Morphology Of Inclusions Research Articles

Effect of Rare Earth Yttrium on Inclusion Characteristics of Grain-Oriented Silicon Steel

To investigate the influence of heavy rare earth element yttrium on the type, morphology, and quantity distribution of inclusions in grain-oriented silicon steel, thermodynamic calculation was carried out on the typical rare earth inclusions in grain-oriented silicon steel containing yttrium. The main inclusions in the experimental steels with and without yttrium were observed and analyzed using field emission scanning electron microscope (FESEM, Zeiss Gemini SEM 300) and energy dispersive spectrometer (EDS, OXFORD Ultim Extreme). The electron backscatter diffraction (EBSD, OXFORD Symmetry) was used to analyze the local average misorientation of the hot-rolled plate. The results show that the inclusions in the Y-free steel are mainly long MnS, irregular Al2O3 and MnS-Al2O3. The inclusions in the Y-bearing steel are spherical rare earth compounds. The number of inclusions in Y-bearing steel decreases and the size increases compared with Y-free steel. The mean value of local average misorientation and the dislocation density of Y-bearing steel are smaller compared with Y-free steel, which could avoid the cracking problem caused by dislocation accumulation during hot rolling. After heating the rough-rolling sample to 1350 °C, there is no obvious difference in the inclusions type between the Y-free steel and Y-bearing steel. However, the area fraction of inclusions in Y bearing steel increases slightly. According to the thermodynamic calculation results, there are mainly three kinds of rare earth inclusions, YS, Y2S3 and Y2O2S, in Y-bearing steel, among which YS has the strongest stability and the stability of Y2O2S is the weakest. The rare earth element yttrium can effectively modify the inclusions, transforming the irregular Al2O3 inclusions, formed during the deoxidation of silicon steel into spherical rare earth inclusions, which suppress the precipitation of long MnS inclusions. Thus, the formability of the steel could be improved.

Analysis of the effect of cerium on the formation of non-metallic inclusions in low-carbon steel

The research focused on the influence of cerium on the chemical composition and morphology of non-metallic inclusions in pre-oxidised steel to which Al, Ca, and Ce was added in different amount and order. Calculations were carried out using our own computer program. The simulation results obtained according to two calculation models helped identify precipitates from the Ce–O–S system. The possibility of CeN formation was also identified. The trace amounts of these inclusions were also found in the results. Consideration of the physicochemical phenomena at the boundary, as well as the interfacial partitioning and the sulfur partition coefficient, influences the favourable chemical composition of the inclusions, limiting it mainly to compounds from the Al2O3, Ce2O3, and CaS systems. It was found that the addition of Ce before Ca causes the elimination of MnS precipitates and Ca-containing inclusions in the steel.

Vacuum degassing impact on non-metallic inclusions during clean steelmaking

ABSTRACT The objective of this article was to study the impact of duration of vacuum degassing process on the type and morphology of non-metallic inclusions which are undesired & unavoidable by product of steelmaking process. During the vacuum degassing stage five top slag and steel samples were taken. All sample occasions measured chemical composition of the molten steel and top slag, and SEM analysis of the non-metallic inclusions. It was seen that during vacuum degassing process the chemistry, dispersions as well as the morphology of the non-metallic inclusions is constantly changing. The Alumina content of the top slag is increased while CaO content is reduced. The percentage share of calcium aluminate type of inclusions verses spinel is increased. In the beginning of the vacuum degassing wt-% of Al in non-metallic inclusions is the highest however as the time passes this wt-% is reduced at the same time inclusions with larger ECDs appear.

