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electrochemical corrosion |
localized corrosion oxygen corrosion hot corrosion stress corrosion cracking corrosion & fatigue hydrogen embrittlement hydrogen sulfide corrosion microbiological corrosion | carbon dioxide corrosion erosion-corrosion elevated-temperature corrosion oxidation sulfidation carburization |
These corrosion mechanisms and their root causes have been studied in most of the commercial alloys and metals including cast irons, carbon steels, low-alloy steels, stainless steels (austenitic, ferritic, martensitic, precipitation hardening and duplex), nickel, copper, aluminum and thier respective alloys. Failure Analysis Failure analysis involves metallurgical investigations of components, equipment, metals, alloys, coatings, linings and structures due to corrosion, environmental degradation and abuse, misapplication of the particular metal and mechanical failure. Studies of failure analysis are particularly strong in the chemical processing, refining, oil & gas and pulp & paper industries. Failure mechanisms evaluated usually include: |
| general corrosion localized corrosion intergranular corrosion weld corrosion stress corrosion cracking fatigue & corrosion fatigue fretting & wear |
| erosion overload brittle fracture hydrogen embrittlemen thydrogen sulfide cracking microbiological corrosion oxidation, sulfidation & carburization |
| These failure types have been investigated in such diverse components as pressure vessels, welded fabrication, piping, heater and boiler tubes, marina docks, storage tanks, drums, towers, columns, pumps, heat exchangers, forgings, bearings, compressors and gearboxes. Another function of the metallurgical engineer is to apply, when indicated, non-metallic coating systems to protect equipment and structures from corrosion and environmental degradation. Over the past 10 years, a major emphasis has been on the specification of coating systems for severe service, including immersion in corrosive environments and concrete containment structures for hazardous waste storage tank systems. The metallurgical engineer must also have knowledge of material and corrosion properties, metals and alloy testing and inspection for applying to evaluations on suitability-for-service, remaining life and mechanical integrity of equipment  Furthermore, a risk-based inspection procedure is necessary to rank process equipment based on the probability of internal failure. This procedure helps companies meet the mechanical integrity requirements of OSHA's 1910.119, Process Safety Management regulations. Corrosion investigations can also involve source identification in ground-water contamination and in chemical analyses of a variety of samples taken, both soil and ground-water. Thus, an interdisciplinary team of scientists and engineers would attend projects involving water supply and ground-water remediation. Note: The environmental field is multidisciplinary by nature, and ELA incorporates input from complimentary disciplines for maximum effectiveness whenever appropriate. |