Title: Formability investigation using a new test design for hot stamping processes

Authors: Mohamed Mohamed; Jianguo Lin; Alistair Foster; Trevor Dean; John Dear

Addresses: Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK; Department of Mechanical Engineering, Faculty of Engineering, Helwan University, Egypt ' Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK ' Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK ' School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK ' Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK

Abstract: Hot stamping is widely used in the forming of lightweight automotive panel components. The process optimisation requires knowledge of constitutive relations of work-piece material but assessment of formability of materials in hot stamping conditions is exceptionally challenging. A testing method and corresponding specimen design are developed in this paper for evaluating formability of materials in hot stamping conditions. A series of tests have been carried out for AA6082 aluminium alloy, at different forming rates and failure modes have been analysed. A set of stress-state dependent damage equations for AA6082 is introduced and this has been input into the FE code, ABAQUS. An FE model is developed and validated from the experimental results. Failure modes at particular forming conditions are predicted and designed specimen shapes are optimised for different forming conditions. It is concluded that work-piece design is related to ductility for hot stamping conditions and recommendations for work-piece design are given.

Keywords: testpiece design; hot stamping; AA6082; CDM model; continuum damage mechanics; formability; FEM; finite element method; process modelling; aluminium alloys; forming rates; failure modes; stress.

DOI: 10.1504/IJMPT.2017.080563

International Journal of Materials and Product Technology, 2017 Vol.54 No.1/2/3, pp.3 - 19

Received: 06 Apr 2015
Accepted: 04 Oct 2015

Published online: 31 Oct 2016 *

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