Numerical Simulation of Lost Foam Casting in Special-Shaped Stainless Steel Stirrer

2011 ◽  
Vol 101-102 ◽  
pp. 479-483
Author(s):  
Zhi Lan Chen ◽  
Ren Wei Yang
Keyword(s):  
Numerical Simulation ◽  
Stainless Steel ◽  
Temperature Change ◽  
Solidification Process ◽  
Lost Foam Casting ◽  
Filling Process ◽  
Gasification Process ◽  
Simulation Techniques ◽  
Foam Pattern ◽  
Lost Foam

The filling process, solidification process, gasification process and node temperature change of special-shaped stainless steel stirrer via lost foam casting was simulated and analyzed by using ProCAST numerical simulation techniques. The results show that the filling and foam gasification process of stainless steel stirrer casting is a top-down, from the middle layers of outward promotion process. In the filling process, foam pattern gasification and decomposition appeared to be exacerbated by heat transfer in the whole casting. Through the node temperature change over time, it can be conformed to the principles of the order of solidification in the entire stirrer casting solidification process.

Numerical Modeling of EPS Foam Decomposition in the Lost Foam Casting Process

2005 ◽  
Author(s):  
X. J. Liu ◽  
S. H. Bhavnani ◽  
R. A. Overfelt
Keyword(s):  
Heat Transfer ◽  
Process Parameters ◽  
Experimental Studies ◽  
Casting Process ◽  
Mold Filling ◽  
Lost Foam Casting ◽  
Interfacial Heat Transfer Coefficient ◽  
Filling Process ◽  
Foam Pattern ◽  
Lost Foam

The importance of smooth mold filling in the lost foam casting process has been recognized for a long time. The more uniform the filling process, the better the quality of the casting products that are produced. Successful computer simulations can help reduce the number of trials and cut down the lead time in the design of new casting products by better understanding the complex mechanisms and interplay of different process parameters in the mold filling process. In this study, a computational fluid dynamics (CFD) model has been developed to simulate the fluid flow of molten aluminum and the heat transfer involved at the interfacial gap between the metal and the expanded polystyrene (EPS) foam pattern. The commercial code FLOW-3D was used because it can track the front of the molten metal by a Volume of Fluid (VOF) method and allow complicated parts to be modeled by the Fractional Area/Volume Ratios (FAVOR) method. The code was modified to include the effects of varying interfacial heat transfer coefficient based on gaseous gap pressure which is related to foam degradation and coating permeability. The modification was validated against experimental studies and the comparison showed better agreement than the basic model. Process parameters such as initial metal temperature, foam pattern property, and gating system were investigated. The defect prediction model was also used to study the dependence of defect formation on the process variables.

Numerical Simulation and Optimization Technology of Lost Foam Casting

2014 ◽  
Vol 936 ◽  
pp. 1681-1686
Author(s):  
Hong Ze Chen ◽  
Hong Zhao Dong ◽  
Zhong De Shan
Keyword(s):  
Numerical Simulation ◽  
Solidification Process ◽  
Lost Foam Casting ◽  
Casting Defects ◽  
Simulation Technology ◽  
Simulation And Optimization ◽  
Solidification Simulation ◽  
Development Direction ◽  
Lost Foam ◽  
Filling And Solidification

The filling and solidification process of casting that is closely related to lots of casting defects and has significant effect on the mechanical properties of castings. In this paper, the research status and development direction of numerical simulation technology of casting, especially of lost foam casting were reviewed and discussed. Also a brief introduction of the basic situations and product characteristics of several outstanding cast filling and solidification simulation softwares were summarized. In addition, the actual domestic application status of numerical simulation technology of lost foam casting in the foundry enterprises was analyzed and some suggestions were given as well.

Numerical Simulation of the Casting Process with Coupled Thermal and Stress Field

2010 ◽  
Vol 29-32 ◽  
pp. 1878-1882 ◽  
Author(s):  
Jian Qiang Zhou ◽  
Fa Zhan Yang ◽  
De Sheng Li
Keyword(s):  
Numerical Simulation ◽  
Stress Field ◽  
Complex Structure ◽  
Solidification Process ◽  
Casting Process ◽  
Stress Fields ◽  
Cooling Process ◽  
Thermal Distribution ◽  
Simulation Techniques ◽  
Simulation Results

To understand the thermal distribution in a complex structure and high quality linkage casting, a mathematical model of temperature and stress field was established. Numerical simulation techniques was applied by using Procast software in the temperature and stress fields of solidification process, and the foundry defect such as old lap, misrun, shrinkage and dispersed shrinkage was predicted. The stress distribution and deformation in cooling process of casting were analyzed. The simulation results can supply a scientific foundation for foundry technology.

Numerical simulation of heat transfer and fluid flow of molten metal in MMA–St copolymer lost foam casting process

2010 ◽  
Vol 210 (14) ◽  
pp. 2071-2080 ◽  
Author(s):  
Ali Charchi ◽  
Mostafa Rezaei ◽  
Siyamak Hossainpour ◽  
Jamal Shayegh ◽  
Sohrab Falak
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Molten Metal ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Lost Foam

Thermal Analysis during Solidification of Mg-4%.wtAl Alloy during Lost Foam Casting Process

2011 ◽  
Vol 686 ◽  
pp. 371-377 ◽  
Author(s):  
D.H. Hou ◽  
S.M. Liang ◽  
Rong Shi Chen ◽  
En Hou Han ◽  
C. Dong
Keyword(s):  
Thermal Analysis ◽  
Grain Size ◽  
Casting Process ◽  
Expanded Polystyrene ◽  
Solidification Structure ◽  
Lost Foam Casting ◽  
Dendrite Morphology ◽  
Dendrite Coherency ◽  
Foam Pattern ◽  
Lost Foam

The lost foam casting (LFC) process utilizes the expanded polystyrene (EPS) foam pattern for the production of metallic components. The thermal degradation of the foam pattern has a significant effect on microstructure of the component. Dendrite coherency is important for the determination of the formation of the solidification structure and cast ability of alloys. The effects of the dendrite coherency on grain size in Mg-4Al alloy have been studied using the two-thermocouple thermal analysis technique in the solidified sample. The results also indicate that the grain size increases with the temperature interval between liquids (TN) and dendrite coherency point (TDCP), The solid fraction at DCP (fsDCP) expressed in percent strongly dependents on the dendrite morphology during solidification.

