scholarly journals Experimental casting of forging ingots from model material

2018 ◽  
Vol 157 ◽  
pp. 05017
Author(s):  
Ján Moravec ◽  
Peter Kopas ◽  
Lenka Jakubovičová ◽  
Bohuš Leitner
Keyword(s):  
Liquid Phase ◽  
Laboratory Test ◽  
Ingot Mold ◽  
Mold Wall ◽  
Silicone Oil ◽  
Solidification Process ◽  
Model Material ◽  
Melt Flow Rate ◽  
Linear Flow ◽  
Naked Eye

The paper describes the process of casting ingots from the model material into a special mold made for these tests. The material was chosen stearin, which proved to be suitable for this type of laboratory test. During the solidification process of the ingot model under laboratory conditions, it was observed how gradually the layer formed on the contour of the casting. Gradual cooling of the ingot resulted in a decrease in the volume of the liquid phase in his body. The fog is readily observable by the naked eye and this is manifested by the formation of a gap between the ingot mold wall and the ingot body. A silicone oil has been used as a separating melt separating layer and the wall of the ingot that has reliably fulfilled this task. Casting was done in two ways, with a standing and lagging mold. The process of filling the cavity itself was to create conditions for the linear flow of the melt. Observation of the ingot after its solidification confirmed the fact that the filling of the cavity proceeded under such conditions in terms of the melt flow rate.

Solidification of Al-Pb Alloy under the Effect of Micro-Alloying Element Ti and C

2016 ◽  
Vol 879 ◽  
pp. 2439-2443 ◽  
Author(s):  
Qian Sun ◽  
Hong Xiang Jiang ◽  
Jiu Zhou Zhao
Keyword(s):  
Phase Transformation ◽  
Liquid Phase ◽  
Microstructure Evolution ◽  
Solidification Process ◽  
Miscibility Gap ◽  
Kinetic Behavior ◽  
Number Density ◽  
Alloying Element ◽  
Refinement Efficiency ◽  
Line Temperature

Experiments were carried to investigate the effect of TiC on the solidification process and microstructure of Al-Pb alloys. It is demonstrated that TiC particles are effective inoculants for the nucleation of the Pb-rich droplets during cooling an Al-Pb alloy in the miscibility gap. A model describing the kinetic behavior of TiC particles in the melt and the liquid-liquid decomposition of Al-Pb was developed. The dissolution, coarsening and precipitation processes of TiC particles as well as the microstructure evolution during the liquid-liquid phase transformation of an Al-Pb alloy were calculated. The numerical results indicate that what determines the refinement efficiency of TiC particles on the Pb-rich droplets/particles is the number density of TiC particles in the melt cooled to the binodal line temperature of the Al-Pb alloy. If the number density of TiC particles in the melt before the beginning of the liquid-liquid decomposition is high enough, the addition of TiC causes a refinement of the Pb-rich droplets/particles and promotes the formation of Al-Pb alloys with a well dispersed microstructure.

Simulations of the Effects of Mold Properties on Directional Solidification

2013 ◽  
Author(s):  
Mark A. Lauer ◽  
David R. Poirier ◽  
Robert G. Erdmann ◽  
Luke Johnson ◽  
Surendra N. Tewari
Keyword(s):  
Finite Element ◽  
Thermal Properties ◽  
Mushy Zone ◽  
Phase Change ◽  
Directional Solidification ◽  
Cross Section ◽  
Cross Sections ◽  
Mold Wall ◽  
Solidification Process ◽  
Thermosolutal Convection

The mold geometry and its thermal properties greatly influence the solidification process. Finite element simulations of directional solidification in various molds are presented. These simulations were performed using volume averaged properties in the mushy zone in order to model the convection, transport of solute and energy, and phase change occurring during solidification. These simulations show the interactions of the mold and alloy with the resultant solidification phenomena, including steepling. Mold geometries can cause macrosegregation because of shrinkage flows, by interrupting the development of the mushy zone, and by causing or influencing thermosolutal convection. Mold materials with different thermal properties result in different macrosegregation patterns even for the same geometries. Changes in cross section and the thermal properties of the mold also affect the gradients and solidification rates obtained in the alloy, as opposed to those measured on the mold wall. Simulations are compared qualitatively to a verification experiment of directionally solidifying a hypoeutectic Al-7wt%Si alloy in a mold with changing cross sections.

