Showing papers on "Ultrasonic testing published in 1970"

Apparatus for ultrasonic inspection of a length of test material

Abstract: Apparatus for ultrasonic inspection of a length of test material adapted for rolling along the material and capable of adjustably aiming an ultrasonic beam at the material to be tested. Yoke means including a plane surface is disposed between axially aligned supporting shafts for adjustably mounting an ultrasonic transducer thereto. Coaxial coupling means is associated with one of the shafts and connected to said transducer for externally adjusting the position of the transducer along the plane of the yoke means for varying the angle of incidence at which the ultrasonic beam is transmitted to the test material. Wheel means including a cylindrical member transparent to the ultrasonic beam is rotatably mounted to the shafts and hermetically encloses the yoke means for providing rotation about the yoke means and the transducer. Back reflection attenuation means is operatively associated with the wheel means for attenuating unwanted back reflections to eliminate their detection by the transducer. Coupling fluid is retained within the wheel means for fluid coupling the ultrasonic beam to the test material through a portion of the cylindrical member in contact with the test material. Valve means is provided for simultaneously bleeding the wheel means as it is being filled with the coupling fluid to provide simultaneous removal of air therefrom, thereby minimizing the formation of air bubbles within the fluid. Traction means operatively associated with the wheel means provides frictional driving contact with the test material and prevents frictional contact of the end portions of the cylindrical member with the test material.

Ultrasonic detection of lumber defects

Abstract: A method of locating, by ultrasonic inspection, internal defects in wood. The transit time of ultrasonic pulses through the wood, in a direction substantially perpendicular to the grain, is measured at approximately one-half inch intervals along the length and across the width of the board. The inspection is made under water. Comparison of the transit times between adjacent measurement locations provides an indication of a defect such as a knot or steep grain area between the measurement points.

Machine with improved operating head traversing workpieces with curved surfaces

Abstract: An ultrasonic inspection machine is disclosed. The ultrasonic transducer is mounted in an operating head which is pivoted in two planes to maintain it perpendicular to the surface of a cambered blade as the head is traversed lengthwise and widthwise over the blade surface. The support for the blade is raised and lowered to maintain a desired spacing between it and the head as the latter is traversed.

Ultrasonic inspection device

Abstract: An ultrasonic device for nondestructively testing flat, bonded panels such as plywood or particle board panels. A transmitting set of roller type ultrasonic transducers are positioned on one side of a workpiece-transporting line, while the receiving transducers are placed on the other side of the line. Transmitters supply an ultrasonic pulse signal to each transmitting transducer. If the panel is well bonded, the associated receiving transducer receives the ultrasonic signal. A clock controls the actuation of the transmitters, turns off the transmitters, and after a time delay, turns on the receivers, responding to reverberations in a good panel. A panel marking device is actuated if a received signal is not present due to a defect in the panel.

Focused piezoelectric transducer and method of making

Abstract: An apparatus and method for fabricating focused high frequency electromechanical transducers especially useful in ultrasonic inspection apparatus is disclosed. An initially flat or planar piezoelectric crystal is placed between a pair of members having mating surfaces contoured to correspond to the desired shape of the crystal. When the members are forced together the crystal is bent or otherwise formed into the desired shape.

Improvements in ultrasonic inspection devices

Abstract: 1294404 Ultrasonic testing DEFENCE, SECRETARY OF STATE FOR 19 April 1971 [3 March 1970] 10040/70 Headings H4D and H4J An ultrasonic test device includes a flexible tyre mounted on a non-rotating hub and a block of solid material fixed to the hub provides an acoustic path between a transducer and the inner wall of that part of the tyre surface which contacts the piece under test. Aluminium hub 3 is fixed to support arms 1, 2 and carries in bearings a tyre 4 mounted on rims 5, 6. An aluminium block 9 carried in an oil-tight housing 11 is fixed to the hub and carries a piezo-electric transducer 8 fixed to its upper surface. The transducer is shaped to provide a convergent beam of acoustic waves into the test-piece 7, or to focus reflections therefrom. The tyre 4 is partially filled with silicone oil 14 to provide lubrication.

Dual-Mode Ultrasonic Apparatus for Measuring Compressional and Shear Wave Velocities of Rock Samples

Abstract: An ultrasonic apparatus and accUiate experimental techniques have been developed for measuring consecutively the bulk velocity of plane compressional and shear waves in samples of porous solid material. The apparatus was developed primarily to study the elastic behavior of rock samples recovered from well bores in the earth as deep as 7800 meters. Appropriate conditions of triaxial st(ess in the range 0-25 000 lbf/in2 (172 × 106 N/m2), fluid saturation, and temperature are imposed on the sample to simulate the surroundings of the parent rock in situ. In the apparatus, two electromechanical transducer cells operating in the frequency range 0.25-5 MHz are placed in direct contact with each end of the sample. Phase-coherent tone-burst pulses are used. The cells contain two sets of piezoelectric ceramic disks. One set generates and detects compressional waves, and the other set serves as the soUice and detector for shear waves, which form by mode conversion at an oil-aluminum interface. The mechanical ·design of the apparatus is based upon sound principles of geometrical acoustics. This method has substantial advantages over existing ones for testing rocks because it has greater accuracy and a shorter testing time. Transit times through nondispersive rocks can be measUied with a resolution of 10-8second. The time formerly required for making separate measurements of compressional and shear wave velocities has been reduced by one half. Velocities and elastic moduli are reported for aluminum, Solenhofen limestone, and Boise sandstone samples under stress.

