Structural Transformations Versus Hard Particles Motion in the Brass Ingots

AbstractA mathematical method for the forecast of the type of structure in the steel static ingot has been recently developed. Currently, the method has been applied to structural zones prediction in the brass ingots obtained by the continuous casting. Both the temperature field and thermal gradient field have been calculated in order to predict mathematically the existence of some structural zones in the solidifying brass ingot. Particularly, the velocity of theliquidusisotherm movement and thermal gradient behavior versus solidification time have been considered. The analysis of the mentioned velocity allows the conclusion that the brass ingots can evince: chilled columnar grains-, (CC), fine columnar grains-, (FC), columnar grains-, (C), equiaxed grains zone, (E), and even the single crystal, (SC), situated axially. The role of the mentioned morphologies is analyzed to decide whether the hard particles existing in the brass ingots can be swallowed or rejected by the solid / liquid (s/l) interface of a given type of the growing grains. It is suggested that the columnar grains push the hard particles to the end of a brass ingot during its continuous casting.

Download Full-text

Some Similarities / Differences between Steel Static and Virtual Brass Static Casting

Archives of Foundry Engineering ◽

10.1515/afe-2017-0020 ◽

2017 ◽

Vol 17 (1) ◽

pp. 109-114

Author(s):

P. Kwapisiński ◽

A. A. Ivanova ◽

B. Kania ◽

W. Wołczyński

Keyword(s):

Heat Transfer ◽

Temperature Field ◽

Thermal Gradient ◽

Gradient Field ◽

Innovative Method ◽

Columnar Grains ◽

Steel Ingots ◽

Equiaxed Grains ◽

Structural Zones ◽

Mathematical Interpretation

Abstract An innovative method for determining the structural zones in the large static steel ingots has been described. It is based on the mathematical interpretation of some functions obtained due to simulation of temperature field and thermal gradient field for solidifying massive ingot. The method is associated with the extrema of an analyzed function and with its points of inflection. Particularly, the CET transformation is predicted as a time-consuming transition from the columnar- into equiaxed structure. The equations dealing with heat transfer balance for the continuous casting are presented and used for the simulation of temperature field in the solidifying virtual static brass ingot. The developed method for the prediction of structural zones formation is applied to determine these zones in the solidifying brass static ingot. Some differences / similarities between structure formation during solidification of the steel static ingot and virtual brass static ingot are studied. The developed method allows to predict the following structural zones: fine columnar grains zone, (FC), columnar grains zone, (C), equiaxed grains zone, (E). The FCCT-transformation and CET-transformation are forecast as sharp transitions of the analyzed structures. Similarities between steel static ingot morphology and that predicted for the virtual brass static ingot are described.

Download Full-text

Numerical Model for Solidification Zones Selection in the Large Ingots

Archives of Foundry Engineering ◽

10.1515/afe-2015-0085 ◽

2015 ◽

Vol 15 (4) ◽

pp. 87-90 ◽

Cited By ~ 2

Author(s):

W. Wołczyński ◽

P. Kwapisiński ◽

B. Kania ◽

W. Wajda ◽

W. Skuza ◽

...

Keyword(s):

Temperature Field ◽

Structure Formation ◽

Thermal Gradient ◽

Steel Ingot ◽

Columnar Structure ◽

Equiaxed Structure ◽

Columnar Grains ◽

Branched Structure ◽

Equiaxed Grains ◽

Structural Zones

Abstract A vertical cut at the mid-depth of the 15-ton forging steel ingot has been performed by curtesy of the CELSA - Huta Ostrowiec plant. Some metallographic studies were able to reveal not only the chilled undersized grains under the ingot surface but columnar grains and large equiaxed grains as well. Additionally, the structural zone within which the competition between columnar and equiaxed structure formation was confirmed by metallography study, was also revealed. Therefore, it seemed justified to reproduce some of the observed structural zones by means of numerical calculation of the temperature field. The formation of the chilled grains zone is the result of unconstrained rapid solidification and was not subject of simulation. Contrary to the equiaxed structure formation, the columnar structure or columnar branched structure formation occurs under steep thermal gradient. Thus, the performed simulation is able to separate both discussed structural zones and indicate their localization along the ingot radius as well as their appearance in term of solidification time.

Download Full-text

Structural Zones in Large Static Ingot. Forecasts for Continuously Cast Brass Ingot

Archives of Foundry Engineering ◽

10.1515/afe-2016-0067 ◽

2016 ◽

Vol 16 (3) ◽

pp. 141-146 ◽

Cited By ~ 1

Author(s):

W. Wołczyński ◽

Z. Lipnicki ◽

A.W. Bydałek ◽

A.A. Ivanova

Keyword(s):

Temperature Field ◽

Steel Ingot ◽

Columnar Structure ◽

Operating Point ◽

Gradient Field ◽

Crystal Formation ◽

Ingot Axis ◽

Columnar Grains ◽

Continuously Cast ◽

Equiaxed Grains

Abstract Some metallographic studies performed on the basis of the massive forging steel static ingot, on its cross-section, allowed to reveal the following morphological zones: a/ columnar grains (treated as the austenite single crystals), b/ columnar into equiaxed grains transformation, c/ equiaxed grains at the ingot axis. These zones are reproduced theoretically by the numerical simulation. The simulation was based on the calculation of both temperature field in the solidifying large steel ingot and thermal gradient field obtained for the same boundary conditions. The detailed analysis of the velocity of the liquidus isotherm movement shows that the zone of columnar grains begins to disappear at the first point of inflection and the equiaxed grains are formed exclusively at the second point of inflection of the analyzed curve. In the case of the continuously cast brass ingots three different morphologies are revealed: a/ columnar structure, b/ columnar and equiaxed structure with the CET, and c/ columnar structure with the single crystal formation at the ingot axis. Some forecasts of the temperature field are proposed for these three revealed morphologies. An analysis / forecast of the behavior of the operating point in the mold is delivered for the continuously cast ingot. A characteristic delay between some points of breakage of the temperature profile recorded at the operating point and analogous phenomena in the solidifying alloy is postulated.

