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इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 2417 (2003): Glossary of Terms Used in Ultrasonic Non-Destructive Testing [MTD 21: Non-Destructive Testing] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 2417:2003 Indian Standard GLOSSARY OF TERMS USED IN ULTRASONIC NON-DESTRUCTIVE TESTING (Second Revision ) ,, “!l { Ics 01,040; 19.100 0 BIS 2003 BUREAU OF INDIAN STANDARDS MANAK BHAVAN. 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 AugiNt 2003 Price Group 6 Non-destructive Testing Sectional Committee, MTD 2I FOREWORD This Indian Standard (Second Revision) was adopted by the Bureau of Indian Standards, after the draft finalized . by the Non-Destructive Testing Sectional Committee had been approved by the Metallurgical Engineering Division Council. This standard was first published in 1963 and subsequently revised in 1977. In this revision the definition of various terms have been made precise and up to date. ... IS 2417:2003 Indian Standard GLOSSARY OF TERMS USED IN ULTRASONIC NON-DESTRUCTIVE TESTING (Second Revision ) 1 SCOPE of incidence of the incident wave, as it travels away from that interface in the same medium. This standard defines the terms relating to ultrasonic testing. Angle of Refraction — The angle which the axis of an ultrasonic beam makes with the normal toatangent 2 TERMS AND DEFINITIONS plane at an interface as it travels away from that interface into the second medium. A Angle of Squint — The angle between the side edge A-scan Display — A cathode-ray tube display or of the probe and the projection of the beam axis on the presentation in which the travel time of the ultrasonic plane of the probe face. pulse is represented along the X-axis and the pulse amplitude is represented along Y-axis. NOTE — Forangle probes this normally relates todeviation in the lateral direction. Absorption — The 10SSor dissipation of sound energy Angle Probe — A contact probe from which the main as ittravels through a medium. This loss is due to the lobe of waves propagates at any angle, other than 0° relaxation or hysteresis, converted in the form of heat or90°, to the normal to the tangent plane to the surface energy. Itis not due to scattering or beam divergence. at the place where the probe is positioned. It forms the part of attenuation. Array — A single housing containing an orderly Accuracy — The deviation of measured value from assembly of crystals in line which may be energized the true value. together ingroups, with or without time delay, to give Acoustic Impedance — See Specific Acoustic directional effects, focused beams or variable angle impedance. beams. Acoustical Impedance Matching — The coupling of Area Amplitude Curve — A curve showing the two media using layers of material with suitable relationship between different areas of reflecting impedances so as to provide optim um transmission of targets located at a constant distance and their acoustical energy between them. respective echo amplitude. Acoustical Shadow — The effect produced in abody Attenuation — The loss ordissipation of sound energy by its geometry, or by a discontinuity in it, whereby as it travels through the medium. This loss is due to ultrasonic energy when traveling in a particular the combination of absorption and scattering. It does direction is prevented from reaching a certain region, not include loss due to mode conversion and beam within the body. divergence. Amplitude — The vertical pulse height of a signal, Attenuation Coefficient — A measure of sound usually base to peak, when indicated by an A-scan attenuation in a medium. It is also a measure of the presentation. diminution inthe amplitude of awave per unit distance travelled. Angle of Beam Spread — Half of the solid angle formed by the peripheral rays in the main lobe of the Attenuator — An instrument control by which the ultrasonic beam. amplitude of an ultrasonic signal can be adjusted by calibrated increments. Angle of Incidence — The angle which the axis of an ultrasonic beam makes with the normal to a plane Automatic Scanning — Systematic relative tangent toasurface atits point of incidence asittravels displacement of the ultrasonic beam and the material towards that surface. under test by use of a manipulator, scanner or some gadget other than manual means. Angle of Reflection — The angle which the axis of reflected ultrasonic beam makes with the normal to AVG Diagram — A generalized family of curves the tangent plane to a reflecting interface, at the point which shows the relationship between normalized 1 --- IS 2417:2003 distance along a beam to gain in decibel compared to projection of the test surface showing in plan view the a particular back wall echo and the specific size of a apparent size and position of reflectors in the volume flat bottom hole reflector assuming zero attenuation. inspected by scanning an area of test surface line by line. The pulse amplitude is manifested by the gray B shade or colours defined inan arbitrary colour scheme. B-Scan Display — A cathode ray tube display or Calibration Block — A piece of material of specified presentation in which the X-axis represents the probe composition, heat treatment, geometrical form and position along the scan line and the Y-axis represents surface texture by means of which the performance of the travel time of the ultrasonic pulse. This shows the ultrasonic flaw detection equipment can be