Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel

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dc.contributor.advisorKnutsen, Robert Den_ZA
dc.contributor.authorMginqi, Lungile Ngubekhayaen_ZA
dc.date.accessioned2016-03-17T12:35:46Z
dc.date.available2016-03-17T12:35:46Z
dc.date.issued1997en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe stress corrosion cracking susceptibility of an experimental high nitrogen Cr-Mn stainless steel, known as Cromanite ™, and conventional AISI 304 stainless steel were investigated in order to compare their stress corrosion performance in solutions where AISI 304 stainless steel is known to be susceptible. Slow strain rate tests (SSRT) were performed on solution treated specimens a t30°C in aerated aqueous sodium chloride (NaCI) solution containing hydrochloric acid (HCI) of varying concentration at open circuit potentials. Static tests in the form of bent-beam tests were performed on both solution treated and aged specimens in 3M NaCI solution containing 0.05 M HCI. Potentiodynamic scans and Tafel plots were used to assess corrosion behaviour and corrosion rate respectively, while the electrochemical potentiokinetic reactivation (EPR) method was used to quantify the degree of sensitisation for the materials. The SSRT revealed poor corrosion behaviour of Cromanite TM in the presence of hydrochloric acid. Whilst AISI 304 could be examined for stress corrosion cracking at HCI concentrations up to 0.5 M HCI, Cromanite ™ exhibited corrosion rates which were too fast to permit assessment of stress corrosion susceptibility at HCI concentrations of 0.15 M or above. SCC started in a salt solution containing 0.05M HCI for AISI 304 while Cromanite TM cracked in both salt solution (3M NaCI) and in 0.05 M HCI +3M NaCI. The bent-beam test performed on solution treated specimens revealed no evidence of cracking for both alloys after 100 days of exposure; however, Cromanite ™ suffered substantial mass loss after this period. While aged Cromanite TM suffered intergranular cracking after only 25 days in the test solution, no cracking was observed for the aged AISI 304 after 75 days.en_ZA
dc.identifier.apacitationMginqi, L. N. (1997). <i>Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/17932en_ZA
dc.identifier.chicagocitationMginqi, Lungile Ngubekhaya. <i>"Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1997. http://hdl.handle.net/11427/17932en_ZA
dc.identifier.citationMginqi, L. 1997. Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Mginqi, Lungile Ngubekhaya AB - The stress corrosion cracking susceptibility of an experimental high nitrogen Cr-Mn stainless steel, known as Cromanite ™, and conventional AISI 304 stainless steel were investigated in order to compare their stress corrosion performance in solutions where AISI 304 stainless steel is known to be susceptible. Slow strain rate tests (SSRT) were performed on solution treated specimens a t30°C in aerated aqueous sodium chloride (NaCI) solution containing hydrochloric acid (HCI) of varying concentration at open circuit potentials. Static tests in the form of bent-beam tests were performed on both solution treated and aged specimens in 3M NaCI solution containing 0.05 M HCI. Potentiodynamic scans and Tafel plots were used to assess corrosion behaviour and corrosion rate respectively, while the electrochemical potentiokinetic reactivation (EPR) method was used to quantify the degree of sensitisation for the materials. The SSRT revealed poor corrosion behaviour of Cromanite TM in the presence of hydrochloric acid. Whilst AISI 304 could be examined for stress corrosion cracking at HCI concentrations up to 0.5 M HCI, Cromanite ™ exhibited corrosion rates which were too fast to permit assessment of stress corrosion susceptibility at HCI concentrations of 0.15 M or above. SCC started in a salt solution containing 0.05M HCI for AISI 304 while Cromanite TM cracked in both salt solution (3M NaCI) and in 0.05 M HCI +3M NaCI. The bent-beam test performed on solution treated specimens revealed no evidence of cracking for both alloys after 100 days of exposure; however, Cromanite ™ suffered substantial mass loss after this period. While aged Cromanite TM suffered intergranular cracking after only 25 days in the test solution, no cracking was observed for the aged AISI 304 after 75 days. DA - 1997 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1997 T1 - Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel TI - Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel UR - http://hdl.handle.net/11427/17932 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17932
dc.identifier.vancouvercitationMginqi LN. Evaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steel. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1997 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17932en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentCentre for Materials Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMaterials Engineeringen_ZA
dc.subject.otherApplied Scienceen_ZA
dc.titleEvaluation of stress corrosion cracking of high-nitrogen Cr-Mn stainless steelen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc (Eng)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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