Numerical Studies of Flow-Induced Defects in Aluminum Ingot Die Casting Process

2011 ◽  
Vol 239-242 ◽  
pp. 825-828
Author(s):  
Xian Hong Han ◽  
Pavel Hora ◽  
Xiao Kong

A numerical modeling of aluminum die casting is discussed in this paper. Emphasis is laid on the flow-induced defects including air entrainment and oxide tracking. An ingot die casting process is designed by considering both laminar zone and turbulence zone. Pure aluminum is used as the casting material. In addition, different process parameters and different shapes of sprue are presented to check their influence to the flow status and flow-induced defects.

2009 ◽  
Vol 618-619 ◽  
pp. 381-386 ◽  
Author(s):  
K. Sadayappan ◽  
W. Kasprzak ◽  
Zach Brown ◽  
L. Quimet ◽  
Alan A. Luo

Magnesium automotive components are currently produced by high pressure die casting. These castings cannot be heat-treated to improve the strength and ductility mainly due to the casting imperfections such as porosity and inclusions created by the air entrainment during the turbulent mold filing. These imperfections also prevent magnesium components to be used for highly stressed body components. Efforts were made to produce high integrity magnesium castings through a Super-Vacuum Die Casting process. The AZ91D castings were found to have very low porosity and can be heat-treated without blisters. The tensile properties of the castings were satisfactory. The mechanical properties and thermal analysis indicate that the conventional heat treatment procedure needs to be optimized for such thin sectioned and rapidly solidified castings which have very fine microstructures.


Author(s):  
Song Qi ◽  
Yuto Takagi ◽  
Ken'ichi Yano ◽  
Tadao Kondo ◽  
Naoto Murakami ◽  
...  

Abstract Die casting is adequate for mass production and has the advantage of being able to yield a complicated shape accurately. However, casting defects caused by plunger movement remain a problem. Velocity control of the plunger is very effective to avoid casting defects. Velocity control input is manually conducted by skilled workers because the analysis of molten metal is very difficult, and injection molding is performed at places in the mold where it is invisible. In this paper, Quid behavior and the amount of air entrainment caused by the movement of the die casting plunger are analyzed using computational Quid dynamics (CFD). The optimum velocity control input of the die casting plunger was calculated in order to reduce air entrainment and molten metal forerunning to prevent the occurrence of defects in the die casting product. Optimization was performed by a Genetic algorithm incorporating CFD simulator.


2016 ◽  
Vol 256 ◽  
pp. 334-339 ◽  
Author(s):  
Song Chen ◽  
Fan Zhang ◽  
You Feng He ◽  
Da Quan Li ◽  
Qiang Zhu

Semi-solid slurry has significantly higher viscosity than liquid metal. This character of fluidity makes product design and die design, such as gating system, overflow and venting system, be different between these two die casting processes. In the present paper, taking a clamp product as an example, analyses the product optimization and die design by comparing the experimental and computational numerical simulation results. For the clamp, product structure is designed to be suitable for characters of SSM die casting process. The gating system is designed to be uniform variation of thickness, making the cross-sectional area uniformly reduce from the biscuit to the gate. This design ensures semi-solid metal slurry to fill die cavity from thick wall to thin wall. Gate position is designed at the thickest location, the gate shape of semi-solid die casting is set to be much bigger than traditional liquid casting. A good filling behaviour can be achieved by aforementioned all these design principles and it will be helpful to the intensification of pressure feeding after filling.


2006 ◽  
Vol 510-511 ◽  
pp. 334-337
Author(s):  
Shae K. Kim

It is obvious that automotive industry worldwide is predicting significant growth in the use of magnesium alloys for weight reduction to decrease fuel consumption and emission. About a half decade ago, the price of magnesium alloys was more than twice that of aluminum alloys on a weight basis. Currently, magnesium alloys cost about one and a half times that of aluminum alloys on a weight basis, and thus the price of magnesium alloys is the same as or lower than that of aluminum alloys on a per volume basis. However, in considering the performance of magnesium components (not their specific mechanical properties) and recycling aspect of magnesium alloys, it is required to realize niche applications of magnesium alloys, which meet the cost requirement on performance basis and/or offer more than weight reduction. There are many other factors that make magnesium a good choice: component consolidation, improved safety for driver and passengers, and improved noise vibration and harshness (NVH), to name a few. As one of these efforts to adopt magnesium alloys in automotive component, this paper describes the research strategy of cold chamber type 2-cavity die casting of AM50 magnesium alloy for developing the steering column lock housing module with emphasis on cost driving factors and necessities for cost reduction, explaining why AM50 magnesium alloy is chosen with design and die casting process optimization.


Author(s):  
L D Clark ◽  
I Rosindale ◽  
K Davey ◽  
S Hinduja ◽  
P J Dooling

The effect of boiling on the rate of heat extraction by cooling channels employed in pressure die casting dies is investigated. The cooling effect of the channels is simulated using a model that accounts for subcooled nucleate boiling and transitional film boiling as well as forced convection. The boiling model provides a continuous relationship between the rate of heat transfer and temperature, and can be applied to surfaces where forced convection, subcooled nucleate boiling and transitional film boiling are taking place in close proximity. The effects of physical parameters such as flow velocity, degree of subcooling, system pressure and bulk temperature are taken into account. Experimental results are obtained using a rig that simulates the pressure die casting process. The results are compared with the model predictions and are found to show good agreement. Instrumented field tests, on an industrial die casting machine, are also reported. These tests show the beneficial effects of boiling heat transfer in the pressure die casting process, including a 75 per cent increase in the production rate for the test component.


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