Melt Duration Research Articles

On the petrogenesis of lunar troctolites: New insights into cumulate mantle overturn & mantle exposures in impact basins

We investigate lunar troctolite petrogenesis with a series of forward models. We simulate the cumulate mantle overturn hypothesis by modeling the adiabatic ascent and decompression melting of primary mantle cumulates produced during differentiation of a lunar magma ocean (LMO). Combined equilibrium and fractional crystallization of candidate liquids generated by the melting model can reproduce the predominant constituents of the lunar magnesian-suite (Mg-suite: troctolites and norites), contrary to previous hypotheses. Model results are consistent with previous studies challenging the proposed and long-standing genetic relationship between Mg-suite and gabbronorites.Our Mg-suite petrogenetic model validates a direct temporal and chemical link between Mg-suite melt production and pressure-release melting of primary LMO cumulates. If so, Mg-suite crystallization ages (4345 ± 15 Ma) can be used to constrain the onset and duration of melting associated with mantle overturn. Based on our model results, we propose an alternative mantle overturn hypothesis whereby upwelling olivine-dominated cumulates experience decompression melting to produce the Mg-suite primary melt (∼1.9% melt at ∼2.1 GPa), but that this melt was extracted from depth akin to lunar picritic glass magmas (low-degree partial melts at depths corresponding to ∼1.3–2.5 GPa). Thus, our revised mantle overturn hypothesis reconciles Mg-suite petrogenesis without the expanse of an olivine-dominated upper mantle (as suggested by the current paradigms, but contradicted by orbital data). This hypothesis supports the presence of a low-Ca pyroxene dominated upper mantle, consistent with mantle stratigraphy constrained by experimental and numerical simulations of LMO differentiation and proposed mantle exposures within impact basins.

Sensitivity analysis of design parameters for erythritol melting in a horizontal shell and multi-finned tube system: Numerical investigation

Latent heat storage systems using phase change materials (PCMs) store large amounts of thermal energy at a near-constant temperature in a compact space. However, PCMs possess relatively low thermal conductivity which prolongs their phase change process; consequently, their applications have been limited. To address this, a numerical investigation was conducted in this study on the heat transfer mechanism in a horizontal shell and multi-finned tube heat exchanger. Erythritol (melting point of 117 °C) was selected as the PCM and Therminol-55 was used as the heat transfer fluid. ANSYS Fluent v. 19.0 was used to numerically solve the governing equations. Once validated by comparing with experimental data, the developed numerical model was then used to investigate the effect of several design parameters regarding tubes and fins on the storage performance. It was found that number of tubes, fin height as well as rotation of fins and tubes significantly influence the melting process. Overall, the melting duration could be decreased by about 44% when the number of tubes increased from 5 to 9. Moreover, the melting time could be decreased by about 31% when the fin height increased from 6 to 15 mm.

Evaluation of passive microwave melt detection methods on Antarctic Peninsula ice shelves using time series of Sentinel-1 SAR

Passive microwave datasets have been used to quantify the extent and duration of surface melt in Greenland and Antarctica from 1978 on with daily and near-daily intervals. These results have important implications for climate analysis and may help evaluate ice shelf stability. However, the accuracy of passive microwave methods used to detect melt is difficult to quantify, especially on the Antarctic Peninsula. Here four different melt detection methods are employed, including a new formulation of a statistical analysis of brightness temperature time series using a K-means clustering algorithm. Strikingly, two of the most widely used passive microwave melt detection methods are found to vary by 48% mean days of melt per year across six different locations on the Larsen C, Wilkins, and George VI Ice Shelves. In the absence of ground truth observations, time series of Sentinel-1 SAR observations from 2016 on provide a comparison dataset. In topographically flat regions where surface melt is spatially uniform, the passive microwave melt detection method based on a K-means analysis and the cross-polarization gradient ratio method demonstrate the highest agreement and correlation with active radar melt detection methods. One issue which has plagued passive microwave analysis is its coarse spatial resolution. High resolution SAR images are able to demonstrate and quantify the spatial variability of melt within individual passive microwave pixels. Melt is shown to be suitably uniform in space for passive microwave applications at the study sites on Antarctic Peninsula ice shelves, but not so in other regions of the Antarctic Peninsula. Spatial heterogeneity of surface melt on the sub-pixel scale is often related to varying surface topography.

