The influence of tempering on the corrosion resistance of newly developed steels

 

Show simple item record

dc.contributor.advisor Ball, Anthony en_ZA
dc.contributor.author Joubert, K J en_ZA
dc.date.accessioned 2016-09-20T12:25:02Z
dc.date.available 2016-09-20T12:25:02Z
dc.date.issued 1989 en_ZA
dc.identifier.citation Joubert, K. 1989. The influence of tempering on the corrosion resistance of newly developed steels. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/21797
dc.description Bibliography: pages 105-113. en_ZA
dc.description.abstract This thesis deals with the effect of heat treatment on the localized corrosion resistance of the low carbon, chromium containing steels, designated 825, 102A and 122 which recently have been developed. The potentiodynamic polarization technique has been employed to determine the corrosion characteristics of the three steels. The results do not accurately reflect the effect heat treatment has on corrosion rates but scanning electron microscopy of corroded surfaces does allow a characterization. Both tempering temperature and time at temperature have a significant influence on the corrosion behaviour of chromium steels because the type, size and morphology of carbide precipitates are determined by the temperature and time of temperi ng. Localized pitting corrosion predominates for specimens tempered at temperatures below 450°C. Intergranular corrosion together with general corrosion occur after tempering at temperatures. in excess of 450°C. The resul ts of hardness tests show that secondary hardeni ng occurs after tempering between 450°C and 600°C. Secondary hardening suggests the presence of chromium carbides which deplete the surrounding matrix of chromium leaving it susceptible to active general corrosion (within the grains) and intergranular corrosion (at grain boundaries). A model showing the effect that 12% chromium, in comparison to 8% chromium, has on the corrosion resistance, is proposed. The significance of these results with regard to the application of the steels is discussed. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Steel - Heat treatment en_ZA
dc.subject.other Steel - Corrosion en_ZA
dc.subject.other Steel - Metallurgy en_ZA
dc.subject.other Materials Engineering en_ZA
dc.title The influence of tempering on the corrosion resistance of newly developed steels en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Centre for Materials Engineering en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Joubert, K. J. (1989). <i>The influence of tempering on the corrosion resistance of newly developed steels</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/21797 en_ZA
dc.identifier.chicagocitation Joubert, K J. <i>"The influence of tempering on the corrosion resistance of newly developed steels."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1989. http://hdl.handle.net/11427/21797 en_ZA
dc.identifier.vancouvercitation Joubert KJ. The influence of tempering on the corrosion resistance of newly developed steels. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1989 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21797 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Joubert, K J AB - This thesis deals with the effect of heat treatment on the localized corrosion resistance of the low carbon, chromium containing steels, designated 825, 102A and 122 which recently have been developed. The potentiodynamic polarization technique has been employed to determine the corrosion characteristics of the three steels. The results do not accurately reflect the effect heat treatment has on corrosion rates but scanning electron microscopy of corroded surfaces does allow a characterization. Both tempering temperature and time at temperature have a significant influence on the corrosion behaviour of chromium steels because the type, size and morphology of carbide precipitates are determined by the temperature and time of temperi ng. Localized pitting corrosion predominates for specimens tempered at temperatures below 450°C. Intergranular corrosion together with general corrosion occur after tempering at temperatures. in excess of 450°C. The resul ts of hardness tests show that secondary hardeni ng occurs after tempering between 450°C and 600°C. Secondary hardening suggests the presence of chromium carbides which deplete the surrounding matrix of chromium leaving it susceptible to active general corrosion (within the grains) and intergranular corrosion (at grain boundaries). A model showing the effect that 12% chromium, in comparison to 8% chromium, has on the corrosion resistance, is proposed. The significance of these results with regard to the application of the steels is discussed. DA - 1989 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1989 T1 - The influence of tempering on the corrosion resistance of newly developed steels TI - The influence of tempering on the corrosion resistance of newly developed steels UR - http://hdl.handle.net/11427/21797 ER - en_ZA


Files in this item

This item appears in the following Collection(s)

Show simple item record