The Mathematical Model Applied to Solidify and Segregation of Ledeburite Tool Steel Ingots

2017 ◽  
Vol 15 (12) ◽  
pp. 28-31
Author(s):  
Vasile Bratu ◽  
Ileana Nicoleta Popescu
Keyword(s):  
Ingot Mold ◽  
Solidification Process ◽  
Height Ratio ◽  
Fluid Equation ◽  
Steel Type ◽  
Solid Diffusion ◽  
Steel Ingots ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Mathematical Model

Abstract In order to determine the optimum geometry of the ingot mold format (the format of ingot mold with a diameter per height ratio H / D <3 and the conicity of minimum 7%) was analyzed by mathematical modeling of solidification and segregation of the carbon and sulfur in it.It was considered 205Cr115 steel type (according with , STAS 3611 - Romanian stardandization) and known also as X210Cr12 steel type (according with European standard). It has been considered an element of volume of coordinates x, y, z in the solidifying ingot and have made the following assumptions: (i) the equilibrium distribution ratio K, is applied to the solid-liquid interface; (ii) solid diffusion is negligible during solidification; and (iii) the solid density is constant during solidification. In carrying out the simulation of segregation mechanisms are resolved heat transfer equation, that simulating the solidification process and are are solved the interdendritic fluid equation of motion.

scholarly journals Polyol-Mediated Synthesis of Nitrogen-Containing Carbon-Dots from Tetracyanobenzene with Intense Red Fluorescence

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1470 ◽  
Author(s):  
Roman Lehmacher ◽  
Claus Feldmann
Keyword(s):  
Polyethylene Glycol ◽  
Liquid Phase ◽  
Quantum Yield ◽  
Carbon Dots ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
Polyethylene Glycol 400 ◽  
Strong Emission ◽  
Red Emission ◽  
Naked Eye

Nitrogen-containing C-dots were prepared by heating (160 °C, 1 h) 1,2,4,5-tetracyanobenzene (TCB) in polyethylene glycol 400 (PEG400). The as-prepared monocrystalline C-dots were 2–4 nm in diameter and contained 24.4 wt. % of nitrogen. They showed intense fluorescence under excitation at 400–500 nm as well as under excitation at 600–700 nm. In addition to an excitation-wavelength-depending emission at 400 to 650 nm, the emission spectra exhibited a strong emission peaking at 715 nm, whose position was independent from the wavelength of excitation. For this deep-red emission a remarkable quantum yield of 69% was detected. The synthesis of nitrogen-containing C-dotswas completely performed in the liquid phase. Moreover, the C-dots could be directly dispersed in water. The resulting aqueous suspensions of PEG400-stabilized nitrogen-containing C-dots also showed intense red emission that was visible to the naked eye.

Single-domain Yba2Cu3Oy thick films and fabrics prepared by an infiltration and growth process

2001 ◽  
Vol 16 (4) ◽  
pp. 955-966 ◽  
Author(s):  
E. Sudhakar Reddy ◽  
J. G. Noudem ◽  
M. Tarka ◽  
G. J. Schmitz
Keyword(s):  
Liquid Phase ◽  
Thick Film ◽  
Growth Process ◽  
Thick Films ◽  
Solidification Process ◽  
Film Coating ◽  
Single Domain ◽  
Free Standing ◽  
Liquid Phases ◽  
Woven Structure

An infiltration and growth process has been developed to produce single-domain Yba2Cu3Oy(123) as thick films on various substrates or as self-supporting fabrics. Commercially available Y2O3 cloths of square woven or satin woven structure were infiltrated with liquid phases from a suitable source containing barium cuprates and copper oxides and subsequently converted into Y2BaCuO5(211) and −123 phases by a series of distinct peritectic reactions. Depending on the final form of 123, the Y2O3 cloth was either clamped firmly at corners to produce a self-supporting 123 fabric or placed on a suitable substrate to result in a thick film coating of 123. The source material for the liquid phase being in the form of solid blocks was placed at corners of the cloth in the case of free-standing 123 fabrics. In case of the thick film configuration the liquid phase powder was spread on the surface of the Y2O3 cloth. A small c-axis-oriented MgO or Nd(123) seed was used to generate an oriented 123 domain in the infiltrated fabric. The solidification process was optimized to transform the entire Y2O3 fabric into a single-domain 123. The microstructure of the single domain was optimized in terms of 211 size and content for high Jc. A detailed description of the process, the growth mechanism, the resulting microstructures was given, and basic superconducting properties of the new form of 123 are briefly discussed.