Optimization and Thermal Analysis of Fe2O3 Nanoparticles Embedded Myristic Acid-Lauric Acid Phase Change Material

Phase change materials (PCM) are commonly utilized materials in latent heat energy storage systems. In the present study, Fe2O3 was incorporated into the eutectic mixture of myristic acid and lauric acid. The composites were prepared by a melting and mixing method. Fourier transform infrared spectroscopy and dynamic light scattering results revealed the physicochemical properties of the eutectic mixture. Thermal analysis was performed on the optimized PCM mixtures with various Fe2O3 loadings of 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%. It is observed from the experimental results that the duration of melting and cooling rates for PCM composite with 4 wt.% Fe2O3 loadings was significantly improved, i.e., 85.72% and 78.31%, respectively, when compared to its pristine counterparts. These enhanced heating/cooling rates and thermal conductivity are attributed to the optimized impregnation of 4 wt.% Fe2O3 nanostructures into the eutectic mixture.

Prolonged Partial Melting of Garnet Amphibolite from the Eastern Himalayan Syntaxis: Implications for the Tectonic Evolution of Large Hot Orogens

AbstractThe Himalayan orogen, which formed due to collision of the Indian and Asian continents during the Early Tertiary, is a prime example of a large, hot collisional orogen. Despite decades of study, the duration of partial melting of migmatitic rocks exposed in the Himalayan orogenic core remains highly controversial. As such, we have performed detailed petrological and geochronological analyses of garnet amphibolite from the eastern Himalayan syntaxis in order to reveal the thermal conditions, tectonometamorphic mechanisms, and timing and duration of anatexis in metabasic rocks that form a major component of the thickened lower crust of the eastern Himalayan orogen. Phase equilibrium modeling and geothermobarometry show that the studied sample underwent high‐pressure granulite‐facies metamorphism and partial melting at 15−17 kbar and 805−840°C. Dehydration melting of amphibole during prograde metamorphism generated up to 20 vol. % partial melt with a granitic composition, which thus represents a potential source for Himalayan syn‐ to post‐orogenic crustal‐derived granites. Zircon U‐Pb geochronology shows that the garnet amphibolite witnessed a long‐lived anatectic and melt crystallization process lasting more than 30 Myr. Prolonged anatexis from ca. 40 to ca. 20 Ma predates initiation of the extrusion of Himalayan metamorphic core by up to 15 Myr, indicating that the thick and weak crust of the Himalayan‐Tibetan orogen must have remained stationary for this length of time, despite the ongoing continental collision. This study thus provides new insight into the tectonic evolution of hot orogens.

Charging performance optimization of a latent heat storage unit with fractal tree-like fins

Abstract The significant deficiency of the latent heat storage (LHS) technology is the poor heat charging and discharging efficiency. Here invokes a fractal tree-like fin to strengthen the melting property of LHS units inspired by bionics in nature. A transient melting model of the shell-and-tube LHS unit with tree-like fins is built and solved numerically. The structure optimization of fractal tree-like fins is conducted for charging enhancement by response surface method (RSM). The results report that the length ratio and thickness index play considerable roles in the competition between natural convection suppression and heat conduction improvement during melting processes. Compared with the plate fin, the distribution of tree-like fins in a multi-level fashion provides point-to-area networks for high heat flows, which benefits to the melting rate acceleration and uniform temperature field owing to that the thermal conduction improvement is more remarkable than convection suppression. More significantly, the total melting duration of the LHS unit with optimal tree-like fins reduces by 26.7%, and the averaged heat storage rate increases by 45.4% relative to the plate fins case. Therefore, a fractal tree-like fin with α = 1.07 and Δ = 0.65 is recommended in practical applications for maximizing energy charging performance of LHS units.

Laser polishing as a new post process for 3D-printed polymer parts

A process strategy – a quasi-top-hat scanning strategy with closed-loop temperature control – for laser polishing of additively manufactured polymer parts is developed to reduce the process to its two main process parameter, polishing temperature and melt duration. A study for SLS-printed PA12 results in an achievable roughness reduction from an initial roughness of Sa = 10.2 µm to Sa = 0.61 µm. Further investigations are performed for PP, TPU, ABS and PEEK.

