RU2280239C1 - X-ray method of estimation of parameters of coinage alloy sheets - Google Patents

Abstract

FIELD: determination of parameters of coinage alloy sheets.

SUBSTANCE: copper specimens of standard thickness and coinage alloy sheets under test are subjected to X-ray inspection. X-ray radiation is performed twice at definite spectral sensitivity along its flux for each specimen and sheet under test; two electric signals obtained at detection are divided each by other and graduation curve is plotted for determination of thickness of coinage alloy sheet. Then coinage alloy sheet under test and standard specimens of fixed magnitude of atomic number equal to thickness of sheet under test are subjected to X-ray radiation and are detected at different spectral sensitivity twice along its flux for each standard specimen and coinage alloy sheet under test; two electric signals obtained during detection are divided each by other and graduation curve is plotted for further determination of equivalent magnitude of atomic number of coinage alloy sheet under test.

EFFECT: enhanced metrological parameters.

2 dwg

Description

The invention relates to a measurement technique, in particular to the field of X-ray non-destructive testing of the thickness and equivalent atomic number of rolled sheet products, strips, tapes based on a copper alloy, for example, copper-nickel, used in coin production.

Known methods for determining the parameters of sheet metal, implementing the known thickness gauge device, which consists in the fact that x-ray radiation along the axis of the stream is detected twice, after which the thickness of the sheet metal is illuminated normally, then the stream is again detected and the received electrical signals from the direct flow detection are compared, by the comparative values of which are judged on the working thickness of the rolled sheet, while to determine the equivalent value of the atomic number of the rolled material the radiation flux reflected from the rolled sheet is detected twice more, and then the electrical signals from double detection in the direct and reflected radiation fluxes are also compared with each other and they are used to judge the equivalent value of the atomic number of the rolled material [patent No. 2221220 (RU) BI 2004 No. 1].

A disadvantage of the known methods is the low accuracy of determining the effective atomic number of the rolled stock material, since the intensity of the reflected x-ray flux is large only from the rental interface (upper and lower surfaces), and the intensity from the inner rolled body is small, especially if the chemical composition of the body is uniform. For ferrous metal alloys, our remark is not critical, but for non-ferrous, especially coin alloys of the MH19 type (copper-nickel alloy), this drawback is significant and economically expensive. The accuracy of measuring the working thickness of the rolled metal as applied to the coin alloy is also unsatisfactory, since a measurement error of 0.1% causes enormous budgetary costs.

The closest technical solution to the claimed one seems to be the X-ray method for determining the parameters of sheet metal made of copper alloy, which consists in first specifying samples of a standard thickness d _et alternately, then real sheet metal with a working thickness d _slave , which passed in the first case through samples, in the second case, through sheet metal, x-rays are individually detected twice in succession along the flow, but with different spectral Sensitivity, wherein the electrical signals I ₁ and I ₂ obtained by detecting, divided in each case on each other and build a calibration characteristic from the ratio of electrical signals I ₁ / I ₂ obtained by detecting the reference samples as a function of d _fl values and the values of the working thickness d of the _{slab of} sheet metal are determined by the ratio of the electrical signals I ₁ / I ₂ obtained from the detection of sheet metal by the calibration characteristic [patent No. 2234677 (RU), BI, 2004, No. 23].

This technology is functionally limited, which is confirmed by measuring only the thickness of the rolled sheet. The accuracy of the method is also unsatisfactory in the study of non-ferrous metal, since the materials of the technical solution do not specify the material of the reference samples, which actually determines the metrology of the materials used in this case.

The essence of the invention lies in the fact that in the method first samples of a reference thickness d _{et are} alternately illuminated by the x-ray flux, then real sheet metal with a working thickness d _{slave is} illuminated, and in the first case, the samples passed through the samples, in the second case, the x-ray radiation is detected in the sheet both cases twice successively along the flow, but with a different spectral sensitivity, while electrical signals I ₁ and I ₂ received in each case by a double detection in each divided with uchae each other and build a calibration characteristic from the ratio of electrical signals I ₁ / I ₂ obtained by detecting the reference samples as a function of d _fl values, and the values of the working thickness d _slave rolled sheet is determined by the ratio of electrical signals I ₁ / I _2, obtained from sheet metal detection by the calibration characteristic, further X-ray radiographic flow alternately reference samples of fixed values of the atomic number Z _fl and the elapsed alternation each of the reference samples of X-ray radiation is detected twice successively along the flow, but with a different spectral sensitivity, while electrical signals I ₃ and I _4, obtained from double detection reference samples with different Z _floor, are divided into each other and build a second calibration characteristic from the values relationship of electrical signals I ₃ / I ₄ depending on the values of Z _et, then made up entirely new actions are repeated on a real sheet of rolled coin alloy with a working value Z _ab, and on the ratio of electrical signals I ₃ / I _4, newly acquired from the dual detection sheet metal of the coin alloy, determine an equivalent value Z _slave on the second calibration characteristic, with an atomic number of material samples used in the procedures of method reference thickness constant appropriate for the material copper, and the thickness of the reference samples of fixed values of the atomic number is also used constant, but equal to the nominal thickness of the rental, taking into account the maximum permissible deviation, established in the technical specifications for the nominal thickness of this product.

