Paper Titles
Projection of Extrusion Force of Spray-Formed Al-25wt%Si with High Temperature Compression
p.374
Effect of Fe Content on Hot Tearing of High-Strength Al-Mg-Si Alloy
p.380
Modelling Dispersoid Precipitation in Scandium Containing Aluminium Alloys
p.386
Alloying with Silicon and Copper in Aluminum Alloys
p.392
A Study of Bubble Entrainment as Related to Runner Velocity in Aluminum Sand Castings Using the Cosworth Process
p.398
Surface Treatment of Aluminum Alloy with Laser Irradition to Increase Wear Resistance
p.404
Evaluation of Friction Spot Joining Weldability of Al Alloys for Automotive
p.411
Atomic Bonding of Precipitate and Properties of Al-Cu-Mg Alloy
p.417
Robust Trimming of Automotive Panels
p.423

A Study of Bubble Entrainment as Related to Runner Velocity in Aluminum Sand Castings Using the Cosworth Process

Article Preview

Abstract:

Traditional gravity pour down-sprue methods of filling moulds in the making of aluminum castings inherently lead to oxide and air bubble entrainment. The reason for this is found in the high velocities the metal flow experiences during the filling of a mould. The Nemak Windsor Aluminum Plant (WAP) produces cylinder blocks using the low-pressure Cosworth process, which includes low velocity up-hill filling of the sand mould package. This doctrine is followed in all except one part of the process: the runner system. The nature of the resulting defect is generally known as Head Deck Porosity. Runners were cast full in open production runners at three different velocities with the resulting quickly chilled castings analyzed using X-ray radioscopy, and Scanning Electron Microscopy. Results reveal that the subject bubble porosity is indeed the result of air entrained during initial transient flow within the production runner system whose velocity is higher than the critical value of 0.5ms-1. This theoretical value is corroborated by experimental results. In addition, a new "sessile" runner of optimized shape, filled at a velocity slower than the critical value, is proposed and analyzed using Magmasoft mould fill modelling software. The design can potentially replace the existing runner providing a casting free of entrained air.

You might also be interested in these eBooks
THERMEC 2006 View Preview

Info:

Periodical:

Materials Science Forum (Volumes 539-543)

Pages:

398-403

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.539-543.398

Citation:

Cite this paper

Online since:

March 2007

Authors:

John C. Burford, Jerry Sokolowski

Keywords:

Aluminum (Al), Bubble, Critical Velocity, Initial Transient, Mould, Oxide, Porosity, Runner

Export:

RIS, BibTeX

Price:

Permissions CCC:

Request Permissions

Permissions PLS:

Request Permissions

Сopyright:

© 2007 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

References

[1] Isawa, T. and Campbell, J., Initial Filling Transient of the Running System. Trans. Japan Foundrymen's Soc., 1994. 13: pp.38-49.

Google Scholar

[2] Campbell, J., Castings Practice The 10 Rules of Castings. 1 ed. 2004, Oxford, England: Elsevier Butterworth-Heinemann. 205.

Google Scholar

[3] Jorstad, J.L. and Rasmussen, W., Aluminum Casting Technology. 2nd ed, ed. A. Donna L. Zalensas. 1993, Des Plaines, Illinois USA: American Foundry Society. 356.

Google Scholar

[4] Sulaiman, S. and Keen, T.C., Flow Analysis Along the Runner and Gating System of a Casting Process. Journal of Materials Processing Technology, 1997. 63: pp.690-695.

DOI: 10.1016/s0924-0136(96)02708-2

Google Scholar

[5] Campbell, J., Castings. 1991, Oxford: Butterworth-Heinemann.

Google Scholar

[6] Drouzy, M. and Mascre, C., Metallurgical Reviews, 1969. 14: pp.25-46.

Google Scholar

[7] Divandari, M. and Campbell, J., A New Technique for the Study of Aluminum Oxide Films. Aluminum Transactions, 2000. 2(2): pp.233-238.

Google Scholar