This is a three-part course sequence that describes the methods commonly used to evaluate the cause(s) of metallurgical and mechanical failures, i.e., completing root-cause failure analyses (RCFA), and recommending actions to prevent recurrences. The process is often known as forensic engineering. The procedures may be applied in legal cases in which the professional engineer doing the RCFA acts as an expert witness. However, here the primary emphasis is on finding the physical cause of metallic material failures and related engineering tasks.
The three courses may be taken separately or as a group. In general, the information in the cases histories in Part C. is built on knowledge given in Parts A. and B. plus facts provided in Course 110, Corrosion Control and Tactics. Alternatively, some P.E.’s may have previous knowledge and work experience with RCFA's of metallic materials and choose less than all three courses.
Part A. describes typical steps and procedures used in a thorough RCFA, some common classes of generic issues that can cause metallic failures, and some of the typical analytical and test techniques that are used to characterize the properties of metals that have failed. Brief comparisons are described between the usual responsibilities of the failure analyst in a legal case versus his or her actions in conducting a RCFA that does not involve legal action.
Part B. describes four common classes of specific failure mechanisms that often occur in metallic part or mechanical component failures, i.e., static stress overload, mechanical fatigue, corrosion and wear. Most of these classes of failures have multiple subclasses and each is reviewed in some detail with emphasis on how these characteristics point to effective corrective actions that may be useful. The many forms of aqueous corrosion are given special attention because of the widespread occurrence and effects of this class of failures.
Part C. provides descriptions of (6) case histories of metallurgical and mechanical failures that were completed. The objective is to provide practical examples of how the RCFA procedures and knowledge of different failure mechanisms presented in Parts A. and B. plus general engineering experience might be used. Several illustrations (sketches and photomicrographs) of the details of the cases are included. Also, a short list is provided of other RCFA examples a failure analyst working with metallurgical or mechanical failures might encounter.