Determination of precision conditions for measuring relative values in mechanical tests of various materials

2021 ◽  
pp. 9-17
Author(s):  
Svetlana Yu. Lohanina ◽  
Olga V. Baranova ◽  
Larisa V. Trubacheva
Keyword(s):  
Wear Resistance ◽  
Mechanical Testing ◽  
Mechanical Tests ◽  
Metrological Characteristics ◽  
Measuring Instruments ◽  
Quantitative Chemical Analysis ◽  
Uniformity Of Measurements ◽  
Multi Stage ◽  
Abrasive Disk ◽  
Accuracy Of Measurements

The problem of insufficient detail of the requirements for the developed and certified measurement methods used in mechanical testing of various materials is considered. The compatibility of the requirements of metrological support for the results of quantitative chemical analysis and indirect results of mechanical tests for the wear resistance of materials when rubbing against a fixed abrasive is relevant. To ensure the accuracy of measurements, it is proposed to use the grain size of the abrasive material and the rotation speed of the abrasive disk as variable factors. In order to establish the requirements for the metrological characteristics of materials during mechanical tests, in particular, when determining the relative wear resistance, the conditions for precision measurements are justified. The results of a multi-stage experiment-testing of materials for wear resistance with the use of various research and consumables, measuring instruments and testing equipment are presented. The conditions for the organization of the experiment in the case of determining other relative mechanical characteristics of the materials under study for establishing precision indicators in the development of methods of mechanical tests for abrasive wear are proposed and justified. The application of the obtained results will allow developers of mechanical testing methods to establish metrological characteristics of materials in compliance with all the requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation.

Evaluation of the accuracy indicators in determination of the coating thickness by crater grinding method

2020 ◽  
Vol 86 (7) ◽  
pp. 39-44
Author(s):  
K. V. Gogolinsky ◽  
A. E. Ivkin ◽  
V. V. Alekhnovich ◽  
A. Yu. Vasiliev ◽  
A. E. Tyurnina ◽  
...  
Keyword(s):  
Coating Thickness ◽  
Functional Dependence ◽  
Measurement Procedure ◽  
Metrological Certification ◽  
Measuring Instruments ◽  
Properties Of Coatings ◽  
Special Equipment ◽  
Grinding Method ◽  
Accuracy Of Measurements ◽  
Wide Range

Thickness is one of the key indicators characterizing the quality and functional properties of coatings. Various indirect methods (electromagnetic, radiation, optical) most often used in practice to measure thickness are based on the functional dependence of a particular physical parameter of the system «base – coating» on the coating thickness. The sensitivity of these procedures to the certain properties of coatings imposes the main restriction to the accuracy of measurements. Therefore, the development and implementation of the approaches based on direct measurements of geometric parameters of the coating appears expedient. These methods often belong to the class of «destructive» and, in addition to measuring instruments, require the use of special equipment. To ensure the uniformity of measurements in the laboratory or technological control, these methods are isolated as a separate procedure (method) and must undergo metrological certification in accordance with GOST R 8.563–2009. We present implementation, metrological certification and practical application of the method for measuring thickness of coatings by crater-grinding method. The principles of technical implementation of test equipment, measurement procedure and calculation formulas are described. The results of evaluating the accuracy indicators of the proposed procedure by calculation and experimental methods are presented. In both cases, the relative error did not exceed 6%. The applicability of the developed technique is shown for a wide range of coating materials (from soft metals to superhard ceramics) of different thickness (with from units to hundreds of micrometers). Apart from the goals of process control and outgoing inspection, the method can be recommended as a reference measurement procedure for calibration of measures and adjusting samples for various types of thickness gauges.

An Experimental Investigation on Mechanical and Wear Properties of Al7075/SiCp Composites: Effect of SiC Content and Particle Size

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Thella Babu Rao
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Ultimate Tensile Strength ◽  
Matrix Material ◽  
Mechanical Tests ◽  
Experimental Investigations ◽  
Wear Properties ◽  
Sic Particles ◽  
Sic Particle

One of the major advantages of metal matrix composites (MMCs) is that their tailorable properties meet the specific requirements of a particular application. This paper deals with the experimental investigations done on the effects of the reinforcement particulate size and content on the Al7075/SiC composite. The composites were manufactured using stir casting technique. The effect of SiC particle size (25, 50, and 75 μm) and particulate content (5, 10, and 15 wt %) on the microstructural, mechanical properties, and wear rate of the composites was studied and the results were analyzed for varied conditions of reinforcement. Scanning electron microscope (SEM) examinations were used to assess the dispersion of SiC particles reinforced into the matrix alloy and was found with reasonably uniform with minimal particle agglomerations and with good interfacial bonding between the particles and matrix material. X-ray diffraction (XRD) analysis confirmed the presence of Al and SiC with the composite. The results of mechanical tests showed that the increasing SiC particle size and content considerably enhanced the ultimate tensile strength and hardness of the composites while the ductility at this condition was decreased. The highest ultimate tensile strength of 310 MPa and hardness of 126 BHN were observed for the composites containing 15 wt %. SiC at 75 μm. Lesser the wear resistance of the reference alloy while it was enhanced up to 40% with the composites. The wear resistance was increased up to 1200 m of sliding distance for all the composites, whereas for the composite containing 75 μm SiC particles, it was extended up to 1800 m.