scholarly journals Liquid Migration in the Paste as the Result of Consolidation

2021 ◽  
Vol 71 (1) ◽  
pp. 131-138
Author(s):  
Uličná Miriam ◽  
Fekete Roman ◽  
Likavčan Adam ◽  
Peciar Marián
Keyword(s):  
Liquid Phase ◽  
Powder Material ◽  
Extrusion Process ◽  
Model Material ◽  
Powder Materials ◽  
Simple Test ◽  
Test Device ◽  
Effect Of Pressure ◽  
Porous Skeleton ◽  
Liquid Migration

Abstract The processing of various powder materials is often done by an extrusion process; the powders being formed into a paste by the addition of a liquid substance. During extrusion, by reason of the extrusion pressure, some properties of the paste are changing, which affect its rheology and thus the extrusion itself. One of the phenomena is the movement of the liquid phase. This paper is focused on monitoring this phenomenon using model material in a simple test device. Its design simulates the effect of pressure in the extruder. The results of the measurements provide a picture of the movement of the liquid phase under the influence of the pressure in the porous skeleton formed by the powder material.

A naked-eye liquid-phase colorimetric assay of simultaneous detect cysteine and lysine

2019 ◽  
Vol 160 ◽  
pp. 151-158 ◽  
Author(s):  
Zhonghua Xue ◽  
Lulu Xiong ◽  
Honghong Rao ◽  
Xiuhui Liu ◽  
Xiaoquan Lu
Keyword(s):  
Liquid Phase ◽  
Colorimetric Assay ◽  
Naked Eye

High Temperature Brittleness of Cast Alloys / Kruchosc Wysokotemperaturowa Stopów Odlewniczych

2013 ◽  
Vol 58 (1) ◽  
pp. 83-87 ◽  
Author(s):  
I. Telejko ◽  
H. Adrian ◽  
B. Guzik
Keyword(s):  
Liquid Phase ◽  
Crack Nucleation ◽  
Marked Change ◽  
Crack Tip ◽  
Solidification Process ◽  
Diffusional Flux ◽  
Cast Alloys ◽  
Last Stage ◽  
Major Factors ◽  
Strength And Ductility

Over-all mechanical properties of alloys are extremely low at the last stage of solidification where alloy exists at brittle temperature range (BTR). When the solidification process is completed a sudden and marked change in strength and ductility of metal is observed. It means that as long as liquid phase is present, metal will fail in a brittle manner. There are known different theories of brittleness of alloys in existence of liquid phase. The idea involved by authors of the paper is as follows: three major factors caused by presence of liquid may be taken into account: - decreasing the energy needed for crack nucleation, - increasing atomic diffusional flux out of the crack tip, - creating a path for abnormally quick diffusion of atoms from the crack tip.

scholarly journals A computer simulation of solidification taking into account the movement of the liquid phase

2018 ◽  
Vol 157 ◽  
pp. 02008 ◽  
Author(s):  
Robert Dyja ◽  
Elżbieta Gawrońska ◽  
Andrzej Grosser
Keyword(s):  
Liquid Phase ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Solidification Process ◽  
Boussinesq Approximation ◽  
Navier Stokes ◽  
The Finite Element Method ◽  
Navier Stokes Equation ◽  
Solidification Simulation ◽  
Heat Released

In the paper, we present the results of solidification simulation taking into account the movement of the liquid phase. The results are obtained from an author software which is implemented on the base of a stabilized finite elements method (Petrov-Galerkin formulation). Using that formulation the Navier-Stokes equation is solved together with the convection term (Boussinesq approximation). The Finite Element Method (FEM) formulation is responsible for solidification, approximating the solution of the heat conduction equation (with the internal heat source term responsible for the heat released during the phase transition). The movement of the liquid phase in a solidifying cast that is caused by convection can significantly affect the process of heat transfer from the casting to the mold, which in turn has an influence on the temperature distribution in the cast and may cause a change in the location of the defects. The presented results allow to assess under what conditions the effect of convection on the solidification process is significant.

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