Numerical Simulations and Experimental Study of Hot Core Distortion Phenomenon in Aluminum Casting

Volume 3 ◽  
2004 ◽  
Author(s):  
Sayavur Bakhtiyarov ◽  
Ruel A. Overfelt ◽  
Amit Suryawanshi ◽  
Johnathon Capps
Keyword(s):  
High Temperature ◽  
Numerical Simulations ◽  
Buoyancy Force ◽  
Metal Flow ◽  
Tensile Tests ◽  
Temperature Limit ◽  
Silica Sand ◽  
Sand Core ◽  
Aluminum Castings ◽  
Cold Box

This paper presents the results of experimental and numerical studies of hot distortion phenomenon in the phenolic urethane cold box systems. Dual Pushrod Dilatometer has been used to measure a thermal expansion/contraction of phenolic urethane cold box sand core specimens at temperature range from 25° C to 800° C. The high temperature tensile tests showed that the tensile strength of the phenolic urethane cold box silica sand cores is significantly affected by the bench life, temperature and binders level. High temperature hot distortion furnace tests on cylindrical cores showed that some aluminum coatings increase the temperature limit when distortion starts, but can’t prevent it. The hot distortion test aluminum castings showed that regardless of the application of coating, the type of coating, and anti-veining additives, all cores (silica sand) with density less than the density of the molten metal (aluminum alloy) were significantly distorted. Numerical simulations of the liquid metal flow around the cylindrical sand core and analysis of dynamic forces acting on the core during fill process showed that a buoyancy force is the major contributor to the hot distortion. It is concluded that the one of the solutions in preventing the hot distortion of sand cores is increasing their weigh, which will balance the buoyancy force and will bring the resultant force to the minimum. The hot distortion test castings using zircon sand cores (both coated and non-coated) with density almost equal to the density of the molten aluminum proved our predictions, and hot distortion has been prevented.

Numerical Simulations and Experimental Study of Liquid Metal Flow Around Sand Core

2005 ◽  
Vol 128 (3) ◽  
pp. 541-547
Author(s):  
Sayavur I. Bakhtiyarov
Keyword(s):  
High Temperature ◽  
Liquid Metal ◽  
Numerical Simulations ◽  
Buoyancy Force ◽  
Metal Flow ◽  
Tensile Tests ◽  
Metal Casting ◽  
Sand Core ◽  
Liquid Metal Flow ◽  
Cold Box

This paper presents the results of experimental and numerical studies of the hot distortion phenomenon in the phenolic urethane cold box systems used in metal casting. Dual Pushrod Dilatometry has been used to measure a thermal expansion/contraction of phenolic urethane cold box sand core specimens at temperatures ranging from 20°C to 600°C. High temperature tensile tests showed that the tensile strength of the phenolic urethane cold box sand cores is significantly affected by the bench life, temperature and binders level. High temperature hot distortion furnace tests on cylindrical cores showed that some coatings increase the temperature limit when distortion starts, but application of coating cannot prevent distortion. The hot distortion test during metal casting showed that regardless of the application of coating, the type of coating, and anti-veining additives, all cores with density greater than the density of the molten metal (magnesium alloy) were significantly distorted. Numerical simulations of the liquid metal flow around the cylindrical sand core and analysis of dynamic forces acting on the core during the fill process showed that a buoyancy force is the major contributor to the hot distortion. It is concluded that the one of the solutions in preventing the hot distortion of sand cores is optimizing their weight, which will balance the buoyancy force and will bring the resultant force to the minimum. The hot distortion test castings using optimized sand cores with density almost equal to the density of the molten magnesium proved our predictions, and hot distortion has been prevented.

Numerical Study of Mold Filling Dynamics in “Cold-Box” Sand Coremaking Process

2001 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Mold Filling ◽  
Sand Core ◽  
Cold Box ◽  
Two Fluid ◽  
Core Shooting Process

Abstract In this paper we present the results of the numerical simulations of sand core shooting process using the CFD package FLOW-3D. The simulations are based on a two-fluid flow approach. The computation results are compared to experimental data obtained earlier.

BIRMAL P.83

Alloy Digest ◽  
1960 ◽  
Vol 9 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Die Casting ◽  
Heat Treating ◽  
Casting Alloy ◽  
Temperature Performance ◽  
Aluminum Castings

Abstract Birmal P.83 is an aluminum-copper-silicon die casting alloy, having excellent castability and improved machinability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, and machining. Filing Code: Al-98. Producer or source: Birmingham Aluminum Castings Company Ltd.

scholarly journals A 4d $$ \mathcal{N} $$ = 1 Cardy Formula

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Joonho Kim ◽  
Seok Kim ◽  
Jaewon Song
Keyword(s):  
Black Holes ◽  
Free Energy ◽  
Asymptotic Behavior ◽  
High Temperature ◽  
Gauge Theory ◽  
Chemical Potential ◽  
Temperature Limit ◽  
Superconformal Index ◽  
High Temperature Limit ◽  
Cardy Formula

Abstract We study the asymptotic behavior of the (modified) superconformal index for 4d $$ \mathcal{N} $$ N = 1 gauge theory. By considering complexified chemical potential, we find that the ‘high-temperature limit’ of the index can be written in terms of the conformal anomalies 3c − 2a. We also find macroscopic entropy from our asymptotic free energy when the Hofman-Maldacena bound 1/2 < a/c < 3/2 for the interacting SCFT is satisfied. We study $$ \mathcal{N} $$ N = 1 theories that are dual to AdS5 × Yp,p and find that the Cardy limit of our index accounts for the Bekenstein-Hawking entropy of large black holes.

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

scholarly journals A computational modeling approach based on random fields for short fiber-reinforced composites with experimental verification by nanoindentation and tensile tests

2021 ◽  
Author(s):  
Natalie Rauter
Keyword(s):  
Numerical Simulations ◽  
Correlation Functions ◽  
Material Properties ◽  
Random Fields ◽  
Tensile Tests ◽  
Short Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Component Level

AbstractIn this study a modeling approach for short fiber-reinforced composites is presented which allows one to consider information from the microstructure of the compound while modeling on the component level. The proposed technique is based on the determination of correlation functions by the moving window method. Using these correlation functions random fields are generated by the Karhunen–Loève expansion. Linear elastic numerical simulations are conducted on the mesoscale and component level based on the probabilistic characteristics of the microstructure derived from a two-dimensional micrograph. The experimental validation by nanoindentation on the mesoscale shows good conformity with the numerical simulations. For the numerical modeling on the component level the comparison of experimentally obtained Young’s modulus by tensile tests with numerical simulations indicate that the presented approach requires three-dimensional information of the probabilistic characteristics of the microstructure. Using this information not only the overall material properties are approximated sufficiently, but also the local distribution of the material properties shows the same trend as the results of conducted tensile tests.

High Temperature Deformation Mechanism Maps of NiAl

2004 ◽  
Vol 449-452 ◽  
pp. 57-60
Author(s):  
I.G. Lee ◽  
A.K. Ghosh
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Calculation Method ◽  
Deformation Behavior ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
Temperature Strain

In order to analyze high temperature deformation behavior of NiAl alloys, deformation maps were constructed for stoichiometric NiAl materials with grain sizes of 4 and 200 µm. Relevant constitute equations and calculation method will be described in this paper. These maps are particularly useful in identifying the location of testing domains, such as creep and tensile tests, in relation to the stress-temperature-strain rate domains experienced by NiAl.

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