SU930100A1 - Adjustment specimen for flaw detectors - Google Patents

Description

(54) SETTING PATTERN FOR DEFECTOS

I

The invention relates to electromagnetic flaw detection and can be used to verify and verify the operability and sensitivity of electro-potential crack depth gauges, as well as a tuning sample for tuning and calibrating electro-potential crack meters.

A tuning sample is known, made in the form of a plate with a defect simulator consisting of a milled groove of rectangular shape pj,

The disadvantages of this sample include: increasing the sample thickness to a value exceeding the upper limit of measuring the depth of cracks by 20-30 (so when measuring the depth of cracks up to 100 mm, it is necessary to make a sample with a thickness of 120130 mm), the need to make a set of samples of different depths, with which checked

linearity of the instrument scales (if there are two measurement ranges, it is necessary to have seven samples, the total mass of which will be 12-15 kg with the instrument weight of 2.1 kg).

The closest to the technical essence of the invention is a tuning sample for flaw detectors containing a plate of electrically conductive material, in which 10 is filled with a groove of variable depth f2j.

The sample is used when checking the operability and resolution of flaw detectors of controlling products of complex shape (surface of a thread, a tooth, etc.,). When testing, it is usually necessary to detect defects in the form of fatigue cracks with a depth of 0.5 mm or more, but not to evaluate their parameters.

20

Claims (2)

The implementation of the wedge-shaped groove makes it possible to reproduce a limited range of measured depths, the values of which are determined by the thickness of the plate. For example, when measuring defects up to 100 mm in depth, it is necessary to make a sample with a simulator in the form of a wedge not less than 120 mm thick, and its length with a given measurement accuracy should be at least -10 times greater than its thickness, which makes it difficult to use This sample is complete with a portable device (its weight will be at least 1520 kg). Therefore, the metrological assurance under the conditions of operation of the device when measuring the depth of the detected cracks is practically impossible. In the manufacture of such a sample by the method of punching, the edges of the defect have a radius of curvature, which reduces the measurement accuracy and limits the distance between the measuring probes, which reduces the resolution, requires expensive equipment, stamps, tooling. The purpose of the invention is to expand the functionality. The goal is achieved by the fact that in the tuning sample the variable depth groove is made with a through section, the slope angle of the groove is (6-20), and the length of the through section is determined from the ratio 2d n - S, where d is the length of the through section pa for, n is the maximum range of measurements of the depth of the defect, S is the plate thickness. Such a solution allows reproducing defects equivalent to any depth without increasing the geometrical dimensions of the plate. FIG. 1 shows a configuration sample, a general view; in fig. 2 - ra cut AA in FIG. The sample is made of a plate 1 of electrically conductive material of finite thickness, in which a groove consisting of two core sections, one of which 2, is made in the form of a through groove, the other 3, which is a continuation of the first, is made in the form of a variable depth groove. us During metrological calibration of the instrument and when testing 4 crack depth gauges based on the electropotential method, the transducer is installed above the sample slot so that the measuring (potential) electrodes turn out to be cracks on different edges (banks). When the transducer is located above the groove of a variable depth, the current supplied by the current electrodes leaks under the defect, partially flowing around it along the edges. The readings of the device will be π 5 proportional to the depth of this groove (up to approximately 0.9 of the depth of the groove). The accuracy of the instrument readings determined by the installation of the converter will depend on the gradient of the change in the angle of inclination of the groove. The smaller the angle of inclination, the more accurate the reading, but this increases the length of the sample. Therefore, based on the required measurement accuracy, the optimum slope angle of the groove, determined by the optimal measurement accuracy and the minimum groove length, is (6-20) I. When installing the transducer over the through slot section, the current supplied by the current electrodes flows over the through slot i.e. flows along the edges of the through section, and then partially flows along the edges of the groove of variable cross section, partially under it. In this case, the instrument readings are mainly determined by the length of the through section. The farther from the site where the slit moves from (inclined to through, the transducer is installed, the more instrument readings. In this case, the measurement accuracy is lower than at a site with a variable depth, but the length of the through section determines the upper range of the measured cracks and 2d P - S, where d is the length of the through groove, the maximum measurement range of the depth of the defect, the plate thickness. The thickness of the plate is determined by the reproducible measurement range with increased accuracy, and is usually equal to 0.9 finite About the value of this range. In case it is necessary to reproduce several measurement subranges, but with the same limiting measurement error, the variable depth slot may have several sections equal to this number of subranges, but with a different slope angle. within 6–20 split into subranges (6 – ff); (8–12f; C10–15G; (12–20) 1) The adjustment sample allows us to produce defects equivalent to any depth without increasing the geometric dimensions. Claims An adjusting pattern for flaw detectors comprising a plate of electrically conductive material in which a variable depth groove is made BUT 1 06, characterized in that, in order to extend the functionality, the groove is made with a through section, wherein the slope angle of the groove is 6-20, and the length of the through section is determined from the ratio 2d p - S, where d is the length of the through plot groove; n is the maximum range of the depth of the defect; S is the plate thickness. Sources of information taken into account in the examination: 1. Non-destructive quality control of products. Proceedings of NIKIMP, M., issue 6,197, p. 15. 2. USSR author's certificate №, cl. G 01 N 27/86, 1977, (prototype).