scholarly journals Non-metallic Inclusions in Different Ferroalloys and Their Effect on the Steel Quality: A Review

2021 ◽  
Author(s):  
Yong Wang ◽  
Andrey Karasev ◽  
Joo Hyun Park ◽  
Pär G. Jönsson
Keyword(s):  
Steel Quality ◽  
Al Content ◽  
Large Size ◽  
Metallic Inclusions ◽  
Steel Cleanliness ◽  
Complex Ferroalloys ◽  
Final Steel ◽  
High Al Content ◽  
Steel Properties

AbstractFerroalloys have become increasingly important due to their indispensable role in steelmaking. In addition, the demand for improved steel qualities has increased considerably, which in turn highlights the quality of ferroalloys. This is due to the fact that the impurities in ferroalloys directly and significantly influence the quality of steel products. To gain a better understanding of the main trace elements and inclusions in ferroalloys (such as FeSi, FeMn, SiMn, FeTi, FeCr, FeMo, FeNb, FeV, FeB, some complex ferroalloys) and their behaviours in steel melt after the additions of these ferroalloys, information from a large number of previous results on this topic was extensively reviewed in this work. The applications of different ferroalloys and their production trends were discussed. In addition, the effects of some trace element impurities from ferroalloys on the inclusion characteristics in steel were also discussed. The possible harmful inclusions in different ferroalloys were identified. Overall, the results showed that the inclusions present in ferroalloys had the following influence on the final steel cleanliness: (1) MnO, MnS and MnO–SiO2–MnS inclusions from FeMn and SiMn alloys have a temporary influence on the steel quality; (2) the effect of large size SiO2 inclusions (up to 200 μm) in FeSi and FeMo alloys on the steel cleanliness is not fully understood. The effect of Al, Ca contents should be considered before the addition of FeSi alloys. In addition, Al2O3 inclusions and relatively high Al content are commonly found in FeTi, FeNb and FeV alloys due to their production process. This information should be paid more attention to when these ferroalloys are added to steel; (3) except for the existing inclusions in these alloys, the Ti-rich, Nb-rich, V-rich carbides and nitrides, which have important effects on the steel properties also should be studied further; and (4) specific alloys containing REM oxides, Cr–C–N, Cr–Mn–O, Al2O3, Al–Ti–O, TiS and Ti(C, N) have not been studied enough to enable a judgement on their influence on the steel cleanliness. Finally, some suggestions were given for further studies for the development of ferroalloy productions.

scholarly journals Tool Steel Quality And Surface Finishing of Plastic Molds

Exacta ◽  
2011 ◽  
Vol 8 (3) ◽  
pp. 307-318 ◽  
Author(s):  
Rafael Agnelli Mesquita ◽  
Reinhold S. E. Schneider
Keyword(s):  
Tool Steel ◽  
Surface Finishing ◽  
Injection Molding Process ◽  
Mold Surface ◽  
Molding Process ◽  
Steel Quality ◽  
Metallic Inclusions ◽  
Plastic Industry ◽  
Constant Growth

Plastic industry is today in a constant growth, demanding several products from other segments, which includes the plastic molds, mainly used in the injection molding process. Considering all the requirements of plastic molds, the surface finishing is of special interest, as the injected plastic part is able to reproduce any details (and also defects) from the mold surface. Therefore, several aspects on mold finishing are important, mainly related to manufacturing conditions – machining, grinding, polishing and texturing, and also related to the tool steel quality, in relation to microstructure homogeneity and non-metallic inclusions (cleanliness). The present paper is then focused on this interrelationship between steel quality and manufacturing process, which are both related to the final quality of plastic mold surfaces. Examples are discussed in terms of surface finishing of plastic molds and the properties or the microstructure of mold steels.

scholarly journals Tool Steel Quality And Surface Finishing of Plastic Molds DOI: 10.5585/exacta.v8i3.2442

Exacta ◽  
2011 ◽  
Vol 8 (3) ◽  
pp. 307-318
Author(s):  
Rafael Agnelli Mesquita ◽  
Reinhold S. E. Schneider
Keyword(s):  
Tool Steel ◽  
Surface Finishing ◽  
Injection Molding Process ◽  
Mold Surface ◽  
Molding Process ◽  
Steel Quality ◽  
Metallic Inclusions ◽  
Plastic Industry ◽  
Constant Growth

Plastic industry is today in a constant growth, demanding several products from other segments, which includes the plastic molds, mainly used in the injection molding process. Considering all the requirements of plastic molds, the surface finishing is of special interest, as the injected plastic part is able to reproduce any details (and also defects) from the mold surface. Therefore, several aspects on mold finishing are important, mainly related to manufacturing conditions – machining, grinding, polishing and texturing, and also related to the tool steel quality, in relation to microstructure homogeneity and non-metallic inclusions (cleanliness). The present paper is then focused on this interrelationship between steel quality and manufacturing process, which are both related to the final quality of plastic mold surfaces. Examples are discussed in terms of surface finishing of plastic molds and the properties or the microstructure of mold steels.

