RU131179U1 - MEASUREMENT COMPARISON DEVICE - Google Patents

Abstract

1. A device for comparing the parameters of melts, containing blocks for determining the temperature dependences of the parameters of viscosity ν, electrical resistance ρ and density d of the melt, having outputs for outputting parameter values in the form of corresponding electrical signals, characterized in that it is connected to a multiplier connected in series, a storage device and a block subtraction, each of the inputs of the multiplier is connected to the corresponding output of one of the blocks for determining the temperature dependences of the viscosity parameters ν, elec electrical resistance ρ and density d of the melt. 2. The device according to claim 1, characterized in that the subtraction unit is made with an adjustable threshold.

Description

The proposed utility model relates to technical physics, namely, to the analysis of the physicochemical parameters of metal alloys, in particular, based on iron or nickel, by photometric determination of the kinematic viscosity ν, electrical resistance ρ, and density d of the heated sample as a function of temperature. The utility model can be used in laboratory research, at the enterprises of the metallurgical industry, when performing laboratory work in universities.

A multi-parameter study of the physicochemical parameters of metallic liquids and melts, in particular, based on iron or nickel, and above all, high-temperature (t _PL = + 1000 ... 2000 ° C), such as determining the kinematic viscosity ν in a sample placed in a crucible with a volume several cubic centimeters, which is suspended on an elastic wire inside a vertical vacuum electric furnace, as well as non-contact determination of the electrical conductivity 1 / ρ or electrical resistance ρ of the sample by the method of rotating magnetic field and determined The density d of this sample by the method of “big lying drops” allows one to analyze materials and give recommendations for producing alloys with desired characteristics at enterprises and, in particular, to adjust technological conditions. The analysis of multicomponent industrial alloys is based on information on the thermal dependences (polytherms) of a number of physical characteristics of metals. Furthermore, analysis POLYTERM number of important experimentally available temperature-dependent parameters of alloys - kinematic viscosity ν, the resistivity ρ and the density d of the heated sample, allows to select the singular points, in particular, start the hysteresis temperature t _r, critical t _kr and the abnormal changes in properties of the melt temperature t _Al , as well as the hysteresis characteristics of the heating – cooling cycle. It should be noted that the experimental determination of the temperature dependences of the above parameters, including hysteresis, i.e. branching of polytherms and its features indicates a predominantly functional relationship of these parameters. Obtaining unambiguous temporal comparative characteristics of the same melt, as well as their comparative analysis with similar melts, is difficult - it is enough to compare the thermal dependencies of various parameters - see Larionov V.N. “Management of the structure and quality of heat-resistant nickel alloy castings by high-temperature melt processing”, in vol. “Properties of metal melts”, part 2, Yekaterinburg, UGTU-UPI, 2008, p.80, Fig. 1. It is generally accepted that the above thermally dependent parameters reflect, to a first approximation, the physical processes of internal friction both at the atomic level and at the level of “electron gas” in metal melts and are interconnected by ratios that quantitatively coincide with experiments — see Baum. B.A. and others. "Metal melts in advanced technologies", in the book. “Properties of metal melts”, part 1, Yekaterinburg, Ural State Technical University - UPI, 2008, p.109 ... 111, Fig. 1 - analogue. In particular, the above parameters are related, at least for pure non-transition metals, by the ratio:

where B is a weak temperature function that slowly decreases in the temperature range from t _pl to 2 t _pl

Thus, the values of the parameters ν, ρ, d in most cases are interconnected, necessary and sufficient to characterize the alloy under study.

Closest to the proposed utility model is a photometric device for determining the kinematic viscosity ν in a melt under study, with the possibility of determining the electrical resistance ρ and density d using the "big drop" method using a rotating magnetic field method, in the form of a computerized set of installations - see V.V. . Konashkov et al. “A complex for studying the physical properties of high-temperature metal melts”, Zh. "Instruments and experimental techniques", 2012, No. 1, p.162-163 - prototype. In this case, the temperature dependences of the viscosity parameters ν, electrical resistance ρ, and melt density d are measured several times in a certain temperature range to obtain the parameter values in the form of electrical signals. The measurement of the above parameters is carried out for each temperature point t _j . to obtain the values of these parameters in the form of electrical signals, after which a similar measurement of the same parameters is performed at the next temperature point t _{j + 1} , etc. Then, the obtained thermal dependences of the parameters are analyzed, in fact, independently of each other.

The device for comparing the parameters of the melts contains a computerized complex of blocks for determining the temperature dependences of the parameters of the kinematic viscosity ν, electrical resistance ρ and density d of the melt, having outputs for outputting the parameter values in the form of corresponding electrical signals.

The device is intended primarily for studying high-temperature melts based on, for example, iron or nickel.