Thermal Conductivity Prediction of Metal Matrix Particulate Composites: Theoretical Methodology and Application

To make more accurate predictions of the effective thermal conductivity (ETC) of the composites, a systematic method for predicting the effective thermal conductivity of metal matrix particle composites with arbitrarily shaped particles was proposed, and the geometry of random particles with controlled shape characteristics is reconstructed. In addition, the geometric vertices of the reconstructed particles are used to characterize the morphology of inclusions with complex profile in two-dimensional isotropic elasticity, and its explicit expression for the Eshelby tensor are explored. Moreover, the material mismatch between the particles and the matrix phase is simulate using a continuously distributed source field based on the Eshelby's equivalent inclusion method. The relationship between micro-structure and effective performance is established. Finally, the effective thermal conductivity of CuCr alloys was predicted using the ETC prediction model. Through the comparison of the numerical simulations, experiments, and calculations, the results show that the ETC model has reliable predictive capability.

Effect of Ca and Sb on the Corrosion Resistance of E690 Steel in Marine Atmosphere Environment

This study investigates the impact of Ca and Sb elements on the corrosion resistance of E690 steel in a simulated marine environment. Electrochemical testing and dry/wet cyclic corrosion testing were conducted on prepared E690 steel specimens. The eroded specimens’ microstructure was observed under a scanning electron microscope, and the inclusion morphology was analyzed using an energy-dispersive spectrometer (EDS). The simulating liquid was designed to emulate the severe marine atmospheric environment in Xisha. Results showed that the addition of Ca and Sb elements effectively enhances the corrosion resistance of E690 steel in the simulated marine environment. The corrosion rates of E690 steel specimens with Ca and Sb additions were lower than those without, and the corrosion morphology was more uniform. These findings suggest that the addition of Ca and Sb elements can improve the corrosion resistance of E690 steel in simulated marine environments and have potential for use in marine engineering applications.

Inclusion Control of 15-5 PH High-strength Stainless Steel through Aluminum Deoxidation

15-5PH high-strength stainless steel is an important alloy used for numerous critical components. Ultra-low oxygen content and inclusion control have become urgent problems that need to be addressed for the broad application of this steel. In this study, we investigate the thermodynamic equilibrium of Al–O and inclusion morphology of 15-5PH stainless steel to understand the basic mechanism behind the results obtained after commercial production of the alloy. The deoxidation behavior of 15-5PH stainless steel depends on the dissolved Al content ([Al%]). When [Al%] <0.001%, mixed Al–Si deoxidation occurs and the deoxidation product is Al2O3–SiO2–MnO–CrOx. When [Al%] ≥0.001%, simple Al deoxidation equilibrium is dominant and the deoxidation product is MgO·Al2O3. The formation of Al2O3–SiO2–MnO–CrOx, low melting point inclusions, and a MgO·Al2O3 interface layer reduces the activity of Al2O3, which is why the calculated results of Al–O thermodynamic equilibrium are higher than the experimental results. The measured results for the Al–O equilibrium demonstrate a relatively good agreement with the calculated values. This proved that the phases formed on the crucible surfaces were in equilibrium with the Al and O contents in the molten steels after holding for 120 min.

Microstructural segmentation using a union of attention guided U-Net models with different color transformed images

Metallographic images or often called the microstructures contain important information about metals, such as strength, toughness, ductility, corrosion resistance, which are used to choose the proper materials for various engineering applications. Thus by understanding the microstructures, one can determine the behaviour of a component made of a particular metal, and can predict the failure of that component in certain conditions. Image segmentation is a powerful technique for determination of morphological features of the microstructure like volume fraction, inclusion morphology, void, and crystal orientations. These are some key factors for determining the physical properties of metal. Therefore, automatic micro-structure characterization using image processing is useful for industrial applications which currently adopts deep learning-based segmentation models. In this paper, we propose a metallographic image segmentation method using an ensemble of modified U-Nets. Three U-Net models having the same architecture are separately fed with color transformed imaged (RGB, HSV and YUV). We improvise the U-Net with dilated convolutions and attention mechanisms to get finer grained features. Then we apply the sum-rule-based ensemble method on the outcomes of U-Net models to get the final prediction mask. We achieve the mean intersection over union (IoU) score of 0.677 on a publicly available standard dataset, namely MetalDAM. We also show that the proposed method obtains results comparable to state-of-the-art methods with fewer number of model parameters. The source code of the proposed work can be found at https://github.com/mb16biswas/attention-unet.

