Modifying and Micro-Alloying Effect on Carbon Steels Microstructure

2021 ◽  
Vol 316 ◽  
pp. 359-363
Author(s):  
Ainagul Toleuova ◽  
Gulnaz Musina ◽  
Saule Kaldybayeva
Keyword(s):  
Nonmetallic Inclusions ◽  
Cast Steel ◽  
High Surface ◽  
Carbon Steels ◽  
Metallographic Analysis ◽  
Alloying Effect ◽  
Metallic Inclusions ◽  
The Matrix ◽  
Resistance To Brittle Fracture ◽  
High Surface Activity

Small additives of elements exhibiting high chemical activity with respect to iron and impurities, included in its composition, have a complex effect on the structure and properties of steel. Moreover, as a result of the modifying and refining effect of micro-additives, the amount, dispersion and morphology of nonmetallic inclusions change, and when alloying the matrix, hardenability, uniformity of structure and resistance to brittle fracture of steels change, too. The article presents a metallographic analysis of carbon steel deoxidized by a complex Са – Ва alloy. Deoxidation of steel using the complex Са – Ва alloy allows significant reducing the content of nonmetallic inclusions, modifying residual nonmetallic inclusions into favorable complexes with their uniform distribution in the volume of steel, and significant increasing the mechanical properties of steel. The high surface activity of barium makes it possible to consider barium as a rather effective modifier. The use of barium in alloys leads to grinding of non-metallic inclusions, homogenization of liquid metal, lowering the liquidus temperature, grinding of primary grains of cast steel, and increasing technological ductility.

Nonmetallic inclusions in rails made of electro-steel alloyed with chromium

2020 ◽  
Vol 62 (12) ◽  
pp. 936-942 ◽  
Author(s):  
A. A. Umanskii ◽  
A. V. Golovatenko ◽  
A. S. Simachev
Keyword(s):  
Hot Deformation ◽  
Ultrasonic Testing ◽  
Nonmetallic Inclusions ◽  
Relative Concentration ◽  
Metallographic Analysis ◽  
High Ductility ◽  
High Concentration ◽  
Metallic Inclusions ◽  
Significant Concentration

Type, relative concentration and size of most characteristic non-metallic inclusions for the elements of rails (head, web) from electro-steel of E79KhF and E90KhАF grades were determined on the basis of metallographic (with a microscope “OLYMPUS GX-51”) and spectral (using spectrometer “ARL iSpark” method “Spark-DAT”) analyses. It was found that the highest relative concentration of manganese sulfides (MnS) is 30.8 – 43.4 ppm. At the same time, 60 – 100 % of inclusions of this type are of small sizes (less than 4 μm), and it does not allow them to be detected using standard metallographic analysis with 100-fold magnification. The revealed high relative concentration of sulfide inclusions directly correlates with the established positive sulfur liquation in considered rail elements, which is up to 40 %. Despite the high concentration of manganese sulfides, their influence on the quality of rails can be considered not dangerous, taking into account their high ductility during hot deformation and the established prevalence of inclusions of this type with small size (less than 4 μm). Among inclusions of a silicate type, SiO2 inclusions (3.4 – 14.9 ppm) have a significant concentration. All detected inclusions of this type have a size not exceeding 4 μm. It was found that the concentration of complex inclusions containing alumina (Al2O3 – CaO – MgO, Al2O3 – CaO – MgO – CaS, Al2O3 – CaO, Al2O3 – MgO) is insignificant: in total it does not exceed 3.1 ppm and 1.6 ppm for individual types. The concentration of corundum (Al2O3) is also insignificant and does not exceed 0.3 ppm. In this case, alumina inclusions of small size (less than 6 μm) prevail. Due to the low contamination (taking into account the relative concentration and size of inclusions) with non-plastic silicate and alumina non-metallic inclusions, their influence on the quality of the rails was not significant. It is confirmed by the absence of defects detected during ultrasonic testing.

scholarly journals CONTENT MODIFICATION OF DIFFERENT TYPES OF NONMETALLIC INCLUSIONS DURING LOW-CARBON IF STEEL LADLE TREATMENT

2019 ◽  
Vol 62 (5) ◽  
pp. 345-352 ◽  
Author(s):  
D. V. Gorkusha ◽  
K. V. Grigorovich ◽  
A. V. Karasev ◽  
O. A. Komolova
Keyword(s):  
Nonmetallic Inclusions ◽  
Ladle Treatment ◽  
Gas Analysis ◽  
Metallographic Analysis ◽  
Steel Ladle ◽  
Interstitial Free ◽  
If Steel ◽  
Low Carbon ◽  
Metallic Inclusions ◽  
Fractional Gas Analysis

Development of advanced materials for the automotive industry allows us to produce a lighter body without losing strength characteristics of the structure. It became possible by the creation and subsequent introduction into the production of such steel grades as IF (Interstitial Free) – steel with no interstitial solute atoms to strain the solid iron lattice and IF-BH (Bake Hardening) – steel with hardening during hot drying. The article provides a brief overview of the history of the emergence of IF steel and the current situation in the production of it in Russia. One of the quality criteria for steels of IF grades is purity of the metal by non-metallic inclusions (NMI), which negatively affect the plastic properties of the material, lead to the formation of surface defects of flat rolled products and reduce the manufacturability due to a decrease in the casting speed of steel, as they cause overgrowing of steel casting nozzles. The article presents investigation results of the content, composition, size and morphology of non-metallic inclusions (NMI) in the metal samples taken at all stages of ladle treatment and casting of IF steel grade production using quantitative metallographic analysis, electrochemical dissolution (ED) followed by X-ray microanalysis of isolated inclusions, Auger electron spectroscopy and fractional gas analysis (FGA). As a result of the analysis of inclusions in the studied samples using a scanning electron microscope, according to morphological features, five characteristic types of inclusions were identified, which reduce the performance properties and strength cha racteristics of the materials produced from them. Results of the analysis of nonmetallic inclusions in metal samples obtained by the ED method are in good agreement with the results of the determination of oxide nonmetallic inclusions by the FGA method. The method of fractional gas analysis shows the dynamics of changes in the content of various types of oxide nonmetallic inclusions during the secondary (ladle) treatment of steel. It is shown that application of the FGA method allows to make analysis of causes of the harmful NMI formation in the metal and to correct operations at ladle treatment.