Download Full-text

Study of structure and mechanical properties of long-length metalware from D19-alloy produced by continuous casting and deformation of metal in solid-liquid state

Perspektivnye Materialy ◽

10.30791/1028-978x-2019-9-75-82 ◽

2019 ◽

pp. 75-82

Author(s):

A. M. Sergeeva ◽

◽

N. S. Lovizin ◽

A. A. Sosnin ◽

◽

...

Keyword(s):

Mechanical Properties ◽

Continuous Casting ◽

Liquid State ◽

Solid Liquid

Download Full-text

Soil Chemical Pollution and Aggressive Pathologies

Revista de Chimie ◽

10.37358/rc.18.8.6515 ◽

2018 ◽

Vol 69 (8) ◽

pp. 2278-2282

Author(s):

Stelian Ioan Morariu ◽

Letitia Doina Duceac ◽

Alina Costina Luca ◽

Florina Popescu ◽

Liliana Pavel ◽

...

Keyword(s):

Health Care Professionals ◽

Scientific Progress ◽

Volcanic Eruptions ◽

Chemical Pollution ◽

Optimal Parameters ◽

Chemical Pollutants ◽

Wide Range ◽

Health Physician ◽

Solid Liquid

Maintaining the soil in optimal parameters is vital for mankind, given its essential role in providing the alimentary base, as well as its extremely slow formation and regeneration (hundreds or thousands of years). The direct and indirect pollution of the soil and especially its chemical pollution represent a corollary of other types of pollution, given that it is produced by solid, liquid and gaseous residues. It may be involved in a wide range of diseases (respiratory, cardiovascular, digestive, renal, haematological, osteoarticular, neurological) of allergic, infectious, degenerative or neoplastic nature, from infancy to the old age. Although there are natural causes of soil pollution (e.g. volcanic eruptions), most pollutants come from human activities, which are the most incriminated in its pollution, degradation and erosion at an accelerated pace. The growing concern of all nations for the adoption of measures to limit the chemical pollution of the soil is partially found so far in viable and effective solutions intended to combat soil contamination and degradation and ensure its restoration. Chemical industrialization leads to technical and scientific progress, but at the same time it can develop related pathologies, which means that the role of the occupational health physician is essential in ensuring prophylaxis and the early detection of occupational diseases. Besides that, the role of the pediatrician is equally precious for the detection of specific diseases caused by chemical pollutants to children, because they will develop into adults with pathological stigma.The chemical pollution of the soil is a major challenge for ecologists, given that it is an important risk factor for many types of afflictions. It requires maximum attention from civil society, health care professionals and government institutions. The specialist in occupational medicine, as well as the pediatrician bear an essential responsibility in both, prevention and treatment.

Download Full-text

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

Water Science & Technology ◽

10.2166/wst.1999.0336 ◽

1999 ◽

Vol 39 (7) ◽

pp. 91-98 ◽

Cited By ~ 3

Author(s):

Ryan N. Jordan ◽

Eric P. Nichols ◽

Alfred B. Cunningham

Keyword(s):

Mass Transfer ◽

Cell Membrane ◽

Substrate Concentration ◽

Water Interface ◽

Industrial Systems ◽

Solid Liquid Interface ◽

Solid Liquid ◽

Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

Download Full-text

Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽

10.3390/fluids6050178 ◽

2021 ◽

Vol 6 (5) ◽

pp. 178

Author(s):

Souhail Maazioui ◽

Abderrahim Maazouz ◽

Fayssal Benkhaldoun ◽

Driss Ouazar ◽

Khalid Lamnawar

Keyword(s):

Flow Behavior ◽

Continuous Phase ◽

Raw Material ◽

Rheological Characterization ◽

Phosphate Ore ◽

Insoluble Particles ◽

Experimental Protocols ◽

Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

Download Full-text

Research on Ethanol Production by Biological Fermentation of Potato Pulp

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.805-806.281 ◽

2013 ◽

Vol 805-806 ◽

pp. 281-285

Author(s):

Zhong Xu

Keyword(s):

Chemical Composition ◽

Ethanol Production ◽

Production Rate ◽

Liquid Ratio ◽

Fermentation Time ◽

Potato Pulp ◽

Fermentation Temperature ◽

Ethanol Production Rate ◽

Solid Liquid

Bioconversion of potato pulp to fuel ethanol, analysing the potato pulp chemical composition and determining the potato pulp in the role of microorganism produce ethanol under the best conditions is the major research. An analysis of the chemical composition of potato pulp showed that : the basic ingredients are Protein (9.72%), Starch (25.52%), Cellulose (17.90%). The effects of ethanol production rate of solid-liquid ratio, fermentation temperature, inoculumconcertration, fermentation time. The results showed that: the best conditions producting ethanol from potato pulp obtained by single factor experiments are: solid-liquid ratio: 1:15, fermentation temperature: 35°C, inoculumconcertration: 3mL, fermentation time: 20h. Under this occasion, the ethanol production rate was 0.183mL·g-1.

Download Full-text