Minimising shrinkage defects in aluminium alloy ingots with the help of computer modelling

Описание

Тип публикации: статья из журнала

Год издания: 2019

Идентификатор DOI: 10.17580/tsm.2019.09.12

Ключевые слова: Aluminium alloys, Casting, Crystallization, Mould, Shrinkage porosity, Small ingot

Аннотация: In order to determine and minimise the number of such casting defects as shrinkage porosity in the body of a casting, casting and crystallization of a small aluminium ingot have been simulated. The hydrodynamic problem of alloy casting in the mould was calculated with the help of ProCAST and the overlaid grids. The standard ?356 alПоказать полностьюloy was used as the ingot material, while the mould was made of grey iron (SCh20). A thermodynamic database was used to calculate the temperature effect on heat conductivity, density, dynamic viscosity and the ratio between the solid and liquid phases of that particular alloy. To solve this problem, a work model was built of a mould with an ingot. A finite element tetragonal mesh was created in the Mesh_Cast module. The mesh included 2,012,845 finite elements. It was found that the use of special reflecting barriers to minimise heat dissipation during crystallization didn’t prove to be effective. Modification of the mould, i.e. making the bottom of the mould thicker to increase its accumulative capacity and prevent solidification of the lower layers of metal, failed to yield any positive result. A 10 mm rise in the bottom padding leads to a 10-15% reduction in porosity in the surface padding area. However, it didn’t produce any noticeable effect on the shrinkage porosity in the casting body. Bigger slots inside the mould help split the porosity zone pushing it towards the ends of the mould and redistributing it in the horizontal plane. The use of cooling fins at the bottom of the mould leads to some redistribution of the porosity zone both vertically and horizontally. However, this design doesn’t appear to make a huge difference. The most acceptable porosity in the casting body can be achieved with the Befesa mould which has a stepped design. © 2019, "Ore and Metals" Publishing house. All rights reserved.

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Издание

Журнал: Tsvetnye Metally

Выпуск журнала: Vol. 2019, Is. 9

Номера страниц: 75-79

ISSN журнала: 03722929

Издатель: "Ore and Metals" Publishing house

Авторы

  • Ilin A.A. (LLC “RUSAL Engineering-Technical Center”, Krasnoyarsk, Russian Federation)
  • Soldatov S.V. (LLC “RUSAL Engineering-Technical Center”, Krasnoyarsk, Russian Federation)
  • Belousova N.V. (Department of Non-Ferrous Metallurgy, Siberian Federal University, Krasnoyarsk, Russian Federation)

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