High Silicon Content Research Articles

Экспериментальное моделирование взаимодействия материалов гидроботанических площадок с компонентами аэротехногенных выбросов

The article presents evaluation results of metal accumulation processes by filtering containers based on mining waste. Serpentine-reached grainy material (an enrichment product of phlogopite mining waste) was used for sorbing heavy metals from atmospheric precipitation. It has been established that the serpentine-reached grainy material is characterized by useful sorption features with respect to heavy metals and high content of calcium, magnesium and silicon.

Operando Microcalorimetry Study on Irreversible Losses in Silicon Anodes

Isothermal microcalorimetry (IMC) is an effective characterization tool for the measurement of irreversible reactions within lithium-ion batteries. When carried out on batteries under an electrical load, the measured isothermal heat flow is composed of three sources: ohmic heat, reversible heat, and parasitic heat. When a highly reversible cell - i.e. with coulombic efficiency greater than 99% - is studied, the equation can be reduced to enable simplified measurement of the total parasitic heat per cycle.1 However, for moderately reversible cells like those studied here, equation 1 is employed in combination with complementary measurements to determine ohmic and reversible contributions, and parasitic heat flow is subsequently isolated.2 (1) dQ/dt = I*(E_load - E_eq) + IT*(dE_eq/dT) + dQ_para/dtHerein, we apply operando IMC to half-cells composed of high silicon content anodes (80 wt.% silicon nanoparticles) versus lithium foil. Silicon is an attractive next-generation anode material for lithium-ion batteries due to it’s low reaction potential and extremely high storage capacity of ~3500 mAh/g. However, silicon electrodes suffer from limited cycle life and continual capacity decay related to mechanical degradation and silicon surface reactivity with the standard carbonate electrolytes employed in lithium-ion batteries. The mechanical degradation arises from the large volume change of silicon during lithiation of nearly 400%, while the surface reactivity is a result of a non-passivating solid-electrolyte interphase (SEI) layer along with continual exposure of fresh active surfaces as the silicon changes volume during cycling.Both the degree of volume change and degree of surface reactivity are dependent upon the voltage window over which silicon is cycled. In addition, both avenues of capacity loss have different thermal indicators: mechanical pulverization is associated with increased ohmic heat due to higher cell resistance, while surface reactivity losses are correlative with parasitic heat flow. In this study we strive to separate the two causes of capacity loss as a function of voltage window, C-rate, operational temperature, and chosen electrolyte. Figure 1 below shows the parasitic heat generated per mole of irreversible lithium loss for silicon half cells operated at 30°C with 1.2M LiPF6 in EC/EMC 3/7 electrolyte. Cells with a 50 mV lower cut-off have non-linear relations between parasitic heat and capacity loss, indicating (along with ohmic heat values not included here) that mechanical pulverization plays a significant role in capacity loss. While the cell with a 100 mV lower cut-off has a linear relation between lost capacity and parasitic heat flow. This suggests that for the 100 mV cell, the capacity loss is primarily related to surface reactions, and the slope of the data curve yields an average enthalpy of reaction for this SEI layer formation as 105 kJ/mol-Li. Such data can help to inform cell design and operational ranges for optimum cycle life, while providing data of the surface species formed on active silicon.References Krause L.J., Jensen, L.D., Dahn J. R., Electrochem. Soc. 159 A937 (2012).Housel L.M., et. al. ACS Appl. Mater. Interfaces 11 37567 (2019). Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government. SAND2020-5384 A. Figure 1

Investigation on wear mechanisms of PVD coatings for form taps in threading of Al–Si alloy

Form tapping of automotive engine grade Al–12Si die-cast alloy faces critical challenges with severe wear of form tap and short tool life. Typically, the lobes of the entry taper of the uncoated tap are progressively worn by both abrasion and adhesion wear. This study is focussed on the evaluation of the coating performance of 10 different PVD coatings to determine the best wear-resistant coating for this application. A novel thin multilayered in-house developed TiAlN coating performs the best in the progressive wear tests. An in-depth wear evaluation was conducted for the selected PVD coatings of the tested taps. A common wear pattern was identified for thin hard coatings on form taps for high silicon content aluminum alloy. In addition, a detailed investigation of the wear mechanisms has shown that coating fractures along the edges of the lobe in a form tap.

