Showing papers on "Ultrasonic testing published in 1969"

A Modified Ultrasonic Pulse‐Echo‐Overlap Method for Determining Sound Velocities and Attenuation of Solids

Abstract: The ultrasonic pulse‐echo‐overlap method described by Papadakis [J. Acoust. Soc. Amer. 42, 1045 (1967)] has been modified to permit simultaneous measurement of the time delay and the relative voltage ratio between any pair of returning echoes in the pulse‐echo train. All the components involved in the present modification are commercially available items, and this instrumentation system for the ultrasonic pulse‐echo‐overlap method is compatible with the pulse superposition method.

Recommendations for testing concrete by the ultrasonic pulse method

Abstract: These recommendations deal with the application of the ultrasonic pulse method to derive the elastic properties, strength and homogeneity of structural concrete, and for locating internal defects, etc. Methods of measuring the pulse velocity, and the influence of test conditions on the accuracy of the measurements are discussed. Recommendations are made which it is hoped will lead to better standardization of measuring techniques. Interpretational difficulties associated with the derivation of elastic properties and strength from in-situ measurements of pulse velocity are given, and methods are recommended for overcoming these difficulties.

Definition of fatigue cracks through nondestructive testing

Abstract: THE ABILITY OF FOUR NONDESTRUCTIVE TESTING (NDT) TECHNIQUES TO LOCATE, IDENTIFY, AND MEASURE FATIGUE CRACKS WAS DETERMINED EXPERIMENTALLY. THE NONDESTRUCTIVE TESTING TECHNIQUES USED WERE: X-RAY, MAGNETIC-PARTICLE INSPECTION, PENETRANT INSPECTION, ULTRASONIC INSPECTION, AND EDDY CURRENT INSPECTION. THE MATERIALS USED WERE 7075-T6511 ALUMINUM AND 4330 VANADIUM MODIFIED STEEL HEAT TREATED TO 220 TO 240 KSI ULTIMATE TENSILE STRENGTH. SURFACE FATIGUE CRACKS WERE INITIATED IN 1/4 IN. THICK, 3 IN. OUTSIDE DIAMETER TEST CYLINDERS. STANDARD NDT INSPECTION PROCEDURES WERE USED TO DETECT AND MEASURE THE LOCATION AND GEOMETRY OF THE CRACK. THE SPECIMENS WERE FAILED IN TENSION TO DETERMINE THE ACTUAL GEOMETRY OF THE CRACK FROM MEASUREMENTS ON THE FRACTURE SURFACE. THE SENSITIVITY OF EACH NDT METHOD IN DETECTING THESE CRACKS WAS DETERMINED FOR EACH CRACK SIZE RANGE CHOSEN. THE SIZE OF THE CRACK AS DETERMINED USING EACH NDT METHOD WAS COMPARED TO THE ACTUAL SIZE OF THE CRACK. THE ACCURACY OF EACH NDT METHOD TO LOCATE THE END POINTS OF THE CRACK ALSO WAS DETERMINED. THE RESULTS SHOW THAT THE RELIABILITY OF THE PRESENT NDT METHODS FOR DETECTING SMALL CRACKS NEEDS TO BE IMPROVED. NO CRACKS SMALLER THAN 0.10 IN. CAN BE DETECTED CONSISTENTLY WITH ANY OF THE NDT METHODS EXAMINED. ALL NDT METHODS HAVE RESULTED IN VERY HIGH ACCURACIES IN LOCATING THE LONGER CRACKS, AND LOW ASSURANCE INDEXES ARE PRIMARILY DUE TO TWO FACTORS: (1) THE INABILITY OF THE NDT METHOD TO MEASURE THE CRACK LENGTHS ACCURATELY AND (2) THE SENSITIVITY OF THE NDT METHODS IN DETECTING CRACKS LESS THAN 0.20 IN. IN LENGTH. THE X-RAY METHODS USED WERE UNABLE TO DETECT SMALL TIGHT SURFACE FATIGUE CRACKS IN BOTH THE ALUMINUM AND STEEL SPECIMENS UNLESS THE CRACK LENGTH WAS OVER 0.45 IN. LONG. THE SENSITIVITY OF THE SHEAR WAVE ULTRASONIC TECHNIQUE USED WAS SUPERIOR TO ALL OTHER METHODS EXAMINED. /AUTHOR/