The disadvantages of the device according to the aforementioned analogue and prototype are, firstly, that the information on the parameters of the melts is ambiguous, including the characteristics of the hysteresis of the temperature dependences and temperatures t _g , t _cr , t _an , while there is no unambiguous visual multiplicative assessment of the data of the group the above measured parameters for the same or different melts.

Secondly, in the case of the need for repeated comparative studies, for example, of the same melt after changing the technology of its creation, or melts close in composition, the whole cycle of multi-parameter experiments is carried out again, from beginning to end. However, due to the fact that there is no comparative combined multiplicative value according to the data of the entire group of measured parameters of the melts, the visibility, unambiguity, and simplification of the comparative assessment of the temporal shifts of the characteristics of these melts are not provided, and the decrease in the complexity and cost of experiments is not provided. Ultimately, the visibility, reliability and accuracy of comparing the values of the melt parameters with temperature changes are reduced, the expansion of the functionality of the device, as well as the simplification and cheapening of the experiment are not provided.

The objective of the proposed utility model is to determine the multiplicative values of the temperature dependences of the properties of the melts, simplify the comparative evaluation of these values, and ultimately increase the visibility, reliability and accuracy of the measurement results of the melt parameters with temperature changes, expand the functionality, simplify and reduce the cost of experiments.

The problem is solved using a device for comparing the parameters of the melts.

A device for comparing the parameters of melts, containing blocks for determining the temperature dependences of the parameters of viscosity ν, electrical resistance ρ, and density d of the melt, having outputs for outputting parameter values in the form of corresponding electrical signals, characterized in that a multiplier, a storage device, and a subtraction unit are connected in series, each of the inputs of the multiplier is connected to the corresponding output of one of the blocks for determining the temperature dependences of the viscosity parameters ν, elec osoprotivleniya density ρ and d melt.

In addition, the subtraction unit is made with an adjustable threshold.

The invention is illustrated by drawings:

figure 1. Block diagram of a measuring complex;

figure 2. Program for microcontroller STM32F103;

figure 3. Thermal dependences of the multiplicative parameters M _i , viscosity ν, electrical resistance ρ and density d of ZhS 26 alloy (• - heating, о - cooling);

figure 4. Thermal dependences of the multiplicative parameters M _i , viscosity ν, electrical resistance ρ and density d of the P6M5 alloy of the first (•) and second (▲) manufacturers during heating;

figure 5. Thermal dependence of the difference (x) of the Δ _M values of the multiplicative parameters M _{i of the} first (♦) and second (▲) producers of the P6M5 alloy during heating.

The device for comparing the parameters of the melts (Fig. 1) contains a computerized complex of 1 blocks (not shown in the diagram) for determining the temperature dependences of the viscosity ν, electrical resistance ρ, and melt density d, as well as a multiplier 2, memory 3, subtraction unit 4, and audiovisual block alarm 5, connected in series with each other, as well as with a computer of a computerized complex 1 (not shown in the diagram). Each of the blocks for determining the temperature dependences of the parameters ν, ρ and d of the melt is equipped with an output for outputting the values of the parameters ν, ρ and d in the form of corresponding electrical signals, for example, unipolar encoded pulse voltage sequences. The output of the multiplier 2 and the input of the subtraction unit 4 are connected to the storage device 3. The audio-visual alarm unit 5 is also connected to the computer of the complex 1. The subtraction unit 4 has the ability to set an adjustable threshold value 6, for example, unipolar coded pulse sequences of the voltage U _then . The unit for measuring viscosity ν is made in the form of a device for the photometric determination of kinematic viscosity ν by measuring the parameters of the exponential damping (decrement) of torsional vibrations of a crucible with a melt suspended on an elastic thread - see US Pat. RF №2386948. The unit for studying the electrical resistance ρ is made in the form of a device for non-contact measurement of the electrical resistance ρ of the melt sample by the method of a rotating magnetic field - see US Pat. RF №2299425. The main nodes (not shown in the diagram) of the temperature dependence of the parameters ν, ρ of the melt are vertical vacuum electric furnaces, in the heating zone of which the crucible with the test sample is coaxially suspended on the suspension, connected to the elastic wire part of the suspension using a ceramic rod, a photometric measuring device , which consists of a mirror mounted on the upper end of the ceramic rod, a light source and a measuring photodetector. In addition, the electrical resistivity study unit ρ contains a source of a magnetic field of a constant-amplitude magnetic field rotating at a frequency of 50 Hz in the form of a stator of a three-phase motor located near the electric furnace heating zone. The unit for determining the temperature dependences of the density d of the melt by the “big drop” method uses a horizontal vacuum electric furnace, in the heating zone of which there is a drop-shaped sample of the melt on the ceramic substrate, the photo of which is recorded by a video camera connected to a computer of computerized complex 1, which calculates the geometric characteristics of the photo image of the drop contour to determine d melt. The main nodes of this block are known - see US Pat. RF for utility model No. 101191. The outputs of the USB ports (or LPT) of the aforementioned computer are the corresponding outputs of the blocks of the device for determining the temperature dependences of the parameters ν, ρ, d of the melt. The audiovisual signaling unit 5 can be performed, for example, according to a circuit with discrete elements based on CMOS chips - see US Pat. RF for utility model No. 96660, or, in the case of software implementation of the audiovisual signaling unit 5, use the display and acoustic emitters of the computer of the computerized complex 1. Multiplier 2, storage device 3, subtraction unit 4, audiovisual signaling unit 5 are made in the form of virtual devices in the composition computer computerized complex 1, working with Excel. The multiplier 2, the storage device 3, the subtraction unit 4, the block of audiovisual signaling 5 can also be performed on the STM32F103 microcontroller from ST. An example program for STM32F103 in language C that implements its use in a utility model is shown in FIG. 2.

