A generator of probing pulses for EMA flaw detectors

It is shown that an increase in the power of a probing-pulse generator is a desirable way to further increase the efficiency of EMA flaw detectors. A generator with an increased power was developed. Such a generator can form radio pulses of a current with a peak value of up to 200 A at a developed voltage of at least 500 V in an EMA transducer. The new generator is mainly intended for stationary EMA flaw detectors. It can supply transducers of virtually any type.     

Real sensitivity of EMA instruments

Results of experimental investigation into the detection of internal, surface, and subsurface flaws by ultrasonic vibration pulses that are excited and received via different types of EMATs are reported. The sensitivity of the EMA instruments developed is shown to be close to the sensitivity of modern contact flaw detectors. An EMAT and a flaw detector that take advantage of the EMA flaw-detection method for the inspection of surface and near-surface zones of metal products are developed.     

A universal attachment for standard ultrasonic flaw detectors and thickness gages

A brief analysis of facilities for nondestructive testing with the use of a contactless EMA method of exciting and detecting ultrasonic vibrations has been performed. A universal electromagnetic-acoustic (EMA) attachment for standard ultrasonic flaw detectors and thickness gages is described. The characteristics of the attachment and its main components—devices for generating radio signals, a generator of probe pulses, a preamplifier, a generator of biasing pulses, and EMA transducers—are presented. Examples of the use of this attachment are given.     

Use of an electromagnetic-acoustic technique in the practice of testing tubes of main gas pipelines

The results of development, design, and industrial testing of an electromagnetic-acoustic (EMA) technique are considered. An ultrasonic EMA pig flaw detector has higher sensitivity to cracks and can work in gas pipelines as well as a magnetic pig flaw detector does. The EMA pig flaw detector reliably detects cracks with a 10-μm opening, which are almost invisible for a magnetic pig flaw detector.     

Improving the quality of diagnostics of gas-main pipelines by using a device for automated control of the velocity of pig flaw detectors

The solution of problems of optimizing the velocity of pig flaw detectors for objective intube diagnostics of gas-main pipelines is discussed. The experience of exploitation of flaw detectors equipped with automated control devices and without them is discussed.     

Comparison of systems for ultrasonic nondestructive testing using antenna arrays or phased antenna arrays

This paper considers the features of forming the images of reflectors using phased antenna array technology and the images obtained by the C-SAFT method by echo signals measured in by double-scanning mode. It is shown that in some cases the images obtained by the phased antenna array technology are less informative, while the images obtained by the C-SAFT method have a higher frontal resolution over the entire area of image restoration; the partial images restored at different positions of the antenna array can be coherently combined to obtain a high and homogeneous resolution throughout the entire volume of thickwalled articles and increasing the signal/noise ratio. For the sake of brevity, the registration of echo signals in the double-scanning mode and restoration of the images of reflectors by the C-SAFT method will be called digital focusing by an antenna array (DFA). The ability to restore the partial images of reflectors by once measured echo signals according to many acoustic schemes with their consequent combination into one high-quality image should provide reliable automation of the process of recognition and dimensioning of scatterers. Another advantage of the images obtained by the C-SAFT method with three-dimensional focusing is the possibility of restoring images in the same coordinate system when using antenna arrays on prisms of different configurations. This facilitates the joint analysis of the images. Speeds of forming the images by the technology of phased-antenna arrays and the images obtained by the C-SAFT method are comparable. If the testing technique is based on the use of nonlinear effects, then in this case PA flaw detectors have a distinct advantage over DFA flaw detectors. However, within the framework of linear acoustics, PA flaw detectors have no fundamental advantages over DFA flaw detectors. It is fairer to say that PA flaw detectors have drawbacks. This article shows images that illustrate the features of the images that were obtained by PA and DFA flaw detectors.     

Automated control of the velocity of in-tube diagnostic tools for main gas pipelines: I. Development,design, and operating principle of a bypass device

The study considers the development, design, and operating principle of a bypass device integrated into existing in-tube diagnostic tools. The bypass device is designed for automated control of the velocity of in-tube pig flaw detectors in main gas pipelines. Equipment of in-tube diagnostic tools with an automated-control system for the velocity provides performance of in-tube inspection without decreasing gas transportation. This facilitates the flaw detection of main pipelines substantially and makes a dispatcher of a gas-compressor station free of controlling the velocity of passage of in-tube diagnostic tools. The results of assembling a bypass device used for automated control of the velocity of in-tube diagnostic tools for main gas pipelines are considered. Arrangement of the bypass device in existing diagnostic tools for nondestructive testing is based on the experience of development, design, and exploitation of pig flaw detectors, which make it possible to locate the elements of the bypass device without any substantial restructuring of the pig flaw detectors.     

The main advantage of electromagnetic-acoustic testing technique

From the analysis of previously published and new experimental data follows the conclusion that flaw detection data obtained with the help of electromagnetic-acoustic (EMA) transducers have better reproducibility than measurements by direct-contact transducers. The EMA technique has considerable advantages over the contact techniques when objects with “rough” surfaces are tested in the automatic mode. The advantages of the EMA technique are due to the features of its electromagnetic channel and feasibility of tuning its parameters in real time.     