scholarly journals Determination of the Error in Transferring of Length Unit’s Size when Measuring the Nanoparticles’ Diameter Using an Analyzer of Particles’ Differential Electrical Mobility

2021 ◽  
Vol 12 (3) ◽  
pp. 194-201
Author(s):  
V. L. Solomakho ◽  
A. A. Bagdun
Keyword(s):  
Particle Size ◽  
Size Distribution Function ◽  
Measuring Instruments ◽  
Random Component ◽  
Electrical Mobility ◽  
Standard Samples ◽  
Reference Measuring ◽  
Condensation Particle Counter ◽  
Uniformity Of Measurements ◽  
Unit Of Length

The quality of nanomaterials and nanotechnologies is largely determined by the stability of the applied technologies, which, to a large extent, depend on the constancy of particle sizes. In this regard, metrological problems arise that are associated both with measuring the dimensions of the microstructure of aerosols, suspensions and powders, and with ensuring the uniformity of measurements when transferring a unit of a physical quantity from a standard to working measuring instruments. The purpose of this work was to determine and calculate the error in transferring the size of a unit of length when measuring the diameter of nanoparticles.An analyzer of differential electric mobility of particles was determined as a reference measuring instrument for which the calculation was made. It allows the separation of aerosol particles based on the dependence of their electrical mobility on the particle size. In combination with a condensation particle counter, it allows you to scan an aerosol and build a particle size distribution function. This measurement method is the most accurate in the field of measuring the diameters of particles in aerosols, therefore, the error in the transmission of particle size must be set as for a standard.The paper describes the physical principles of measurement by this method and presents an equation for determining the diameter of nanoparticles. Based on this equation, the sources of non-excluded systematic error were identified. Also, an experimental method was used to determine the random component of the measurement error of nanoparticles and to calculate the error in transferring the size of a unit of length when measuring the diameter of nanoparticles.The obtained results will be used for metrological support of standard samples of particle size, ensuring traceability of measurements of aerosol particle counters and for aerosol research.

scholarly journals MECHANICAL STRENGTH OF COAL: METHODS OF DETERMINATION AND FACTORS OF INFLUENCE (REVIEW)

2021 ◽  
Vol 6 ◽  
pp. 4-17
Author(s):  
V.V Koval ◽  
D.V. Miroshnichenko ◽  
O.V. Bogoyavlenska
Keyword(s):  
Mechanical Strength ◽  
Physical Properties ◽  
Physical And Mechanical Properties ◽  
Mechanical Tests ◽  
Point Of View ◽  
Statistical Characteristics ◽  
Measuring Instruments ◽  
Industrial Processing ◽  
Average Value ◽  
Advantages And Disadvantages

The article substantiates the importance and problems of determining of such an indicator of the quality of solid fossil fuels, as mechanical strength. The strength of coal depends on a large number of factors (viscosity, brittleness, properties of structural bonds, etc.), the change of which is impossible to take into account. Therefore, the strength of coal in the sample, piece, pack and formation must be represented by some integral index, which inevitably fluctuates around a certain average value and can be determined only approximately. The evaluation of the strength properties of coal should be carried out on the basis of mass tests using statistical methods that allow to calculate the average value and coefficient of variation. Since the strength dispersion is mainly due to the natural inhomogeneity of the coal, the excessive accuracy of the measuring instruments has almost no effect on the statistical characteristics. Laboratory methods of mechanical tests of mine samples, in comparison with full-scale, as a rule, are very accessible and, at qualitative performance of tests, are highly reliable. The properties of coal as an object of enrichment and use are largely related to its physical properties. The physical properties of coal and mineral impurities significantly affect the formation of the main parameters that characterize the particle size distribution and fractional composition, it`s changes during the mining, transportation and enrichment processes. The basic physical and mechanical properties of solid fuels from the point of view of their industrial processing have been listed, the review has been made of the most widespread methods of study of coals mechanical durability and the equipment used for these purposes. The main advantages and disadvantages have been summarized of these methods, as well as their relationship. The factors have been Indicated tinfluencing the mechanical strength of coal. The expediency of using existing methods from the point of view of informativeness for thesphere of its application has been estimated. The methods common in the coal processing industry are considered in more detail. Keywords: coal, solid fuel mining, mechanical strength, determination methods, influencing factors, grinding strength, crushing index. Corresponding author V.V. Koval, e-mail: [email protected]

