Failure Analysis of Engineering Materials
This text introduces the important aspects associated with the failure analysis of engineering components, and provides a treatment of both macroscopic and microscopic observations of fracture surfaces.
TABLE OF CONTENTS Failure Analysis of Engineering Materials
Chapter 7: Case Studies
7.1 Introduction
In this chapter we present metallurgical case studies chosen to illustrate the principles of failure analysis. In each study references are made to specific points covered in the previous chapters in order to show how these were used in the analyses.
These studies deal with real failures, in which the scope of the failure analysis was limited by factors such as the time that could be devoted to the problem, the expense of the testing desired, and particularly incomplete information about the failure situation. Thus the reader will find that some of the conclusions are quite tentative, which is a common result of analyses of such real failures.
Microstructural analysis is invariably a part of most metallurgical failure analyses. However, in this book we have made no attempt to review the physical metallurgy of the alloys examined. The reader will find this information in many books and references, such as the two listed in the Bibliography.
7.2 Case A: A Cracked Vacuum Bellows [*]
7.2.1 Introduction
Tubular metal bellows are useful devices for joining components. One use is to make a vacuum seal for a movable component which must be inserted into a vacuum chamber, such as a shaft that must be moved, either axially or sideways. An example is shown in Fig. 7.1a. This device is used to move the seat, with its rubber gasket, down onto a flat surface to provide a vacuum seal. This is accomplished by turning the shaft, which is connected to a...
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