A study on effects of ceramic foam filter on flow aspect through water modeling experiment
Tóm tắt
Casting defects that are closely related to entrapped air bubbles and metallic oxides occur very frequently in the sand mold casting process. Many researchers have shown that these defects can be reduced by adopting an appropriate gating system design. However, it is difficult for field engineers to identify a specific gating system that is more appropriate for their products. In this study, we tried to draw a comparison between two gating system designs with and without a ceramic foam filter. The ceramic foam filter was added to the horizontal runner just after the down sprue to prevent air bubble generation and reduce turbulence without a change of gating system design. The water modeling experiment was conducted with four different amounts of the initial volumes of water in the reservoir to verify the effects of initial pouring velocity. The results of the experiment applying the filter showed remarkably changed flow characteristics. The use of the filter was found to convert the flow pattern of water in the desired direction. The ceramic foam filter performed well to reduce flow velocity and stabilize the water stream.The flow pattern without a filter can be improved significantly even with the the use of just a 10 PPI irregular filter. Although the study confirmed that use of the filter may change the flow characteristics, it needs to be noted that the use of the ceramic filter alone cannot solve all the problems caused by a poorly designed gating system.
Tài liệu tham khảo
Campbell J. Invisible Macrodefects in Castings. Journal de Physique IV, 1993, 03(C7): C7861–C7872.
Laslaz G and Laty P. Gas Porosity and Metal Cleanliness in Aluminum Casting Alloys. AFS Transactions, 1991, 99: 83–90.
Divandari M. Mechanisms of Bubble Damage in Castings. Ph.D thesis, The University of Birmingham, UK, 2001.
Reilly C, Green N R, and Jolly M R. Oxide Entrainment Structures in Horizontal Running Systems. Shape Casting Symposium, San Francisco, USA, 2009.
Bonollo F and Odorizzi S. Numerical Simulation of Foundry Processes. Servizi Grafici Editoriali, Padova, Italy, 2001.
Liu L, Samuel A M, and Samuel F H. Influence of Oxides on Porosity Formation in Sr-treated Al-Si Casting Alloys. Journal of Material Science, 2003, 38(6): 1255–1267.
Kuriyama Y, Yano K and Nishido S. Optimization of Pouring Velocity for Aluminum Gravity Casting. Fluid Dynamics, Computational Modeling and Applications, 2012, 26, Dr. L. Hector Juarez (Ed.), Japan.
Masoumi M, Hu H, Hedjazi J, et al. Effect of Gating Design on Mold Filling. AFS Transactions, 2005, Paper 05–152(02).
Hsu Fu-Yuan, Jolly M R and Campbell J. A Multiple-Gate Runner System for Gravity Casting. Materials Processing Technology, 2009, 209(17): 5736–5750.
Campbell J. Castings. 2nd ed., Butterworth-Heinemann, Oxford, 2003.
Campbell J. Castings Practice the 10 Rules of Castings. Modern Castings Elsevier Butterworth-Heinemann, 2004, 44: 39–40.
Svoboda J M. Basic Principles of Gating and Risering. American Foundry Men’s Society Cast Metals Institute AFS-CMI, 1995.
Ricardo Fuoco. The Effect of Gating System Design on the quality of Aluminum Gravity Casting. Computational Materials Science, 2006, 36(4): 457–467.
Bao S, Engh T A, Syvertsen M. Inclusion (particle) removal by interception and gravity in ceramic foam filters. Journal of Materials Science, 2014, 47(23): 7986–7998.
Fuwang Chen, Xuebing Huang and Yong Wang. Investigation on foam ceramic filter to remove inclusions in revert superalloy. Materials Letters, 1998, 34: 372–376.
Jonas B, Svensson I L, and Yasuhiro M. Evaluation of Filter Parameters from Direct Observations of Metal Flow in Aluminium Castings. In: Proc. 1st International Conference on Gating, Filling and Feeding of Aluminum Castings, 1999.
Hatef H, Ramin R. Naturally-Pressurized Running Systems: The Role of Ceramic Filters. Journal of Applied Sciences, 2009, 9(1): 2115–2122.
Roger S K. The use of foam filters to improve production control in the aluminium automotive foundry. In: Proc. 1st International Conference on Gating, Filling and Feeding of Aluminum Castings, 1999.
Hadi A, Baghshahi S, Emadi R. Different pore size alumina foams and study of their physical and mechanical properties. Mater. Sci. Eng., 2009, 132: 340–343.
Yury Lerner. Development of an improved direct pour system for aluminum casting. In: Proc. 1st International Conference on Gating, Filling and Feeding of Aluminum Castings, 1999.
Moreira E A, Innocentini M D M, Coury J R. Permeability of ceramic foams to compressible and incompressible flow. Journal of the European Ceramic Society, 2004, 24: 3209–3218.
Kennedy M W, Zhang K X, Fritzsch R. Characterization of Ceramic Foam Filters Used for Liquid Metal Filtration. Metallurgical and Materials Transactions B, 2013, 44(3): 671–690.