Characterization and analysis of alumina clusters in steel by X-ray Micro-CT

The properties of steel are affected by the non-metallic inclusions. It is critical to control the morphology of inclusions for producing the high-quality steel. However, due to the morphology of inclusions is complex and diverse, it is difficult to reveal the real morphology of inclusions by using the traditional two-dimensional (2D) observation method, and making it hard to quantitatively analyze the size and morphology of inclusions. In this study, the three-dimensional (3D) morphology of the alumina clusters in steel samples was observed by using the X-ray Micro-CT in the beamline of BL16U2 at Shanghai Synchrotron Radiation Facility (SSRF). Avizo software was used to reconstruct the 3D morphology of the alumina clusters, which intuitively shows the actual morphology of alumina clusters. The accuracy of 2D and 3D observation methods is discussed based on the stereological analysis of individual alumina cluster. A series of parameters were defined to characterize the morphological characteristics of the alumina clusters based the 3D observation. The fractal theory was introduced to quantitatively describe the morphological of alumina clusters. In the current study, the 2D fractal dimension of alumina clusters was determined as 1.64. The complexity of 3D morphology of alumina clusters was analyzed by 3D fractal dimension and shape factor. The current work provides an effective method for quantitative description of the morphology and spatial distribution of inclusions, which provides an important reference for effective control of alumina inclusions.

Influence of Mg on Inclusions in 21-4N Valve Steel

In order to explore the influence of different magnesium contents on the morphology, size, distribution and composition of inclusions in 21-4N austenitic valve steel, the inclusions in 21-4N austenitic valve steel with different magnesium contents smelted by high temperature resistance furnace were analyzed by Zeiss metallographic microscope and scanning electron microscope. The results show that the average yield of magnesium in steel is only 4.50% due to the high vapor pressure of magnesium in the laboratory smelting process. When the mass fraction of magnesium is 0-60ppm, with the increase of magnesium content, the main inclusions in steel mostly change from the initial Al2O3 and Al-Mn-O inclusions to Al-Mg-O spinel inclusions and Al-Mg-O composite inclusions. With the further addition of Mg, a large number of large-size MgO inclusions began to appear in steel. The average size of inclusions in 21-4N steel decreased from 4.576μm to 2.89μm, and the density of inclusions increased from 54 to 132 /mm2. The distribution uniformity of inclusions is obviously improved.

Cleanliness improvement and microstructure refinement of H13 die steel by laboratory magnetic-controlled electroslag remelting

The current work investigated the impact of transverse static magnetic field (TSMF) with varied magnetic flux density (MFD) on cleanliness and microstructure of laboratory scale electroslag remelted H13 die steel. The inclusion morphology and microstructure evolution of electroslag remelted ingots were examined utilizing scanning electron and optical microscopes, respectively. The number and size of inclusions in ingots were detected using the FEI Aspex Explorer. The results demonstrated that the number/size of inclusions in H13 electroslag remelted ingots were decreased as the MFD of applied TSMF increased. This resulted from the application of the TSMF, which produced the thinner liquid melting film (LMF), smaller droplets, and shallower metal molten pool, strengthening the kinetic conditions for inclusion migration to the slag-metal interface and the removal process. When the MFD of the applied TSMF was higher (95 mT and 140 mT), the LMF became thinner, the droplets became smaller, and the metal pool became shallower were more visible. Moreover, the metal pool became shallower and the local solidification time became shorter after applying TSMF with larger MFD, resulting in finer dendritic structure and carbides.