Increasing in effi ciency of steel refi ning process by using production waste

The results of the possibility for using of spent ANF-6-1 fl ux for electroslag remelting and breakage of spent silicon carbide abrasive wheels in the smelting of 20GFL steel are presented. Noticeable advantage of the experimental smelting technology is shown. Saving of expensive materials, reduction of harmful impurities in the metal and increase in the desulfurization rate from 0.0004 to 0.0007 %/min are noted. The use of spent ANF6-1 fl ux for electroslag remelting made it possible to reduce the duration of melting, the consumption of slagforming materials and reducing agents. There is also decrease in electricity consumption by 11 kW/h per ton of liquid steel. Increase in the plastic characteristics and impact toughness of 20GFL steel is shown when using the experimental melting technology in comparison with the current one. At the same time, the strength characteristics of steel remained at the same level. The economic effect at using of secondary materials in the smelting of 20GFL cold-resistant steel is 430...450 rubles per ton of liquid steel.

Rapid and Localized Soldering Using Reactive Films for Electronic Applications

Abstract The rapid and localized heating techniques allow the joining of temperature-sensitive materials and components without thermal induced damage commonly encountered when high-temperature solder reflow processes are used. This is also advantageous for making assemblies with materials having a large difference in the coefficient of thermal expansion without induced bowing or cracking. The use of exothermic reactive foil sandwiched between solder preforms is a promising local and rapid soldering process because it does not require any external heat source. The reactive foil is formed from alternatively stacked nanolayers of Ni and Al until it reaches the total film thickness. Once the film is activated by using an external power source, a reaction takes place and releases such an amount of energy that is transferred to the solder preforms. If this amount of energy is high enough, solder preforms melt and insure the adhesion between the materials of the assembly. The influences of the applied pressure, the reactive film (RF) thickness as well as the solder, and the attached materials chemical composition and thickness were investigated. It was shown that the applied pressure during the process has a strong effect on the joint initial quality with voids ratio decreases from 64% to 26% for pressure values between .5 and 100 kPa, respectively. This can be explained by the improvement of the solder flow under higher pressure leading to a better surface wettability and voids elimination. Otherwise, the joint quality was found to be improved once the solder melting duration is increased. This relationship was observed when the thickness of the reactive foil is increased (additional induced energy) or the thickness of solders, Cu, and/or Si is decreased (less energy consumption). The microstructure of the AuSn joint achieved using the RFs shows very fine phase distribution compared with the one obtained using conventional solder reflow process in the oven because of high cooling rate. The mechanical properties of the joint were evaluated using shear tests performed on 350-μm-thick silicon diodes assembled on active metal brazed substrates under a pressure of 100 kPa. The RFs were 60 μm thick and sandwiched between two 25-μm-thick 96.5Sn3Ag.5Cu (SAC) preforms. The voids ratio was about 37% for the tested samples and shear strength values above 9.5 MPa were achieved which remains largely higher than MIL-STD-883H requirements. Finally, the process impact on the electrical properties of the assembled diodes was compared with a commonly used solder reflow assembly and the results show a negligible variation.

Energy and exergy analysis of an experimentally examined latent heat thermal energy storage system

In this study, an experimental investigation is carried out on a Latent Heat Thermal Energy Storage system (LHTES). All the experimental data are optimized using thermodynamic principles in which exergy analysis is conducted to examine the system’s performance at different time constants. The proposed system uses paraffin wax RT35 as Phase Change Material (PCM) and water as Heat Transfer Fluid (HTF). The water enters the successive helical rounds of the tube and the melting process initiates from locations around the tube and propagates throughout the shell. In recent years, surface enhancement through using spiral and helical configurations of the tube is preferred by scientists to overcome the problem of slow charging in the outermost positions of the subdomain filled with PCM. Hence, the effect of the change in the coil number of the heat exchanger is investigated by choosing three different helical coil diameters which are 50, 70 and 90 mm, respectively. It is aimed to find the most efficient case capable of storing the maximum energy possible as well as higher exergy efficiencies in minimum melting duration through the phase change process. Parameters such as the transferred heat from HTF to PCM, PCM average temperature, melting front growth, Nusselt number, exergy efficiency, and the entropy generation number are investigated meticulously. Results showed that for the highest used helical diameter (90 mm) compared to the lowest one (50 mm), better melting performance is observed in which the melting time is reduced by 72.6%. Moreover, although some cases may achieve higher exergy efficiencies at their full melting time, they are not offered as best choices due to the limitations in heat storage time duration.