Ultrasonic flaw detection circuit

Abstract: Ultrasonic inspection apparatus for directing ultrasonic energy into a member to be inspected and for producing output signals only during that time when true flaw signals would be expected to occur, the apparatus comprising: A SOURCE OF RECURRING PULSES, A FIRST TRANSDUCER COUPLED TO SAID SOURCE OF RECURRING PULSES FOR PRODUCING CORRESPONDING PULSES OF ULTRASONIC ENERGY, SAID TRANSDUCER DIRECTING ULTRASONIC PULSES ALONG A SINGLE PATH THAT IS OBLIQUE TO A NEAR SURFACE OF THE MEMBER AND ALSO PRODUCING FLAW PULSES IN RESPONSE TO RECEIVED ULTRASONIC PULSES REFLECTED FROM FLAWS WITHIN SAID MEMBER, A SECOND TRANSDUCER LOCATED ADJACENT SAID NEAR SURFACE AND DISPOSED TO RECEIVE PULSES OF ULTRASONIC ENERGY TRANSMITTED BY THE FIRST TRANSDUCER ALONG SAID PATH AND REFLECTED FROM THE NEAR SURFACE, SAID SECOND TRANSDUCER PRODUCING NEAR SURFACE REFLECTED PULSES IN RESPONSE TO THE RECEIVED ULTRASONIC PULSES REFLECTED FROM THE NEAR SURFACE, MEANS COUPLED TO SAID SOURCE OF RECURRING PULSE FOR PRODUCING A GATING PULSE AT A TIME AFTER THE OCCURRENCE OF EACH TRANSMITTED ULTRASONIC PULSE, EACH GATING PULSE HAVING A TIME DURATION THAT INCLUDES THE EXPECTED TIME OF ARRIVAL AT SAID SECOND TRANSDUCER OF AN ULTRASONIC PULSE REFLECTED FROM THE NEAR SURFACE, A FIRST GATING MEANS FOR GATING EACH NEAR SURFACE REFLECTED PULSE THAT OCCURS SIMULTANEOUSLY WITH A GATING PULSE, MEANS RESPONSIVE TO NEAR SURFACE REFLECTED PULSES PASSED BY THE FIRST GATING MEANS FOR PRODUCING CORRESPONDING FLAW GATING PULSES, SAID FLAW GATING PULSES HAVING A TIME DURATION TO INCLUDE THE EXPECTED TIME OF ARRIVAL OF A CORRESPONDING ULTRASONIC PULSE RECEIVED AT THE FIRST TRANSDUCER AFTER HAVING BEEN REFLECTED FROM A FLAW IN SAID MEMBER, A FLAW GATE COUPLED TO SAID FIRST TRANSDUCER AND CONTROLLED BY SAID FLAW GATING PULSES FOR PASSING FLAW PULSES FROM SAID FIRST TRANSDUCER, AND OUTPUT MEANS RESPONSIVE TO THE OCCURRENCE OF FLAW PULSES PASSED BY SAID FLAW GATE.

Ultrasonic inspection method and apparatus

Abstract: Testing method and apparatus, incorporating a pair of transducers positioned on opposite sides of a weld seam. The transducers are alternately energized, and signals from the transducers are gated to develop signals representative of defects in various regions of the workpiece under test. Individual references are established for the different regions, and the signals are compared with the associated references. Output signals representing major defects are generated in accordance with various relationships of signals from the different regions of the workpiece.

Ultrasonic inspection apparatus and method for nondestructive testing of tubular member having varying inner diameter

Abstract: The invention is particularly useful for ultrasonic inspection of tubular goods having upset ends, i.e., end regions which have been worked during manufacture to produce wall thicknesses which are greater than in the remaining portions of the members, the upset ends having tapering inner and/or outer surfaces over a portion of their thickened regions.

Elongate element ultrasonic inspection system

Abstract: Apparatus is described which includes ultrasonic search wheels or the like for ultrasonically scanning a vertical elongated element. The search wheels operate in unison across the workpiece in response to a follower which in turn is mounted to a carriage. The follower is constructed to ride on the top surface of the vertical element. The search wheels are pivotally mounted in such a manner that the ultrasonic energy radiated into the element is always normal to the surface of the element.