Co-disposal of municipal solid waste incineration fly ash and bottom slag: A novel method of low temperature melting treatment

Conventional melting for disposing municipal solid waste incineration (MSWI) fly ash or bottom slag needed high temperature and consumed high energy. High calcium content in fly ash and high silicon content in bottom slag brought them high melting point, respectively. Based on the analysis of chemical composition and phase diagram, suitable contents, namely 30%−40% CaO, 45%−60% SiO2 and 10%−15% Al2O3, were proposed to obtain a lower-melting-point mixture system. When the mass ratio of fly ash to bottom slag was 1:5, lowest melting point can be obtained. It was 1,190 ℃, lower than that of fly ash (1,448 ℃) and bottom slag (1,310 ℃). The toxicity characteristic leaching procedure of slags obtained from low melting treatment met the leaching toxicity of Chinese standard GB 5085.3-2007, and the slags containing about 25 wt% CaO, 10 wt% Al2O3 and 45 wt% SiO2 can be used for preparing CaO-Al2O3-SiO2 glass ceramics. The co-process of fly ash and bottom slag realized the low temperature melting treatment with low energy consumption.

Reinforcing the Near Eutectic Aluminum–Silicon Alloy with Graphene: An Approach toward Self‐Lubricating Composite

Mechanical and physical properties of aluminum alloys make them suitable for automotive and other structural applications. The high silicon content in aluminum improves the hardness to a great extent but at the cost of ductility. Herein, the reinforcement of near eutectic Al–Si (ADC12) alloy with the reduced graphene oxide (rGO) is demonstrated. The ADC12 alloy and its composite with rGO are cast using the gravity stir die‐casting process. The structural, mechanical, metallurgical, and tribological characteristics are conducted to understand the role of rGO as a reinforcement phase. The 0.7 wt% rGO as a reinforcement phase to ADC12 alloy reduces the friction and wear volume by 50% and ≈90%, respectively, whereas it improves the hardness by 27%. The high‐resolution transmission electron microscopy (TEM) image reveals the wrapping of microstructural silicon by rGO, which inhibits the growth of primary silicon and improves the interfacial strengthening. The high mechanical strength and low shearing properties of rGO, uniform dispersion in the ADC12 alloy, and restrained growth of primary silicon make the ADC12 alloy‐based composites potential materials for structural and low‐frictional building blocks in a diversified range of applications.

High silicon concentrations in grasses are linked to environmental conditions and not associated with C4 photosynthesis.

The uptake and deposition of silicon (Si) as silica phytoliths is common among land plants and is associated with a variety of functions. Among these, herbivore defense has received significant attention, particularly with regard to grasses and grasslands. Grasses are well known for their high silica content, a trait which has important implications ranging from defense to global Si cycling. Here, we test the classic hypothesis that C4 grasses evolved stronger mechanical defenses than C3 grasses through increased phytolith deposition, in response to extensive ungulate herbivory ("C4 -grazer hypothesis"). Despite mixed support, this hypothesis has received broad attention, even outside the realm of plant biology. Because C3 and C4 grasses typically dominate in different climates, with the latter more abundant in hot, dry regions, we also investigated the effects of water availability and temperature on Si deposition. We compiled a large dataset of grasses grown under controlled environmental conditions. Using phylogenetically informed generalized linear mixed models and character evolution models, we evaluated whether photosynthetic pathway or growth condition influenced Si concentration. We found that C4 grasses did not show consistently elevated Si concentrations compared with C3 grasses. High temperature treatments were associated with increased concentration, especially in taxa adapted to warm regions. Although the effect was less pronounced, reduced water treatment also promoted silica deposition, with slightly stronger response in dry habitat species. The evidence presented here rejects the "C4 -grazer hypothesis." Instead, we propose that the tendency for C4 grasses to outcompete C3 species under hot, dry conditions explains previous observations supporting this hypothesis. These findings also suggest a mechanism via which anthropogenic climate change may influence silica deposition in grasses and, by extension, alter the important ecological and geochemical processes it affects.