The determination of temperature dependences (ν, ρ, d) = f (t _j ) and the subsequent determination of the multiplicative value M _i = ψ (t _j ) of temperature dependences of the properties of the melts are carried out in accordance with the formula:

where: l, m, n are any numbers, including fractional ones, as follows.

After preparatory work on each of the blocks of computerized complex 1, they carry out the corresponding experiments to remove the temperature dependences ν, ρ, d of this melt in the required temperature range at the same temperature points t _j that are used in the experiment. Each of these points t _j must be set with the maximum possible degree of coincidence of the value of t _j , for example, with a spread of less than +/- 5 ° С in the temperature range t _j = + (1000 ... 2000) ° С, while the points t _{j of the} cycle "Heating-cooling" can be separated from each other and at the same time do not exactly coincide in size. Electrical signals reflecting ν, ρ, d of the same melt in the required temperature range at the same temperature points t _j are supplied from the output buses, for example, the USB ports of each of the corresponding units in the computerized complex 1, to the corresponding the inputs of the multiplier 2. In addition, the values of the parameters ν, ρ, d are simultaneously stored in the storage device of the computerized complex 1 (not shown in the diagram), which is used as an internal or removable computer memory. In the embodiment, as described above, of the multiplier 2, the storage device 3, the subtraction unit 4, the audio-visual signaling unit 5, made in the form of virtual devices as part of the computer of the computerized complex 1 working with Excel, these values of the parameters ν, ρ, d are entered in Excel, multiply, calculate M _i using the functions included in Excel according to the formula:

where: l, m, n are any numbers, including fractional ones, in particular l = m = n = 1

It is possible that the experimental values of ν, ρ, d during long-term accumulation of data, including during repeated studies, may require making corrections to the value of M _i , which can be mathematically expressed as an empirical power exponent l, m, n ≠ 1 for each of values of ν, ρ, d. However, at least at the initial stage of research, it is necessary and sufficient to use simple values: l = m = n = 1:

The values of M _i are stored in the storage device 3 as a specific parameter characterizing the melt. In a subsequent experiment with the same melt or a melt of another manufacturer, the values of the ν, ρ, d parameters of the melt are also determined exactly at the same temperature values t _j , the values of these parameters are again stored in memory 3, entered into the Excel table, multiplied, calculated M _i , receive new values of the multiplicative parameter M _{i + 1} , the values of M _{i + 1 are} also remembered as a specific parameter characterizing the melt. The values of M _i , M _{i + 1} are stored in the storage device of complex 1 (not shown in the diagram), which is used as an internal or removable computer memory, and in the storage device 3, feeding the values of M _i , M _{i + 1} to the input of the storage device 3. After the values M _i , M _{i + 1 are} fixed in the memory device 3, these values in the form of pulsed signals from the output of the memory device 3 are fed to the input of the subtraction unit 4, and the difference Δ _M = ϕ (t _j ) in accordance with the formula:

The presence of the subtraction unit 4 the possibility of installing, for example, at an additional input, a threshold value of 6, for example, in the form of voltage pulses U _then , is not mandatory at the initial stages of research. The choice of the threshold value of 6 is appropriate for the accumulation of a data bank, including repeated repeated studies. At the initial stages of the research, the threshold value of 6 is zero, it does not affect the difference value Δ _M To save the value of the difference value Δ _M from the output of the subtraction unit 4, signals corresponding to the value Δ _M are sent in parallel to the additional input of the storage device 3 and the storage device of the computerized complex 1, as well as an audiovisual alarm unit 5.

