Determination of the critical drop height and critical flow velocity of aluminum alloy (AL-91% Mg-8% Fe-0.4% Zn-0.2%) in gravity sand casting

Year 2023, Volume: 7 Issue: 2, 149 - 156, 15.04.2023

Francis Inegbedion , James Orjı

https://doi.org/10.31127/tuje.1077467

Cited By: 1

Abstract

Casting is a manufacturing process in which molten metal is poured through the gating system to fill the mould cavity where it solidifies. Variations in casting parameters by different researchers have led to significant variations in casting guidelines, which have forced Foundry Engineers to carry out a number of trial-and-error runs to create guidelines based on their own experience. These variations in guidelines have led to defects occurring in casting during the mould filling process. This work aimed at determining the critical drop height and critical flow velocity of a certain molten aluminum alloy as it flow down the mould sprue in gravity sand casting. The continuity equation was used to describe the velocity distribution of the aluminum alloy as it flows down the sprue. The mathematical tool used in this research is the finite element method. It involves the discretization of the domain of interest into smaller finite elements. The weak form of the governing equation was obtained and integrated over the domain of interest. The results obtained, established the critical flow velocity of aluminum alloy, down the sprue, as 2.565 × 103 mm/s and the critical drop height as 377mm. Results obtained were compared with literature and were also used to produce various casts, it was observed that casts produced, using sprue height below the critical drop height obtained prevented casting defects, while at sprue height above the critical drop height, the danger of casting defects could not be avoided.

Keywords

Critical drop height, Critical velocity, Gravity sand casting, Finite element method, Sprue

References

• Feng L., (2008). Optimized Design of Gating/Riser System in Casting Based on CAD and Simulation Technology, Submitted to the faculty of the Worchester Polytechnic Institute in partial fulfillment of the requirements for degree of Master of science in Manufacturing Engineering.
• Attar E.H., Babaei R.P., Asgari K., Davami P., (2005). Modelling of air pressure effects in casting moulds, Journal of Modelling and Simulation in Materials Science and Engineering, 13, 903-917
• Lee P. D., Chirazi A., & See D. (2001). Modelling micro porosity in Aluminium - Silicon alloys: a review, Journal of Light Metals, 1, 15-30
• Sowa L. (1998). Model of the Casting Solidification taking into consideration the motion of liquid phase, Archives of Mechanical technology and Automatization, 18, 287 – 296
• Sowa, L., (2010). Mathematical Modelling of the Filling Process of a slender mould cavity, Scientific Research of the Institute of Mathematics and Computer Science, 9(2) 219-227
• Salih A. (2011). Conservation Equations of fluid Dynamics, Department of Aerospace Engineering, Indian Institute of space Science and technology, Thiruvananthapuram publishers 4-7
• Sowa L. & Bokota A. (2007). Numerical Modelling of Thermal and Fluid Flow Phenomena in the Mould Channel, Archives of Foundry Engineering, 7(4), 165 – 168.
• Sowa, L., (2010), Numerical Analysis of the Thermal and Fluid Flow Phenomena of the Fluidity test, Archives of Foundry Engineering, 10(1), 157 – 160.
• Bird R. B., Stewart W.E., & Lightfoot E.N., (2002). Transport Phenomena, 2nd edition, Wiley: NY.
• Aris, R., (1962). Vectors, Tensors, and the Basic Equations o Fluid Mechanics, Prentice Hall Publishers, Englewood Cliffs, NJ
• Ik-Tae I., Woo-Seung K., & Kwan-Soo L., (2001). A unified analysis of filling and solidification in casting with natural convection, International Journal of Heat and Mass Transfer, 44, 1507-1515
• Sowa, L., Sczygiol, N. Domoilski, T., & Bokota, A., (2008). Simplified Model of Metal Solidification in the Thin Plane Cavity of the Casting Mould, Archives of Foundry Engineering, 8(1), 309 – 312
• Bokota A. & Sowa L. (2010). Numerical Modelling of the thermal and fluid flow phenomena of the fluidity test, Archives of Foundry Engineering 10(1), 15–18
• Mishima S., & Szekely J. (1989). The modelling of fluid flow and heat transfer in mould filling, ISIJ International, 29(4), 324-332
• Majchrzak E., Jasinski M., & Kaluza G. (2004). Sensitivity analysis of solidification process with respect to the geometrical parameters of casting and mould, Archives of Foundry Engineering, 4(14) 279-284.
• Reddy J. N., (2006). An Introduction to the Finite Element Method, Third Edition, International Edition McGraw- Hill., 146 – 147, 441 - 442.
• Singiresu S. R. (2004). The Finite Element Methods in Engineering, fourth edition, Elsevier Science and Technology Books Publisher
• Hutton V. D. (2004). Fundaments of Finite Element Analysis, 1st Edition, McGraw-Hill Companies, Inc. 293 – 295
• Rohaya B. D. (2013). Design and Analysis of Casted LM6 - TIC in Designing of Production Tooling, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka (UTEM) 63 – 69
• Inegbedion F. and Akpobi J.A. (2019). Determination of the Critical Velocity of Molten Metal Flow in Casting Mould Sprue, International Journal of Engineering Trends and Technology (IJETT) – 67(10), 27 – 33.