
	IR / Nuclear		Infrared (IR), nuclear and beta gauge instruments use the absorption of radiation to measure the thickness or basis weight of webs, sheet materials or coatings. With nonmetallic materials such as paper or plastic films or webs, the amount of radiation that is reflected back or transmitted through the material is measured to determine absorption levels. An increase in mass, density or thickness will result in increased absorption. Often, the gauge is calibrated with a sample of known thickness, density or mass. The radiation source used can be IR (i.e., infrared electromagnetic), nuclear (i.e., beta particles) or other (e.g., x-ray, gamma rays) and depends upon the material and inspection conditions.
	Eddy Current / Electromagnetic		Eddy current, penetrating radar and other electromagnetic techniques detect or measure flaws, bond or weld integrity, thickness, electrical conductivity and the presence of rebar or metals. Eddy current is the most widely applied electromagnetic NDT technique. This method is also useful in sorting alloys and verifying heat treatment.  Eddy current testing uses an electromagnet to induce an eddy current in a conductive sample. The response of the material to the induced current is sensed. Since the probe does not have to contact the work surface, eddy current testing is useful on rough surfaces or surfaces with wet films or coatings.
	Electromagnetic Acoustic Resonance		Electromagnetic acoustic resonance (EMAR) uses a non-contact electromagnetic transducer to impart a signal for resonant acoustic analysis. The non-contact, EM-induced signal produces a pure resonant response. Mechanical vibration from surrounding machinery does not influence the ultrasonic signals in the materials or parts being inspected. Localized or wide acoustic fields can be generated, depending what features need to be isolated and measured. Small surface or subsurface flaws or anomalies can also be isolated. Specifically, the entire part can be resonated for elastic stiffness and structural integrity assessments.
	Magnetic / Barkhausen		Several different magnetic techniques are used in non-destructive testing to determine material condition or to detect internal flaws or porosity such as induction, Barkhausen Noise, Hall effect or magneto-optical methods. Barkhausen Noise, micro-magnetic or magnetoelastic techniques are commonly applied to access residual stress and microstructure.
	Optical / Laser		Optical-based NDT instruments use techniques such as laser shearography, magneto-optical methods and holographic interferometry to detect flaws and residual stress, or to measure thickness.
	Ultrasonic		Ultrasonic (UT) inspection techniques detect surface and subsurface flaws, or to measure thickness. Beams of high-frequency acoustic energy are introduced into the material and subsequently retrieved. Distance calculations are based on the speed of sound through the material under evaluation. The most widely used of all UT techniques is the pulse-echo technique. Flaws are detected and sizes estimated by comparing the amplitude of a reflected echo from an interface (e.g., flaw or back surface) with that of a reference interface of known size.
	X-ray		X-ray equipment for non-destructive material analysis can fall into three categories: Radiographic: X-rays or gamma rays penetrate and image the internal structure of a part or finished product.  Density and composition of the internal features will alter the intensity or density of these features in the X-ray image. X-ray diffraction: X-ray diffraction can be used to definitely determine residual stress and crystal structure or levels of retained austenite, ferrite and other phases. While typically a laboratory technique, portable units are available. X-ray fluorescence: A spectroscopic technique that uses the characteristic x-ray of element for chemical analysis. The technique is useful for material or alloy sorting and content determination.
	Other		Other unlisted nondestructive techniques or technologies.
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	Form Factor:
	Your choices are...
	Portable / Hand Held / Mobile		Devices are portable, handheld or mobile.
	Monitoring System		Devices are monitors or monitoring systems used to continuously detect or measure flaws, thickness or corrosion.
	Other		Other unlisted or proprietary form factors.
	Bench / Rack / Cabinet		Devices sit atop a bench or desktop, or are mounted in a rack or cabinet.
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Properties Measured

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	Alloy Sorting / Content		Alloy sorting devices and content testers sort alloys based on chemical composition. Chemical composition can alter conductivity and other physical properties detectable by eddy current and other NDT methods.
	Conductivity / Resistivity Instruments		Conductivity or resistivity instruments measure the conductivity or resistivity of materials.
	Density		Instruments measure density changes. These density variations can alter radiation absorption, reduce conductivity or attenuate sound waves which can be detected by beta gauge, eddy current, ultrasonic and other nondestructive test instruments.
	Heat Treatment		Instruments test heat-treated materials. Heat treatment can alter the conductivity and magnetic properties of a metal alloy since phases precipitate and the distribution of the alloying element changes.
	Residual Stress		Instruments detect residual stress, which is commonly measured with x-ray diffraction and magnetic (e.g., magnetoelastic, micromagnetic) or Barkhausen noise techniques. The strain from the residual stress alters the atom spacing in a crystal. X-ray diffraction is useful in measuring the changes in atomic spacing. Barkhausen noise techniques are useful on ferromagnetic materials such as steels. Ferromagnetic materials consist of small magnetic regions resembling individual bar magnets called domains, with each domain separated by a domain wall. Each domain is magnetized along a certain crystallographic easy direction of magnetization. Alternating magnetic fields will cause domain walls to move back and forth and result in an overall change in magnetization.  An electrical pulse is induced by the magnetization in a micromagnetic probe or coil of conducting wire placed near the sample while the domain wall moves. The electrical pulses produced by all domain movements are added together to generate the noise-like signal called Barkhausen noise.
	Tensile / Yield Strength		Instruments measure tensile or yield strength. Because tensile strength can be inferred from hardness values in specific steels, instruments that provide an indication of hardness or microstructure can also provide an indication of tensile strength. Resonant ultrasonic spectroscopy or other ultrasonic techniques can also provide an indication of material strength. Flaw levels, density and microstructure also influence material stress and can be measured by NDT instruments.
	Other		Other unlisted or unspecified measurement types.
	Microstructure		Microstructure instruments detect or measure ferrite, retained austenite, carbides, second phases or other microstructural features in steel or other materials. Often, these instruments use magnetic induction or Barkhausen noise technology for microstructural variation detection. Ultrasonic techniques are also used to detect microstructural variations in cast iron, since there is a consistent difference in sound velocity between pure iron, nodular cast iron and gray cast iron.
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Features

	Programmable / Digital Control Unit?		The unit is controlled by computer programs, or by other digital methods.
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	Pulsed Unit?		The system functions by producing short-range pulses of x-rays.
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	Rotating Probe Drive?		Rotating probe drives have a drive system that rotates the probe to radially scan the inner diameter of a pipe, tube, cylinder, liner, or other internal surface for flaws.
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	Uses Magnetic Sensors?		The instrument is capable of using magnetic induction probes in addition to eddy current probes.
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