Liquid Metal Stream Junction Defects in Aluminum Lost Foam Casting

2002 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt ◽  
Amit Suryawanshi
Keyword(s):  
Liquid Metal ◽  
Process Parameters ◽  
Mold Filling ◽  
Metal Stream ◽  
Lost Foam Casting ◽  
Lost Foam

The purpose of this work is to study fold defects in gravity and counter gravity lost foam casting processes, and to determine the process parameters which will improve the casting properties. The experiments are focused on the time and spatial dependent aspects of mold filling in frame shape styrofoam patterns.

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.

scholarly journals Effect of primary silicon crystals on the fluidity of eutectic and hypereutectic Al-Si alloys in lost foam casting

2021 ◽  
Author(s):  
Shailesh Kamble
Keyword(s):  
Process Parameters ◽  
Metal Flow ◽  
Primary Silicon ◽  
Lost Foam Casting ◽  
Minor Role ◽  
Automotive Components ◽  
Silicon Crystals ◽  
A Minor ◽  
Lost Foam

The hypereutectic Aluminum-Silicon (Al-Si) Alloys are gaining impetus in the automotive components, mainly due to their wear resistance. This property in these alloys is derived from the primary silicon crystals. However, there are unique metal flow and mold filling problems associated with hypereutectic Al-Si alloys in Lost Foam Casting (LFC). This investigation is a pioneering work undertaken to gain a better understanding of the role of primary silicon crystals and other phases in the LFC of hypereutectic Al-Si alloys. Time-temperature and first derivative curves were used to determine velocity of metal flow and to calculate solid fractions. Process parameters such as superheat, gating design and alloy composition were manipulated to change the morphology of primary silicon crystals. Microscopy and image analysis of castings enabled study of precipitated particles. Solidification, interlocking and melt sluggishness of precipitated particles significantly influenced fluidity, and the routine process parameters played a minor role.

Numerical Simulation and Thermometric Measurements on Mold Filling Dynamics

2002 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt ◽  
Matthew Edmondson
Keyword(s):  
Numerical Simulation ◽  
Liquid Metal ◽  
Flow Velocity ◽  
Software Package ◽  
Mold Filling ◽  
Cfd Simulations ◽  
Pressure Losses ◽  
Flow Simulations ◽  
3D Software ◽  
Lost Foam

In this paper we present the results of the CFD simulations of the mold filling dynamics in gravity and counter-gravity lost foam castings. FLOW-3D software package (Flow-Simulations, Inc.) has been used to predict flow velocity distributions and pressure losses when liquid metal flows in the step pattern. The results of simulations are compared to those obtained experimentally.

Functions of Step Gating System in the Lost Foam Casting Process

2012 ◽  
Vol 591-593 ◽  
pp. 940-944 ◽  
Author(s):  
Hong Zhou ◽  
Li Heng Luo
Keyword(s):  
Mass Flux ◽  
Flux Ratio ◽  
Casting Process ◽  
Mold Filling ◽  
Lost Foam Casting ◽  
Gating System ◽  
Bottom Side ◽  
Total Mass Flux ◽  
Filling Characteristics ◽  
Lost Foam

In order to explore whether the step gating system played a role in lost foam casting (LFC) process, this paper simulated the mold filling process of a step gating system with an auxiliary sprue and three side ingates by using the gravity LFC model of the code FLOW-3D, and analyzed its mold filling characteristics in LFC. It is found the mass flux ratio through the bottom-side ingate exceed 82% the total mass flux, much more than through the others. And it is also found the metal temperature of the middle region in the height direction is lower than the upper region or bottom region. The results show that the step gating system is not able to achieve its main roles in LFC. Our results can be used to design gating system in LFC.

scholarly journals Investigation of temperature, degree of vacuum, pattern coating thickness effects on mold filling in lost foam casting (LFC) process of A356 alloy

2015 ◽  
Vol 18 (2) ◽  
pp. 94-103
Author(s):  
Ha Ngoc Nguyen ◽  
Phong Quoc Le ◽  
Tri Nhat Nguyen ◽  
Hoai Dinh Lai
Keyword(s):  
Coating Thickness ◽  
A356 Alloy ◽  
Mold Filling ◽  
Complex Model ◽  
Production Costs ◽  
Lost Foam Casting ◽  
Pouring Temperature ◽  
Casting Technique ◽  
Lost Foam ◽  
Dipping Time

Lost foam casting (LFC) process with outstanding advantages has been known as a new casting technique in foundry engineering. Especially, the operation restricts errors of a mould because of using expanded patterns without parting line being appropriate for the complex model. Great interest in this technology of the casting manufacturers is mainly lower, compared with the traditional process, investment outlays and production costs. The use of unbounded sand also reduces its treatment cost, more friendly and simple with the environment. The study examines the simultaneous effects of pouring temperature, degree of vacuum, coating thickness (through dipping time) on mold filling in LFC. A356 aluminum alloy is used in this study. By using a full two-level factorial design of experimental technique to identify the significant manufacturing factors affecting the mold filling. Results of this investigation indicated that increasing pouring temperature, degree of vacuum and decreasing dipping time obtain casting with higher filling rate.

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