Prediction on the Mechanical and Forming Behaviors of Ferrite-Martensite Dual Phase Steels Based on a Flow Model

Abstract

An innovative flow model incorporating the mixture hardening law, anisotropic yield function, and incremental strain formulations was elaborated and applied to DP590 ferrite-martensite dual phase steel. To verify the flow model, both the macro/micro stress-strain responses and the forming patterns of DP590 steel with different martentite contents were simulated during the processes of the cup deep-drawing and the unconstrained cylindrical bending to evaluate the influence of martensite content on the mechanical and forming behavior of the steel. It was found that maternsite content has a significant impact on the macro/micromechanical and forming behavior of the steel, i.e., the ferrite and steel effective stresses and the effective macro/micro-strain distribution in the cup. Under the unconstrained cylindrical bending, the simulated effective maximum macro/micro-strains were in good agreement with the calculated results from the mixture law-based model. It was concluded that the Buaschinger effect is the main reason for an 8 % error between the simulated and experimental results. The flow model was proved to predict the macro/micro flow and forming behavior of the dual phase steels with a good accuracy.

Numerical analysis of springback with experimental validation using UCB test

“…However, this is costly in resources and time, while nowadays numerical procedures may be applied to predict and compensate the elastic recovery of component after tool removal (Chongthairungruang et al 2013). The UCB (unconstrained cylindrical bending) test is a benchmark, which was proposed by Numisheet conference series for assessment of springback (Lee et al 2009, Gou et al 2020 and it is chosen in this research to evaluate the behavior for proposed materials, since it involves a simple geometry while promoting high elastic recovery for the metallic sheet and includes contact with friction, thus evaluating also the numerical approach and accuracy of the finite element analysis (Lee et al 2009, Gou et al 2020. The geometry of the tools is predefined and depicted in the Figure 2.…”