The technical result of the invention is the high metrological indicators of the X-ray method in determining the thickness and equivalent value of the atomic number of the material of expensive rolled products used for minting coins, orders, medals, anniversary signs and accessories.

Figure 1 shows the calibration characteristic of the ratio of electrical signals from the double detection of copper reference samples depending on their thickness; in Fig.2 is a calibration characteristic of the ratio of electrical signals from double detection of the reference nominal thickness of samples from a material with different atomic numbers.

In the process of controlling the thickness of the rolled sheet and determining the atomic number of its material, reference samples and the real anode voltage of the x-ray source are kept constant.

The detection operations in the method are carried out with different spectral sensitivity, which is determined by the choice of atomic numbers Z of different converting elements, for example, detectors (cameras) providing detection, and the greater the difference in the values of atomic numbers, the higher the sensitivity of the method. Since the speed of propagation of X-ray radiation in the medium is close to the speed of light propagation, the detection operation is considered quasi-simultaneous, despite the fact that the detection is carried out sequentially along the x-ray flux.

Copper is used as the material of samples of the standard thickness, as the dominant material in the coin alloy, for example, the MH19 alloy contains 81% copper and 19% nickel. The thickness of the samples with a reference value of the atomic number is assigned to be constant equal to the nominal thickness of the real sheet metal, taking into account the maximum permissible deviation to the thickness established in the technical conditions for this particular product.

The technical novelty of the method is given by enhanced functionality and high metrology for determining the parameters of expensive copper-based alloys.

Method Functions

The sequence of the method consists in the fact that the x-ray flux is first radiated alternately on the samples of the reference thickness d from copper material, and then on the samples of the reference value of the atomic number of the material of the samples of the same (constant) thickness. The flux illuminated by the samples in both cases is detected twice in succession along the radiation flux with different spectral sensitivity. The electrical signals I ₁ and I ₂ obtained in each case from double detection for samples of the reference thickness and I ₃ and I ₄ for samples of the reference value of the atomic number of their material with different spectral sensitivity. The signals in both cases are divided into each other and build from the obtained relations I ₁ / I ₂ and I ₃ / I ₄ calibration characteristics depending on d _et and Z _et {I ₁ / I ₂ = f (d _et ) and I ₃ / I ₄ = f (Z _c )}.

The above actions are completely repeated on a real (working) controlled sheet metal with the current thickness and atomic number of the rolled material, except that according to the newly obtained values of the ratios I ₁ / I ₂ and I ₃ / I ₄ on the workpiece, they are determined by the calibration characteristics (Fig.1 and 2) the values of d _slave and Z _slave controlled rental. To stabilize the metrological indicators of the method, the value of the anode voltage of the x-ray source during all procedures is kept constant.

A positive result of the invention is the high metrological indicators in determining the thickness and atomic number of materials of a copper alloy, which is achieved by strict implementation of the method with reference samples.

Claims (1)

An X-ray method for determining the parameters of a coin-alloy sheet metal, which consists in first showing samples of a standard thickness d _et alternately through an X-ray stream, then real sheet metal with a working thickness d _slave and transmitted in the first case through the samples, in the second case through the sheet rolled X-ray radiation is detected in both cases twice in series along the flow, but with different spectral sensitivity, while the electrical signals I ₁ and I ₂ obtained In each case, from double detection, they are divided into each other in each case and the calibration characteristic is constructed from the ratio of the electrical signals I ₁ / I ₂ obtained from the detection of reference samples, depending on the values of d _et , and the values of the working thickness d are _slave sheet rolled is determined by the ratio of electrical signals I ₁ / I ₂ received from the detection sheet metal, a calibration characteristic, characterized in that the further flow of radiographic X-ray radiation pooche edno reference samples of fixed values of the atomic number Z _fl, and passed through each of the reference samples of X-ray radiation is detected twice successively along the flow, but with a different spectral sensitivity, while electrical signals I ₃ and I _4, obtained from double detection reference samples with different Z _fl is divided by each other and build a second calibration characteristic quantities from the relationship of electrical signals I ₃ / I ₄ depending on the values of Z _et then performed the above steps for completely toryayut on a real sheet products of the coin alloy with a working value Z _slave, and by the ratio of electric signals I ₃ / I _4, newly acquired from the dual detection sheet metal of the coin alloy, determine an equivalent value Z _slave on the second calibration characteristic, with an atomic number the material of samples of a reference thickness is used in the procedures of the method constant, corresponding to the material of copper, and the thickness of the reference samples of fixed values of the atomic number is also used constant, but the nominal nominal thickness of the rolled metal, taking into account the maximum permissible deviation established in the technical specifications for the nominal thickness of this rolled metal.

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