Microstructual evolution of a dual phase steel during continuous annealing

Master thesis (2016)

Authors

Contributors

J. Sietsma (mentor)
Department
Materials Science and Engineering (MSE) (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2016 Wu, X.
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Published Date

29-08-2016

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Faculty

Mechanical, Maritime and Materials Engineering

Department

Materials Science and Engineering (MSE)

Abstract

With a combination of high strength and good formability, dual-phase steels have gained much interest in the automobile industry. The final microstructure, which leads to mechanical properties of the product, is strongly dependent on the processing of the steel. Apart from hot-rolling and cold-rolling, the parameters during continuous annealing are of great importance to control the properties of the final product. This thesis is aimed to study the influence of heating rates on the microstructual evolution of a DP-steel during continuous annealing lines. The microstructual evolution evolves several phenomena, such as ferrite recrystallization, pearlite degradation, and austenite phase transformation. Experimental approaches as dilatometry and SEM are used to investigate the evolution, by applying different heating rates and stop-quenching at different temperature and soaking times. Modelling approaches, CA-model and phase field model, are also introduced to provide a further insight into the phenomena.