Characterization of Magnesium Automotive Components Produced by Super-Vacuum Die Casting Process

2009 ◽  
Vol 618-619 ◽  
pp. 381-386 ◽  
Author(s):  
K. Sadayappan ◽  
W. Kasprzak ◽  
Zach Brown ◽  
L. Quimet ◽  
Alan A. Luo
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Air Entrainment ◽  
Automotive Components ◽  
Vacuum Die Casting ◽  
Heat Treated ◽  
Conventional Heat Treatment ◽  
Die Casting Process ◽  
Rapidly Solidified ◽  
Pressure Die Casting

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.

Applications of Squeeze Casting for Automobile Parts

2013 ◽  
Vol 773-774 ◽  
pp. 887-893
Author(s):  
Pongsak Dulyapraphant ◽  
Ekkachai Kittikhewtraweeserd ◽  
Nipon Denmud ◽  
Prarop Kritboonyarit ◽  
Surasak Suranuntchai
Keyword(s):  
High Pressure ◽  
Squeeze Casting ◽  
Die Casting ◽  
Solution Treatment ◽  
Casting Process ◽  
High Pressure Die Casting ◽  
Heat Treated ◽  
Automotive Parts ◽  
Die Casting Process ◽  
Pressure Die Casting

With an increasing pressure on automotive weight reduction, the demand on the lighter weight automotive components continues to increase. In recent years, squeeze casting processes have been used with different aluminium alloys to produce high integrity automotive parts. In this study, the indirect squeeze casting processes is adopted to cast a motorcycles component originally produced by a high pressure die casting process using aluminium alloy ADC12. To minimize amount of gas porosity inside squeeze casts, concepts of (1) minimization of ingate velocity along with (2) bottom filling pattern during the die filling, and (3) maximization of intensifications casting pressure are applied. Then parts are casted with both conventional high pressure die casting and indirect squeeze casting processes. Comparative evaluation of mechanical properties was made between HPDC casts and squeeze casts both in as-cast and heat treated conditions. Results from the experiment have shown that squeeze casts can pass the blister test at 490 °C for 2.5 hours. Then, squeeze casts are heat treated by solution treatment at 484 °C for 20 minutes and artificial age at 190 °C for 2.5 hours, respectively. This improves UTS of the heat treated squeeze cast to 254.14 MPa with 1.84% of elongation, while the UTS of as cast condition from both processes is not significantly different.

scholarly journals Industrial Semi-Solid Rheocasting of Aluminum A356 Brake Calipers

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
U. A. Curle ◽  
J. D. Wilkins ◽  
G. Govender
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Shot Sleeve ◽  
Process Stability ◽  
X Ray ◽  
Initial Stage ◽  
Heat Treated ◽  
Die Casting Process ◽  
Semi Solid ◽  
Pressure Die Casting

Industrial semi-solid casting trials of aluminum A356 brake calipers were performed over five days with the CSIR-RCS and high-pressure die casting process cell. Consecutive visual passed castings were used as the measure of process stability, and common defects between trials were categorized. Short fill results are erratic and caused by unintended underdosing by the furnace or incomplete billet discharge at the delivery point in the shot sleeve. Cold shuts can be significantly reduced by adjusting the shot control profile. Surface finish defects include surface roughness and staining caused by lubricant burn off. Visual passed castings display none of the above-mentioned external defects. X-ray examination and pressure testing of heat-treated castings from the consecutive visual passed castings show improvement over the five days. These initial-stage industrialization efforts pave the way for process commercialization.

Predicting heat extraction due to boiling in the cooling channels during the pressure die casting process

2000 ◽  
Vol 214 (3) ◽  
pp. 465-482 ◽  
Author(s):  
L D Clark ◽  
I Rosindale ◽  
K Davey ◽  
S Hinduja ◽  
P J Dooling
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Die Casting ◽  
Casting Process ◽  
Nucleate Boiling ◽  
Heat Extraction ◽  
Film Boiling ◽  
Cooling Channels ◽  
Die Casting Process ◽  
Pressure Die Casting

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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