Showing papers on "Ultrasonic testing published in 1972"

Method for ultrasonic inspection

Abstract: An ultrasonic transducer is disclosed having an alternating current conductor located in the field of a permanent magnet with said conductor defining a serpentine path lying parallel to the surface of a test object to induce eddy currents in the test object flowing in directions transverse to the field of the permanent magnet. Two such transducers are provided and are employed as a transmitter-receiver pair to generate and detect Rayleigh, Lamb, or other elastic waves within the object under test without requiring contact of the transducers with the object.

Method and apparatus for ultrasonic inspection of weldments

Abstract: Ultrasonic inspection apparatus and method for detecting discontinuities in thick section zones of interest, such as weldments. Ultrasonic energy is beamed at and accoustically coupled to the surface of a material having a weldment therein. The angle of incidence of the beam with the surface is controlled to provide in the material a refracted beam of ultrasonic energy in the longitudinal wave mode at an angle and in a direction which intersect the weld at an oblique angle relative to the surface at the weld. An ultrasonic receiving transducer positioned over the weld senses ultrasonic energy redirected by any discontinuity in the weld.

Pulse-echo ultrasonic test apparatus with cathode ray tube digital display

Abstract: In an ultrasonic pulse-echo test apparatus a two-coordinate display and digital data correlated with certain parameters of the two-coordinate display are displayed on the same cathode ray tube screen. To this end, the apparatus comprises a pulse-echo ultrasonic circuit and a digital character writing circuit. Both circuits are synchronized by a common timing means and are alternatingly coupled by multiplexing means to the deflection amplifiers of the CRT. Means are provided to convert pulse-echo analog information to digital information, to select the desired analog information for display, and to cyclically control the writing of the two-coordinate display and of the digital information.

Ultrasonic testing device

Abstract: Improvement to devices for ultrasonic testing and measurement of a cylindrical product by helicoidal exploration of the product. A rotary head comprising transducers placed in a radial chamber is so positioned that each transducer faces a mirror and that the ultrasonic ray is reflected at a suitable angle on to the part under test, the chamber remaining filled with water by centrifugal force. For application to dimensional testing and fault-seeking in industrially manufactured tubes or bars.

Improvements in ultrasonic testing equipment

Abstract: 1285715 Ultrasonic testing equipment JOHN THOMPSON Ltd 30 Oct 1969 [30 Nov 1968] 56942/68. Headings H4J and H4X An ultrasonic testing probe comprises an ultrasonic generator 10, a wedge 12, preferably of polymethylmethacrylate, and a lens 16, within which ultrasonic vibrations travel at a velocity which differs by at least 500 metres per second from the velocity with which the vibrations travel through the wedge. In one embodiment, the lens 16, Fig. 4, preferably of P.T.F.E. or water is of cylindrical planoconvex form positioned as shown, or the lens can be positioned (Figs. 1, 2, 3, not shown) with its axis of curvature at right angles to that shown in Fig. 4; thus the ultrasonic vibrations can be focused in planes at right angles to one another. In other embodiments, Figs. 5, 6, 7, and 8 (not shown), similar to above, a lens (17) or (18) is located on that side of the wedge adjacent to the ultrasonic generator 10. Simultaneous focusing in two planes at right angles can be achieved by having a pair of lenses, one on either side of the wedge. In a further embodiment, Fig. 9, a pair of lenses 22 and 23 are used, the lenses being formed of a material such as steel and of a cylindrical plano-concave form.

Substation Insulator Failure Prevention by Ultrasonic Corona Detection

Abstract: Ultrasonic detection of electrical corona discharge has become an important and useful tool for the detection of faulty insulators. The ultrasonic test unit consists of a hand-held probe-microphone responsive to acoustic energy in the 36-to 44-kHz range and is battery powered. Solid-state electronics translate high-frequency sonics to the audible range and provide amplification through a speaker or headset. The characteristics associated with a phenomenon are preserved through translation. Energy released at 40 kHz by corona or arcing is recognizable as the familiar ``frying'' sound. Similarly, air pressure leaks emit ``hissing'' sounds at 40 kHz. Application of this principal has resulted in the replacement of numerous insulators before occurrence of serious electrical failures. Minute inspections and tests revealed porcelain cracks and mechanical imperfections that would have eventually resulted in critical electrical faults. Similarly, leaks have been eliminated in compressed air systems, thereby reducing compressor service demands.

Method and apparatus for ultrasonic testing of tubes and rods

Abstract: Plural ultrasonic transmitter-receiver units are rotated about a pipe or rod to be tested and alternatingly operated in receiving and transmitting modes so that for a quarter turn four helical quadrants are tested and the pipe can axially advance by a distance equal to 4 times the beam width during one complete revolution.

