In 2023, the Institute for Reference Materials will celebrate its 60^th anniversary. The main stages of the development of the Institute, the results of activities during the past years are considered. The All-Union Institute for Standard Samples and Spectral Standards (VNIISO) was established in 1963 in Sverdlovsk. Yuri L. Pliner was appointed Director of the Institute, Deputy Director for Research — Vasily V Stepin.

For the first 10 years, the institute has developed 225 reference materials (RM) of raw materials and mate­rials for metallurgical production. Samples for the ferrous metals’ spectral analysis were developed espe­cially rapidly, their number increased by 2.3 times. The Institute was transformed into ISO TsNIIchermet in 1974 and included in the Central Research Institute of Ferrous Metallurgy named by I. R Bardin. The branch system of CRMs created in the years ahead ensured the reliability of quality control of raw materi­als and products of the metallurgical complex. The duties of the Head Organization of the Metrological Service of the Ministry of Ferrous Metallurgy of the USSR for measurements of the chemical composition and standard samples were assigned to the institute in 1978. The system of metrological control (MK) was created and introduced into the practice of analytical laboratories at subsequent period (1978 - 1985). Metrological requirements for CRM, measurement methods certification and normatives for operational, internal and external analysis results quality control were established by ISO TsNIIchermeta. Verification of the implementation of MC in analytical laboratories of the metallurgical industry was carried out in the process of their metrological certification, which was carried out by the leading specialists of the institute since 1982. In 1992, the Institute was transformed into a JSC “The Institute for Certified Reference Mate­rials” (ICRM). The Institute is accredited in accordance with the requirements of the International Stan­dard ISO 17034 as a RM producer, in accordance with the requirements of GOST ISO/IEC 17043 as a pro­ficiency provider. The testing analytical center of ICRM is accredited in accordance with GOST ISO/TEC 17025. The article presents the institute’s and its staff current state data.

Establishment and demonstration of the metrological traceability of measurement results is one of the main goals of testing laboratories. In physicochemical measurements, the problem of establishing metrological traceability is still far from being solved and is very relevant. One of the basic principles of quantitative chemical analysis, as well as other types of measurements, is to ensure the traceability to the “standard” of the corresponding unit of physical quantity, but the unit of quantity of a substance “mole” does not have a standard. At the same time, the amount of a chemical element or stoichiometric com­pound in moles can be expressed in the units of mass — kilogram, and vice versa, the mass of any element or stoichiometric compound can be expressed in moles, using standard reference data on the atomic weight of chemical elements and their isotopes. When determining the chemical composition of matrix materials, as a rule, the mass fraction of the analyzed element (component) is determined. Algorithms for calculating the results of physical and chemical measurements are considered from the viewpoint of the metrological traceability using the example of individual methods. It is shown that the results of measure­ments of the mass fraction of elements can be traced to the standard unit of mass of SI system “kilogram.” Measuring instruments that have been verified do not always meet the requirements of GOST ISO/IEC 17025 for metrological traceability. For a significant part of universal individually calibrated analytical in­struments, the normalized metrological characteristics indicate only their capabilities and are only indi­rectly related to the uncertainty of measurements performed using these instruments. Certain difficulties are attributed to the necessity of confirming the metrological traceability of the values of certified refer­ence materials. The variants of statements on metrological traceability presented in the certificates of for­eign manufacturers of certified reference materials are considered. In conclusion, the authors provide a statement on the traceability of the certified characteristics of certified reference materials produced by ICRM.

Institute for Certified Reference Materials (ICRM) is a leading manufacturer of certified reference materi­als (CRM) for ferrous metallurgy. The entire process of CRM production from the purchase of a material to the certificate issuance takes about two years. The determination of the metrological characteristics is the longest stage of CRM production. The metrological characteristics of reference materials, are evaluated, as a rule, according to the results of an interlaboratory experiment and, in addition, in combination with a comparison method. The interlaboratory experiment arranged by ICRM, involves at least 10 competent analytical laboratories. The interlaboratory comparative tests are also carried out to test the qualification of laboratories. Since 2017, ICRM has been accredited by the Federal Accreditation Service as a profi­ciency provider of interlaboratory comparison.