In a number of studies, it may be sufficient to use only one value of M _i , for example, as an estimated specific parameter characterizing the melt. In this case, the determination of the difference in the values of Δ _{M is} not required. However, in the case of using the difference in Δ _M values in experiments, its minimum value characterizes the temporal stability of the parameters ν, ρ, d for one alloy under study, or the identity of these parameters in different alloys. For example, we can assume that the value Δ _M = (0.03-0.10) M _i indicates a discrepancy between the values of both parameters M _i and M _{i + 1} by a value commensurate with the measurement errors, i.e. the value Δ _M = (0.03-0.10) M _i in most experiments is negligible. On the other hand, the difference in the values of Δ _M in the experiments, reaching values that are several times greater than, for example, several times, the values of any of the multiplicative parameters - M _i or M _{i + 1} indicates the differences associated primarily with the prehistory of charge materials, uniformity, alloy smelting technology, and not with measurement error.

As an example, figure 3 shows the temperature dependence of ν, ρ, d Ni - heat-resistant alloy ZhS26 during heating and cooling in the range t _j = + (1500-1700) ° C, as well as the corresponding temperature dependence M _i for these parameters. It is obvious that the thermal dependences M _{i are} higher than the individual components - ν, ρ, d: for example, at a temperature t _j = + 1500 ° С, the relative - more obvious than absolute, hysteretic changes in the thermal dependence M _i are 30%, while individual hysteresis changes for each of the parameters ν, ρ, d <15%. The number of temperature points t _j in this case: h≥5 is recorded in most practical cases, which is sufficient to process the experimental results without establishing a distribution law, but provides a deviation of the measurement results close to the normal distribution law and slightly reduces the level of reliability.

Figure 4 shows illustrative examples of temperature dependences in the heating mode for Fe - alloy P6M5 from different - the first and second manufacturers, and figure 5 shows a graph of the difference in values of Δ _M for the multiplicative parameters M _i - the first and M _{i + 1} - the second manufacturers . Moreover, Δ _M can also be expressed in percentage form, i.e. in relative values in relation, for example, to M _i, which is sometimes more convenient or more visual than absolute values. From Fig. 5 it follows, firstly, that the relative value of this difference in the values of Δ _{M is} quite stable and in percentage terms Δ _M (%) = 20% in the range t _j = + (1500-1700) ° С, with a slight deviation from this value - up to 23% at a temperature t _j = + 1600 ° С. Secondly, the samples presumably differ in the prehistory of charge materials, degree of homogeneity, alloy smelting technology, since the value of 20% exceeds the measurement error ν, ρ, d. equal to (3 ... 10)%.

In addition, it is advisable to use the specific values of the difference in the values of Δ _M and (or) the multiplicative parameters M _i with respect to the temperature unit, for example, similarly to the TCS (temperature coefficient of resistance) or tabular values of the ratio of conductivity 1 / ρ, 1 / Ohm · cm, to the thermal conductivity of metals k, W / cm · deg, given for a number of temperatures t for iron and nickel - see V. A. Zinoviev et al. "Brief technical reference", M., L., 1949, Gos. ed. technical and theoretical literature, part 1, p. 175, tab. 66. The utility model allows you to compare the temperature increments of the above values. For example, for the above examples of the difference in the values of Δ _M and (or) the multiplicative parameters M _i and M _{i + 1} shown in Fig. 5, the temperature coefficient K _t for Δ _M is equal to:

K _t ≈ 2.10 ^-9 / 200 ° С≈10 ^-11 conventional units / ° С;

K _t for M _i and M _{i + 1} is, respectively, K _t ≈3 · 10 ^-11 conventional units / ° С and ≈3 · 10 ^-11 conventional units / ° С The data, which are carried out in FIG. 3, 4, 5 confirm that physically the values of Δ _M and M based on the interconnected parameters ν, ρ, d reflect internal friction processes in the generalizing multiplicative parameter M both at the atomic level and at the level of the "electron gas" in metal melts.

The utility model provides the determination of the multiplicative values of the temperature dependences of the properties of the melts, the simplification of the comparative difference estimation of these values, and ultimately the increase in the visibility, reliability and accuracy of the measurement results of the melt parameters with temperature changes, the expansion of the device’s functionality, simplification and cheapening of experiments.

Claims (2)

1. A device for comparing the parameters of melts, containing blocks for determining the temperature dependences of the parameters of viscosity ν, electrical resistance ρ and density d of the melt, having outputs for outputting parameter values in the form of corresponding electrical signals, characterized in that it is connected to a multiplier connected in series, a storage device and a block subtraction, each of the inputs of the multiplier is connected to the corresponding output of one of the blocks for determining the temperature dependences of the viscosity parameters ν, elec resistance ρ and density d of the melt. 2. The device according to claim 1, characterized in that the subtraction unit is made with an adjustable threshold.

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