Allocating nodes to hubs for minimizing the hubs processing resources: A case study

2019 ◽  
Vol 53 (3) ◽  
pp. 807-827
Author(s):  
Ali Balma ◽  
Mehdi Mrad
Keyword(s):  
Telecommunication Network ◽  
Real Life ◽  
Optimal Solutions ◽  
Total Flow ◽  
Nonlinear Formulation ◽  
Large Size ◽  
Processing Resources ◽  
Reformulation Linearization

This paper addresses the problem of allocating the terminal nodes to the hub nodes in a telecommunication network. Since the flow processing induces some undesirable delay, the objective is to minimize the total flow processed by the hubs. This study focuses on a real life network of the tunisian operator Tunisie Telecom whose operations managers are concerned by the quality of service. We provide three compact formulations that give optimal solutions for networks of large size. In particular, the last two are obtained by applying the Reformulation-Linearization Technique to a nonlinear formulation of the problem. The latter formulation derived within this approach is the most computationally effective, as pointed out by the computational experiments conducted on the real life network of Tunisie Telecom with 110 nodes and 5 hubs. Finally, we discuss and compare between the single allocation and double allocation configurations.

Research on trajectory planning of non-developable surface for automated tape placement processing of composite

2017 ◽  
Vol 24 (6) ◽  
pp. 929-936
Author(s):  
Lin Liu ◽  
Jun Xiao ◽  
Yong Li
Keyword(s):  
Trajectory Planning ◽  
Local Stress ◽  
Developable Surface ◽  
Software Environment ◽  
Quantitative Characterization ◽  
Large Size ◽  
Variable Step ◽  
The Cost ◽  
Wing Panel

AbstractTape placement manufacturing process, as one of the automated forming technologies for composite material, not only substantially improves the productivity of composite component and reduces the cost of production significantly but also raises the reliability and stability of composite structure. Automated tape placement technology is mainly applied for manufacturing the fuselage and wing panel of airplane characterized by small curvature and large size. For these kinds of structural components with a non-developable surface, trajectory planning by “natural path” method could reduce the internal stress and improve the quality of composite products to a certain extent but not be optimized by quantitative characterization. On the basis of preliminary work, the theoretical model of “unnatural degree” (UD) is introduced in the first step, which could characterize the tensile and shear strain of the laying tape quantitatively. Secondly, by adjusting the iterative step and laying direction to diminish the UD, local stress could be softened in order to optimize the laying track. Ultimately, the simulation model of the non-developable surface is established under the Matlab software environment, and the “variable step-angle” algorithm is adopted to verify the adjustment effect of the tape-laying track.

Effect on Position of Electromagnetic Stirring on Inclusion Behaviors in Billet

2013 ◽  
Vol 805-806 ◽  
pp. 1716-1719 ◽  
Author(s):  
Gui Fang Zhang ◽  
Yue Hua Ding ◽  
Zhe Shi
Keyword(s):  
Liquid Steel ◽  
Electrical Current ◽  
Medium Carbon Steel ◽  
Electromagnetic Stirring ◽  
Cast Billet ◽  
Inclusion Removal ◽  
Optimum Position ◽  
Steel Cleanliness ◽  
Plant Trials

A considerable number of research works have been carried out to study the effects of electric current and frequency of Electromagnetic Stirring (EMS) on the quality of cast steels, but there are only a few studies available addressing the effects of EMS location on inclusion removal and steel cleanliness An ideal position of EMS will improve inclusion floatation and separation from liquid steel. However, inappropriate installation will lead to the entrapment of the slag into liquid steel, and impact the quality of cast billet. The current applied for these plant trials was 300A at a frequency of 3Hz,positions form axial centers of EMS to the top of the mold were 450mm, 510mm and 690mm respectively . 130 billets of medium carbon steel were produced and samples were taken for spectral analysis to study the effects of installation location of EMS on steel cleanliness. The experimental results show that the optimum position of EMS should be placed 510mm from the top end of the copper mold when the electrical current is 300A at frequency of 3 Hz. The three parameters of placement of EMS in paper were obtained from the simulation results, and this paper focused mainly on the effect EMS position on inclusion behaviors in billet.

