Investigations of the High Vacuum Die Castings of Dumbbell Specimens

2009 ◽  
Vol 628-629 ◽  
pp. 727-734
Author(s):  
Rong Yuan Jou
Keyword(s):  
Die Casting ◽  
High Vacuum ◽  
Testing Machine ◽  
Casting Process ◽  
Process Use ◽  
Vacuum Die Casting ◽  
Small Feature ◽  
Visualization Experiments ◽  
Die Casting Process ◽  
Die Castings

Compare to atmosphere die casting or moderate vacuum die casting process, use of the high vacuum die casting can enhance excluding gas volumes in the mold, improve the casting mechanical properties and density, and increase the fabrication feasibility for casting small feature size, shape, and higher quality of product. The process of high vacuum die casting for dumbbell specimens is established and implemented for evaluation of this innovative manufacturing technology. A transparent acrylic mold is fabricated to investigate the vacuum injection for vacuum die casting process and a metal mold is fabricated to test the real manufacturing of high vacuum die casting. To visualize the flowing pattern inside the mold under the consequence of evacuation processing, flow visualization experiments are conducted. Then, the specimen is molded by the high vacuum die casting process and the specimen castings are test by a universal testing machine for its loading-elongation relationship. The porosities of specimen casting are examined by scale weighting and direct visual inspection ways. Experimental results show that the high vacuum die casting process is effective to reduce the porosity (5.47% increment in weight) and to increase the strength (4.83% increment in maximum stress) of the investigated specimen. An obviously vortex roll is established along the centerline position of dumbbell specimen which may be became the source of porosity in real processing. Meanwhile, an excellent vacuum sealing is critical to the success of high vacuum die casting.

Floating Behavior of Entrapped Gas in Semi-Solid Metal

2017 ◽  
Vol 898 ◽  
pp. 1254-1260
Author(s):  
Hong Xing Lu ◽  
Qiang Zhu ◽  
Da Quan Li ◽  
Fan Zhang
Keyword(s):  
Solution Heat Treatment ◽  
Die Casting ◽  
Casting Process ◽  
Acceptance Rate ◽  
Solid Metal ◽  
High Quality ◽  
Casting Technology ◽  
Die Casting Process ◽  
Semi Solid ◽  
Die Castings

Semi-solid die casting technology has great advantages at defects control and has been successfully used to produce high quality aluminum alloy components for several years. In this process, semi-solid metal with high apparent viscosity and low plunger velocity are used to avoid surface turbulence which is the main source of entrapped gas in conventional die casting processes. But, entrapped gas still has other sources, such as melting, pouring, surface flooding and confluence weld. Solution heat treatment is always used to strengthen semi-solid die castings. The entrapped gas leads to blister defects, which directly decreases the acceptance rate of semi-solid die castings. So, the entrapped gas is still a serious issue in semi-solid die casting process. We studied the floating behavior of entrapped gas bubble in semi-solid metal. Two floating models were established for gas bubbles with different sizes. These models were used to analyze the possibility of entrapped gas escaping from semi-solid metal in casting practice. The results showed that entrapped gas from feed billet could not escape from the semi-solid metal in the casting process of impeller, which was proved by experiment results. These results emphasized the importance of clean melt and semi-solid metal. Some advices were given at last for avoiding or removing the entrapped gas in semi-solid die casting process.

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.

On the Microstructure and Impact Properties of Slow Injection A356 Die Castings with Local Pressurization

2009 ◽  
Vol 628-629 ◽  
pp. 587-592
Author(s):  
Yan Fei Bai ◽  
Hai Dong Zhao ◽  
Yuan Yuan Li ◽  
Zhi Xin Kang
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Fracture Mechanisms ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Die Casting Process ◽  
Die Castings ◽  
Pressure Die Casting ◽  
The Impact ◽  
Slow Injection

Microstructure and impact properties of slow injection A356 die castings with local pressurization have been investigated. The microstructure in the casting different regions were analyzed and compared. The casting impact absorbed energy varies from 1.17 to 2.35J, and is higher than that of other pressure die casting process. Furthermore, fracture mechanisms of different regions in castings are discussed. The results show that, the impact absorbed energy decreases with increase in SDAS. Also significant fluctuations of the impact properties in the thick-walled and local pressurization regions are found.

Study on Pressure Variations in the Mold of Magnesium Alloy Die Castings

2007 ◽  
Vol 353-358 ◽  
pp. 1614-1616
Author(s):  
Yan Gai Liu ◽  
Zhao Hui Huang ◽  
Hao Ding ◽  
Ming Hao Fang ◽  
Shou Mei Xiong
Keyword(s):  
Magnesium Alloy ◽  
Real Time ◽  
Time Pressure ◽  
Die Casting ◽  
Solidification Process ◽  
Casting Process ◽  
Mold Filling ◽  
Die Casting Process ◽  
Die Castings ◽  
Filling And Solidification

High pressure die casting is the most common method in making magnesium alloys for both auto parts and 3C products. Pressure variations in the mold during mold filling and solidification process have direct influences on the quality and properties of die castings. In this paper, a cylinder head cover was produced to experimentally study pressure variations in the mold during magnesium alloy die-casting process in real time for the first time. Pressure varies at different positions in the mold during die casting process. This study indicates that mold filling and solidification process of magnesium alloy die castings can be described by pressure curves obtained by pressure measurement at different test positions in the cavity in real time.

Increase Pressure and Homogeneity of Die Castings from EN AC 47100 Alloy

2015 ◽  
Vol 729 ◽  
pp. 108-113
Author(s):  
Stefan Gaspar ◽  
Jan Pasko
Keyword(s):  
Die Casting ◽  
Casting Process ◽  
Internal Quality ◽  
Control Methods ◽  
Technological Factors ◽  
Great Reliability ◽  
Die Casting Process ◽  
Die Castings ◽  
Pressure Die Casting

In the pressure die casting process, a great attention is paid to a die castings quality improvement. This quality has to be ensured with a great reliability and, at the same time, it is necessary to apply control methods to a technological process which provide a complete picture of a die casting process as well as internal quality of the produced die castings. It requires control of the present technological factors of a pressure die casting process. The contribution deals with the effect of die casting plunger velocity inside a filling chamber on mechanical properties of a die casting product from EN AC 47100 alloy.

Key Technologies in the Design of a Vacuum Die Casting Mould for Aluminum Alloy Joints

2010 ◽  
Vol 97-101 ◽  
pp. 390-394
Author(s):  
Xiao Hong Ge ◽  
Hong Wu Huang ◽  
Hui Li ◽  
Hui Huang Yang
Keyword(s):  
Aluminum Alloy ◽  
Die Casting ◽  
High Strength ◽  
Casting Process ◽  
Whole Process ◽  
Vacuum Die Casting ◽  
Section Design ◽  
Bus Body ◽  
Die Casting Process ◽  
Cae Simulation

Aluminum alloy joints are a key component of a light-weight bus body, hence, they have a complicated structure and high strength requirement. A vacuum die casting mould has been developed and joints have been manufactured using a CAE simulation, a “whole-process-vacuum exhaust” vacuum die casting process and a decreased cross-section design for vacuum-pumping. The joint’s internal porosity has been noticeably reduced and its mechanical properties have been considerably improved in comparison with joints manufactured from die casting.

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