Effect of tellurium on sulfide inclusion, microstructure and properties of industrial bars of a medium-carbon microalloyed steel

Tellurium is used for optimizing sulfide inclusion morphology in the iron and steel industry. In this study, the effects of tellurium on sulfide inclusion, microstructure, mechanical properties, fatigue performance, machinability, and corrosion resistance of industrial 38MnVS bars were investigated. The results show that the weight ratio of Te/S of the tellurium-treated steel was 0.043. Further, tellurium was mainly in the form of an MnS substitutional atom. The MnS inclusions were refined and strengthened via tellurium modification, promoting ferrite transformation and refinement. Additionally, the yield strength increased, and the elongation anisotropy decreased slightly after tellurium modification. However, the tellurium modification had an insignificant effect on the ultimate tensile strength. The ferrite refinement also promoted fatigue performance. Moreover, tellurium modification is beneficial for machinability. The cutting force was reduced, and the surface quality was improved after tellurium modification. Under the tellurium content conditions described herein, tellurium modification has an insignificant effect on corrosion resistance. The suggested tellurium content is below 0.075 times sulfur content for medium carbon microalloyed steels.

Effects of Rare Earth La–Ce Alloying Treatment on Modification of Inclusions and Magnetic Properties of W350 Non-Oriented Silicon Steel

In order to study the effects of rare earth La–Ce alloying treatment on the characteristics of inclusions in non-oriented silicon steels, industrial experiments were conducted studying the composition, morphology, size and quantity of inclusions in W350 non-oriented silicon steel during the RH (Ruhrstahl-Hereaeus) refining process and tundish process, after rare earth treatment. The products were analyzed by means of ICP-MS (inductively coupled plasma mass spectrometry), SEM/EDS (scanning electron microscope-energy dispersive spectrometry), and ASPEX (automated SEM/EDS inclusion analysis). The research results showed that the types of inclusions in experimental steel changed significantly after rare earth treatment. The types of inclusions after RE (rare earth) treatment are typically rare earth composite inclusions that are mainly composed of (La, Ce)Al2O3, and conventional inclusions. The addition of rare earth promotes the agglomeration of inclusions; the morphologies of the inclusions are mostly blocky, and some are distributed in long strips. After rare earth treatment during the RH refining process, the number of inclusions with sizes of 1.0~3.5 μm in the experimental steel is increased, and the average size of the inclusions is 2.66 μm. In addition, the number of inclusions larger than 4 μm in the specimens increases due to the collision and growth of inclusions caused by the RH circulation. After rare earth treatment during the tundish process, the number of micro inclusions with sizes of 1.0~2.5 μm in the specimen steels decreases, while the number of inclusions larger than 5 μm increases. The size distribution of micro inclusions in hot-rolled sheets after rare earth treatment was studied using TEM (transmission electron microscopy). In the specimens without rare earth, the content of micro inclusions (≤1 μm) is 51,458.2/mm2 and the average size is 0.388 μm. In the specimens with rare earth added, the content of micro inclusions (≤1 μm) is 24,230.2/mm2 and the average size is 0.427 μm. Compared to sheet produced by the original process, the iron loss of the 0.35 mm finished experimental sheet is reduced by 0.068 W/kg, and the magnetic induction is increased by 0.007 T. The iron loss of the 0.50 mm finished experimental sheet is reduced by 0.008 W/kg, and the magnetic induction is increased by 0.004 T. After rare earth treatment, the average size of micro inclusions increases and the magnetic properties are obviously improved.

Effect of cooling conditions on the size evolution of typical inclusions in the Al-Ti deoxidised steel

ABSTRACT Confocal laser scanning microscopy was used to perform experiments with various cooling rates for the solidification of Al-Ti deoxidised steel. The effects of cooling rate on the morphology, size distribution of observed with typical inclusions, Al2O3, TiS, and Al2O3-TiS in the steel were investigated. The experimental results demonstrate that the inclusion morphology is significantly influenced by the cooling rate. With an increase in cooling rate, the number of inclusions smaller than 3 μm rises while the number of inclusions bigger than 3 μm continues to fall. The number density of the inclusions increases gradually with the increase of the cooling rate. The nucleation and growth of inclusion were calculated using a combination of kinetics and thermodynamics. It was found that the cooling rate has no influence on the precipitation temperature of inclusions but has slightly influence on the segregation of solute elements during solidification. TiS inclusions can precipitate at the end of solidification while Al2O3 inclusions can precipitate in the liquid phase based on the thermodynamic calculations. As the cooling rate rises, the size of the inclusions decreases gradually and the effect of cooling rate on inclusion decreases.

