Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2009. / Materials in almost all components are subjected to some kind of loading that must
be correctly predicted to produce reliable designs. The understanding of a material's
properties significantly impacts appropriate selection for a structure. This kind of
material characterization is also important in the development of improved or new
materials for high strength and novel applications. There are numerous metallurgical
variables (composition and process parameters) that influence the physical and
mechanical properties of materials.
The aim of this work has been to study the influence of microstructure on mechanical
properties of steel, specifically the effect of grain sizes within solid phase mixtures.
Parameters for simple models of the variation of material properties with grain size
can be determined. These models can then be incorporated in the material data sets
of Finite Element Analysis programs which will then allow for structural analysis with
zones in a material having different grain sizes.
The deformation and damage behaviour of EN 8 steel have been stUdied with
emphasis on the effects of grain size on the elastic-plastic response of the material.
For that purpose, EN 8 specimens with a range of microstructures (grain size and
phase) were prepared by heat treatment The microstructural features were carefully
characterized using two different experimental surface microscopy techniques; Light
Optical Microscope and Scanning Electron Microscope. The deformation and
hardness characteristics have been studied with the help of tensile and hardness
tests. The mechanical properties were determined as a function of microstructure
(grain size and phase). The yield stress followed the classical Hall-Petch relation.
The results indicated that tensile strength and hardness increases with decrease in
grain size while elongation decreases.
The main philosophy behind this research has been the study of the microstructure
and information from the iron-carbon phase diagram together with numerical analysis
of stress-strain data, in order, to understand the influence of grain size on mechanical
behaviour of EN8 steel. This combination was then used to make general
conclusions on mechanical behaviour of EN 8 based on heat treatment history.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/1254 |
| Date | January 2009 |
| Creators | Moleejane, Cullen Mayuni |
| Publisher | Cape Peninsula University of Technology |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by-nc-sa/3.0/za/ |
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