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The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420
Dissertation (MSc)--University of Pretoria, 2010.
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University of Pretoria
2013
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| _version_ | 1867613568278462464 |
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| access_status_str | Open Access |
| author2 | Du Toit, Madeleine |
| author_browse | Du Toit, Madeleine |
| author_facet | Du Toit, Madeleine |
| collection | Thesis |
| dc_rights_str_mv | © 2009, 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 | Dissertation (MSc)--University of Pretoria, 2010. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/29839 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:38:12.930Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| 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:2263/29839 The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 Du Toit, Madeleine lilian.barlow@kioltd.com Barlow, Lilian Debra M23c6 M7c3 Retained austenite Stainless Martensitic Carbide Austenitising temperature UCTD Dissertation (MSc)--University of Pretoria, 2010. The effect of austenitising and tempering practice on the microstructure and mechanical properties of two martensitic stainless steels was examined with the aim of supplying heat treatment guidelines to the consumer or fabricator that, if followed, would result in a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 HV and 740 HV (hardness on the Vickers scale) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI type 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. The effect of various austenitising and tempering heat treatments was examined. Steel samples were austenitised at temperatures between 1000°C and 1200°C, followed by quenching in oil. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbide precipitates. The influence of tempering, double tempering, and sub-zero treatment was investigated. Optical and scanning electron microscopy was used to characterise the as-quenched microstructures, and X-ray diffraction analysis was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 HV to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD™ model) were used to explain these microstructures based on the solubility of the carbide particles in the matrix at various austenitising temperatures. The carbide particles were found to be mainly in the form of M7C3 at elevated temperatures, transforming to M23C6 on cooling. Materials Science and Metallurgical Engineering unrestricted 2013-09-07T16:53:32Z 2010-02-05 2013-09-07T16:53:32Z 2009-09-02 2010-02-05 2009-11-26 Dissertation Barlow, LD 2009, The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/29839 > E10/53/gm http://hdl.handle.net/2263/29839 http://upetd.up.ac.za/thesis/available/etd-11262009-182934/ © 2009, 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 application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | M23c6 M7c3 Retained austenite Stainless Martensitic Carbide Austenitising temperature UCTD The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 |
| title | The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 |
| title_full | The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 |
| title_fullStr | The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 |
| title_full_unstemmed | The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 |
| title_short | The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420 |
| title_sort | effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel aisi 420 |
| topic | M23c6 M7c3 Retained austenite Stainless Martensitic Carbide Austenitising temperature UCTD |
| url | http://hdl.handle.net/2263/29839 http://upetd.up.ac.za/thesis/available/etd-11262009-182934/ |