The effect of non-metallic inclusion morphology on the hydrogen induced cracking (HIC) resistance of L80 steel

The hydrogen induced cracking (HIC) resistance of four (4) L80 casing steels, with different nominal compositions and processing conditions, was determined using the NACE TM0284 HIC test. Microstructural and inclusion characterization of each steel was undertaken using optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The morphology (equivalent diameter, aspect ratio and major length) of inclusions over identical analysis regions were measured for each steel. In total, >15,000 inclusions were characterized. Non-linear models correlating inclusion morphology with the measured values of CLR (crack length ratio) and CTR (crack thickness ratio) were developed. The models show that both CLR and CTR are complex functions of the diameter (equivalent) of oxide-based inclusions and the major length of the manganese sulfide (MnS) stringers. The models show that oxides <10 μm in diameter were found to have negligible effect on HIC resistance (CLR) while oxides >20 μm exhibited a significant and escalating negative impact on HIC resistance comparable to long (>50 μm) MnS stringers.

The Chlamydia trachomatis IncM Protein Interferes with Host Cell Cytokinesis, Centrosome Positioning, and Golgi Distribution and Contributes to the Stability of the Pathogen-Containing Vacuole.

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes ocular and urogenital infections in humans. The ability of C. trachomatis to grow intracellularly in a pathogen-containing vacuole (known as an inclusion) depends on chlamydial effector proteins transported into the host cell by a type III secretion system. Among these effectors, several inclusion membrane proteins (Incs) insert in the vacuolar membrane. Here, we show that human cell lines infected by a C. trachomatis strain deficient for Inc CT288/CTL0540 (renamed IncM) displayed less multinucleation than when infected by IncM-producing strains (wild type or complemented). This indicated that IncM is involved in the ability of Chlamydia to inhibit host cell cytokinesis. The capacity of IncM to induce multinucleation in infected cells was shown to be conserved among its chlamydial homologues and appeared to require its two larger regions predicted to be exposed to the host cell cytosol. C. trachomatis-infected cells also displayed IncM-dependent defects in centrosome positioning, Golgi distribution around the inclusion, and morphology and stability of the inclusion. The altered morphology of inclusions containing IncM-deficient C. trachomatis was further affected by depolymerization of host cell microtubules. This was not observed after depolymerization of microfilaments, and inclusions containing wild-type C. trachomatis did not alter their morphology upon depolymerization of microtubules. Overall, these findings suggest that IncM may exert its effector function by acting directly or indirectly on host cell microtubules.

Gemological and Chemical Characterization of Varicolored Gem-Grade Spinel from Mogok, Myanmar

Spinel is a precious gem with a long history, but people are far less familiar with it. Previous studies on Mogok spinel from Myanmar focused on inclusion analysis, chromogenic mechanism with a single-color gemstone and heat treatment, whereas systematic studies on varicolored gem-grade spinel are lacking. In this study, the gemological and geochemical analysis of four colors of spinel samples from Mogok were carried out for basic gemology, inclusion morphology and identification, spectroscopy and geochemistry. The aim was to explore the occupation of elements of spinels in the crystal structure, as well as the chromogenic mechanism of varicolored spinels and the geological and geodynamic conditions of the formation. Mogok spinel samples are characterized by octahedral negative crystals filled with calcite and chondrodite inclusions, indicating that they are derived from a marble metamorphic-type deposit. The spinel samples of four colors are magnesia–alumina spinel (MgAl2O4). The contents of V and Cr in Mogok spinel are generally high, with a significant high content of Zn being the most characteristic, and trace elements vary greatly. The infrared spectra of spinel samples in different colors are basically similar. According to the UV–Vis spectrum, pink and red samples are mainly colored by Cr and/or V, whereas orange samples are mainly colored by V. Two wide absorption bands in the range 300~600 nm are mainly attributed to the spin-allowed transition and spin-forbidden transition of Cr3+ and/or V3+. The purple samples are mainly colored by Fe and the UV–Vis spectrum is mainly attributed to the spin-forbidden transition of TFe2+. This study is a favorable supplement to the research on Mogok spinels of various colors from multiple perspectives.