The definition of tThe definition of the concept of stability and the list of instability indicators are provided for different metallurgical materials of CRMs. The methods and the results of studying the stability of dispersed materials of CRMs of the iron ore, ferroalloys, slags, and fluxes are presented. A few examples of unstable metallurgical materials of CRM are given. The study and monitoring of the stability of dispersed materials provides reasonable determination of the expiration date of the CRM instance. The chemical composition of chips and powders of steels, cast irons and alloys remained the same for 30 years. Monolithic CRMs of steels, alloys and cast irons for physical methods of analysis do not change their metrological characteristics for more than 50 years and do not require any control of stability during indicated period of time. 

A technology for production of special steels of a given chemical composition for reference samples is considered. The developed technology includes smelting of the steel (alloy) of a given composition in a vacuum induction furnace using high purity charge materials followed by forging of the ingot in several stages on hammers with a mass of the falling part 7 and 3 tons and rolling on a universal mill 250 into finished bars. Alloys of several grades were preliminarily smelted in a laboratory vacuum induction furnace in accordance with the chosen scheme of metal microalloying and then subjected to hot deformation and hot plasticity tests. The hot plasticity was evaluated on a plastometer designed by the Research Institute of Metallurgy (Chelyabinsk). The data obtained during the research made it possible to adjust the technology of smelting (by optimization of the amount of microalloying elements) and hot deformation of metal (by the choice of heating temperature for forging) in conditions of pilot production. This technology was repeatedly used to obtain metal products which formed a base for reference samples of LG32 - 36, LG56 - 64, NG15 -17 series and some others manufactured at the Institute for Certified Reference Materials (Yekaterinburg). The developed technique ensures a high purity of the produced metal in terms of dissolved gases, harmful impurities and non-metallic inclusions, which made it possible to provide the customer with high-quality metal in a short time frame.

An ICP-AES method with Concentration Ratio Calibration (calibration in relative concentrations) makes it possible to improve significantly the metrological characteristics of certified reference materials (metals, alloys, technical and geological materials). The main reasons for this improvement are the advantages of the ICP-AES in combination with the advantages of the Concentration Ratio Calibration. The errors of sample weighting and the uncertainty of final volume, as well as the error attributed to the addition internal standard aliquot are excluded from the total error of analysis. Lithium hydroxide fusion in silver crucibles has been developed for the complete transfer of the ilmenite and zirconium concentrates, as well as Mg- and Cr- based refractories into solution. Compared with fusion with lithium metaborate in platinum crucibles, the proposed method is advantageous for a significantly lower cost of crucibles, higher solubility of the melt, and possibility of boron determination as an impurity in the analyzed materials. When certifying the reference samples, it is necessary to use the main principle of Concentration Ratio Calibration, i.e., the total amount of certified mass fractions and positive errors of the components to be determined should not exceed 100 % even when the ICP-AES method is not used. While conventional calibration methods use one-dimensional space and one-dimensional traceabihty the concentration ratio calibration works in re-dimensional space and provides higher accuracy of results due to n-dimensional traceabihty It is necessary to develop a theory of re-dimensional traceabihty which will provide a more reliable certification of reference samples in practice than the one-dimensional traceabihty that exists today. 

Certified reference materials are an integral part of laboratory metrological support. They are used in spectral analysis for calibration of measuring instruments, quality control of measurement results, in verification and ensuring the traceability of measurement. The interchangeability between sets, samples of new and earlier issues is rather important. The Institute for Certified reference materials maintains the current nomenclature of certified reference materials for spectral analysis of cast irons. New samples are developed not only to reproduce the previously available characteristics, but also to expand them by increasing the number of certified characteristics or ranges of certified values. The possibility of joint use of the new and previously released sets is shown. To comply with consumer demands, we are going to produce in the second half of 2023 CJSC ISO nodular cast iron with a large number of certified impurities, the total content of which does not exceed 0.30%. 

The Institute for Certified Reference Materials launched a set of certified reference materials (CRM) of carbon and low-alloy steels for calibration of atomic emission and X-ray spectrometers ISO UG141 - ICRM UG146. The composition of the set is designed in a way that ensure obtaining calibration characteristics for 26 elements to be controlled by the program of low-alloy and carbon steels with the minimum number of samples. At the same time, the content of such rare elements as cerium, lead, bismuth, tantalum, etc. are also certified in ISO UG141 - ISO UG146. A tentative composition of the set as well as the calibration curves obtained on Spectrolab Mil (AES), Q8 Magellan (AES), and ARL 9900 (XRF) spectrometers are presented. An experiment was performed to prove the consistency of this set with ISO UG01 - ICRM UG91 samples and similar samples produced by foreign manufacturers. 