Synthesis of Silicon Hybrid Phenolic Resins with High Si-Content and Nanoscale Phase Separation Structure

In this paper, a set of silicon hybrid phenolic resins (SPF) with high Si-content were prepared by mixing phenolic resins with self-synthesized silicon resins. In order to obtain the nanoscale phase structure, condensation degree and the amount of Si-OH groups in silicon resins were controlled by the amount of inhibitor ethanol in the hydrolytic condensation polymerization of siloxane. Increasing the amount of ethanol resulted in more silanol groups and a lower degree of condensation for silicon resins, which then led to more formation of Si-O-Ph bonds in hybrid resin and improved compatibility between silicon resin and phenolic resin. When 400% ethanol by weight of siloxane was used in the sample SPF-4, nanoscale phase separation resulted. The residual weight of the cured SPF-4 at 1000 °C (R1000) significantly increased compared to pure phenolic resins. The result of the oxyacetylene flame ablation and the Cone Calorimeter test confirmed the improved ablative property and flammability after the modification. The performance improvement of the cured SPF-4 was attributed to the nanoscale phase structure and high silicon content, which promoted the formation of dense silica protective layers during pyrolysis.

Research of the influence of impurities on the occurrence of intermetallic phases in AlMg3 alloy

The main aim of this work was to investigate the influence of impurities on the occurrence of interemtalic phases in AlMg3 alloy. The effect of accompanying (admixture) elements was studied, namely: manganese, iron and silicon in various combinations of AlMg3 alloy. There was a high manganese content in one melt for AlMg3, a high iron and manganese content in the second, and a high manganese, iron and silicon content in the third. The reason for identifying and monitoring the occurrence of intermetallic phases in these accompanying elements is their limited solubility in aluminum, where they are practically secreted only in the form of different types of intermetallic phases. These intermetallic phases then reduce the resulting mechanical properties, especially ductility and also reduce the corrosion resistance of the AlMg3 alloy. Decrease of ductility causes consequently worse formability of the material and brittle intermetallic phases initiate microcracks with subsequent cracking of the material

Influence of Silicon on the Properties of Aluminum Alloy Powders of the Silumin Type and the Mechanical Properties of Products Made from These Powders by Selective Laser Melting

Technologies for the 3D printing of metallic powders are being increasingly extensively used around the world as alternatives to casting and machining to manufacture components of complex shapes and prototypes. Silicon-alloyed aluminum alloys are the most widely used materials in the selective laser melting technologies, which is caused by the price of these alloys and their high manufacturability for the layer-by-layer fused deposition, owing to their low susceptibility to hot cracking under thermal and shrinkage stresses. High rates of cooling the melt facilitate the formation in the material of ultradispersed silicon-containing phases, which results in increased strength. In the article, exemplified by two cast alloys (AK7ch and AK9ch), the speeds of the process of building up the products by the selective laser melting technology have been determined at a laser-beam power of 300 and 325 W and an energy density within the range 89–32 J/mm3. It is shown that, for the AK9ch alloy, lower porosity values are achieved within the investigated energy density range when compared with the AK7ch alloy and better mechanical properties of the alloy with a higher silicon content are achieved within the range of lower laser-beam energy densities than for the alloy with a lower silicon content. The mechanical properties of the materials produced under the optimal selective laser melting conditions comply with the most stringent requirements for the mechanical characteristics of the castings of the AK7ch alloy upon heat treatment.

Mineral Deposit Formation in Gas Engines During Combustion of Biogas from Landfills and Municipal WWTP

Abstract The biogas produced in municipal wastewater-treatment plants (WWTP) should be cleaned before it can be used as a fuel in internal combustion engines. Efficient running of such engines is possible only subject to using high quality biogas and lubricating oil. Otherwise, biogas impurities in course of complex chemical reactions may form deposits on various engine parts as well as seriously contaminate the lubricating oil. In this paper, mineral deposits containing high concentration of bismuth, silicon, sulphur, calcium and zinc are studied. Silicon deposits demonstrating strong friction properties are formed during combustion of volatile silica compounds. As these deposits build up, abrasion problems, ignition failure and even engine failure result. The bismuth containing deposits comes from bearings degradation, zinc and calcium were derived from the additives present in commercially available lubricating oil, while lead, aluminium, copper, nickel, iron and chromium were introduced by engine wear phenomena. The highest bismuth content was located at the engine cylinder heads and the lowest at the exhaust elements, whereas highest calcium content was registered on the pistons. Silicon containing deposits are highest in the exhaust and lowest at the engine head. Zinc deposits are highest at the piston.