scholarly journals Wear Resistance of TiC Reinforced Cast Steel Matrix Composite

2017 ◽  
Vol 17 (1) ◽  
pp. 143-146 ◽  
Author(s):  
S. Sobula ◽  
E. Olejnik ◽  
T. Tokarski
Keyword(s):  
Wear Resistance ◽  
Matrix Composite ◽  
Base Alloy ◽  
Cast Steel ◽  
Composite Layer ◽  
Wear Loss ◽  
Steel Matrix ◽  
Soft Matrix ◽  
Base Steel ◽  
The Matrix

Abstract Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g for base steel.

Metallographic analysis of dynamics of dendrite roughening in carbon steels

2007 ◽  
Vol 37 (1) ◽  
pp. 7-10
Author(s):  
V. A. Il’inskii ◽  
L. V. Kostyleva ◽  
S. S. Goremykina
Keyword(s):  
Carbon Steels ◽  
Metallographic Analysis ◽  
Analysis Of Dynamics

Production and Properties of Biosurfactants from a Newly Isolated Pseudomonas fluorescens HW-6 Growing on Hexadecane

2006 ◽  
Vol 61 (7-8) ◽  
pp. 553-559 ◽  
Author(s):  
Evgenia Vasileva-Tonkova ◽  
Danka Galabova ◽  
Emilia Stoimenova ◽  
Zdravko Lalchev
Keyword(s):  
Pseudomonas Fluorescens ◽  
Industrial Wastewater ◽  
High Surface ◽  
Emulsifying Properties ◽  
Effective Surface ◽  
Mineral Oils ◽  
Air Water Interface ◽  
Polluted Sites ◽  
High Concentrations ◽  
High Surface Activity

The newly isolated from industrial wastewater Pseudomonas fluorescens strain HW-6 produced glycolipid biosurfactants at high concentrations (1.4-2.0 g l-1) when grown on hexadecane as a sole carbon source. Biosurfactants decreased the surface tension of the air/ water interface by 35 mN m-1 and possessed a low critical micelle concentration value of 20 mg l-1, which indicated high surface activity. They efficiently emulsified aromatic hydrocarbons, kerosene, n-paraffins and mineral oils. Biosurfactant production contributed to a significant increase in cell hydrophobicity correlated with an increased growth of the strain on hexadecane. The results suggested that the newly isolated strain of Ps. fluorescens and produced glycolipid biosurfactants with effective surface and emulsifying properties are very promising and could find application for bioremediation of hydrocarbon-polluted sites.

scholarly journals A novel biosensor based on Blu-ray disc coating film for determination of total amino acid content in tea leaves

RSC Advances ◽  
2021 ◽  
Vol 11 (63) ◽  
pp. 39666-39671
Author(s):  
Lanling Chu ◽  
Yunzheng Wang ◽  
Yu Zhou ◽  
Xuejun Kang
Keyword(s):  
Low Cost ◽  
High Surface ◽  
Amino Acid Content ◽  
Substrate Material ◽  
Total Amino Acid ◽  
Coating Film ◽  
The Novel ◽  
Total Amino Acid Content ◽  
High Surface Activity

The novel biosensor substrate material based on a simple BD coating film displayed preferable merits with high surface activity, low cost, easy making, easy using, and extensive application prospect.

scholarly journals Interfacial Engineering of Graphene Nanosheets at MgO Particles for Thermal Conductivity Enhancement of Polymer Composites

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 798 ◽  
Author(s):  
Wu Pan ◽  
Miaomiao He ◽  
Li Zhang ◽  
Yi Hou ◽  
Chen Chen
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Polymer Composites ◽  
Graphene Nanosheets ◽  
High Surface ◽  
Precipitation Method ◽  
Conductivity Enhancement ◽  
Interfacial Engineering ◽  
The Matrix ◽  
Thermally Conducting

An important task in facilitating the development of thermally conducting graphene/polymer nanocomposites is to suppress the intrinsically strong intersheet π-π stacking of graphene, and thereby to improve the exfoliation and dispersion of graphene in the matrix. Here, a pre-programmed intercalation approach to realize the in situ growth of graphene nanosheets at the inorganic template is demonstrated. Specifically, microsized MgO granules with controlled geometrical size were synthesized using a precipitation method, allowing the simultaneous realization of high surface activity. In the presence of a carbon and nitrogen source, the MgO granules were ready to induce the formation of graphene nanosheets (G@MgO), which allowed for the creation of tenacious linkages between graphene and template. More importantly, the incorporation of G@MgO into polymer composites largely pushed up the thermal conductivity, climbing from 0.39 W/m∙K for pristine polyethylene to 8.64 W/m∙K for polyethylene/G@MgO (60/40). This was accompanied by the simultaneous promotion of mechanical properties (tensile strength of around 30 MPa until 40 wt % addition of G@MgO), in contrast to the noteworthy decline of tensile strength for MgO-filled composites with over 20 wt.% fillers.

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