Effect of Graphite Morphology on the Thermomechanical Performance of Compacted Graphite Iron

Compacted graphite iron (CGI) has gained significant attention in automotive industry applications thanks to its superior thermomechanical properties and competitive price. Its main fracture mechanism at the microscale—interfacial damage and debonding between graphite inclusions and a metallic matrix—can happen under high-temperature service conditions as a result of a mismatch in the coefficients of thermal expansion between the two phases of CGI. Macroscopic fracture in cast iron components can be initiated by interfacial damage at the microscale under thermomechanical load. This phenomenon was investigated in various composites but still lacks information for CGI, with its complex morphology of graphite inclusions. This research focuses on the effect of this morphology on the thermomechanical performance of CGI under high temperatures. A set of three-dimensional finite-element models was created, with a unit cell containing a single graphite inclusion embedded in a cubic domain of the metallic matrix. Elastoplastic behaviour was assumed for both phases in numerical simulations. The effect of graphite morphology on the thermomechanical performance of CGI was investigated for pure thermal loading, focusing on a high-temperature response of its constituents. The results can provide a deeper understanding of the correlation between graphite morphology and CGI fracture mechanisms under high temperatures.

Modification of Rare Earth Ce on Inclusions in W350 Non-Oriented Silicon Steel

In this paper, the effect of rare earth Ce content on the morphology, composition, type and size distribution of inclusions in W350 non-oriented silicon steel was investigated by means of ICP-MS (inductively coupled plasma mass spectrometry), SEM/EDS (scanning electron microscope-energy Dispersive Spectrometer), and ASPEX (automated SEM/EDS inclusion analysis). The results showed that with the increase of Ce content in the steel, the modification sequence of inclusions was CeAlO3→Ce2O2S→CexSy. The type and size distribution of inclusions in the steel obviously changed with the difference in added Ce content. When the added Ce content in the steel was 10 ppm, 14 ppm, 20 ppm and 30 ppm respectively, the rare earth inclusions were mainly CeAlO3-Ce2O2S. Furthermore, when the added Ce content increased to 60 ppm, the rare earth inclusions were mainly Ce2O2S with a small amount of CeAlO3 contained in part inclusions. When the added Ce content increased continually to 95 ppm, the rare earth inclusions were mainly CexSy-Ce2O2S. The critical Ce content for the conversion between CeAlO3 and Ce2O2S was 41 ppm. To ensure that inclusions transform from CeAlO3 to Ce2O2S, the Ce content in the steel should be greater than 41 ppm. Under the current experimental conditions, it was found that when the Ce content was 20 ppm, the number density and proportion of inclusions in the steel were lower, and their average size was larger. When the added Ce content increased to 95 ppm, the number density of inclusions in the steel significantly increased, which deteriorated the steel cleanliness.

THEINFLUENCE OF MODIFICATION WITH YTTRIUM ON THE STRUCTURE AND PROPERTIES OF CASTINGS OBTAINED FROM THE ЖС6У-ВІ ALLOY RETURN