A guide for ultrasonic testing and evaluation of weld flaws

Abstract: This document presents procedures and acceptance limits for contact ultrasonic inspection of steel butt welds in the thickness range of 1/4 to 2 inches. The acceptance limits described in the following sections are compatible with those set forth in SSC-177, “Guide for Interpretation of Nondestructive Tests of Welds in Ship Hull Structures” for radiographic inspection and should therefore result in satisfactory ship welds.

Ultrasonic inspection device

Abstract: A nondestructive material tester which is comprised of a search unit of lithium niobate cut normal to the 0 DEG Y axis. The parallel faces normal to the 0 DEG Y axis have electrical energy of ultrasonic frequency applied thereto and receive ultrasonic energy from a test object.

Precooling apparatus for continuous automatic ultrasonic inspection

Abstract: A continuous automatic ultrasonic inspection apparatus detects flaws in a material by transmitting pulses or continuous waves into the material to be inspected through the medium of a laminar flow water jet column. The precooling apparatus is provided near the laminar flow water jet column and improves the accuracy of flaw detection of the material at high temperature moving at high speed and also increases the maximum inspection temperature.

The visualization of ultrasound in solids

Abstract: In order to improve ultrasonic testing methods, a highly sensitive Schlieren apparatus has been built to visualize the propagation of ultrasound in solids. The design of the apparatus is described and some of the initial results are shown.

Ultrasonic testing of hot welds

Abstract: Steel of certain qualities, particularly for use in thick-walled objects, must be pre-heated before welding to 200–300°C. Since standard ultrasonic probes fail to operate properly at temperatures much above 50°C, it is necessary to cool hot test pieces before ultrasonic inspection of weld seams and weld repairs can be undertaken. Thus, if the weld or repair is found to be defective, it must be reheated before further repairs can be made. This process is time consuming and costly and this article explores the possibility of ultrasonic testing at high temperatures. The design of special probes, the choice of suitable coupling media and the effect of temperature on the response of the flaw detector are discussed.

Ultrasonic testing apparatus

Abstract: Apparatus for ultrasonically testing a plate includes a pair of spaced-apart rails between which the plate is positioned in a horizontal plane A crane mounted on the rails for movement therealong supports a trolley for movement transverse of the rails The trolley carries a sonic testing wheel which contacts the top of the plate and rolls along the plate as the trolley traverses it

A method for the Ultrasonic Recording of Faults in the Walls of Very Thin-Walled Tubes.

Abstract: 1,181,608 Ultrasonic inspection devices COMMISSARIAT A L'ENERGIE ATOMIQUE 10 Oct, 1968 [27 Oct, 1967], No 47994/68 Heading H4D An ultrasonic pulse-echo method for indicating in two separate channels the presence of flaws in the inner wall or outer wall of a very thin tube comprises rotating the tube (which is air-filled) about its axis in a tank of water, directing the beam of a single transmit/receive transducer whereby the angle of incidence of the beam on the tube is such that an outer-wall flaw gives a relatively high amplitude singleecho signal and an inner-wall flaw gives a relatively low amplitude damped train of echo signals, applying the echo signals for display against an oscilloscope time-base via an amplifier, maintaining the amplifier gain relatively low in that time period containing the outerwall flaw echo, maintaining the amplifier gain relatively high in the later time period containing the inner-wall echo train, and selecting the outer-wall echo and one of the inner-wall echoes by means of two time-gates The gain control ensures that the flaw echoes can be separated, on an amplitude basis, from fixed interfering echoes arising from, eg, the wall of the water tank

Significance of a detection of defects in rails

Abstract: The article describes the principal types of defects which may be found in rails, and indicates those which are inherent in the manufacturing processes and those which arise as a result of service loads. The principles of resonance and pulse-echo ultrasonic flaw detection as applied to rails are given, and the current ultrasonic testing practice at British Rail is described.