Device for measuring parameters of propagation of ultrasonic oscillations in material of article

Abstract: 1277065 Ultrasonic inspection devices INSTITUT MEKHANIKI POLIMEROV AKADEMII NAUK LATVIISKOI SSR 22 Sept 1969 [20 Sept 1968 (2)] 46464/69 Heading H4D In a system for measuring the ultrasonic wave propagation characteristics in a specimen by comparing the waves received at one receiving transducer from two transmitting transducers or at two receiving transducers from one transmitting transducer after travelling two paths in the specimen of different length but having at least part thereof in common, the comparison is made on a cathode-ray tube (CRT) with delayed sweep by superimposing the two displays of the waves received via the two paths, the two paths are travelled in respective half-cycles of a commutator cycle, and two delay generators are so controlled by the commutator that one provides the sweep delay and the other provides the differential delay #t needed to bring the two displays into coincidence on the CRT time-base In the Fig 2 embodiment pulser 6 energizes transducer 7 once per half-cycle of commutator 5 and two-channel amplifier 9 is gated such that in alternate half-cycles the outputs of receiving transducers 8, 8 1 respectively are fed to the Y-plates of CRT 10 Calibrated attenuators may be used for comparing the amplitudes of the two outputs Sweep delay generator 13 enables a selected portion of the output to be displayed and calibrated delay generator 12 provides an additional sweep delay #t in those half-cycles where the longer path 7 to 8 1 is travelled in specimen 16 #t is thus a measure of the propagation characteristics over path l Calibration markers 18, 20, may be used in calibrating the dial of delay generator 12 Transducer 7 1 may be used as transmitter for reversing the propagation direction so that measured values may be averaged to reduce acoustic coupling errors In a second embodiment (Fig 3, not shown) the delay #t is imparted to the transmission pulse in alternate half-cycles instead of to the sweep delay circuit In third embodiment (Fig 4, not shown), using two transmitters and one receiver, the transmitters are pulsed in respective half-cycles of the commutator, a single channel receiver amplifier is used, and the delay #t is imparted to the transmission pulse in alternate half-cycles The invention enables propagation velocity, attenuation, wave dispersion and resonance oscillations to be studied

Improvements in and relating to ultrasonic devices for use in measuring displacements

Abstract: 1300160 Ultrasonic testing COMMISSARIAT A L'ENERGIE ATOMIQUE 4 Aug 1970 [18 Aug 1969] 37574/70 Heading H4D A device for measuring the position of a discontinuity in a fluid comprises two probes each including a piezo-electric transducer, a waveguide, a mirror reflecting sound waves from the waveguide on to a surface, said surface being for one probe a fixed reflector whose position is known and for the other probe the discontinuity; and a signal generator and receiver connected to the probes through a transmitreceive switch. The position of discontinuity 9, which may be an object or the fluid level, inside a nuclear reactor is determined by measuring the transit time, t, of n pulses from the waveguide 2 to the reflector. The other probe is used to measure the sound velocity, v, in the fluid. The displacement I is given by vt/2n. The transit times are measured by apparatus identical with that disclosed in Specification 1,300,159, a further changeoever switch being provided to connect the two probes alternately to the receiver. Tubes 10 are provided to prevent turbulence in the liquid sodium 5 across the measurement paths.

Ultrasonic testing device

Abstract: The specification discloses an ultrasonic testing device for non-destructively testing electrically welded steel tubing. The device comprises a mechanical mounting arrangement for one or more ultrasonic transducers which automatically tracks the path of movement of steel tubing through the device to insure substantially uniform positioning of the transducers with respect to the tubing notwithstanding deviations in the path of movement of the tubing. The device includes a box having a pair of aligned sealed openings through which the tubing passes, and in which the tubing and the ultrasonic transducers may be immersed in water which serves as a couplant for transmission of sound waves emitted from the transducers to the tubing and reflected back to the transducers.