Flaw size evaluation in immersed ultrasonic testing

Abstract: The factors which affect the evaluation of flaw size by echo amplitude measurements are discussed and fundamental weaknesses in the flat-bottomed hole test block system are outlined. The need for knowledge of operating frequency is stressed and the consequent corrections required are explained. Finally scanning methods rather than amplitude measurements are proposed as offering a way of eliminating most of the uncertainties in flaw size evaluation

Ultrasonic thickness measuring system

Abstract: ULTRASONIC THICKNESS MEASURING SYSTEM IN WHICH BURSTS OF ULTRASONIC ENERGY ARE TRANSMITTED INTO A FRONT SURFACE OF A PART WITH RECEIVED SIGNALS BEING DEVELOPED FROM REFLECTIONS FROM THE BACK SURFACE OF A PART, THE TIME INTERVAL BETWEEN A TRANSMITTED BURST AND A CORRESPONDING RECEIVED SIGNAL BEING MEASURED ELECTRONICALLY, PREFERABLY BY DIGITAL MEANS. AN IMPORTANT FEATURE IS IN THE PROVISION OF MEANS FOR AUTOMATICALLY CONTROLLING THE GAIN OF AN AMPLIFIER TO DEVELOP AMPLIFIED RECEIVED SIGNALS OF CONSTANT AMPLITUDE IN RESPONSE TO BACK REFLECTIONS OF VARYING AMPLITUDE WHICH PERMITS MUCH MORE ACCURATE MEASUREMENT. ANOTHER IMPORTANT FEATURE IS IN THE PROVISION OF AN INTEGRATOR FOR PRODUCING A CONTROL SIGNAL HAVING A DURATION DIRECTLY PROPORTIONAL TO AND AT LEAST SEVERAL TIMES LARGER THAN THE TIME INTERVAL BETWEEN A BURST AND THE CORRESPONDING REFLECTION, WHICH PERMITS MUCH MORE ACCURATE MEASUREMENT WITH A PRACTICAL DESIGN OF TIME MEASURING MEANS. THE INTEGRATOR MAY COMPRISE A MEANS FOR CHARGING A CAPACITOR AT A UNIFORM RATE DURING THE TIME INTERVAL BETWEEN A BURST AND THE CORRESPONDING REFLECTION AND FOR DISCHARGING THE CAPACITOR AT A UNIFORM BUT MUCH SLOWER RATE. A FURTHER FEATURE RELATES TO THE OPERATION OF THE TIME INTERVAL MEASURING MEANS PERIODICALLY AT A SLOW RATE SUCH THAT THE MAXIMUM DURATION OF THE TIME INTERVAL MEASURED IS A SMALL FRACTION OF THE TIME BETWEEN OPERATIONS OF THE MEASURING MEANS, WHICH CONSERVES POWER AND IS OTHERWISE ADVANTAGEOUS.

Ultrasonic image color display system

Abstract: AN ULTRASONIC TESTING SYSTEM INCLUDES A TRANSMITTING TRANSDUCER FOR BEAMING SONIC ENERGY THROUGH A TANK FILLED WITH A COUPLING MEDIUM TO A RECEIVING TRANSDUCER. THE RECEIVED SONIC ENERGY IS CONVERTED INTO AN ELECTRICAL SIGNAL WHICH IS THEN PHASE DEMODULATED INTO THREE PARTS ACCORDING TO THE PHASE OF THE RECEIVED SONIC ENERGY. EACH OF THESE THREE PARTS IS APPLIED TO A SEPARATE COLOR RELATED INPUT TERMINAL OF A COLOR TV RECEIVER. HENCE, THE IMAGE ON THE PICTURE TUBE IS DISPLAYED IN COLOR ACCORDING TO THE PHASE OF THE RECEIVED SIGNAL.

Ultrasonic search unit

Abstract: A nondestructive ultrasonic test system which includes a search unit with a crystal transducer which is cylindrical in shape end radiates beams of ultrasonic energy normal to the cylindrical axis of the crystal. A conically shaped reflector surrounds the cylindrical crystal transducer and reflects the beams therefrom into the workpiece. The reflector is deformable for change of the included angle of the conical shape to focus the beam.

Coupling network for an ultrasonic testing system

Abstract: This disclosure relates to an ultrasonic-testing system, and includes circuitry for damping low frequency oscillations in an ultrasonic transmitted pulse signal. A low frequency filter is connected across a limiting circuit to dampen low frequency signals to permit reflected signals from short distances to be detected.

Ultrasonic inspection apapratus

Abstract: A multiple transducer probe for pulse-echo ultrasonic testing, and especially for image-forming at depth within objects, comprising a transducer system focused along a line and having its component transducers situated along an arc of a circle. Separate transmitting and receiving transducers are preferably mounted covering end-to-end quadrants of a conical depression machined in a metallic transducer block. The transducer block is, in turn, mounted for movement on a coupling block having one surface shaped to fit a surface of the object to be tested.

