The article presents a review and comparison of the requirements of the International Standard ISO 6892-1:2019 and the Interstate Standard GOST 1497-84 establishing a method for measuring the mechanical properties of metals under static tension.A comparative analysis of the requirements for metrological support of static tension tests for parameters that affect the measuring results of mechanical properties, including test conditions, was carried out.The main problems of applying GOST 1497-84 are highlighted, which require its harmonization with the International Standard ISO 6892-1:2019 and improvement of the metrological support system for static tension tests in the Russian Federation.The scheme for ensuring the metrological traceability during static tension testing of the measuring results of mechanical properties to the primary reference measurement procedure, which requires the development of certified reference materials (CRMs) for various test units, was considered.The authors believe that the proposed systematic approach to ensuring the uniformity of measurements of the characteristics of mechanical properties, using the primary reference methodology as a basis for comparison, will allow laboratories to ensure the reliability of the measuring results of mechanical properties, using not only intermediate precision measures, but also the correctness.

The article is devoted to the special aspects of application of a certified reference material as a basis for comparison as one of the main tools for ensuring traceability and accuracy control of the measurement results of mechanical properties.In the course of the research, an analysis of the approach of theoretical principles based on GOST 34100.3–2017 / ISO/IEC Guide 98–3:2008 and GOST R ISO 21748–2021 calculation algorithms for evaluating measurement uncertainty was carried out. The methodology of application of the reference material for the mechanical properties of steel grade 20 GSO 11854–2021 for evaluating the uncertainty of the static tensile test results was considered.It was established that evaluating the uncertainty of the static tensile test results to ensure the traceability of the result leads to the need to account the systematic component of the laboratory when calculating the uncertainty of test results, either as a correction or as a contribution to the standard total uncertainty. Two accounting options for the systematic component of the laboratory were proposed.The practical significance of the research is the possibility of applying the model-based approach of theoretical principles based on GOST 34100.3–2017 / ISO / IEC Guide 98–3:2008 and GOST R ISO 21748–2021 calculation algorithms (Equation 1) when evaluating uncertainty according to clause 7.6 of GOST ISO/IEC17025–2019 by accredited laboratories.

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Introduction. The article presents results of developing a certified reference material for the physical properties of the soil clay (loam). The certified characteristics of the reference material are as follows: moisture content at the liquid limit via fall-cone test, moisture content at the plastic limit, soil particle density via pycnometer method.Materials and methods. The certified values of the physical properties of the soil clay (loam) were determined using the method of interlaboratory metrological experiment.Results. The bounds of absolute error of the certified values are as follows: 1.9 % for moisture content at the liquid limit via the fall-cone test, 1.5 % for moisture content at the plastic limit, 0.03 g/cm3 for soil particle density. The validity period of the certified reference material is 5 years.Discussion and conclusion. The developed reference material was registered in the State Register of type-approved reference materials as GSO 11038–2018. The reference material is aimed at: controlling the accuracy of the measurement results of certified characteristics; conducting interlaboratory comparisons; testing laboratories proficiency.

The article presents the investigation of a certified reference material (CRM) of the steels mechanical properties. At present traceability of measurement results of mechanical stresses is ensured to the standard of time, but not mechanical stresses, and a metrological approach to ensuring the uniformity of measurements of mechanical stresses requires the development of a basis for comparison.The aim of the work was the characterization and certification of standard samples of a special form, traceable to SI units-force and length, intended for transferring a unit of magnitude of mechanical stresses to measuring instruments that implement a temporary method of acoustic type of nondestructive check based on the phenomenon of acoustoelasticity. The article discusses the key stages of the development of reference materials: selection of the source material for reference materials; study of the homogeneity of the source material; carrying out experimental studies with the use of reference device (the state standard unit of strength of the 1st category) and establishing the metrological characteristics. As a result of type approval tests CRM was registered in the State Register of CRM’s as GSO 11544-2020/11545-2020. The certified characteristics of the CRM are proportional limit mechanical stress σpl; proof strength σ02 (plastic extension 0,2 %); tensile strength σв; modulus of elasticity E. Limits of the relative error of the certified values at a confidence level of 0,95 do not exceed 12 %. The authors believe that the CRM of the mechanical properties of steels GSO 11544-2020/11545-2020 will provide metrological traceability of the results of measurements of mechanical stresses by measuring instruments that implement the by acoustic type of nondestructive check, when using the GSO as a basis for comparison in the verification scheme.