Measurement of Kinetic Zone Temperature and Heat Transfer Coefficient in the Lost Foam Casting Process

2004 ◽  
Author(s):  
X. J. Liu ◽  
S. H. Bhavnani ◽  
R. A. Overfelt
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Foam Pattern ◽  
Lost Foam ◽  
The Heat Transfer Coefficient ◽  
Zone Temperature

A thermometric technique has been developed to study the thermal characteristics of the foam-metal interaction in the lost foam casting process. A cylindrical foam pattern and heated steel block have been used to estimate the endothermic losses associated with the thermal degradation of the expanded polystyrene at the metal front. Thermocouple readings have been analyzed to determine the temperature of the kinetic zone between the advancing metal front and the receding foam pattern. The heat transfer coefficient between the metal front and the foam pattern has been calculated from the thermal data at the simulated metal front. The results confirmed that the endothermic degradation of the polystyrene pattern at the metal front introduced a steep thermal gradient in the metal and a consistently increasing heat flux. It is found that the heat transfer coefficient, initially 150 W/m2·K increases to 220 ~ 300 W/m2·K during the process. Foam density has marginal effect on the heat flux and heat transfer coefficient, whereas the increase of simulated metal front velocity enhances the heat transfer at the metal front. The kinetic zone temperature is measured to be in the range of 150 to 290°C with an average of 200°C and a gaseous gap size of 1 to 4 cm.

Numerical Study on Mold Filling Process of Casting

2008 ◽  
Vol 575-578 ◽  
pp. 87-92
Author(s):  
Xiao Qiang Pan ◽  
Hong Zhu Sun ◽  
Jun Da Chen ◽  
Yu Ling Zhu
Keyword(s):  
Numerical Simulation ◽  
Initial Conditions ◽  
Numerical Study ◽  
Solidification Process ◽  
Mold Filling ◽  
General Purpose ◽  
Filling Process ◽  
Numerical Heat Transfer ◽  
Multiphase Fluid Flow ◽  
Multiphase Fluid

Techniques of numerical simulation on mold filling process of casting are investigated in this paper. The mathematical model is formed on the ground of some selected theories in computational fluid dynamics (CFD), Numerical Heat Transfer (NHT) and computational methods to interfacial tracking. The discrete solution to the governing equations appeals to Finite Volume Method (FVM) on structured mesh. As for viscous turbulence flow and multiphase fluid flow in mold filling, engineering turbulence model and Volume of Fluid (VOF) method are adopted in the algorithms, respectively. As a debut, the general-purpose CFD software is used to establish the practicable mechanical model for the simulation. By means of numerical simulation, variation and distribution of velocity, temperature, stress and configuration of casting, etc. with respect to time and space in the filling process can be quantitatively analysed in detail, which is helpful for engineers to optimize their design of technics with less time and less cost and is meaningful to provide the subsequent simulation, solidification process of casting, with initial conditions.

scholarly journals Influence of Pattern Coating Thickness on Porosity and Mechanical Properties of Lost Foam Casting of Al-Si (LM6) Alloy

2013 ◽  
Vol 300-301 ◽  
pp. 1281-1284
Author(s):  
Shamsuddin Sulaiman ◽  
M.K.A.M. Ariffin ◽  
S.H. Tang ◽  
A. Saleh
Keyword(s):  
Mechanical Properties ◽  
Molten Metal ◽  
Coating Thickness ◽  
Air Entrainment ◽  
Expanded Polystyrene ◽  
Lost Foam Casting ◽  
Polystyrene Foam ◽  
Porosity Distribution ◽  
Foam Pattern ◽  
Lost Foam

The combination of Aluminum alloy with lost foam casting (LFC) process is best applied in automotive industry to replace steel components in order to achieve light weight components for reducing fuel consumption and to protect the environment. The LFC process involves process parameters such as the degree of vacuum, foam degradation, expanded polystyrene (EPS) foam density, permeability of foam pattern coatings, pouring temperature, filling velocity, cooling rate, and pressure. The effect of polystyrene foam pattern coating thickness on the porosity and mechanical properties of Aluminum Al-Si LM6 alloy were evaluated experimentally. The coating thickness was controlled by slurry viscosity at range between 18sec to 20sec using Zahn viscosity cup No.5 and the foam pattern was coated up to fifth layer. Aluminum Al-Si (LM6) molten metal was poured into expandable mould and castings were examined to determine porosity distribution, mechanical properties and microscopic observation. Results from X-ray testing reveal the porosity distribution on Aluminum Al-Si LM6 castings is greater at thicker foam pattern coating sample. Meanwhile, the tensile strength of casting decreases when foam pattern coating thickness increases. Microscope observation portray the present of porosity on the casting which shows more gas defects present at thicker foam pattern coating sample. The source of porosity in LFC process is due to air entrainment or the entraining gases from polystyrene foam decomposition during pouring of molten metal. As a conclusion, mechanical strength has inverse relationship with porosity.

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