Establishing Gerger (<i>Eruca sativa</i>) Leaves as Functional Food by GC-MS and <i>In-vitro</i> Anti-lipid Peroxidation Assays

Conventional food that safeguards against chronic illnesses is known as a functional food. Establishing functional foods starts with phytoconstituent analysis and in-vitro characterization of health benefits. Eruca sativa, popularly known as gerger or jarjeer in Saudi Arabia, is an annual edible shrub cultivated worldwide. Gerger leaves are consumed raw in salads and have additional health benefits. This study investigated the phytochemical profile of aqueous decoction of gerger leaves of the Saudi origin by GC-MS assay. We also performed in-vitro anti-lipid peroxidation and total antioxidant capacity assays using gerger decoction. Twenty-seven chemical compounds belonging to seven classes constituted the gerger decoction: organic siloxanes (39.75%), organic silyl esters (18.28%), phenolics (17.87%), aromatic and aliphatic esters (10.48%), terpenoids (7.09%), heterocycles (3.83%), and sulfur compounds (2.70%). This study reported the presence of compounds mentioned above for the first time in gerger leaves. The decoction method was efficient in the extraction of heat-stable terpenoids like astaxanthin (2.23%), cilonasterol (1.48%), ingol-12-acetate (0.4%), and phytol (2.98%). The in-vitro anti-lipid peroxidation study demonstrated the ability of gerger decoction to inhibit hepatic lipid peroxidation in a significantly dose-dependent (150 to 400 μg/ml) manner compared to quercetin. A dose of 400 μg/ml of gerger decoction resulted in 68.46 ± 0.01% inhibition of oxidation of hepatic lipids. The total antioxidant capacity of gerger leaves reported as the IC50 of the decoction was 217.90 ± 2.2 μg/ml and also statistically significant. The in-vitro models suggested the antioxidant mechanism of gerger was by hydrogen atom transfer and reduction of metal ions. The study substantiated that gerger is a functional food besides established the phytochemical profile contributing to the antioxidant activity. Given that the gerger decoction has a high silicon content and antioxidants, attempt to determine the bioavailability and to identify the molecular targets are essential to overcome bone disorders and oxidative stress.

Identification of virgin martensite in quenched microstructures of new generation of forging steels with higher silicon content using colour etching

Observation and identification of products of transformation of austenite during austempering, Q-P processing, or quenching and tempering are often challenging. The reason is that the resulting microstructures are typically very fine and provide insufficient contrast between microstructural components. Their analysis requires scanning or transmission electron microscopy which demand rather complex sample preparation procedures and involve high costs of maintenance of microscopes and accessories. However, in-process inspection of products of heat treatment calls for simpler and rapid methods of microstructure analysis using a light microscope.

Assessment of physicochemical parameters and metal distribution in bog peat of the western segment of the North European part of Russia (Arkhangelsk region).

This article is devoted to the study of physicochemical parameters and the assessment of the accumulation and distribution of metals in peat deposits from the North European part of Russia (Arkhangelsk region). Peat profiles were selected both in the area with a high anthropogenic load and in a bog remote from industrial pollution. The determination of metals was carried out by using the methods X-ray fluorescence analysis and atomic absorption spectroscopy. It was determined that the studied bogs can be attributed to the low ash type, and the recorded pH and mineralisation values make it possible to attribute these deposits to the acid-oxidising facies of oligotrophic peatlands, characteristic of taiga landscapes. Assessment of metal accumulation showed a high content of titanium, chromium, lead, nickel, vanadium, cobalt, aluminium, silicon, and copper in peat, mainly caused by the burning of fossil fuels and industrial production, as well as the burning of urban and industrial waste. The peat profiles are characterised by significant fluctuations in the content of elements in different horizons. Studies have shown the need to monitor the content of metals in peatlands from the Arkhangelsk region to assess atmospheric pollution from industrial emissions, both at the moment and in the past.

Microstructure and Composition Evolution of a Fused Slurry Silicide Coating on MoNbTaTiW Refractory High-Entropy Alloy in High-Temperature Oxidation Environment.

In this paper, the Si-20Cr-20Fe coating was prepared on MoNbTaTiW RHEA by a fused slurry method. The microstructural evolution and compositions of the silicide coating under high-temperature oxidation environment were studied. The results show that the silicide coating could effectively prevent the oxidation of the MoNbTaTiW RHEA. The initial silicide coating had a double-layer structure: a high silicon content layer mainly composed of MSi2 as the outer layer and a low silicon content layer mainly contained M5Si3 as the inner layer. Under high-temperature oxidation conditions, the silicon element diffused from the silicide coating to the RHEA substrate while the oxidation of the coating occurred. After oxidation, the coating was composed of an outer oxide layer and an inner silicide layer. The silicide layer moved toward the inside of the substrate, led to the increase of its thickness. Compared with the initial silicified layer, its structure did not change significantly. The structure and compositions of the oxide layer on the outer surface strongly depended on the oxidation temperature. This paper provides a strategy for protecting RHEAs from oxidation at high-temperature environments.