Thermal expansion of rib cartilage implants at the non-isothermal cooling and heating

This paper presents the results of a thermo-analytical study of the thermal expansion of rib cartilage used for autotransplantation. Deformations of rib cartilage implants caused by thermal expansion of tissue during Peltier cooling and laser heating in the temperature range from − 10 to + 40 °C. It is revealed that thermal expansion of the cartilage is influenced by the anisotropy of the internal structure of the tissue. Samples of rib cartilage, cut along the fiber bundle, are deformed four times stronger in length than in width. The anisotropy of the cartilaginous tissue structure affects the rate of heating of the samples at different conditions of heat transfer. Thus, the samples cut from the rib in two different ways, along or across the fiber bundle, have different heating rates and duration of the phase transition. Laser heating rate of frozen samples cut across the fiber bundle is 20% higher than along cut. Duration of ice melting for both types of the samples differs by 25%. These studies are important for planning operations of laser reshaping of cartilaginous tissue and for the preliminary selection of frozen implants.

Thermal characteristics of aluminium hollowed bricks filled with phase change materials: Experimental and numerical analyses

Based on the thermal management requirements of bearing structures in the thermal protection system of aircrafts, a group of aluminium hollowed bricks with low porosity is manufactured. The thermal response characteristics of these bricks filled with 48.3–57.8 °C paraffin are experimentally studied. The results show that the infilling of PCMs may significantly retard the heat transfer through the bricks due to the large latent heat absorption, and the temperature control time is thus 2.5 times that for the case without PCMs. The samples with higher porosity have longer melting duration times and lower entire temperatures after completely melting. A higher porosity or larger hole diameter is more beneficial for the thermal control at the cold end because of the lower effective thermal diffusivity. A numerical model is also established to further analyse the field distributions of the samples. The simulation shows that the natural convection of the liquid PCMs in holes is a laminar flow. In contrast to the sensible heat period, the temperature uniformity of the aluminium base is better in the latent heat period, and the corresponding temperature fluctuation amplitudes along the centre-lines of the holes are larger. Furthermore, whether for bottom heating or top heating, the holes that are closer to the bottom of the sample have stronger natural convection. These findings can provide beneficial guidance for the design of a thermal control system with metallic hollowed geometries.

Large-Area Electron Beam Melting: Frequency Analysis and Critical Frequency Prediction

During large-area electron beam irradiation, high energy flux pulses of electrons melt a thin layer of material. The objective of this work is to analyze the spatial frequencies of a turned, S7 tool steel surface before and after electron beam melting. It was observed that high frequency features are significantly reduced following melting, but lower frequency features were created and increased the unfiltered areal average roughness. Previous work on laser remelting-based polishing derived a critical frequency that defines the frequency above which higher frequency features are dampened. As the critical frequency depends on the melt duration that the surface experiences, a one-dimensional, transient temperature prediction model was created for this work to estimate the melt time for a single electron beam pulse. This model allowed for the calculation of a critical frequency that showed good ability to predict the frequencies that are dampened.

Melt Procedure Affects the Photosynthetic Response of Sea Ice Algae

The accuracy of sea ice algal production estimates is influenced by the range of melting procedures used in studies to obtain a liquid sample for incubation, particularly in relation to the duration of melt and the approach to buffering for osmotic shock. In this research, ice algal photophysiology from 14C incubations was compared in field samples prepared by three melt procedures: i) a rapid ≤ 4 h melt of the bottommost (< 1 cm) ice algal layer scraped into a large volume of filtered seawater (salinity 27 - 30), ii) melt of a bottom 5 cm section diluted into a moderate volume of filtered seawater over 24 h (salinity 20 - 24), and iii) melt of a bottom 5 cm section without any filtered seawater dilution over about 48 h (salinity 10 -12). Maximum photosynthetic rate, photosynthetic efficiency and production at zero irradiance were significantly affected by the melt treatment employed in experiments. All variables were greatest in the highly diluted scrape sample and lowest in the bulk-ice samples melted in the absence of filtered seawater. Laboratory experiments exposing cultures of the common sea ice diatom Nitzschia frigida to different salinities and light conditions suggested that the field-based responses can be attributed to the rapid (< 4 h) adverse effects of exposing cells to low salinities during melt without dilution. The observed differences in primary production between melt treatments were estimated to account for over 60% of the variability in production estimates reported for the Arctic. Future studies are strongly encouraged to replicate salinity conditions representative of in situ values during the melting process to minimize hypoosmotic stress, thereby most accurately estimating primary production.

Extending the Record of Surface Melt on the Larsen C Ice Shelf

The first use of Advanced Scatterometer radar data to determine melt duration on an Antarctic ice shelf shows the season has decreased by up to 2 days per year during the extended 21st century record.