assessed apparent size and position of reflectors inthe test piece and calibrated for the examination of material of the on a cross-sectional plane which is normal to the test same general composition. surface and contains the beam axis of the probe during Calibration Reflector — A reflector of ultrasonic a single line scan. waves, such as a drilled hole (flat bottom or side Back Wall Echo — A pulse of ultrasonic energy drilled), amachined slot or the end face of a specimen reflected from the boundary ofabody directly opposite representative of the material under test, which can be to the surface on which the probe is positioned and used to calibrate or set up the optimum conditions of returned to that surface by the shortest possible path. the equipment for inspection purposes. The term is generally restricted to normal Combined Double Probe — See Twin Probe. compressional waves and is sometimes referred to as bottom echo or end echo. Compressional Wave — A form of wave motion in which the particle displacement at each point in a Backing — The material attached to the rear surface material is parallel to the direction of propagation. of the piezoelectric disc to increase the damping of Synonymous terms are longitudinal wave, dilatational the transducer. wave, and irrotational wave. Band Width — The difference between two Contact Scanning — Scanning carried out by means frequencies on either side of the resonance frequency of an ultrasonic probe (or probes) in contact with the where the amplitudes are reduced to 0.7 (–3 dB) of the body under examination through a very thin layer of amplitude at the peak frequency in the frequency couplant. spectrum of the reflected pulse. Continuous Wave (CW) — A continuous flow of Base Line — The horizontal trace, time of flight or ultrasonic waves as opposed to pulse. distance, across the CRT display inthe absence of any signal. Contracted Sweep — Acontraction of the horizontal sweep line or time axis on the viewing screen of the Beam Angle –– Same as Angle of Ref r action, ultrasonic instrument. Beam Axis — The locus of points of maximum Convergence Point — The point of intersection of intensity in the far field in abeam of ultrasonic waves, the axes of the transmitting and receiving sound fields and its geometrical prolongation into the near field. in a twin probe. This is also usually the focus of the Beam Divergence — The divergence of the main lobe twin probe. of an ultrasonic beam in the far field. Synonymous Corner Effect — The reflection of ultrasonic energy term is Beam Spread. back to a point coincident with, or very close to, its Beam Index — The point on the surface of a body point of origin after impinging successively on two or through which the beam axis passes (cJ ‘probe index’). three orthogonal surfaces. Beam Spread — Same as Beam Divergence. Couplant — Aliquid or semi-solid medium interposed betsveen the probe and the object under examination Blind Area — See Dead Zone. to enhance the transmission of ultrasonic energy Boundary Echo (First) — A pulse of ultrasonic between them. Synonymous terms are Coupling Film energy reflected from any boundary of a body to the and Coupling Medium. surface on which the probe (or probes) is positioned Coupling Film — Same as Couplant. and returned to that surface by the shortest possible path. Coupling Losses — The reduction in amplitude of ultrasonic waves as a result of their passage through c the couplant. C-Scan Display — A two dimensional graphical Coupling Medium — Same as Couplant. 2 IS 2417:2003 Coupling Monitor — A probe operating in the Decibel — A unit used to express the magnitude of a receiving mode and positioned such that it detects change inthe amplitude of an ultrasonic signal, defined ultrasonic energy originating from asecond probe (or by the equation, dB = 2010g10 (A/A2), where A, and probes) thereby monitoring that successful coupling A2are the amplitudes of the ultrasonic signals 1and 2, istaking place between the second probe and the body. respectively. Critical Angle — The angle of incidence of a beam Defect Detection Sensitivity — The level of of ultrasound on to an interface at which one of the sensitivity setting of an ultrasonic flaw detector for refracted wave modes has an angle of refraction of revealing the presence of minimum specific size of 90°. defects in a given application. Cross Talk — Acoustical or electrical signal leakage Delay — A cathode ray tube control that is used to across an intended barrier between the transmitting and shift the initial part of the time scale laterally. receiving transducer elements such as in case of twin Synonymous terms are Delayed Time Base Sweep and probe. Synonymous term is Cross Noise. Zero Shift. Crystal (Ultrasonic) - Part of a single crystal or Delayed Sweep — An A-scan or B-scan presentation polycrystalline plate having piezoelectric properties, in which the initial part of the screen is shifted. used for the generation and /or reception of ultrasonic Delayed Time Base Sweep — Same as Delay. waves. Ceramic material isalso usually called ascrystal in ultrasonics though it is not correct in strict sense. Depth of Penetration — Maximum depth inthe object Synonymous term is Transducer Element. under examination where the ultrasonic energy is sufficient for proper detection of discontinuities. Crystal Loading — The mechanical power per unit surface area deli~ered by a crystal to a medium Depth Range — See Range. acoustically