Ultrasonic testing of welds

Abstract: AN ULTRASONIC SYSTEM FOR TESTING THE NUMBER OF ACCEPTABLE WELDS IN A DEVICE INCLUDES MEANS FOR INDEXING THE DEVICE AND THEN ROTATING IT FOR ONE REVOLUTION PAST AN ULTRASONIC TRANSDUCER SIGNALS ARE TRANSMITTED AND RECEIVED BY THE TRANSDUCER THE RECEIVED SIGNALS INDICATIVE OF ACCEPTABLE WELDS ARE COUNTED TO DETERMINE IF ANY WELDS ARE MISSING OR UNACCEPTABLE

Ultrasonic testing device

Abstract: An ultrasonic-testing device including four crystals fixed to a member which may be rotated to a variety of positions Each crystal when vibrated is adapted to emit ultrasonic waves of a frequency different from the other three One crystal only is selectively vibrated at any given time, and the position of that vibrated crystal, and thus the direction of ultrasonic waves emitted therefrom, may be varied to an extent by rotation of the member to such variety of positions

Ultrasonic testing of solids at elevated temperatures.

Abstract: High temperature ultrasonic testing to measure and control solid materials early in processing

Ultrasonic Testing of a Rubber to Metal Bond

Abstract: 1,166,427. Ultrasonic testing of bonds. FORD MOTOR CO. Ltd. 16 July, 1968, No. 33759/68. Heading H4D. A bond between a metal member and a rubber body is tested by applying a stress tending to separate the body and member, applying ultrasonic vibrations to the member, and determining the amplitude of echoes from the metal/ rubber interface, bond flaws benig indicated by abnormally high amplitude echoes. In the embodiment shown, for testing an engine mounting comprising a rubber bush 13 and metal flanges 11, 12, stress is applied to the mounting by an hydraulic piston and cylinder arrangement. Probe 22 comprising transmitting and receiving transducers is coupled to flange 11 by a liquid film and is scanned over flange 11. If many similar mountings are to be tested, single-shot multivibrators 27, 29 open gate 26 for a fixed period embracing the arrival time of echoes from the interface between flange 11 and bush 13, and these echoes are passed to amplitude discriminator 31 which actuates a lamp or bell if the echo amplitude is excessive. If different mountings are to be tested the echoes are observed on an oscilloscope triggered by the pulse transmission.

Ultrasonic inspection system for materials

Abstract: 1,147,089. Ultrasonic inspection devices. NATIONAL RESEARCH DEVELOPMENT CORP. 21 Nov., 1967 [22 Nov., 1966], No. 52169/66. Heading H4D. In an ultrasonic pulse-echo inspection system a plurality of transducers including at least one shear-wave transducer, scans a workpiece in a zig-zag scanning pattern and received echoes are gated with respect to time and recorded. For inspecting butt or fillet welds transmitting/ receiving transducers 1, 2, 3, 4 are floatmounted on slide 5 which is reciprocated by pneumatic cylinders 6 in carriage 7, and carriage 7 is provided with pneumatic cylinders 10 and pneumatically-operated clamps 9 which, with cylinders 6, are operated in sequence so that the carriage is stepped along guide rails 8 tempor. arily fixed to the workpiece, whereby the transducers follow the scanning pattern shown along the weld run. Transducer 1 transmits and receives compressional wave pulses (e.g. two or three cycles of 2A5 to 5 Mc/s. carrier at a repetition rate of 2000 per sec.) and the received pulses are applied via a swept gain amplifier and preset time gate to a C.R.O. display and to a first recording channel of a high-speed pen recorder. This channel also receives signals indicating the transducer position and provides a plan position indication of the weld edges and any flaws. The transducer 1 signals are also applied to a second recording channel (and the C.R.O. display) via a strobing flaw gate which scans (e.g. at 25-50 times per sec.) the time period in which echo pulses are expected to arrive, to determine the arrival times of the echo pulses and thus to provide a recording of flaw depth in the workpiece. The first and second channels thus provide a three-dimensional record of the weld region. Transducers 2 and 3 each transmit and receive shear waves at a selected angle with the workpiece surface and are directed towards each other for detecting flaws extending normal to the surface. They are pulsed alternately to reduce cross-talk (but some cross-talk is retained as a check that both transducers are coupled acoustically to the surface) and are connected as in the second channel, via strobing flaw gates to third and fourth recording channels. Transducer 4 transmits and receives shear waves at an angle of 45-70 degrees to the surface along the line of the weld to detect transversely-extending flaws and is connected via a strobing flaw gate to a fifth recording channel. Actuators 11 and switch 12 provide locating markers on the recording. Additional transducers 13 may be mounted on carriage 7. When inspecting butt welds transducer 1 and the first and second recording channels need not be used.

