- Title
- Modelling the effect of graphitization on the fracture toughness (JIC) of service exposed ASTM A-515 Gr. 65 material by the small punch test method
- Creator
- Grewar, Stephen James
- Subject
- Graphitization Fracture mechanics
- Date Issued
- 2017
- Date
- 2017
- Type
- Thesis
- Type
- Masters
- Type
- MEng
- Identifier
- http://hdl.handle.net/10948/18849
- Identifier
- vital:28737
- Description
- Small Punch Testing is a recent testing methodology with numerous favourable applications in engineering assessments. The advantages of this small specimen method are utilised to derive fracture toughness measurements on service exposed and graphitized steel designated ASTM A-515 Gr. 65. The EPRI-FAA “innovative method”, involving finite element analysis, is applied to obtain fracture toughness estimates and investigate the effect of localised graphitization on localised fracture toughness. The method is described in a stepwise manner and validated favourably against standard fracture toughness testing methods as well as the work of forerunners in this field. Analysis of twenty tested small punch disk specimens extracted from a service exposed welded pipe coupon showed that toughness decreases logarithmically with increased graphitization volumetric percentages in the small samples. Therefore graphitization is found to have a significant influence on local fracture toughness (JIC) of ASTM A-515 Gr. 65 steel under room temperature conditions. The possibility of documenting the effect of microstructural changes on other static properties such as yield strength and strain hardening exists provided that analysis of each disk specimen is performed prior to punch testing. A relationship between percentage graphitization and material toughness has been proposed for ASTM A-515 Gr. 65 at room temperature.
- Format
- xx, 100 leaves
- Format
- Publisher
- Nelson Mandela Metropolitan University
- Publisher
- Faculty of Engineering, the Built Environment and Information Technology
- Language
- English
- Rights
- Nelson Mandela Metropolitan University
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