Influence of biomass ash additive on fusion characteristics of high-silicon-aluminum coal ash

The influence of cow dung ash (CDA) additive on the ash fusion characteristics of high-silicon-aluminum coal ash (SHA) was investigated using ash fusion temperature analyzer (AFTA), X-ray diffraction (XRD), thermogravimetric analyzer (TG-DSC) and FactSage thermodynamics software. In order to clarify the shrinkage/expansion and flow behavior of ash, high-temperature heating stage coupled with optical microscope (HSOM) was used to record the morphological change of ash in the heating process. The results show that the ash fusion temperatures (AFTs) decreased firstly and then increased with the addition of CDA. There was a minimum value of AFTs when the addition amount of CDA was 60%. Due to the high content of silicon and aluminum in SHA, the mullite with skeleton structure became the main crystalline phase in molten ash, which led to the high AFTs of SHA. The addition of CDA resulted in the increase of calcium and phosphorus in coal ash. Consequently, low-melting-temperature minerals such as anorthite and chlorapatite, which were responsible for the decrease in AFTs of blended ash, would be formed. With the continuous addition of CDA, the decrease of amorphous content led to the increase of AFTs. According to the results of ash fusion characteristics, SHA melting process only underwent the sintering stage due to the high AFTs, and its ash fusion behavior followed “softening-melting” mechanism. For CDA and blended ash (60% CDA), the melting process went through the sintering and melting stages, and the ash fusion behavior followed the “melting-dissolution” mechanism.

Investigation on Surface Quality of a Rapidly Solidified Al-50%Si Alloy Component for Deep-Space Applications.

To meet the requirements for high-performance products, the aerospace industry increasingly needs to assess the behavior of new and advanced materials during manufacturing processes and to ensure they possess adequate machinability, as well as high performance and an extensive lifecycles. Over the years, industrial research works have focused on developing new alloys with an increased thermal conductivity as well as increased strength. High silicon content aluminum (Al–Si) alloys, due to their increased thermal conductivity, low coefficient of thermal expansion, and low density, have been identified as suitable materials for space applications. Some of these applications require the use of intricate parts with tight tolerances and surface integrity. These challenges are often tied to the machining conditions and strategies, as well as to workpiece materials. In this study, experimental milling tests were performed on a rapidly solidified (RS) Al–Si alloy with a prominent silicon content (over 50%) to address challenges linked to material expansion in deep space applications. The tests were performed using a polycrystalline cubic boron nitride (PCBN) tool coated with amorphous diamond to reduce tool wear, material adhesion, surface oxidation, and particle diffusion. The effects of cutting parameters on part surface roughness and microstructure were analyzed. A comparative analysis of the surface with a conventionally utilized Al6061-T6 alloy showed an improvement in surface roughness measurements when using the RS Al–Si alloy. The results indicated that lower cutting speed and feed rate on both conventional and RS Al–Si alloys produced a better surface finish. Reduced vibrations were also identified in the RS Al–Si alloy, which possessed a stable cutting time at low cutting speeds but only displayed notable vibrations at cutting speeds above 120 m/min.

Preparation of soft magnetic composite from Fe-6.9wt%Si by different heat treatment strategies.

Present study investigated the effect of isothermal heat treatment strategies between 800 °C and 1150 °C on the magnetic properties of toroidal samples made from Fe-6.9wt%Si powder. The samples were prepared by classical powder metallurgy method since the classical sheet forming methods no longer work with the high silicon content. Our results presented here are part of a series of comparative experiments where we study the effectiveness of the insulating layers created during and before the compacting of soft magnetic composites (SMCs). Our goal was to create a soft magnetic composite made of ferromagnetic and inorganic insulating material with a frequency limit already in the megahertz range and a Snoek limit of few gigahertz. In the case of samples made from Fe-6.9wt%Si powder, the computed tomography results showed that significant porosity is to be expected after pressing. Its positive effect occurred during the heat treatment in the atmospheric agent, where silicon is precipitated and deposited on the surface of the particle. This coating is an electrically insulating layer at the grain boundaries. Depending on the heat treatment strategy, 1 or 2 ferromagnetic phases were observed. The frequency limit approached the target values, but due to the low value of static permeability, the Snoek limit did not reach the gigahertz range. However, there is a significant improvement in magnetic properties compared to the heat-treated samples in a protective gas.

