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

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.

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.


2013 ◽  
Vol 773-774 ◽  
pp. 887-893
Author(s):  
Pongsak Dulyapraphant ◽  
Ekkachai Kittikhewtraweeserd ◽  
Nipon Denmud ◽  
Prarop Kritboonyarit ◽  
Surasak Suranuntchai

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.


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.


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