Modelling of formation of stock surface and subsurface layers in breakdown rolling of aluminium alloy

Abstract

Simulations of the reheating and breakdown rolling of the Al-Mg-Mn aluminium alloy AA3104 carried out using a two-high laboratory mill were supported by detailed numerical modelling of the stock surface layer formation. The model of the stock/roll interface is usually a micro-part of a more complex macro-finite-element model. Corresponding linking of modelling scales is a necessary stage for numerical analysis of fine mechanisms of the interface formation. This procedure allows for consideration of the fine mechanisms responsible for formation of the scale/metal interface while, at the same time, reducing the number of elements under consideration. It has been shown that a small amount of Mg (as oxides) was intermixed into the subsurface layer of a few microns depth by deformation during rolling. The mechanisms which led to the deformation and mixing of the oxide particles into the subsurface layer arose from slip at the roll/stock interface and the action of roll surface asperities on the stock surface.