Purpose. To study the effect of modification of nickel-yttrium ligature with additives on the structure and physical and mechanical properties of ЖС6У-ВІ alloy, smelted using its own technological return in the charge.&#x0D; Research methods. On the УППФ-3М installation with the base crucible, experimental melting of standart technological return of the ЖС6У-ВІ alloy was carried out using high-temperature melt processing.&#x0D; Experimental samples for mechanical tests and determination of stress-rupture strength were cast from the obtained ingots, cut into measured batch blanks and cleaned in a shot blasting drum, using the method of equiaxial crystallization in ceramic molds.&#x0D; When pouring one ceramic mold, the metal melt at a temperature of 1540 °C was modified with a nickel-yttrium ligature of the ІтН1 brand (grain size 2...5 mm) in the amount of 0.136 % of the mass of the charge in a crucible with a holding time of 1 min 15 s ... 1 min. The second block was poured without modification.&#x0D; Cooling of the poured blocks was carried out at the melting site at normal ambient temperature.&#x0D; The samples underwent heat treatment according to ОСТ 1 90126-85: heating to a temperature of 1210 ± 10 °C, holding for 4 hours, cooling in air.&#x0D; The balance of the chemical composition of the experimental alloys was evaluated by the computational and analytical method.&#x0D; The chemical composition of the alloy of experimental variants was determined. The microstructure and mechanical properties at room temperature were studied. Stress-rupture strength tests were performed at 975 °C under a load of 230 MPa.&#x0D; Results. Experimental melting of the charge was carried out, which consisted exclusively of our own technological return of the ЖС6У-ВІ alloy with the use of high-temperature processing of the melt and modification with a nickel-yttrium ligature.&#x0D; The chemical composition, microstructure of the experimental alloy, its mechanical properties at room temperature, and heat resistance indicators were studied.&#x0D; A method of determining the degree of balance of the chemical composition of modern superalloys based on the total content of groups of alloying elements is proposed.&#x0D; Scientific novelty. Calculations carried out in accordance with the proposed method of determining the degree of balance of the chemical composition of the alloy show that for the experimental variants, phase separations may form along the grain boundaries. Studies of the microstructure confirmed the separation of the γ-γ' eutectic phase in the form of a “white” border along the thickened grain boundaries in the metal of the ЖС6У-ВІ alloy sample.&#x0D; According to the calculations of the metal alloying system balance for experimental melts, not only the thickening of the grain boundaries and the separation of the γ-γ' eutectic phase, but also a decrease in mechanical properties and stress-rupture strength can be observed.&#x0D; The application of modification with nickel-yttrium ligature in the amount of 0.136 % in the remelting process with the use of high-temperature processing of the ЖС6У-ВІ alloy return melt allows to ensure the formation of grain boundaries without visible discharges (pollution).&#x0D; It was established that in the metal of the experimental melting with the application of modification with nickel-yttrium ligature, carbides have globular and lamellar morphology. There is no separation of the γ-γ' eutectic phase.&#x0D; The mechanical properties and stress-rupture strength of the metal of the experimental melts with the use of high-temperature processing of the melt of the conditioned return of the ЖС6У-ВІ alloy, both with and without modification by nickel-yttrium ligature, meet the requirements of OST 1 90126-85, but at the same time, they are lower than the properties of the alloy cast with charge refreshment.&#x0D; Practical value. A computational and analytical method of determining the degree of balance of the chemical composition of modern heat-resistant alloys based on the total content of certain groups of alloying elements is proposed.&#x0D; It was established that the modification of nickel-yttrium ligature with additives significantly improves the microstructure of castings obtained from the technological return of the ЖС6У-ВІ alloy and creates conditions for a general improvement in the quality of the material of the responsible castings.&#x0D; The conducted studies show that the use of 0.136 % nickel-yttrium ligature allows to clean grain boundaries, change the morphology of non-metallic inclusions and counteract the segregation of eutectic inclusions in nickel-based superalloys alloys.

Effect of Rare Earth Ce on Inclusions in Q345 Steel

Q345 steel is an important raw material for the production of suspension spring steel and valve spring steel. Improving its comprehensive mechanical properties and fatigue resistance and ensuring the production continuity of Q345 steel is a topic of general concern in the industry. The addition of rare earth can effectively control the number, size, morphology, composition and distribution of inclusions in Q345 steel, which is of great significance for improving the quality of Q345 steel. However, at present, the addition process of rare earth Ce in the production process of 55SiCr spring steel is faced with problems such as low yield and difficult continuous production of Shuikou nodules and blockage. However, adding rare earth slag to refining slag is an effective solution to improve the yield of rare earth Ce. However, there is still a lack of research in this direction in the industry. In order to improve the yield of rare earth Ce, determine the ratio of rare earth refining slag and achieve the best metallurgical effect, it is the main research direction of this project.