Effect of Solid Fraction and Pressure on Microstructure and Mechanical Properties and Reduction in Liquid Segregation in the Thixo-Die-Casting Process with Al-7 Pct Si Alloy

Abstract The work is a continuation of research on the use of water mist cooling in order to increase efficiency of the die-casting process for aluminum alloys. The paper describes the multipoint sequential cooling system of the casting die and its computer control and monitoring. It also includes results of the tests and analysis of cooling methods during making of the casting. These methods differ from each other in the sequence of casting die cooling and cause effective changes in microstructure and mechanical properties of castings made of AlSi11 alloy. The study demonstrated that the use of multipoint sequential cooling with water mist affects the microstructure refinement and reduces the segregation in the cast as well as more than by 20% increases the mechanical properties of castings in the rough state. The study also demonstrates that the sequential cooling of casting die accelerates the cooling of the casting and shortens die-casting cycle.

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The Effect of Stirring Current and Stirring Time on Microstructure and Mechanical Properties in Rheo Die Casting Process

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.116-117.526 ◽

2006 ◽

Vol 116-117 ◽

pp. 526-529

Author(s):

P.K. Seo ◽

C.G. Kang ◽

Byung Min Kim

Keyword(s):

Mechanical Properties ◽

Die Casting ◽

Casting Process ◽

Solid Particles ◽

Semisolid Processing ◽

Experimental Conditions ◽

Microstructure And Mechanical Properties ◽

Stirring Time ◽

Die Casting Process ◽

Pressure Die Casting

Semisolid processing is now becoming of greater interest for the production of various parts than pressure die casting. In the rheo die casting process, the important thing is to control the solid particles behavior during the rheo die casting process. So, in this paper, to find out the effect of stirring current and stirring time on the microstructure and mechanical properties, rheo die casting experiments were performed according to the stirring current such as 0, 20, 40 and 60 A and the stirring time such as 20, 40 and 60 sec. The results to the experimental conditions were analyzed.

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Study on Local Extrusions' Effects on Improvement of Die Casting Prismatic Parts' Forming Quality

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.312.475 ◽

2013 ◽

Vol 312 ◽

pp. 475-479

Author(s):

Wei Gang Zheng ◽

Cun Hong Yin ◽

Yu Hong Yuan ◽

Zhen Min Pan ◽

Chao Tang

Keyword(s):

Mechanical Properties ◽

Die Casting ◽

Casting Process ◽

Extrusion Process ◽

Shrinkage Porosity ◽

Shrinkage Cavity ◽

Prismatic Parts ◽

Porosity Defects ◽

Die Casting Process ◽

Casting Production

This paper analyzes traditional die casting process to find out the reasons that cause shrinkage cavity and porosity defects in casting. An optimized process of die casting by using local extrusion is proposed. A device used in local extrusion which realizes forcing compensating contraction on key parts of crankcase is designed and the parameters of local extrusion process are discussed. Compared the mechanical properties and microstructure of local extrusion used in die casting production with traditional. It shows that local extrusion used in die casting production can not only achieve the aim eliminating shrinkage porosity and cavity of a casting but also can refine grain to improve the mechanical properties.

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The Effect of Scandium on the Mechanical Properties of A356 Aluminium Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.707.144 ◽

2016 ◽

Vol 707 ◽

pp. 144-147

Author(s):

Ying Pio Lim ◽

Wei Hong Yeo ◽

A. Masita

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Aluminium Alloy ◽

Die Casting ◽

A356 Alloy ◽

Charpy Impact ◽

Casting Process ◽

Die Casting Process ◽

Charpy Impact Strength ◽

A356 Aluminium Alloy

In this project, the addition of scandium (Sc) into A356 aluminium alloy was studied for its effect on the mechanical properties after gravity die casting process. Scandium addition was administered at the weight percentages of 0.1, 0.2 and 0.3. The results obtained in this work revealed that scandium can significantly enhance the mechanical properties of A356 alloy in terms of tensile strength, hardness and charpy impact strength. In general, the addition of 0.2 wt% Sc in A356 alloy was found to be able to achieve the maximum tensile strength of 172.94MPa as compared to 136.03MPa for sample without Sc. No significant improvement in tensile strength was found when more than 0.3wt% added to the alloy. As for hardness, the sample with 0.3 wt% Sc attained the maximum Vicker’s hardness of 86.60 HV as compared to 76.48 HV for unmodified A356. Similarly, the addition of 0.3wt% Sc in A356 can achieve highest impact energy of 2.71J as compare to 1.09J for unmodified A356.

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Development of Horizontal Reheating System for Semi-Solid Die Casting and Its Microstructure Evaluation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.377 ◽

2005 ◽

Vol 475-479 ◽

pp. 377-380

Author(s):

P.K. Seo ◽

Byung Min Kim ◽

Chung Gil Kang

Keyword(s):

Die Casting ◽

Casting Process ◽

Complicated Shape ◽

Forming Process ◽

Globular Structure ◽

Liquid Segregation ◽

Die Casting Process ◽

Semi Solid ◽

Reheating Process ◽

High Frequency Induction

The parts manufactured by die casting process usually contain liquid segregation and porosities. To solve these problems, the semi-solid forming process has been applied. The process enables material in the semi-solid state to be completely filled, and parts with the complicated shape to be fabricated by applying relatively low pressure. This process is necessary in order to control the microstructure of the billet as well as to achieve the desired semi-solid billet state. In this study, a horizontal high-frequency induction heating device which can be fabricated by semi-solid forming irrespective of a billet's size was developed. A globular structure of the reheated billet and a billet's temperature distribution during the reheating process for A356 were investigated.

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