基于弱磁探伤的钢丝绳无损检测技术

研究了基于弱磁探伤的钢丝绳无损检测原理与技术.通过对国内现有的钢丝绳弱磁探伤仪进行实验研究,展示了现有钢丝绳弱磁探伤技术的优势和劣势所在,并对存在的问题进行分析,针对问题提出了钢丝绳弱磁探伤技术未来发展的方向.     

A marker system of equipment for nondestructive testing of gas main pipelines

Contemporary means of in-tube nondestructive testing are passed through a gas pipeline during its exploitation. In-tube pig flaw detectors are passed under a gas pressure from the launching to the receiving chamber for diagnostics of the gas pipeline. For some reasons, the pig flaw detectors are stuck in the gas pipeline. The marker system is designed not only for searching for a stop of a pig flaw detector on the route, but also designed for additional topographic referencing of the in-tube equipment for nondestructive testing during diagnostics of a gas pipeline.     

Ultrasonic Multichannel Flaw Detector for Testing Rails with Signal Recording

Although automated testing instruments have been introduced intensely on the railways of Russia, up to 95% of hazardous flaws in rails are detected by ultrasonic two-line (removable) flaw detectors. The paper describes the functional diagram and basic functions of an ultrasonic detector of the new generation, AVIKON-01, with continuous recording of data. The instrument is supplied with the software package for analysis of testing results, and it has advantages of both hand-held removable flaw detectors and high-performance instruments for nondestructive testing of rails.     

Increasing the sensitivity of EMA devices

It has been established that, at the present stage, it is advisable to increase the sensitivity of EMA devices via an increase in the power of the probing-pulse generator. New types of generators that allow a substantial enhancement in the sensitivity of EMA instruments have been developed. The characteristics and potential of EMA devices with a new generator have been studied. An example of detecting a model of a flaw in the form of a 1-mm-diameter flat-bottom reflector is used to show that the detection sensitivity has increased by a factor of several with an increased gap between the electromagnetic-acoustic transducer and the surface of the inspected metal.     

Toroidally focused ultrasonic flaw detectors

New-type toroidally focused ultrasonic flaw detectors, whose application provides an appreciable increase in the flaw detection rate with retention of high sensitivity to flaws, are considered. The construction of a flaw detector is presented, the sizes of a gauge for the formation of the toroidal surface of a lens are given, and the technology of the manufacturing of a toroidal lens is described.     

Magnetic pipe flaw detector ДМТП

-A ДМТП magnetic flaw detector with transverse magnetization of pipes, which was designed at ZAO Spektr is described in brief. It is to be used for inspecting the state of buried gas-main pipelines, detecting mechanical, erosion, and corrosion flaws in them, and estimating their dimensions and location in the tested section. Performance characteristics of the flaw detector are compared with those of earlier designed flaw detectors with longitudinal magnetization of tested pipes.     

便携数字式超声探伤仪

介绍了超声检测在起重运输机械中的应用,在分析超声波探伤原理的基础上,提出超声波探伤系统的硬件和软件设计方法.该系统用于起重运输以及其相关的行业,是安全作业和运行的有力保障.经过长时间的运行,证实系统工作稳定、性能良好.     

Portable flaw detectors for magnetic-powder inspection of objects under operating conditions

The performance specifications and the use of magnetic-powder flaw detectors under the operating conditions of objects are considered.     

ADD Diagram as an Indicator of Errors

Examples in which imaginary inaccuracies of constructed ADD diagrams made it possible to detect errors in manufacturing flaw detectors and transducers are given.     

Software for Solving Inverse Magnetostatic Problem with a View to Calculating Flaw Parameters

On the base of the authors' experience and publications, technical grounds for developing software for magnetic flaw detectors are considered. Preliminary versions of such programs are briefly discussed.     

A LED-based thermal detector of hidden corrosion flaws

Results of using powerful LED matrices to inspect metal articles for hidden corrosion by active thermal-wave method are described. The effect of the color of paint-and-lacquer coating on the efficiency of heating with LED and halogen emitters is analyzed. The possibility of using powerful LED panels as thermal stimulation sources in portable flaw detectors is described.     

On Figures of Merit in the Metrological Provision of General-Purpose Ultrasonic Flaw Detectors

Problems of the metrological provision of general-purpose ultrasonic flaw detectors (GUSFDs) of second and third groups that appear when changing from ultrasonic flaw detection to defectometry are considered stage by stage. The correspondence of the information on the GUSFD figures of merit to data on the testing quality has been analyzed. Examples are presented that demonstrate the application of the functional dependence of the received echo-signal amplitude on the defect model to the metrological provision of up-to-date GUSFDs, which is aimed at the elimination of systematic error and an increase in the accuracy of measuring the defects' parameters.