Improvements in and relating to ultrasonic apparatus for the inspection of welds

Abstract: 1,270,387. Ultrasonic inspection devices. INTERNATIONAL RESEARCH & DEVELOPMENT CO. Ltd. 30 May, 1969 [7 June, 1968], No. 27194/68. Heading H4D. [Also in Division F1] Ultrasonic apparatus for the inspection of the weld between a heat-exchanger tube 2 and tubeplate 3 comprises an expandable plug la, 1b, forming a fluid-tight seal with the inner wall of tube 2, a housing 5 sealed at 9 to the tube plate 3 to define with space 4 a chamber for containing an acoustic coupling liquid, a transmitting/receiving transducer 10 and an adjustable mirror 12 for directing ultrasonic waves from the transducer to the weld, the transducer and mirror being mounted on a common driving shaft 41 capable of rotational and longitudinal movement. In use, plug la, 1b is expanded to fit the tube bore by actuating pneumatic ram 18 to retract rod 16 through coaxial sleeve 15 and so compress the plug axially between discs 15a, 16a; housing 5 is then pressed against plate 3 by turning nut 6. The transducer and mirror orientations are set up at 11, 13 so that the ultrasonic beam is normal to the tube wall at the weld zone. Shaft 14 is rotated back and forth by a pinion 23 meshing with a linear rack which is reciprocated by a pneumatic control system (see Division F1). A cam on the rack drives a cam-follower and pawl for engaging a circular ratchet to index shaft 14 longitudinally between each rotation. Echo pulses from the weld region are fed to conventional ultrasonic flow detectors for display against a time scale: good welds produce little ultrasonic reflection at the tube/tube-plate interface.

Nondestructive testing by ultrasonics

Abstract: The use of ultrasound in studying the physical properties of materials is referred to as 'ultrasonic testing'. With low intensities only elastic strains are normally induced and, because the material under test remains otherwise unaffected, the method is said to be nondestructive.

Transmission of ultrasound in liquid steel and measurement of ultrasonic attenuation during cooling

Abstract: A technique has been developed which enables ultrasonic frequencies to be transmitted through liquid, solidfying and solid steel. Investigations have shown that a classical curve exists which relates ultrasonic attenuation and the temperature of cooling. This attenuation temperature curve is related to the phase changes which occur during the cooling cycle.

Evaluation and optimization of the advanced signal counting techniques on weldments

Abstract: The signal counting technique with the Delta ultrasonic method is evaluated and optimized for flaw detection in aluminum welds. A comparison is made between the counting and conventional amplitude-gate methods to detect flaws. No conclusion is drawn on the sensitivity of these two methods to detect flaws when the mismatch at the welds is small (25 mils or less). When the mismatch is 25 mils or more, the signal counting method is more sensitive. Of the 24 welded specimens, 50 flaws were found by X-ray inspection and 59 by the Delta method. On 1/4-inch thick welds, X-ray is equal to or slightly more sensitive than Delta method, but on the 1/2-inch thick welds Delta ultrasonic appears more sensitive in flaw detection.

A Multiple‐Crystal Holder for Ultrasonic Measurement

Abstract: A multiple‐crystal holder for simultaneous ultrasonic measurement on several crystals is presented. Figures are included to show clearly how it is assembled and how each component works.

Nondestructive Ultrasonic Inspection of Braze Bonds in High Current Electrical Contact Assemblies

Abstract: Ultrasonic techniques are being increasingly used for nondestructive testing and quality control of bonds between the electrical contacts and the support members of the contact assemblies. The state-of-the-art of this valuable tool is analysed and discussed from a control standpoint. Two ultrasonic techniques, namely, the delayed pulse echo and the through-transmission, are described and discussed with respect to their limitations and merits for the brazed bond quality between the silver-cadmium oxide or silver contact and the copper support. The Instrument calibration technique, the range of test frequencies and the resolution of the voids are determined, for various thicknesses of the contact and the support material. The instrumentation and data including C-scan chart recording of the voids for discrete components as well as for continuous bonding of strip materials are presented and discussed.

Ultrasonic method of determining the resin content and porosity of glass-reinforced plastics

Abstract: The possibility of using the pulsed ultrasonic testing method for checking the resin content and porosity of unidirectional glass-reinforced plastics is considered in relation to the case of broad independent variation of the parameters.

A new approach to the old problem of determining flaw size

Abstract: In the ultrasonic inspection of a material, the size of a defect is conventionally estimated by the use of standard reference blocks with flat-bottomed holes, artificial flaws machined into the test material itself, or, to a smaller extent, the Krautkramer AVG diagram [i] which eliminates the need of artificial defects. Each of these methods is based on the amplitude of the ultrasonic pulse reflected by the defect and gives accurate results if the natural flaw closely approximates the characteristics of an ideal flaw. However, the reflected amplitude depends very strongly on the orientation, surface texture and contour, and composition (e.g., a crack as distinguished from an inclusion) of the defect and on other factors unrelated to the flaw such as variable attenuation in the sanrple, the condition of the surface of the sample, the condition of the surface of the sample, and transducer beam characteristics. Even for the case of forgings in which flaws tend to be nearly planar and aligned parallel to major surfaces, correction factors as large as five have been found [2] between flaw size estimated by amplitude techniques and true flaw size determined by sectioning.