Ultrasonic detection of inclusions in steel

Abstract: METHODS OF DETECTION OF NONMETALLIC INCLUSIONS IN STEEL ARE DISCUSSED, WITH EMPHASIS ON: (1) SHALLOW STRESS WAVE FOR BEARING COMPONENT INSPECTION; RESEARCH APPLICATIONS INCLUDE DETECTION OF POTENTIAL FATIGUE NUCLI, STUDYING INCIPIENT SUBSURFACE FAILURE CRACK GROWTH, AND PREDICTION OF BEARING GROUP LIFE PERFORMANCE. (2) DEVELOPMENT OF ASTM METHOD FOR "DETECTION OF INCLUSSIONS IN BEARING QUALITY STEEL BY THE ULTRASONIC METHOD" (MATERIAL RESEARCH AND STANDARDS, SEPT. 1969); INCLUDED ARE PERTINENT ASTM ULTRASONIC TASK FORCE CONTRIBUTIONS WHICH WILL IMPORTANTLY AFFECT RELIABILITY OF NEARLY ALL OTHER EXISTING ULTRASONIC INSPECTION SYSTEMS; FATIGUE CORRELATION STUDIES AND STEEL HEAT INCLUSION DISTRIBUTION PATTERNS ARE ALSO DISCUSSED. (3) BIFOCAL LENS, A SPECIAL FOCUSED TRANSDUCER DESIGN PERMITS OPTIMUM CONCENTRATION OF ENERGY FOR DETECTION OF MINUTE DISCONTINUITIES IN CYLINDRICALLY SHAPED PARTS. EMITTED ULTRASONIC BEAM EXHIBITS A LONGER FOCAL ZONE AND A DECREASE IN FRESNEL DESTRUCTIVE INTERFERENCE. /AUTHOR/

Automatic rotary probe system for the ultrasonic inspection of steel tube

Abstract: Manual systems for tube inspection are unable to keep pace with high-speed tube manufacturing processes, and only provide an imprecise test. A range of high speed rotating ultrasonic probe systems and static probe assemblies has been developed for automatic quality control and acceptance testing of tubes. These systems afford automatic inspection of tubes in the diameter range 0.5–44in(12.7mm–12.118m), seamless or welded tubes, at inspection speeds up to 200ft/ min(60.96m/min). The systems incorporate several novel features in the ultrasonic and electronic design. One of these systems is described in detail.

Improvements in or relating to flaw detection

Abstract: 1,207,385. Ultrasonic inspection devices. STATNI VYZKUMNY USTAV PRO STAVBU STROJU. 25 Oct., 1967 [1 Nov., 1966], No. 48428/67. Heading H4D. In an ultrasonic pulse-echo system for inspecting a rod moved axially relative to several probes disposed in a plane normal to the rod axis, three-dimensional flaws (e.g. cavities and occlusions) and two-dimensional flaws (e.g. cracks) are distinguished on the basis that the three-dimensional flaws return echoes to more probes than do the two-dimensional flaws. In the Fig. 4 embodiment an m-phase synchronizer 10 controls m circuits 6 to 9 for pulsing m probes 1 to 4 sequentially in m respective periods which together make up an operating cycle. Echo signals returned to the probes are applied to gating circuits 11 to 18 which are opened by synchronizer 10 for times such that in the nth period echoes received by the nth probe and the (n+1)th probe are passed via lines 25, 26 to amplifiers 27, 32 respectively. The amplifier outputs are applied via flaw echo-gating circuits 28, 33 to staircase waveform generators 29, 34 whose outputs comprise as many steps as there are echoes from a flaw in one cycle, the generators being reset to zero at the end of each cycle. It is argued that an ultrasonic pulse from the nth probe is likely to be reflected to both the nth and (n+ 1)th probes if the flaw is three-dimensional, but to one probe only if the flaw is two-dimensional. Hence, at the end of each cycle the waveforms of both generators 29 and 34 will have m steps if the flaw is three-dimensional: this condition is detected by lower level limiters 30, 35 and coincidence circuit 37. The presence of fewer than m steps in either or both waveforms is detected by upper level limiters 31, 36 and a crack indicator 38. Output signals from circuit 37 and indicator 38 are applied to a recording device, an evaluating computer, or to an audible or visual signalling device. Indicator 38 is inhibited if circuit 37 is actuated.

Where stands nondestructive testing of concrete and whither

Abstract: Nondestructive methods of testing concrete are reviewed and their relative merits discussed. Each method has its own limitations and skill in required in interpreting the results. An indication is given of areas where research into nondestructive techniques would be profitable. Several methods of ultrasonic testing are described, and the most suitable technique recommended for a particular set of conditions. Radioactivity methods using x-rays or gamma radiation are given; these cover both radiography and radiometry. The use of magnetic devices to measure the depth of steel reinforcement, and neatron meters to measure moisture content is described. Methods where the dielectrical properties of concrete have been used to determine moisture content are given. Chemical analysis of the wet concrete is mentioned as a means of predicting the strength of the hardened concrete. The authors conclude that although nondestructive testing has many advantages its progress is hindered by the lack of background training of testing engineers. /TRRL/