scholarly journals Investigation of temperature, degree of vacuum, pattern coating thickness effects on mold filling in lost foam casting (LFC) process of A356 alloy

2015 ◽  
Vol 18 (2) ◽  
pp. 94-103
Author(s):  
Ha Ngoc Nguyen ◽  
Phong Quoc Le ◽  
Tri Nhat Nguyen ◽  
Hoai Dinh Lai

Lost foam casting (LFC) process with outstanding advantages has been known as a new casting technique in foundry engineering. Especially, the operation restricts errors of a mould because of using expanded patterns without parting line being appropriate for the complex model. Great interest in this technology of the casting manufacturers is mainly lower, compared with the traditional process, investment outlays and production costs. The use of unbounded sand also reduces its treatment cost, more friendly and simple with the environment. The study examines the simultaneous effects of pouring temperature, degree of vacuum, coating thickness (through dipping time) on mold filling in LFC. A356 aluminum alloy is used in this study. By using a full two-level factorial design of experimental technique to identify the significant manufacturing factors affecting the mold filling. Results of this investigation indicated that increasing pouring temperature, degree of vacuum and decreasing dipping time obtain casting with higher filling rate.

2011 ◽  
Vol 101-102 ◽  
pp. 934-937
Author(s):  
Ji Qiang Li ◽  
Zhong Zhao ◽  
Zi Tian Fan ◽  
Zhi Xin Jia ◽  
Wen Liu ◽  
...  

Fluidity of ZL101 aluminium alloys in the low-pressure lost foam casting (LP-LFC) process has been investigated by altering various temperature variables. The experimental results indicate that the LP-LFC process had fine fluidity, and the pouring temperature was lower than conventional lost foam casting. The effect of the metal temperature on the fluidity is marginal in the LP-LFC process. Excessive pouring temperature not only aggrandizes energy consumption but also deteriorates porosity defect. The success of casting cooling fin demonstrates the advantages of LP-EPC process in producing high-complicated castings.


2011 ◽  
Vol 71-78 ◽  
pp. 694-697
Author(s):  
Jian Zhou ◽  
Li Jun Li ◽  
Jian Wen Yi ◽  
Ming Yang

The article studies the method which hydroturbine part is manufactured by lost foam casting for obtaining higher quality product.The lost model material is polystyrene foam plastics,the EPS diameters are selected in 0.5-0.76mm,the casting raw material is lower carbon martensite stainless steel(ZG06Cr13Ni4Mo).The style of open pouring system is adopted, ∑Fin-gate:∑Fcross-gate:∑Fdown-sprue=1:1.1:1.2, fireproof coating is mixed and coated,square sand box is used. The pouring temperature of liquid is 1600-1650°C.If the technology is strictly according to the design,good quality casting can be gotten.


2013 ◽  
Vol 300-301 ◽  
pp. 1281-1284
Author(s):  
Shamsuddin Sulaiman ◽  
M.K.A.M. Ariffin ◽  
S.H. Tang ◽  
A. Saleh

The combination of Aluminum alloy with lost foam casting (LFC) process is best applied in automotive industry to replace steel components in order to achieve light weight components for reducing fuel consumption and to protect the environment. The LFC process involves process parameters such as the degree of vacuum, foam degradation, expanded polystyrene (EPS) foam density, permeability of foam pattern coatings, pouring temperature, filling velocity, cooling rate, and pressure. The effect of polystyrene foam pattern coating thickness on the porosity and mechanical properties of Aluminum Al-Si LM6 alloy were evaluated experimentally. The coating thickness was controlled by slurry viscosity at range between 18sec to 20sec using Zahn viscosity cup No.5 and the foam pattern was coated up to fifth layer. Aluminum Al-Si (LM6) molten metal was poured into expandable mould and castings were examined to determine porosity distribution, mechanical properties and microscopic observation. Results from X-ray testing reveal the porosity distribution on Aluminum Al-Si LM6 castings is greater at thicker foam pattern coating sample. Meanwhile, the tensile strength of casting decreases when foam pattern coating thickness increases. Microscope observation portray the present of porosity on the casting which shows more gas defects present at thicker foam pattern coating sample. The source of porosity in LFC process is due to air entrainment or the entraining gases from polystyrene foam decomposition during pouring of molten metal. As a conclusion, mechanical strength has inverse relationship with porosity.


2012 ◽  
Vol 591-593 ◽  
pp. 940-944 ◽  
Author(s):  
Hong Zhou ◽  
Li Heng Luo

In order to explore whether the step gating system played a role in lost foam casting (LFC) process, this paper simulated the mold filling process of a step gating system with an auxiliary sprue and three side ingates by using the gravity LFC model of the code FLOW-3D, and analyzed its mold filling characteristics in LFC. It is found the mass flux ratio through the bottom-side ingate exceed 82% the total mass flux, much more than through the others. And it is also found the metal temperature of the middle region in the height direction is lower than the upper region or bottom region. The results show that the step gating system is not able to achieve its main roles in LFC. Our results can be used to design gating system in LFC.


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