Prediction of casting shrinkage using solidification simulation for pure aluminum

Other Title(s)

تحديد انكماش المسبوكات باستخدام محاكاة التجمد للألمنيوم النقي

Dissertant

Harb, Marwah Ali

Thesis advisor

Jabbur, Adnan Shamkhi

Comitee Members

Khushnaw, Farhad M.
al-Karim, Imad Abbud S.
Ali, Diya Chasib

University

University of Basrah

Faculty

Engineering College

Department

Department of Material Engineering

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

During the solidification , shrinkage defects will appear in the casting and these shrinkage defects take many forms , shrinkage cavities , porosities and surface sinks. The aim of this work is to estimate the shrinkage defects, where the final amount, size and distribution of voids are determined by several strong interacting process and metal variables, the estimation of shrinkage defects has been done by the combination of experimental and numerical studies.

The main goal of the experimental work is to predict the shrinkage defects locations in the final castings (which made of commercial pure Al) for five samples and the effect of chill on its location in sample five.

This can offers the ability of correcting the casting system to overcome the presence of these defects inside the castings. Numerical solution has been carried out using a program written in a Fortran language by adopting explicit finite difference method using [3-D] transient heat conduction differential equation.

Several factors were taken into consideration in this system, such as variation of liquid to solid volume fractions during solidification and changing the thermophysical properties of the cast metal with changing metal state.

Also, the latent heat of freezing was converted into an increase of apparent specific heat of the metal in the solidification temperature range. The model was built up to calculate the solidification parameters cooling rate, gradient temperature, solidification velocity and solidification period.

After simulation of a specified ingots , solidification parameters were calculated and the figures that show the variation in solidification parameters along the mid surface for each casting were drawn using MATLAB Version 7, 2004.

The shrinkage cavities have been predicted from the results of calculating the solidus time.

The appearance of a closed loop in the solidus time contours was taken as the criterion for this type of shrinkage.

By comparison between the sliced samples and simulated diagram, the simulation program showed a good ability of cavity prediction of location and extension.

Also , the program developed give a good responce to the cooling direction and variation which was confirmed by adding a copper chill in the casting mold of one sample.

Main Subjects

Engineering & Technology Sciences (Multidisciplinary)

Topics

• Mechanical properties
• Aluminum alloys
• Cracking(Chemistry)

No. of Pages

91

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-317155