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An investigation into the formability of advanced high strength steels in roll forming

Hanselman, S.J. (2014) An investigation into the formability of advanced high strength steels in roll forming.

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Abstract:The demand for fuel-efficient and cheap but reliable vehicles has forced the automotive industry to introduce new materials and to improve the accuracy of the metal forming process. A solution has been found in the application of advanced high strength steels in the massproducing roll forming process. To improve the accuracy of roll formed products made from advanced high strength steels with improved high quality standards, a main objective has been formulated, which is to analyse the formability of the DP1000 and CP800 advanced high strength steels in the roll forming manufacturing process. In general, an accurate Finite Element Model (FEM) is needed in which the manufacturing process can be optimized. In turn, an accurate FE model demands an accurate material model characterization. Therefore the first sub-objective was to characterize a Dual-Phase (DP) steel. The characterization included an analysis of the microstructure and chemical composition, a quasi-static tensile test to determine the tensile properties in a uni-axial state, a bending test to analyse the bending behavior of the DP sheet metal, a bending-unbending test to determine the hardening model and a loading-unloading test to analyse the elastic behavior of the material during elastic recovery. The second sub-objective was to validate the formability of the before mentioned DP steel and a Complex-Phase (CP) steel in the roll forming process. The materials have been roll formed into a U-shaped profile. The longitudinal strains near the strips edge have been measured. Common shape deviations such as the bow and springback in the final profile have been measured as well. The size of these shape deviations indicate the formability of these materials. Next to the roll forming trials, the minimum bend radius of the Dual-Phase steel has been determined. The third sub-objective was to improve the predictability of the material behavior of the DP and CP steel grades in the roll forming production process by improving the numerical models. This is still an ongoing project and is not completed yet.
Item Type:Internship Report (Master)
Clients:
Deakin University, Australia
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
Link to this item:http://purl.utwente.nl/essays/70286
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