Metallurgical failure analysis

Metallurgical failure analysis is the process determine the mechanism that has caused a metal component to fail. It has been estimated that the direct annual cost of corrosion alone in the United States was $276 billion, approximately 3.1% of GDP, in 1998. Corrosion costs have continued to skyrocket and total corrosion costs now are greater than $1 trillion annually in the United States as of 2012.

There are several root causes but some of the most important are design errors, usage, materials and production defects. Design errors often include dimensioning and materials selection but it can also be the complete design. Usage often involves ageing such as corrosion, wear and abrasion. It can also be other factors such as impact, high stress load case or wrong handling. Materials and production defects are closely related. It can be casting defects, such as cold shut, hot tears or slag inclusions. It can be surface treatment problems, processing parameters such as ramming a sand mold or wrong temperature during hardening.

Often a combination of both environmental conditions and stress will cause failure. Metal components are designed to withstand the environment and stresses that they will be subjected to. The design of a metal component involves not only a specific elemental composition but also specific manufacturing process such as heat treatments, machining processes, etc. The huge arrays of different metals that result all have unique physical properties. Specific properties are designed into metal components to make them more robust to various environmental conditions. These differences in physical properties will exhibit unique failure modes. A metallurgical failure analysistakes into account as much of this information as possible during analysis. The end goal of failure analysis is to provide a determination of the root cause and a solution to any underlying problems to prevent future failures.[1]