Analysis and Modeling of Stress–Strain Curves in Microalloyed Steels Based on a Dislocation Density Evolution Model

Evelyn Sobotka*, Johannes Kreyca, Maria Cecilia Poletti, Erwin Povoden-Karadeniz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Microalloyed steels offer a good combination of desirable mechanical properties by fine-tuning grain growth and recrystallization dynamics while keeping the carbon content low for good weldability. In this work, the dislocation density evolution during hot rolling was correlated by materials modeling with flow curves. Single-hit compression tests at different temperatures and strain rates were performed with varying isothermal holding times prior to deformation to achieve different precipitation stages. On the basis of these experimental results, the dislocation density evolution was evaluated using a recently developed semi-empirical state-parameter model implemented in the software MatCalc. The yield stress at the beginning of the deformation σ0, the initial strain hardening rate θ0, and the saturation stress σ—as derived from the experimental flow curves and corresponding Kocks plots—were used for the calibration of the model. The applicability for industrial processing of many microalloyed steels was assured by calibration of the model parameters as a function of temperature and strain rate. As a result, it turned out that a single set of empirical equations was sufficient to model all investigated microalloyed steels since the plastic stresses at high temperatures did not depend on the precipitation state.

Original languageEnglish
Article number6824
JournalMaterials
Volume15
Issue number19
DOIs
Publication statusPublished - Oct 2022

Keywords

  • computational materials engineering
  • dislocation density evolution
  • flow curve
  • mechanics of materials
  • microalloyed steel

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Fields of Expertise

  • Advanced Materials Science

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