Implications of stubble management on snow hydrology and meltwater partitioning

Spring snowmelt is the most important hydrological event in agricultural cold regions, recharging soil moisture and generating the majority of annual runoff. Melting agricultural snowcovers are patchy, which leads to melt rate enhancement by energy advection from warm moist snow-free surfaces to cool dry snowcovers. Agricultural snowmelt is also impacted by crop residue. Adoption of zero-tillage agricultural practices means vast areas of the Canadian Prairies are now characterized by standing crop stubble. Stubble influences snow accumulation through blowing snow processes and snowmelt through the impact of emerging stubble upon the surface energy balance. Unfortunately, stubble emergence and advection to patchy snowcovers are unaccounted for in snow hydrology models and a complete process description has been unavailable. Here, both advection and stubble influences on snowmelt hydrology are modelled by coupling new stubble-snow-atmosphere surface energy balance and advection models to existing blowing snow and frozen soil infiltration models. Long-term meteorological datasets from sub-humid and semi-arid locations in Saskatchewan, Canada are used to quantify the influence of stubble characteristics on accumulation, melt, and meltwater partitioning processes with respect to interannual variability, antecedent soil moisture, and climatic differences on the Canadian Prairies. The hydrological response to increasing stubble height is increased meltwater, melt rate, infiltration, and runoff, and negligible changes in melt duration. The response of these processes to changes in stubble height was more pronounced at a semi-arid site versus a sub-humid site as stubble more effectively suppresses blowing snow sublimation in the windier, drier semi-arid environment of southwestern Saskatchewan. Recommendations for stubble management to meet specific runoff or infiltration objectives are summarised; stubble management can be an effective tool to influence infiltration where soils are dry and runoff where soils are wet. This framework allows the diagnosis of the influence of stubble management on meltwater partitioning in cold agricultural regions.

Femtosecond laser induced nano-meter size surface structures on ZnSe film

We realize femtosecond laser-induced high spatial frequency nano-meter size periodic surface structures with a periodicity about 140nm-170 nm on ZnSe film in one step. Compared with bulk ZnSe, the periodicity and fluence threshold of the surface structure on ZnSe film are smaller and lower. We propose the shortened melting duration, which caused by the higher thermal conductivity of the sapphire substrate, is the origin of the difference between the bulk ZnSe and ZnSe film. Surface capillary wave is easier frozen with shorter melting duration leaves smaller periodicity. Meanwhile, we also found stripes on the surface of sapphire with much lower threshold than previously reported values. The results can benefit advanced optoelectronic device fabrication and fundamental research.

Numerical investigation of one-dimensional steady detonation wave characteristics for magnesium particle-air mixture

Magnesium particles have broad application prospects as fuel or additive for detonation combustion power systems due to their high energy density, ignition characteristics and combustion efficiency. In this paper, a one-dimensional steady-state model is established for the magnesium particle-air mixture. The distribution of the flow field and the influences of factors such as phase transition process, inlet velocity, particle radius and initial particle density on the structure of detonation wave are analyzed numerically under different working conditions. The studies have shown that the process accelerating to the sound speed due to the expansion of the gas phase mainly occurs in the pure evaporation reaction stage of the magnesium particles. The duration of magnesium and magnesium oxide melting accounts for a small proportion of the entire combustion process. Under the initial conditions of normal temperature and pressure, the theoretical maximum temperature in the detonation wave during self-sustaining propagation is lower than the dissociation temperature of the magnesium oxide. The heat absorbed in the magnesium melting process is released into the gas phase for expansion work as the reaction progresses, leading to a small effect of magnesium melting on the structure of the detonation wave. The amount of exothermic heat absorbed in the magnesium oxide melting process is so large that the process of expansion of the gaseous working fluid is almost stopped. Moreover, the absorbed heat cannot be used for gas phase expansion work. Therefore, the melting process of magnesium oxide has a great influence on the structure of the detonation wave. The detonation wave of the magnesium particle-air mixture can be stabilized and self-sustained only at the eigenvalue velocity. Below this value, a singular point appears in the flow field. Above this value, the wave cannot be accelerated to the speed of sound, and the downstream flow field disturbance can pass through the reaction combustion zone and weaken the intensity of the detonation wave. When the end of the detonation wave is in the melting process, the detonation wave can still stabilize the self-sustaining propagation when a certain inflow velocity and a magnesium particle density are satisfied. Otherwise, the detonation wave can propagate only at an average speed with oscillation. The initial particle concentration corresponding to the peak of the eigenvalue velocity is smaller than the stoichiometric one corresponding to the peaks of the density, pressure and temperature, indicating that the eigenvalue velocity is not dependent solely on the heat release of the reaction because the interaction between the two phases also affects the conversion efficiency of thermal energy into gas phase kinetic energy. Under the premise of uniform distribution of internal temperature of magnesium particles, the particle size mainly affects the size of the detonation wave, but has little effect on the characteristic value of the eigenvalue velocity and the Chapman-Jouguet parameters. The model in this paper comprehensively reflects the influence of the phase transition process in the combustion process on the structure of the detonation wave and the self-sustaining propagation mechanism. It has a certain guiding significance for designing the detonation power device using powder fuel.

