Effects of the entrained surface film on the reliability of castings

Jiawei Mi, Richard Harding, John Campbell

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

The tilt pouring and gravity top pouring of an Al-4.5 pct Cu alloy have been studied. A computer-controlled rollover casting wheel was used to perform the tilt pouring. Filling sequences with tranquil or turbulent flow patterns have been visualized using real-time X-ray video radiography and modeled using a computational fluid dynamics (CFD) code. The area of the free surface film entrained into the bulk of liquid metal in different filling conditions has been calculated using a filling sequence free from surface turbulence as a baseline. The tensile properties of the castings have been quantitatively assessed for reliability using a two-parameter Weibull distribution function. The study reveals that the liquid metal flow in the mold filling process can be accurately simulated using a CFD code. In addition, the computed total surface area of the entrained surface film can be used as a criterion to judge the deterioration of reliability. The high Weibull modulus achieved by filling a mold without surface turbulence was reduced by a factor of 2.5 of its original value by entrained surface films. Entrainment of bubbles required surface turbulence, but folded films could be entrained simply by contraction of the free surface, creating excess surface film that necessarily folds inward.
Original languageEnglish
Pages (from-to)2893-2902
Number of pages10
JournalMetallurgical and Materials Transactions A
Volume35A
DOIs
Publication statusPublished - 1 Sep 2004

Fingerprint

Dive into the research topics of 'Effects of the entrained surface film on the reliability of castings'. Together they form a unique fingerprint.

Cite this