A Case Study on Using Corrosion Analysis in Forensic Engineering
Material failures occur in products due to changes in the original characteristics that prevent satisfactory performance of a functional system for its intended purpose and could produce losses to human life and economic infrastructure. Metals’ characteristics change due to cyclic stress, strain, and corrosion. This paper presents a case study that deal with the application of corrosion fundamentals in the determination of the origin of failures in a metallic part —galvanic corrosion failure in a water supply plumbing system. Metallographic examination, chemical analysis of the parts, and fractography were conducted, and the cause of failures was determined as a galvanic corrosion.
The early stages of a metallurgical engineering forensic analysis include the collection of background information and the selection of appropriate samples for laboratory testing. Additional steps should include site inspection, a timeline of the failure, material specifications, review of maintenance and repair records, information on past failures for the same component, and any material substitutions made. A visual examination of the failed part or structure, non-destructive testing of the component, and photographic documentation should be performed first. The failed parts selected for laboratory testing and analysis should be carefully stored or protected during transport to prevent any damage to the fracture surfaces from humidity, dust, dirt, and contamination from human contact.
Galvanic corrosion of metals, which has been called dissimilar metal corrosion, is a process by which one metal corrodes another one in contact through an electrolyte. An example of galvanic reaction is manifested in batteries to produce a voltage. The phenomenon has been recorded in detail in the literature, and engineering approaches to avoid galvanic process have been presented in engineering and technology curricula.
Water piping systems in multi-story buildings may require different configurations and flexibility for various passages in the design of the system.
Challenges of customizing pre-assembled hose systems to meet local building code requirements require a good knowledge-based background and experience in corrosion science and technology to successfully modify the original design of the hose.
A large water leak caused major damage in a high-rise building. The water leak was due to failure of assembled drain couplings on copper elbows in flexible braided hose connectors. Installation of a drain port with a steel coupling on a copper elbow was an improper decision. To prevent galvanic corrosion, interaction of dissimilar metals should be avoided in a wet environment.
By Materials Engineering Solutions, LLC
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AUTHOR: Reza MirshamsExpert Website: https://metallurgyexperts.com
Call (469) 777-6684
Copyright Materials Engineering Solutions, LLC
Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.For specific technical or legal advice on the information provided and related topics, please contact the author.
