Effect of Cold Deformation on the Paint-Baking Response of Al-Mg-Si Alloy Sheet for Automotive Body

Abstract:

The effect of cold deformation on the yield strength and precipitate behavior of Al-1.3Mg-1.2Si-0.5Cu-0.7Mn alloy sheet subjected to T4P temper for automotive body panels before and after paint-bake treatment were investigated by tensile test and differential scanning calorimetry (DSC) analysis. The results show that the T4P alloy sheet has significant work-hardening response (WHR), and the yield strength increment exceeds 190MPa as the tensile deformation strain approaches 15%. The unstrained T4P alloy sheet has obvious paint-baking response (PBR), and the yield strength increment is up to 80MPa, while the PBR of the cold stretched T4P alloy sheets decrease with increasing level of tensile deformation, and the minimal PBR is only 17.8MPa. The prior tensile deformation accelerates the precipitation of β″ and β′ phase from the T4P alloy matrix during paint-bake cycle but weakens the age-hardening response (AHR) and PBR of T4P alloy sheet. Moreover, it is evident that the T4P alloy sheet simulation paint-bake treated at 170°C for 30min can not fully exert the aging potential of the alloy sheet.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 414-419
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.414
• Online since: January 2012
• Authors: Ni Tian, Lei Pan, Chun Cheng Liu, Jian Jun Wang, Gang Zhao, Liang Zuo, Chun Ming Liu
• Keywords: Al-Mg-Si Aluminum Alloy Sheet, Cold Deformation, Paint-Baking Response, T4P Temper

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