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The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa
Thesis (PhD)--University of Pretoria, 2019.
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| Language: | English |
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University of Pretoria
2019
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| _version_ | 1867613574991446016 |
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| access_status_str | Open Access |
| author2 | Mostert, R.J. (Roelf) |
| author_browse | Mostert, R.J. (Roelf) |
| author_facet | Mostert, R.J. (Roelf) |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2019. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/70603 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:19.381Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2019 |
| publishDateRange | 2019 |
| publishDateSort | 2019 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/70603 The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa Mostert, R.J. (Roelf) u11154315@tuks.co.za Kapito, Asimenye UCTD Carbide-free alloy Heat treatment process Forged rail wheel Railway infrastructure Alloy design Sustainability in transport Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action Thesis (PhD)--University of Pretoria, 2019. This study investigates the carbide-free bainitic steels for forged rail wheel applications in South Africa. This project emanated from the need for durable rail steels by the South African industry, particularly for wheel applications. The pearlitic steels have reached a threshold in their development and bainitic steels have emerged as the third generation of rail steels, particularly the carbide-free bainitic alloys. The addition of high silicon has been found to retard the formation of carbides in bainite, forming what is called carbide-free bainite. This thesis gives an in-depth literature review on carbide-free and pearlitic steels, their wear properties and failure mechanisms when applied as rail steels. It also gives details on the experimental procedure followed to manufacture and test experimental alloys, as well as the results found. There is also a discussion on the future work to be completed. In this study a number of carbide-free bainitic alloys were manufactured with the addition of 1 wt% - 2 wt% silicon and other alloying elements, such as carbon, manganese and chromium. A thermodynamic study of the effects of alloying elements showed that the addition of molybdenum, vanadium and boron were beneficial in increasing the hardenability of the alloys. Examination of the bainite using transmission Kikuchi diffraction showed no carbides in the microstructure. The mechanical properties of the experimental carbide-free alloys were ranked against those of the commercial AAR Class C. The yield and tensile strengths of Alloy F were better than those of the reference. Alloy H showed better elongation and impact properties even though the impact properties of experimental carbide-free alloys was generally poor with high ductile to brittle transition temperatures. The sliding wear resistance of Alloy I heat treated at 400°C was similar to that of AAR Class B. In this study a number of alloy compositions and heat treatments were used to produce a carbide-free bainitic microstructure. The three different Alloy Series 1 to 3 studied the carbide-free bainitic microstructure under different test conditions. The carbide-free bainite alloy composition ranges have been developed for forged rail wheel applications for different sets of parameters: • Series 1 alloys (Alloys A to D) were produced to study the effect of alloying elements and heat treatment (isothermal and continuous cooling) on the carbide-free microstructure. • Series 2 alloys (Alloys E to H) were used to study the mechanical properties (hardness, tensile and impact) of the carbide-free bainitic microstructure. • Series 3 (Alloy I) was used to study the wear behaviour of the carbide-free microstructure. The best performing alloys for the different series tested are summarised in the table below. mi2025 Materials Science and Metallurgical Engineering PhD Unrestricted SDG-04: Quality education SDG-08: Decent work and economic growth SDG-09: Industry, innovation and infrastructure SDG-11: Sustainable cities and communities SDG-12: Responsible consumption and production SDG-13: Climate action 2019-07-08T09:46:59Z 2019-07-08T09:46:59Z 2019/04/10 2019 Thesis Kapito, A 2019, The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/70603> A2019 http://hdl.handle.net/2263/70603 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Carbide-free alloy Heat treatment process Forged rail wheel Railway infrastructure Alloy design Sustainability in transport Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa |
| title | The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa |
| title_full | The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa |
| title_fullStr | The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa |
| title_full_unstemmed | The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa |
| title_short | The design of a carbide-free alloy compsition and heat treatment process for forged rail wheel application in South Africa |
| title_sort | design of a carbide free alloy compsition and heat treatment process for forged rail wheel application in south africa |
| topic | UCTD Carbide-free alloy Heat treatment process Forged rail wheel Railway infrastructure Alloy design Sustainability in transport Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-11 SDG-11: Sustainable cities and communities Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-13 SDG-13: Climate action |
| url | http://hdl.handle.net/2263/70603 |