A comparative analysis of the methods used for determination of a number of elements in steels and cast irons by atomic absorption spectroscopy with flame atomization have been carried out (vanadium by COST 12351-2003, GOST 22536.12-88, GOST 2604.7-84; chromium by GOST 12350-78, GOST 22536.7-88, GOST 2604.6-77; copper by GOST 22536.8-87, GOST 12355-78, GOST 2604.9-83, GOST 4943-2010; manganese by GOST 12348-78, GOST 22536.5-87, GOST 2604. 5-84; nickel by GOST 12352 - 81, GOST 22536.9-88, GOST 2604.8-77, GOST 4940-2010; in alloyed and unalloyed steels and alloyed and unalloyed cast irons). Analysis of the data obtained revealed the possibility of combining the considered Russian national standards into universal multi-element methods for the materials under study. The developed methods have been then certified in the analytical laboratory of the testing center of the Institute for certified reference materials (ICRM). The proposed methods provide an extension of the range of determined concentrations under optimal conditions of analysis. Comparison of the developed methods for the determination of vanadium, chromium, copper, manganese, nickel in steels and cast irons with international standards ASTM E350-18, ASTM E351-18, ASTM E352-18 have been carried out. 

The capabilities of inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of tantalum in alloy steels without separation of matrix components have been analyzed. The analytical lines of tantalum and the method of sample preparation are selected. The effect of acids present in the analyzed solution on the analytical signal of Та has been studied. Optimal conditions of measurements were determined by changing one of the operational plasma parameters at simultaneous stabilization of all other parameters. The influence of the components of alloy steels on the analytical signal of tantalum has been studied. The metrological characteristics of the technique were evaluated proceeding from the results of analysis of certified mixtures (CM). To assess the correctness of the results obtained we used certified mixtures and standard addition technique. A method for measuring the mass fraction of tantalum in alloy steel samples by ICP-AES in the content range from 0. 01 % to 0. 05 % has been thus developed.

The Institute for Certified Reference Materials (ICRM) issued for the first time certified reference materials (CRM 11777-2021) of the mass fraction of hydrogen, oxygen and nitrogen in titanium-based materials, i.e., titanium alloy 2V (ISO 1-1) and titanium VT 1-00 (ISO 1-2). The finished material is presented in the form of cylinders 2.5 mm in diameter and 5-6 mm height. The mass of a cylinder is about 0.1 g. To certify gas-forming elements, we used the methods of fusion under inert gas flow (hydrogen, oxygen, nitrogen) and high-temperature vacuum extraction with mass spectroscopy (hydrogen). The analyzers were calibrated using CRM, a gas dose (for hydrogen), and a substance of constant stoichiometric composition (potassium nitrate). Conditions for the determination of the mass fraction of hydrogen, oxygen, and nitrogen in titanium and titanium alloys using an ELTRA ONH-2000 gas analyzer in solid materials have been refined in the analytical laboratory ICRM. The accuracy indicators (assigned characteristics) of the measurement procedure were determined using a great bulk of experimental data. 

A brief comparative analysis of the concepts and procedures of "validation" and "verification" appeared in the national regulatory framework in relation to measurement techniques over the introduction of GOST ISO/IEC 17025-2019 which set the requirements for the competence of testing and calibration laboratories is carried out. Conditions for using a specific technique in an analytical laboratory providing reliable results of analyses are formulated proceeding from the regulatory documents: non-standard methods developed by a given laboratory and standard methods but used outside the scope or somehow modified, are the subject to validation; standard methods validated by another laboratory, as well as the methods developed by another laboratory and certified by an authorized organization are to be verified. 

The last four years in the activities of accredited conformity assessment bodies have been marked by global modernization of the FSIS (Federal State Information System) of the Federal Service for Accreditation and e-services of the national accreditation system. The accredited conformity assessment bodies (ICRM among them) encountered a number of problems which have arisen in this regard, i.e., the impossibility of complying the requirements of normative legal acts being put into effect, the unstable operation of the functionality and, as a result, the disruption of the rated deadlines for providing information about the activities of an accredited body, ineffectual appeals to technical support, impossibility to realize the requirements of accreditation experts when working with the accreditation scope configurator. Thus, the digitalization which has been realized by the Federal Service for Accreditation failed to bring the desired results and save time of the accredited bodies.