MESII - 2019

Permanent URI for this collectionhttp://192.248.9.226/handle/123/17182

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Browsing MESII - 2019 by Author "De Silva, GIP"

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    item: Conference-Abstract
    Study of the effects of sulphide stress corrosion on tensile strength of pipeline steel used in petroleum industry
    (Department of Materials Science and Engineering, 2019-01) Peiris, MDHC; Perera, LWL; De Silva, GIP; Sivahar, V; Sitinamaluwa, HS
    The phenomenon of sulfide stress corrosion (SSC) can result in catastrophic failures of pressurized equipment and piping, resulting in extensive damage, injuries and possible fatalities. Sulfide stress corrosion, a major degradation process in metals, is commonly associated with the petroleum industry where high concentrations of H2S is involved. The term, "Sulphide Stress Corrosion", is a customary term for aqueous corrosion in the presence of hydrogen sulfide (H2S) at a level high enough to significantly affect the corrosion behavior and corrosion products compared with the same conditions without H2S. Sulphide stress corrosion resistance of pipe line steel is evaluated in NACE "B" solution at room temperature This research focuses on the corrosion mechanism and variation of tensile strength with time. A constant stress of 40 MPa that is 10% of yield stress of the API 5L Grade B steel was applied to a set of samples and they were kept at a constant H2S environment for a predetermined time period. Thereafter, microstructural analysis was carried out for cross sections of the corroded specimens using SEM /EDS. The depth of corrosion versus exposure time and tensile strength versus exposure time graphs were plotted while monitoring corrosion propagation within the pre-determined time slots.
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    item: Conference-Abstract
    Studying the effects of quenching mediums on the mechanical properties of EN8 steel
    (Department of Materials Science and Engineering, 2019-01) Samaraweera, PDIP; Bandara, MMEN; Fernando, WSMGS; De Silva, GIP; Sivahar, V; Sitinamaluwa, HS
    Presently, ENS steel is widely used for induction hardened gear wheels due to its superior mechanical properties which are essential for gear wheels. This project focuses on achieving the required level of mechanical properties for a gear wheel of a starter motor using a low-cost quenching medium. Specimens of ENS alloy steel were examined after heating between S00°C-850°C using an Induction Furnace and quenched in different quenching mediums such as natural oils and heavy vehicle radiator coolants. The mechanical properties such as hardness and impact toughness are determined using the micro hardness tester and Charpy impact testing machine respectively. When replacing the AH Metalworking Fluid (Active Heavy duty) which is the industrially used quenching medium, with above-mentioned low-cost quenching medium, soaking time and temperature at the metal surface during induction hardening need to be varied in order to obtain the required level of hardness and impact toughness. The micro hardness of the case was measured as per the linear point system across the center point of the cross section of the samples. The basic properties of the quenching mediums such as viscosity, heat capacity, water content and flash points were measured and compared with the presently used oil.