Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application
| dc.contributor.advisor | Knutsen, Robert | |
| dc.contributor.author | Matjee, Mapula Regina | |
| dc.date.accessioned | 2021-08-17T14:41:01Z | |
| dc.date.available | 2021-08-17T14:41:01Z | |
| dc.date.issued | 2021 | |
| dc.date.updated | 2021-08-17T14:40:15Z | |
| dc.description.abstract | Stainless steels are used for many industrial applications because of their strength and fabrication characteristics. Stainless steel grades of SAF2205 and AISI304 can readily meet a wide range of design criteria of service life, maintenance, load and corrosion resistance. | |
| dc.identifier.apacitation | Matjee, M. R. (2021). <i>Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application</i>. (). ,Faculty of Engineering and the Built Environment ,Department of Mechanical Engineering. Retrieved from http://hdl.handle.net/11427/33795 | en_ZA |
| dc.identifier.chicagocitation | Matjee, Mapula Regina. <i>"Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application."</i> ., ,Faculty of Engineering and the Built Environment ,Department of Mechanical Engineering, 2021. http://hdl.handle.net/11427/33795 | en_ZA |
| dc.identifier.citation | Matjee, M.R. 2021. Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application. . ,Faculty of Engineering and the Built Environment ,Department of Mechanical Engineering. http://hdl.handle.net/11427/33795 | en_ZA |
| dc.identifier.ris | TY - Master Thesis AU - Matjee, Mapula Regina AB - Stainless steels are used for many industrial applications because of their strength and fabrication characteristics. Stainless steel grades of SAF2205 and AISI304 can readily meet a wide range of design criteria of service life, maintenance, load and corrosion resistance. The SAF2205 and AISI304 are Fe-Ni-Cr alloys, whereby SAF2205 consists of austenite-�� and ferrite-�� microstructure and AISI304 is monophasic comprising of an austenite-�� microstructure. Welding is frequently used in the manufacturing process of stainless steel products and it alters the base metal microstructure by introducing secondary phases or causing sensitisation in the Heat Affected Zones (HAZ) when it is not carried out correctly. The synergistic effects of the chloride environment and residual stress has a potential to increase susceptibility of the weldments due to precipitation of the deleterious intermetallic phases, which can be worsened by a Post Weld Heat Treatment (PWHT). An investigation to determine SAF2205 and AISI304 weldment susceptibility to SCC and intergranular attack for marine environment application has been conducted. The purpose of the investigation is to characterise the microstructure of a PWHT of SAF2205 and AISI304 weldments by comparing the welded material in the conditions of as-weld, as-received and PWHT. The tested materials will be evaluated for their corrosion performance specifically at the weldments when they are exposed to the marine environment. Thin rectangular specimens were sectioned such that the weldments are maintained at the centreline, followed by PWHT at 500℃ for 3 hours and 800℃ for 2 hours and then air cooled. The PWHT was completed to exaggerate the intermetallic formation in SAF2205 and sensitisation of AISI304 HAZ. Tensile tests were performed to determine the elastic limit of SAF2205 and ASIS304, so that specimens are fixed in the holder without plastic deforming, but they maintain a yield stress level at the bend specimen apex or weld just below the yield stress. The mounted specimens were exposed to Cyclic Corrosion Testing (CCT-1) in a salt chamber. The exposure conditions included application of 5wt.%NaCl fog at 35℃ for 4 hours, 100% humidity at 50℃ for 2 hours and drying at 60℃ for 2 hours and at 40℃ for 30 minutes. After 10 months of corrosion exposure, AISI304 specimens showed corrosion pits and rust at the apex of the bend specimens whereas SAF2205 specimens were defect free, and thus unaffected by the testing conditions. Additionally, the Strauss test was completed to determine the intergranular attack susceptibility for the tested material, at the Fusion Zone (FZ), BM (Base Material) and HAZ at the conditions of asweld and PWHT at 800℃ for 2 hours and 500℃ for 3 hours. The SAF2205 specimen, PWHT at 800℃ for 2 hours, cracked during the material qualification bend test, particularly at the HAZ and FZ. These regions were further analysed using Scanning Electron Microscopy (SEM: BSE and EDS). The EDS analysis on the HAZ revealed the presence of Mo-rich precipitates of chi (��)-phase and Cr-rich precipitates of sigma (��)-phase at the grain boundaries and triple points growing into the ferrite-��, making these regions to become brittle. The FZ revealed brittle sigma (��)-phase at the grain boundaries with no chi (��)-phase detected. The AISI304 exposed to similar conditions did not suffer intergranular attack but demonstrated full ductility during the bend test. DA - 2021 DB - OpenUCT DP - University of Cape Town KW - Engineering LK - https://open.uct.ac.za PY - 2021 T1 - Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application TI - Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application UR - http://hdl.handle.net/11427/33795 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/33795 | |
| dc.identifier.vancouvercitation | Matjee MR. Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application. []. ,Faculty of Engineering and the Built Environment ,Department of Mechanical Engineering, 2021 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/33795 | en_ZA |
| dc.language.rfc3066 | eng | |
| dc.publisher.department | Department of Mechanical Engineering | |
| dc.publisher.faculty | Faculty of Engineering and the Built Environment | |
| dc.subject | Engineering | |
| dc.title | Investigation of the stress corrosion cracking resistance of SAF2205 and AISI304 weldments for the marine environment application | |
| dc.type | Master Thesis | |
| dc.type.qualificationlevel | Masters | |
| dc.type.qualificationlevel | MSc |