coupled to it. DGS Diagram — Same as AVG diagram. Crystal Mosaic — A regular assembly of ultrasonic Diffraction — Deviation in the propagation of crystals, in which each crystal is of identical material ultrasonic wave from its normal course. See Fresnel and cut, and ismounted insuch away that the assembly Diffraction and Fraunhofer Diffraction. or matrix of crystals tends to behave as though itwere a single cr-ystai. Diffuse Reflection — Reflection of anultrasonic wave from arough surface inamanner such that the reflected Curved Crystal — A non-planar crystal generally energy is detectable over a range of angles on either used to improve coupling or focusing. side of the theoretical angle of specular reflection that Cylindrical Reflector — A reflecting surface in the is, reflection in a non-specular manner. form of a circular cylinder. Directional Sensitivity — The relationship between D the angle made with the normal to the surface of a reflector by z beam of ultrasonic waves and the D-Scan Display — A two dimensional graphical amplitude of the resultant echo. projection onto aplane normal to the test surface and normal to the projection of the beam direction on the Dilatational Wave — See Compressional Wave. test surface, showing the apparent size and position of Direct Scan — See Single Traverse Technique, reflectors inthe volume inspected by scanning an area of test surface. Discontinuity — A break or interruption, either intentional or otherwise, in the normal physical Damped Oscillations — Oscillations in which the structure or configuration of material. amplitude of successive cycles diminish. Dispersive Medium — A material inwhich the phase Dead Zone — The region in a material adjoining the velocity of an ultrasonic wave varies with frequency. surface of entry from which no direct echoes from discontinuities can be detected due tothe characteristics Distance Amplitude Correction — Change in of the ultrasonic equipment and probe in association amplification of ultrasonic signals to provide equal withthe material under test and its surface condition. amplitude from equal area reflectors at different distances. Synonymous terms are Time Compensated Decay Technique — A technique of using ultrasonic Gain and Swept Gain. waves to assess the quality of a material or abond by studying the amplitudes of successive echoes. Distance Amplitude Curve — A curve constructed from the peak amplitude responses from reflectors of dB — Acronym for decibel. equal area at different distances in the same material. 3 ... IS 2417:2003 Distortional Wave — See Shear Wave. two fields producing amechanical deformation of the surface thereby generating ultrasonic vibrations and Double Bouncer Technique — See Triple Traverse vice versa. Acronym is EMAT. Technique. Electronic Noise — Unwanted, ra~dom signals that Double Crystal Probe — See Twin Probe. vary rapidly with time, caused by electronic pick up Double Probe Technique — An ultrasonic testing and thermal noise inthe amplifier of the flaw detector. technique involving the use of one probe for Entry Surface Resolution — Ability to resolve entry transmission and the other for reception. surface echo (transmission pulse in contact testing and Double Skip Technique — An ultrasonic testing interface echo in immersion testing) from the echo of technique whereby the distance between the point a nearby reflector. where the waves enter the body and the region under Evaluation — The process of deciding the severity of examination is twice the skip distance. the condition after the echoes have been interpreted, Double Transreceiver Technique — An ultrasonic Evaluation leads to the decision as to whether the part testing technique involving the use of two probes; each tested needs toberejected, salvaged or may be accepted being used simultaneously asatransmitter and receiver. for use. Double Traverse Technique — A testing technique Expanded Time Base Sweep — See Scale Expansion. in which abeam of ultrasonic waves is directed into a F region of abody under examination after having been reflected by a surface of the body. Synonymous term Far Field — The region in an ultrasonic beam where is Single Bounce Technique. the pressure starts falling as inversely proportional to the square ofthe distance due to Fraunhofer diffraction. Dry Coupling Probe — A probe fitted with soft Synonymous terms are Fraunhofer Region and polymer pad on its radiating face. The pad, under Fraunhofer Zone. pressure, adapts to the peaks and troughs of the test surface, making good contact and obliviating the need Far Resolution — Ability to resolve echoes from two of couplant for transmission of ultrasonic waves into nearby reflectors in the far field. See also Echo Width. the test material. Filter — Device to suppress unwanted frequency Dual Probe — See Twin Probe, components electronically. Synonymous term is Frequency Filter. Dynamic Range — The range of signal amplitude that can be handled by electronic or ultrasonic equipment Flat Bottomed Hole — A cylindrical blind hole with without overloading or excessive distortion and aflat bottom, the flat bottom surface being used as the without being too small for detection. It is usually ultrasonic reflector. expressed in decibels (dB). Flat Bottomed Hole Equivalent — The size of flat E bottomed hole which gives an echo height equal to that from the discontinuity, at the same distance. Echo -– Adistinct pulse of ultrasonic energy