ПРОГНОЗИРОВАНИЕ ВРЕМЕНИ ПЛАВЛЕНИЯ КОМПЛЕКСНЫХ ФЕРРОСПЛАВОВ МЕТОДОМ ФИЗИКО ХИМИЧЕСКОГО МОДЕЛИРОВАНИЯ

The purpose of this work is to implement a new approach to the description of the duration of melting (dissolution) of complex new generation ferroalloys during the deoxidation and doping of a metal melt. This approach is aimed at developing a methodology and criteria for the quantification and accounting of the micro-heterogeneity of multicomponent metal melts and their prediction on such important for steelmaking production characteristics as the melting time of ferroalloys, the description of the inter-mine interaction, which allows a deeper understanding of the process. deoxidation and refining of steel. In the work, the approach developed in the Institute of Ferrous Metallurgy of the National Academy of Sciences of Ukraine to solve problems of modeling of non-conformities that relate the composition, structure and properties of melts is used in the work. It is based on the original concept of physicochemical modeling of the processes of interatomic interaction in melts and solutions, developed by E.V. Prihodko. According to it, metal melts are considered as chemically unified systems. Changing their composition affects the complex of physicochemical properties due to changes in the parameters of their electronic structure. The method of calculation of criteria (∆Zy and d), characterizing the degree of difference between the electronic and structural state of the melt, as a chemically unified system, from the mechanical mixture of their initial components and the parameter was used to evaluate and account for the influence of the micron homogeneity of the structure of the metal melts of ferroalloy production. ρl, which takes into account the cluster spin in metal melts. Using these criteria and the available experimental data, analytical dependences were obtained to calculate the melting time of complex (ma-manganese, vanadium, niobium and boromatic) ferroalloys of the new generation. This will allow them to evaluate their effectiveness of application, which is associated with the highest assimilation of the main elements that affect

Integrated influence of melting parameters of rail steel on rail products quality and technical and economic indicators of the production

Analysis of literature and production data has shown that despite the significant improvement in quality of domestic rail products, achieved in the last decade due to fundamental technical re-equipment of rail production, there is a problem of increased rejection of rails for surface defects. Based on studies of influence of rail steel chemical composition on quality of rails produced by «EVRAZ ZSMK», there was established a significant effect of increasing copper content in the range of 0.07 - 0.15 % and of sulfur - in the range of 0.006 - 0.011 % in E76KhF steel to increase rejection caused by rail surface defects. Mechanism of the influence of these elements concentration in rail steel on finished rails quality was revealed. Decisive influence of ratio of pig iron and scrap in metal charge on copper and sulfur content in rail steel was evidenced - higher rate of cast iron in metal charge within 20 - 50 % contributes to decrease of copper concentration and increase of sulfur content. To justify optimal composition of the charge for rail steel melting in regard to rail products quality and technical and economic indicators of production, study of the effect of cast iron (liquid and solid) to scrap ratio in metal charge on basic parameters of furnaces’ operation was conducted. As a result, it was found that with an increase in share of both liquid and solid iron in metal charge, there are linear decrease in specific electricity consumption, increase in specific oxygen consumption according to parabolic law and a linear decrease in manganese content in furnace output. The obtained dependences of melting duration on ratio of charge components in metal charge indicates presence of prominent minimum, when using liquid iron in the range of 35 - 40 %, and when using solid iron - in the range of 30 - 35 %. Based on the regression equations, statistical model was constructed for the influence of metal charge composition on technical and economic performance of the melt charge in rail steel smelting, in which optimization parameters are: total cost, depending on the metal stock composition and performance of the shop for suitable billets produced by continuous casting. Application of the obtained model allows to develop reasonable recommendations on the optimal proportion of iron in the metal for current level of prices for materials and energy used in electric smelting, taking into account changes in the shop productivity.