Use this URL to cite or link to this record in EThOS:
Title: Microstructure-mechanical property relationships during the thermomechnaical simulation and annealing of novel interstitial free steels
Author: Porter, S. L.
Awarding Body: University of Wales Swansea
Current Institution: Swansea University
Date of Award: 2005
Availability of Full Text:
Access from EThOS:
Interstitial Free (IF) Steels are widely used in the automotive industry. Their excellent mechanical property characteristics, such as the high formability typified by high rmean-values, low yield strength and high elongation make them very suitable for manufacturing into automotive body panels. However, their properties and microstructures are affected by their composition and processing conditions. This research program is focused on the optimisation of the properties of two Interstitial Free Steel Grades, an experimentally produced mild Ti-Nb IF Grade and a commercially produced high strength Ti-IF grade. The optimisation of the processing conditions is vital to the enhancement of obtained properties and is investigated in two parts within this research program. The first part will simulate the effect of variable hot rolling parameters on these two grades. This study will aim to investigate the effect of the finishing temperature, effect of run-out table cooling and coiling temperature, all of which are extremely important parameters within the hot mill and may have a significant effect on the microstructure and properties of the two grades. For this work the Gleeble 3500 thermomechanical system has been employed to simulate the hot rolling conditions. The second part will aim to simulate the effect of batch annealing sequences on cold rolled strips of these two grades. This shall aim to determine the optimum annealing conditions to obtain desirable properties on the studied grades. The work demonstrated the differences in microstructure and properties of the two grades investigated, with respect to the simulated processing parameters. It could be observed that the microstructures obtained on these two grades were indeed very different, with the microstructure of the high strength commercial Ti-IF grade consisting of mainly non-equilibrium ferritic and / or bainitic structures, while the microstructure of the mild experimental Ti-Nb IF Grade mainly consisting of recrystallised equiaxed ferrite. Testing of the batch annealed strips, revealed that the rmean -values were very high for both steels, thus permitting a determination of the annealing temperature for which optimum strength and formability values could be obtained.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available