Improvements in and relating to ultrasonic inspection apparatus and methods.

Abstract: 1,173,481. Ultrasonic inspection; cathoderay tube operating circuits. PICKER ELECTRONICS Inc. 14 March, 1967, No. 11795/67. Headings H4D and H4T. The invention relates to ultrasonic inspection apparatus comprising an electroacoustic transducer directing a beam of ultrasonic energy at a test object and carried by an arm made up of at least three pivotally connected sections connected to respective position transducer means, the signals from which are utilized to control the position on a visual read-out device of a display which is produced by the signal output of the electroacoustic transducer due to the reception of ultrasonic energy reflected by the test object. The invention also relates to a method of ultrasonic inspection in which a beam of ultrasonic energy is directed, successively, at different points on the surface of a test object and at each point, swept through an angle, the echo signals due to reflection by the test object of the ultrasonic energy being utilized to produce a display the position of which is controlled in accordance with the position of the beam relative to the test object. Fig. 1 shows the construction in which the electroacoustic transducer 32 is carried by a first arm 40 pivotally connected to a second arm 36 pivotally connected to a third arm 34 the latter being pivotally connected to parallel members 28 (also Fig. 2, not shown) secured to a frame 10 adjustably mounted on a support 12, 14 by means 16, 17. Each arm is attached to a respective pulley 60, 54, 52 (see also Fig. 7) which rotates about the respective pivots 43, 39, 37 as the associated arms are rotated and this motion is transmitted via belt means, e.g. steel wire (the pivots 39 and 37 also carrying freely mounted additional pulleys) to pulleys 47, 62, 49 secured to sine-cosine potentiometers 22, 24, 26 (Fig. 4), carried by the frame 10. The outputs of potentiometers 22 and 26 indicative, respectively, of motion of arms 34 and 36 are combined in Y and X adders as shown in Fig. 9 to provide signals determining the position of the origin of a raster scan which is produced on a display tube 74 by sweep generators 80, 82. The latter generate sawtooth waveforms the time rate of rise of which is determined by the sine-cosine outputs from potentiometer 24 in accordance with the angular position of the arm 40 (i.e. in accordance with the angular position of the ultrasonic beam from transducer 32 relative to the horizontal). The scan is initiated by trigger pulses from a clock 84 which controls the pulses 88 driving transducer 32 via a delay device 86 which compensates for the time of travel of acoustic wave over a distance equal to that between the radiating face of transducer 32 and pivot 43 so that the sweep will have advanced an equivalent distance before energization of the transducer. In operation the transducer is positioned against the test object, which may compris eportions of the human body, and at each position it is oscillated through an angle as indicated in Fig. 10B, received echo signals being utilized via amplifier 90 to bright-up the beam of the display tube which is also brightened by the transmitted pulses so that the distance of the reflecting (impedance discontinuity) surface from the outside of the body is indicated. The size of the display may be varied by variation of the voltage supplied to potentiometer 24 (e.g. by rheostat 94 or by varying the gains of amplifiers 72, 78.

Photoelastic studies of ultrasonic waves in a large plate

Abstract: This paper presents the results of a series of experiments which were conducted to study the feasibility of using the photoelastic method to observe ultrasonic waves in a large plate on quantitative basis. The frequency used was as high as 0.79 MHz. Due to inherent limitations of the power of the ultrasonic driving systems, very low fringe orders were produced. In order to analyze low-order fringes quantitatively, a dynamic compensating system was developed and used. The photoelastic fringes were recorded with the aid of the dynamic compensator by a still camera with a flashlight source synchronized with the oscillator pulses. The analysis of the photographic record was carried out with the aid of a microdensitometer. The photoelastic method is found to be feasible for observing ultrasonic waves in transparent media. The attenuation of stress waves was determined. The dynamic compensating system developed in this investigation was found to be satisfactory.

Ultrasonic inspection of weldments using the delta technique.

Abstract: Delta technique for ultrasonic weld inspection, noting ability to detect randomly oriented weld defects

Ultrasonic test procedure for rating internal cleanliness of semi-finished material.

Abstract: : An investigation was conducted to evaluate and standarize upon various ultrasonic instrument and operational parameters which may alter inspectional response in the detection of nonmetallic inclusions and cleanliness rating of semi-finished material. In order to obtain an acceptable degree of uniformity of test results between various laboratories, recommendations are presented with regard to specimen preparation, instrumentation requirements, search unit specifications, system calibration, inspection procedure and data processing. (Author)