Welcome to the 2021 edition of ASM Handbook, Volume 11, Failure Analysis and Prevention.

As with previous editions of this volume, the goal of the editors and authors is to provide the “go-to” reference for those who are confronted with the failure of a machine or component. And we recognize that our audience wishes to both understand the causes of failures and prevent future occurrences. If the root or underlying cause is not correctly identified, then the chances of remediation and prevention will be diminished.

The emphasis of this volume is on general principles with the widest applicability to situations that the reader is likely to encounter. References and sources of further information are provided throughout.

While the subject of Volume 11 is typically referred to as “Failure Analysis,” we recognize this term is something of a misnomer. Machines and components, and the materials from which they are constructed, do not really “fail” in the way most of us understand the term. Materials respond to the elements in their environments in ways that scientists and engineers strive to understand. Characterization of the environment over time may include determining mechanical loads, the possible presence of aggressive chemicals, temperature, and a variety of other factors.

Thus, the “failure” turns out to be a failure to meet expectations. And materials engineers are an important part of the investigation, as there are often questions regarding whether the materials met specifications and were appropriate for the environment. Careful study of the materials can also reveal much regarding the circumstances of a particular event.

Experienced analysts are often frustrated when, despite extensive engineering research, investigations, and reports, the same types of failures occur again and again. Thus, the analyst should strive to uncover the underlying, or root, cause of the failure. The fact that a specific component appears to have failed in some way does not automatically mean that the component itself is defective. The problem may lie in the way the component was used, inspected, or maintained. If it is truly defective, then the analysis should determine whether the defect originates in the design, manufacture (fabrication and assembly), material selection/processing, or an unanticipated service environment.

A root cause investigation attempts to answer such questions as:

• Was the operating environment properly anticipated in the design?

• Did the manufacturing process meet specifications? If not, why not?

• Were maintenance and inspections performed properly?

• Was the machine or component at issue used properly? If not, did the user or operator receive proper instruction and training?

Again, ASM Handbook, Volume 11 provides a starting point for investigation into all of the above areas and more. As the results of a failure investigation are often painstakingly scrutinized by multiple parties, and different interpretations of the evidence are possible, it is important to follow a scientific approach. Consider alternate explanations for the evidence and test your hypotheses to determine which one best explains the evidence. Do NOT make the mistake of hastily accepting the first conclusion that arises.

Because of the potential for a degree of subjectivity, controversy is, perhaps, inherent in the very nature of failure analysis. If anything, that is even truer today when real or perceived failures are the subject of litigation. There can be differences of opinion among failure analysts regarding some issues. It is up to the reader to determine whether the information presented here is applicable and helpful in a particular situation. More experienced analysts should be consulted if there is any doubt. The ASM Handbook series should be used with care and should not be the sole source of information when critical decisions are to be made. While it is our goal that this volume be the first resource you consult when confronted with a broken or otherwise failed part, it should not be your only resource. The reader is encouraged to pursue additional sources of information to understand the function and history of the component, machine, or system that is under investigation.

In addition to this volume, the ASM Handbook series currently comprises 37 other volumes, any of which may contain information relevant to a particular investigation. This volume on failure analysis and prevention is not intended to duplicate information readily available elsewhere. For example, the reader may complete a given investigation by researching material properties (ASM Handbook, Volumes 1, 1A, 2, 2A, 3, and 20), corrosion (ASM Handbook, Volumes 13A, 13B, and 13C), fractography (ASM Handbook, Volume 12), friction, lubrication, and wear (ASM Handbook, Volume 18), fatigue and fracture (ASM Handbook, Volume 19), and other volumes on various manufacturing processes. There are specific considerations associated with common types of components. These will be included in the companion ASM Handbook, Volume 11A, Analysis and Prevention of Component and Equipment Failures, scheduled for publication in 2021. Besides the ASM Handbook series, much additional useful information is available in other reference books from ASM International. Whatever source is utilized, given the critical nature of failure analysis, it is most important that the information be reliable and authoritative.

As is the case with all volumes of the ASM Handbook series, Volume 11 reflects the efforts of many people. Except for the staff of ASM International, all participants are volunteers. Most of the volunteers are fully employed and many contributed their personal time to the project. Neither they nor their employers receive any monetary compensation for their efforts. They participated for the satisfaction that accrues from being able to share what they have learned, prevent failures, and contribute to safer, more reliable products.

The names of the authors, editors, reviewers, and ASM staff are acknowledged individually elsewhere in this volume and are too numerous to list here. However, ASM staff members Steven Lampman and Amy Nolan deserve special mention for their unflagging commitment to this project.

It has been most enjoyable and professionally rewarding to work with all who were involved in this effort. On behalf of ASM International and the readers of this volume, we express our appreciation to all for the time and effort expended and for their willingness to share their knowledge and lessons derived from their experience. Many of the contributors have established national and international reputations in their respective fields. More than any words of appreciation in a Preface such as this, however, it is our hope that the volume itself will be a most fitting tribute to all participants, both now and well into the future.