EXPERIENCE OF PLANTING LARGE SIZE CONIFEROUS WOODY SPECIES IN THE SPRING-SUMMER PERIOD ON THE KOLA NORTH

2021 ◽  
Vol 21 (3) ◽  
pp. 57-70
Author(s):  
E.A. Svyatkovskaya ◽  
◽  
N.V. Saltan ◽  
E.P. Rybalka ◽  
N.N. Trostenyuk ◽  
...  
Keyword(s):  
Root System ◽  
Picea Glauca ◽  
Polar Region ◽  
Woody Species ◽  
Larix Sibirica ◽  
Morphometric Parameters ◽  
Summer Period ◽  
Large Size ◽  
Urban Conditions

The first experience of transplanting large-sized coniferous dendrointroducents (Picea glauca (Moench) Voss, Larix sibirica Ledeb.) in the spring-summer period without preliminary prepara-tion of the root system in the urban conditions of the Polar region was presented. Four specimens of middle-aged plants of both species were selected. The transplant was carried out with the max-imum use of mechanized equipment, which ensures good preservation of the lump and the tree it-self. There were four mutually related stages of work (preparatory, digging out plants, transporta-tion, planting), the quality of which depends on the success of plant survival. A brief description of the decorative qualities, morphometric parameters and the state of the experimental plants has been given. It has shown that due to the peculiarities of the soil and the location of the root system in coniferous introduced species, a clod of earth should be at least 60 cm thick, with a diameter of 110 to 130 cm. The main agrotechnical methods for the creation and care of plantings from large-sized plants were given.

a-Si TFT Technologies for AM-LCDS

1994 ◽  
Vol 345 ◽  
Author(s):  
Nobuki Ibaraki
Keyword(s):  
Implantation Technique ◽  
Picture Quality ◽  
Large Area ◽  
Aperture Ratio ◽  
Large Size ◽  
Ion Doping ◽  
Doping Technique ◽  
Future Technologies ◽  
Improved Characteristics

AbstractA technical trend for a-Si TFTs is their application to large-size, high-pixel density AMLCDs such as XGA, EWS, and HDTV. In order to realize these LCDs, the TFT device characteristics must be improved. Future technologies, which will be necessary to fabricate TFTs with improved characteristics are as follows,(1) Fully self-aligned TFT technology: A SA-TFT structure reduces the feedthrough voltage caused by parasitic capacitance due to gate/source overlap. This results in an improved picture quality and a higher aperture ratio. Fabrication of such a structure would require ion doping technology.(2) Ion doping technology: This non-mass-separated implantation technique has large area doping capability and much higher doping speed compared to conventional ion implantation technique. The major problems with the ion doping technique is the implantation of unwanted species which deteriorate the quality of source/drain and channel regions of TFTs.

Dielectric properties of anodized Al-Ta alloy films with high Al content

1975 ◽  
Vol 27 (1) ◽  
pp. 111-121 ◽  
Author(s):  
A. Schauer ◽  
M. Roschy ◽  
W. Juergens
Keyword(s):  
Dielectric Properties ◽  
Alloy Films ◽  
Al Content ◽  
High Al Content

scholarly journals Growth and Characterization of Epsomite Single Crystals Doped with KCl from low Temperature Aqueous Solutions

1970 ◽  
Vol 33 (1) ◽  
pp. 47-54 ◽  
Author(s):  
S Ferdous ◽  
J Podder
Keyword(s):  
Aqueous Solutions ◽  
Single Crystals ◽  
Optical Quality ◽  
Dielectric Studies ◽  
Slow Cooling ◽  
Large Size ◽  
Isothermal Evaporation ◽  
Academy Of Sciences

Highly transparent and well faceted large size epsomite single crystals have been grown in pure form and doped with KCl from aqueous solutions by slow cooling and isothermal evaporation method. The optical quality of the epsomite improves on doping by KCl. Mass growth rates were found to increase with doping of lower concentrations of KCl and then decreases with the higher concentration of KCl. KCl doped epsomite crystal reveals that structures are slightly distorted due to adsorption of Cl- ion into the crystal lattice. DC conductivity along the growth axis for all of the grown crystals increases with temperature in the range of 25 to 70ºC and also increases with the KCl concentration. Dielectric constant is found to be almost independent of frequency up to range of 106Hz. The dielectric studies show the suitability of these grown crystals for optoelectronic applications. DOI: 10.3329/jbas.v33i1.2949 Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 47-54, 2009

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