Yu. L. Gobov

Feasibilities of Using the ELCUT Software for Calculations in Nondestructive Testing

Examples of calculations of typical nondestructive testing problems with the use of the ELCUT 4.1 software designed for simulating the physical fields are given. A method which permits, using this software, to increase significantly the accuracy and the reproducibility of the results is proposed. The calculation results obtained using versions 4.1 and 4.2 of the ELCUT software are compared. It is shown that the calculations carried out with the use of versions 4.1 of the software distributed freely via the Internet makes it possible to establish the basic relations of the problems solved.

Automatic ultrasonic inspection of large-diameter pipes

A device and a principle of operation of some ultrasound scanners-flaw detectors for diagnosing the basic metal mass of main oil and gas pipelines in reinsulation is considered. Different methods, materials, and devices for efficient excitation and reception of ultrasound waves in pipelines with wall thicknesses of 6–20 mm and the selection of Lamb and Rayleigh wave modes for testing as a function of the pipe-wall thickness are discussed. The principle of operation of a unidirectional primary EMA transducer is described.

An Electromagnetic-Acoustic Transducer with Pulsed Biasing

Pulsed magnetizing systems of EMA transducers with a tangential biasing field with respect to the surface of a test object are considered. A method for calculating the parameters of a U-shaped pulsed electromagnet, which can produce strong magnetic fields in the material of a test object and allows the efficiency of exciting and receiving ultrasonic waves by the EMA method to be increased, is presented. As an example, the parameters of a U-shaped electromagnet are calculated for an EMA transducer that excites Lamb and Rayleigh waves.

A magnetizing system for an EMA scanner-flaw detector

Various magnetizing systems of EMA transducers, which make it possible to improve the efficiency of the excitation and reception of ultrasonic waves in metals by the EMA method and can be used in automated EMA scanners-flaw detectors, were considered. A method for the generation of strong fields from modern permanent magnets using magnetizing systems is presented.

Magnetic Field of a Circular Butt Weld of a Trunk Oil and Gas Pipeline

The results of computer simulation (using the ELCUT software) of the magnetic field of a weld of ferromagnetic pipes both in the weld body and from outside the weld are given. Both linear and nonlinear cases of magnetization are considered. It is shown that in the nonlinear case the magnetic permeability and induction in the weld body are extremely nonuniformly distributed over its thickness, i.e., different weld layers operate on significant different sections of the magnetization curve.

Decrease in the effect of a gap on coercimetry results when taking the properties of an attachable transducer into account

A method that allows the effect of a gap on the results of coercimetric quality control of articles to be decreased that is based on taking properties of an attachable transducer into account is proposed. The properties of a transducer are taken into account using a preliminary recorded demagnetization line of an attachable electromagnet whose magnetic circuit is not closed by an article. It is shown that the tangential component of the magnetic field of an inspected article during magnetization reversal along this line equals the coercive force of the article if its cross section does not exceed the electromagnet cross section.

In-tube demagnetizing pig flaw detector

A method of in-tube demagnetization that can be realized using a demagnetizing magnetic plunger that passes through a tube and is driven by a transported product has been developed as a result of analysis of qualitative and quantitative characteristics of the demagnetization process.

Development and certification of the MAΓEOC calibration block for magnetic properties of a pipeline with local heterogeneities

Some general features of metrological supplementation for techniques and means of nondestructive testing of materials and articles are discussed. In particular, the CO MAГEOC calibration block for magnetic properties of a pipeline with local inhomogeneities that was developed and certified at CПEKTP, in cooperation with the Ural Research Institute of Metrology (ФГУП УНИИМ), is considered.

Measuring coercive force in local domains of a sample

A method has been proposed for determining the coercive force in local domains of bulk samples magnetized normally to the surface. The method is based on local measurement of the normal magnetic-field component at the sample surface, in the gap between the sample and the pole of a magnetizing device. The coercive force is determined by the magnetic field for which local magnetization in the measured domain becomes zero. Conditions for the correctness of coercive-force measurements have been established.

Measuring saturation magnetization in a local sample area

The problem of determining saturation magnetization in a local area of a bulky ferromagnet is considered. A mockup of the device is presented. Experimental data are provided for local measurements of the saturation magnetization of a ferromagnetic sample, based on the stray field at the boundary of the magnetized area.