Prediction of Earing of Hot-Rolled Al Sheets from Pole Figures

Adrienn Hlavacs,Marton Benke,Valeria Mertinger,Mate Szucs

doi:10.3390/met11010099

Abstract

The formation of uneven cup heights during deep drawing is called earing. This phenomenon is caused by the planar anisotropy of formability in sheets, which is the result of crystallographic texture. In addition to analytical and finite element methods, a simple and quick method was developed recently to predict the earing profile of Al sheets solely from the data of {200} pole figures. So far, the method was applied on final state sheets cold rolled to 0.3–3 mm thickness and subsequently annealed. Within this manuscript, the earing prediction method is applied on 3003 type Al sheets with the thickness of ~6 mm, being in the hot-rolled state. Texture examinations were performed at different depths, from which earing profiles were calculated. For comparison, earing profiles were calculated from Lankford values that were determined by tensile tests. It is shown that in the case of hot-rolled Al sheets, if the grain structure is uniform across the thickness of the sheet, the earing profile can be appropriately calculated from the full {200} pole figure obtained from surface X-ray Diffraction (XRD) texture measurements.

Highlights

The plastic anisotropy of aluminum sheets can be characterized experimentally through deep drawing tests performed on circular blanks
The correlation was used in the work by Lelotte et al [20] in which the Lankford values were determined from finite element (FE) simulated tensile tests and the deep drawing tests were simulated
It was shown that such the earing profileprofile that isthat calculated from surface texturetexture measurements and theand in cases, such cases, the earing is calculated from surface measurements earing profile profile that is obtained from Lankford values determined by tensileby tests—describing the earing that is obtained from Lankford values determined tensile tests—dethescribing earing behavior the full thickness of the sheet—show a good correlation

Summary

Introduction

The plastic anisotropy of aluminum sheets can be characterized experimentally through deep drawing tests performed on circular blanks. Despite that the earing prediction methods are time and cost efficient, deep drawing tests did not vanish completely since the calculation method needs to be experimentally validated, and they are still practiced by some companies. Such tests cannot be carried out above a certain sheet thickness. Hot-rolled aluminum sheets are generally in the range where deep drawing experiments cannot always be performed. The r-values are obtained first through experimental tensile tests from which the earing profile is calculated using

Methods

Results

Discussion

Conclusion