reflected from any surface or discontinuity. Its display on Flaw Echo — Echo from an imperfection inan object cathode ray tube is usually a rectified pulse. under examination. Echo Amplitude — See Echo Height. Flaw Location Scale — A specially graduated device that can be attached to a shear wave probe which, in Echo Height — Amplitude of echo measured from conjunction with the position of the flaw echo on the base of cathode ray tube, when displayed in A-scan. screen of the cathode ray tube, gives a direct reading Synonymous terms are Echo Amplitude and Pulse of the location of the discontinuity within the body. Amplitude. Focal Diameter — Diameter of the circle with centre Echo Width — Width of back wall echo with aheight atthe focal point inthe focal plane, the points atwhose of 80 percent FSH, at near field or focus, read off at a circumference has half the acoustic pressure of that at screen height of 20 percent. [t is a measure of far the focal point. resolution of probe. Focal Distance — The distance from the transducer Electromagnetic Acoustic Transducer — A to focal point. transducer in which eddy currents are produced at a conducting surface adjacent to the transducer in the Focal Plane — The plane normal to the beam axis presence of a static magnetic field, the interaction of and passing through the focal point. 4 . 1 IS 2417:2003 Focal Point — The point in the acoustic field of the Gap Scanning — A form of scanning in which the transducer having maximum acoustic pressure or a probe carrier follows the contour of the material under point from where a small reflector gives maximum examination but the probe, whilst not in direct contact echo height. with its surface, is coupled to it through a layer orjet of liquid which is maintained between the surfaces of Focused Probe — A probe incorporating an acoustic the probe and the material. Synonymous term is lens or a suitably curved crystal, so as to produce Bubbler Technique. focusing of the ultrasonic beam. Gate — An electronic means of monitoring aselected Fractional Band Width — The ratio of band. width region of the cathode ray tube display of an ultrasonic to resonance frequency, usually expressed in flaw detector. percentage. Gate Width — The width ofthe gate on the time scale, Fraunhofer Diffraction — It results into the usually expressed as percentage of the range selected. divergence of ultrasonic beam after the last maximal of the Fresnel region. The acoustic pressure along the Ghost Echo — An unwanted echo or an indication beam axis is inversely proportional to the square of arising from an incorrectly matched combination of the normalized distance. pulse repetition frequency and sweep frequency (time base range). Synonymous term is Phantom Echo or Fraunhofer Region — Same as Far Field, Wrap Around. Fraunhofer Zone — Same as Far Field. Grass — Spatially random signals arising from the Fresnel Diffraction — [tresults into the variation of reflection of ultrasonic waves from grain boundaries acoustic pressure near the ultrasonic transducer in the and/or microscopic reflectors in a material. Fresnel zone. The pressure along the beam axis shows Synonymous term is Hash. a number of maximal and minimal. Grazing Incidence — Angle of incidence slightly less Fresnel Region — See Near Field. than 90°. Used in immersion testing for directing the beam on the surface of the sample. Fresnel Zone — See Near Field. Group Velocity — The velocity with which the Frequency Band Width — Same as Band Width. envelope of a wave propagates. Frequency Filter — Same as Filter. H Frequency Spectrum — Variation of signal amplitude with frequency. The frequency spectrum of an echo Half Skip Technique — An ultrasonic testing shows the variation of amplitude with frequency of technique in which the inspection of a surface region constituent sine wave pulses. Synony mous term is ofabody isaccomplished by using angle beam entering Ultrasonic Spectrum. from the opposite surface of a point corresponding to the half skip distance. FSH — Abbreviation for Full Screen Height, equivalent to maximum height of the cathode ray tube Hard Faced Probe — A probe in which the contact display or range of the vertical scale. surface isof hard material, such as steel or ceramic, to minimize wear and tear. Fundamental Resonance Frequency — The lowest frequency at which the resonance occurs. Harmonics — The integral multiple of fundamental resonance frequency, the second harmonic being twice Full Skip Technique — An ultrasonic angle beam the fundamental frequency. testing technique whereby the inspection of a region of a body is accomplished by using shear waves Hash — Same as Grass. entering the same surface at a point that is one full Head Wave — Ashear wave that isgenerated by mode Vee path away. transformation when a compressional wave travels at grazing angle on a free solid surface. In steel, for G example, the head wave is at an angle of 33°. Gain Control — Same as Attenuator. Hole Bottom — The flat reflecting surface of a flat Gain Reserve — The difference in dB between the bottom hole. gain control positions of the ultrasonic flaw detector Holography (Ultrasonic) — An ultrasonic image at which the back wall echo at near field length 50 from two transducers, the beams of which are percent FSH and at which the noise level is 2 percent positioned to produce an interference pattern, usually FSH. on a liquid surface, which is illuminated by laser light 5