Determination of changes of metrological characteristics of measuring instruments with time

1978 ◽  
Vol 21 (2) ◽  
pp. 158-163
Author(s):  
I. V. Abuladze ◽  
A. I. Belyaevskii ◽  
A. A. Dzhevdet
Keyword(s):  
Metrological Characteristics ◽  
Measuring Instruments

scholarly journals Use of statistical analysis methods in processing population survey data

2021 ◽  
pp. 58-60
Author(s):  
Vasilij Kalinchik ◽  
Vitaliy Pobigaylo ◽  
Vitaliy Kalinchyk ◽  
Daniil Filjanin
Keyword(s):  
Total Error ◽  
Current Transformer ◽  
Measuring Channel ◽  
Measuring Circuit ◽  
Metrological Characteristics ◽  
Measuring Instruments ◽  
Voltage Transformer ◽  
Current Transformers ◽  
Collection Device ◽  
Communication Lines

The article analyzes the structures of the measuring channels of electricity metering systems. It is shown that such a structure is determined by the types of measuring instruments used and the scheme of their connection, in particular, by the types of electricity meters installed at the metering points. Moreover, the counters can have a pulse or interface information output. It is shown that the path for measuring and metering electricity includes a measuring circuit consisting of measuring current and voltage transformers, an electricity meter, communication lines, a metering device and a data collection device. The applied method is based on the standardization of the metrological characteristics of individual elements of the measuring path and their synthesis based on the metrological characteristics of the entire electricity metering system. To calculate the total error of the measuring channel, a formula is used that takes into account only the errors of the measuring circuit. It is shown that in recent years there has been a tendency when measuring current transformers and, accordingly, electricity meters operate in the mode of low current loads. In this case, the errors of the elements of the measuring path are poorly studied. The graphs of errors of current transformers depending on load currents are given. It is shown that the values of the errors of current transformers vary with the magnitude of the load current and are in the region of negative values. Therefore, the wrong choice of current transformers can lead to a significant underestimation of electricity. The errors of voltage transformers depend mainly on the load on the secondary winding and do not significantly affect the total error. The resulting error of the measuring path current transformer - voltage transformer - electricity meter in the area of low loads is given. A change in errors in the area of low loads leads to serious metrological losses (underpayment of electricity). In the automation of electricity metering, graphs of changes in errors in the area of low loads are presented, which can serve as a basis for correcting the error of the measuring paths.

scholarly journals The requirements of the international standards on traceability of measurement results at OJSC «BSW – Management Company of Holding «BMC»

2019 ◽  
pp. 70-72
Author(s):  
E. V. Borisenko ◽  
I. V. Buyanova
Keyword(s):  
Metrological Traceability ◽  
International Standards ◽  
Measuring Instruments ◽  
International Level ◽  
Product Testing ◽  
Management Company ◽  
Uniformity Of Measurements ◽  
Effective Functioning ◽  
Measurement Results ◽  
Traceability Of Measurement Results

A serious barrier to the sale of products on the market is the trust in organizations that perform measurements during product testing, as well as calibration (verification) of the used measuring instruments. Confidence and recognition of measurement results at the international level is ensured through an accreditation mechanism. To ensure effective functioning at the international level, accreditation organizations enter into a multilateral agreement that provides for the use of common standards in the conduct of accreditation. One of the important requirements of these standards is the implementation and demonstration of metrological traceability, which is a tool for ensuring the uniformity of measurements.

scholarly journals INVESTIGATION ON PREPARATION, CHARACTERIZATION AND PROPERTY EVALUATION OF FGM AL-SI ALLOY CASTINGS PRODUCED BY CAST-DECANTCAST (CDC) PROCESS

2021 ◽  
Vol 6 (5) ◽  
Author(s):  
Dr. B. Anandavel ◽  
Dr J Anburaj ◽  
Dr K Thillairajan ◽  
V Devakannan
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Mechanical Testing ◽  
Outer Layer ◽  
Wear Behavior ◽  
Functionally Gradient ◽  
Property Evaluation ◽  
Microstructural Behavior ◽  
Alloy Castings ◽  
Metallurgical Characterization

Aim of this research paper is to study the microstructural behavior and mechanical properties of Functionally Gradient (FG) layer of Al-Si alloy castings produced by CDC process. The effect of decantation time on the thickness of functionally gradient castings of Al-4.5 wt % Si alloy as an inner layer and Al-Si alloy with 12.5 wt %Si as outer layers was studied by CDC process. The three different combinations of FGM castings were characterized for microstructural and wear behavior using metallurgical characterization and mechanical testing. From the microstructural and wear behavior of FGM casting at outer layer, FG layer and inner layer, it is observed that the FG layer of FGM casting showed very wear resistance compared to other two layers in the FGM casting.

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