Evaluation of the Possibility to Obtain Nanostructured Bainite in High-Carbon and High-Silicon 9XC Bearing Steel

The main aim of this research is the evaluation of the possibility of obtaining a nanostructured bainite after isothermal heat treatment of 9XC (according to GOST standard) bearing steel. It was found that the annealing at low temperature (250 °C) allows to obtain the microstructure of nanobainite consisting of nanometric-scale bainitic ferrite laths and austenite with a dominant film-like morphology. In the case of higher isothermal treatment temperature (300 °C), a microstructure was slightly coarser and the proportion of austenite with blocky morphology increased. The identification of a highly refined microstructure was performed using TEM and SAED methods. Besides, isothermal annealing temperature significantly affects hardness. The hardness difference between annealing at 250 °C (630.0 ± 4.4 HV1) and 300° C (517.3 ± 1.1 HV1) was over 100 HV. Such a substantial decrease in hardness was caused by the fraction and morphology of the occurred phases. Due to the high silicon content in the tested steel (1.54%), the carbide precipitation was delayed, but locally the cementite precipitates were confirmed. Based on the research, it was found that the commercial 9XC steel is appropriate for nanostructurization in the low ranges of bainitic transformation. Designing of further heat treatment should be focused on the lowest possible temperature of isothermal annealing (even below 250 °C).

Plant silicon as a factor in medusahead (Taeniatherum caput-medusae) invasion

AbstractMedusahead [Taeniatherum caput-medusae (L.) Nevski] is one of the most detrimental invasive annual grasses impacting the sustainability and function of rangeland in the western United States. This annual grass possesses high concentrations of tissue silicon (Si) that may facilitate invasion through key plant characteristics such as increased plant fitness, structure, and antinutritive qualities. These characteristics may affect known invasive processes such as increased plant productivity, slow litter decomposition, and decreased herbivory, facilitating a positive feedback cycle of invasion. However, Si is not considered an essential element and is often overlooked as a factor of T. caput-medusae invasion. Thus, this article provides a synthesis of plant Si, T. caput-medusae, and the self-reinforcing feedback cycle of invasion. We also discuss how current control strategies address plant characteristics determined by Si and suggest research avenues that may aid in novel or improved control strategies that target the T. caput-medusae–silica relationship.

Mathematical modeling of strength characteristics of chromium ferritic-martensitic steels

To predict the chemical composition of heat-resistant high-chromium steels with ferritic-martensitic structure (HFMS) (with the number of alloying elements up to 10 and the same number of parameters of production and heat treatment technology), a mathematical model is needed. In this work, I searched for the dependences of the yield strength and ultimate strength of HFMS on the content of alloying elements and test temperature without analyzing technological factors due to their uniformity. Analysis of the samples from ten steel grades was carried out on the basis of the experimental data including 63 tensile tests at 20 – 720 °С. Regression multiplicative dependencies are proposed to take into account exponential and power-law form through the corresponding factors: solid solution and dispersion hardening, total temperature softening of the steel, carbon content, total molybdenum and tungsten content, and strengthening effect of manganese. Estimates of the effect of nitrogen and silicon on the predicted strength characteristics have shown that a factor that takes into account the effect of nitrogen improves the model and is necessary in the general formula, and introduction of a factor that takes into account silicon content, worsens the model. Introduction of a silicon factor in the formula may be necessary in analysis of steels with high silicon content (type EP-823). The experimental fact of a close relationship between yield strengths and tensile strengths for the studied HFMS steels made it possible to use for the yield strength the form of equation and forecast for the ultimate strength, which differs only by coefficients in variables. Deviation of the calculated model yield strengths and tensile strengths from experimental is 13 – 18 %. An example of analysis of the yield strength behavior of steels with experimental chemical compositions is given. It is shown that the dependences found for the yield strength and tensile strength are stable with respect to the increase of experimental data matrix: with an increase in the number of experiments from 94 and higher, the coefficient of variation V monotonously decreases up to a maximum array size of 299 experiments.