Graduate Research Papers

Availability

Open Access Graduate Research Paper

Keywords

Aluminum castings--Cooling;

Abstract

Besides proper design of gating and risering systems, there are several methods used to control and modify solidification behavior of cast alloys. Within these methods, the most widely used are local cooling aids employing cooling fins (thin segments attached to problematic areas of casting) or external chills (metal inserts placed into mold walls to accelerate heat withdrawing from potential hot spot). The later helps to promote directional solidification when traditional methods are not possible to use due to limitations related to the casting design. Despite relatively wide application in aluminum foundries, there are no specific recommendations on cooling aids parameters selections have been published.

The objective of the study was to compare effectiveness of different local cooling aids and to develop practical recommendations on their applications. The research has been conducted via computer modeling of solidification process, based on finite difference computation method (FDM). Results of modeling were compared with experimental. Fourteen different fin sets and twenty-six different chills were studied. As an integral indicator of the fins / chills effectiveness, normalized solidification time of aluminum (A206) test casting in shape of rectangular (4x4x0.75 in) plate was used. Normalized solidification time was calculated as the ratio between the actual solidification time and the solidification time of test casting with no fins or chills. Established as a result of the study, nonlinear relations between fin sets and chills parameters and their impact on solidification behavior allowed developing general guideline for cooling aids selection depending upon particular casting solidification conditions. Practically, it allows selecting optimal geometry of a chill depending on chill material properties (thermal conductivity and specific heat) and desirable effect. It also enables to calculate parameters of fins with the similar effect.

Year of Submission

5-7-2003

Degree Name

Master of Arts

Department

Department of Industrial Technology

First Advisor

Yury Lerner

Comments

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Date Original

5-7-2003

Object Description

1 PDF file (56 pages)

Language

en

File Format

application/pdf

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