Mechanical Behaviour of a Rephosphorized Steel for Car Body Applications — Effects of Temperature, Strain Rate and Pre-treatment
Journal article, 2011

Temperature and strain rate effects on the mechanical behaviour of a commercial rephosphorized, interstitial free steel have been investigated by uniaxial tensile testing, covering applicable temperatures (-60 – +100°C) and strain rates (1•10-4 – 1•102 s-1) experienced in automotive crash situations. The effect of prestraining to 3.5 % with or without successive annealing at 180°C for 30 min has also been evaluated. These treatments were used to simulate pressing of the plates and the paint-bake cycle in the production of car bodies. Yield and ultimate tensile strengths, ductility including uniform and total elongation and area reduction, thermal softening effect at high strain rate and strain rate sensitivity of stress were determined and discussed in all cases. It was found that the Voce equation [σ = σs- (σs -σ0) exp (ε/ε0)] can be fitted to the experimental true stress-true plastic strain data with good precision. The parameter values in this equation were evaluated and discussed. Furthermore, temperature and strain rate effects were examined in terms of thermal and athermal components of the flow stresses. Finally, a thermal activation analysis was performed.

thermal and athermal components

tensile properties

strain rate sensitivity

Rephosphorized interstitial free steel

Voce equation

temperature effects

strain hardening


Yu Cao

Chalmers, Materials and Manufacturing Technology, Surface and Microstructure Engineering

Johan Ahlström

Chalmers, Materials and Manufacturing Technology, Materials Technology

Birger Karlsson

Chalmers, Materials and Manufacturing Technology, Materials Technology

Journal of Engineering Materials and Technology, Transactions of the ASME

0094-4289 (ISSN) 1528-8889 (eISSN)

Vol. 133 2 021019-1 - 021019-11- 021019

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Sustainable development

Subject Categories

Materials Engineering

Areas of Advance

Materials Science



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