This chapter covers the failure modes and mechanisms associated with boiler components and the tools and techniques used to assess damages and predict remaining component life. It begins with a review of the design and operation of a utility boiler and the materials used in construction. It then describes the various causes of failure in boiler tubes, headers, and steam pipes, explaining how and why they occur, how they are diagnosed, and how to mitigate their effects. The final and by far largest section in the chapter is a tutorial on damage and life assessment techniques for boiler components and assemblies. It demonstrates the use of various methods, including analytical techniques that estimate life expenditure based on operating history, component geometry, and material properties; predictive methods based on the extrapolation of failure statistics; methods that predict life based on dimensional measurements; methods based on metallographic studies; methods based on temperature estimates; and a method for estimating remaining life under creep conditions based on stress-rupture testing of service-exposed material samples. The chapter also discusses the use of fracture mechanics and presents a number of cases in which life assessments are made based on the integration of several methods.

This chapter gives a brief overview of the role of fatigue in component failures. It presents examples of fatigue failures along with statistics on the causes and costs of fatigue damage in various industries. It also includes a chapter-by-chapter summary of the content in the book, noting that the book deals primarily with fatigue at temperatures below the creep range with high-temperature fatigue being treated in a companion publication.

Statistics, data analysis, root cause analysis, and problem-solving processes play a key role in failure investigations. This chapter explains how to collect failure investigation data, how to build and maintain a database for company-related failures, and how to use corresponding statistics including type of failure, material, and root cause. It describes the purpose and benefits of conducting a root cause analysis and the factors, namely relative failure importance and company value, that determine when an investigation should be performed. The chapter also discusses the four-step problem-solving process as it applies to failure investigation, how to assemble an investigation team, and the details of organization and planning. It concludes with a case history of the Firestone 500 steel-belted tire failure, stressing the importance of a systematic approach to failure investigations.

Failure analysis can sometimes involve considerations of statistics and probability. This chapter reviews some of the basic types of statistical distributions in order to understand some basic principles in their use. The main focus is on the uses of the normal distribution, which is the most commonly used statistical distribution. The chapter also includes a section discussing the reliability and probability of passing.

This chapter surveys both basic quality and basic reliability concepts as an introduction to the failure analysis professional. It begins with a section describing the distinction between quality and reliability and moves on to provide an overview of the concept of experiment design along with an example. The chapter then discusses the purposes of reliability engineering and introduces four basic statistical distribution functions useful in reliability engineering, namely normal, lognormal, exponential, and Weibull. It also provides information on three fundamental acceleration models used by reliability engineers: Arrhenius, Eyring, and power law models. The chapter concludes with information on failure rates and mechanisms and the two techniques for uncovering reliability issues, namely burn-in and outlier screening.

This chapter discusses the factors that play a role in fatigue failures and how they affect the service life of metals and structures. It describes the stresses associated with high-cycle and low-cycle fatigue and how they differ from the loading profiles typically used to generate fatigue data. It compares the Gerber, Goodman, and Soderberg methods for predicting the effect of mean stress from bending data, describes the statistical nature of fatigue measurements, and explains how plastic strain causes cyclic hardening and softening. It discusses the work of Wohler, Basquin, and others and how it led to the development of a strain-based approach to fatigue and the use of fatigue strength and ductility coefficients. It reviews the three stages of fatigue, beginning with crack initiation followed by crack growth and final fracture. It explains how fracture mechanics can be applied to crack propagation and how stress concentrations affect fatigue life. It also discusses fatigue life improvement methods and design approaches.

This appendix provides supplemental information on the metallurgical aspects of atomic structure, the use of dislocation theory, heat treatment processes and procedures, important engineering materials and strengthening mechanisms, and the nature of elastic, plastic, and creep strain components. It also provides information on mechanical property and fatigue testing, the use of hysteresis energy to analyze fatigue, a procedure for inverting equations to solve for dependent variables, and a method for dealing with the statistical nature of failure.

The ability to accurately assess the remaining life of components is essential to the operation of plants and equipment, particularly those in service beyond their design life. This, in turn, requires a knowledge of material failure modes and a proficiency for predicting the near and long term effects of mechanical, chemical, and thermal stressors. This chapter presents a broad overview of the types of damage to which materials are exposed at high temperatures and the approaches used to estimate remaining service life. It explains how operating conditions in power plants and oil refineries can cause material-related problems such as embrittlement, creep, thermal fatigue, hot corrosion, and oxidation. It also discusses the factors and considerations involved in determining design life, defining failure criteria, and implementing remaining-life-assessment procedures.

This chapter provides an introduction to statistical process control and the concept of total quality management. It begins with a review of quality improvement efforts in the extrusion industry and the considerations involved in developing sampling plans and interpreting control charts. It then lays out the steps that would be followed in order to implement statistical testing for billet casting, die performance, or any other process or variable that impacts extrusion quality. The chapter concludes with an overview of the fundamentals of total quality management.

Casting quality and consistency need to be carefully controlled. This chapter discusses the procedures that describe the process and product quality controls. In addition, it provides information on quality assurance programs.

Mechanical tests are performed to evaluate the durability of gears under load. The chapter first discusses the processes involved in the computations of stress for test parameters of gear. Next, the chapter reviews the four areas of specimen characterization of a test program, namely dimensional, surface finish texture, metallurgical, and residual stress. The following section presents the tests that simulate gear action, namely the rolling contact fatigue test, the single-tooth fatigue test, the single-tooth single-overload test, and the single-tooth impact test. Finally, the chapter describes the test procedures for surface durability (pitting), root strength (bending), and scoring (or scuffing) testing.

Electronics spans a number of devices, their configurations, and properties. A challenge is to identify those electronic subjects essential for failure analysis. This article reviews the normal operation and terminal characteristics of MOSFET. It describes the electronic behavior of bridges, opens, and parametric delay defects, which is essential for understanding the symptoms of a failing IC. These electronic principles are then applied to a CMOS failure analysis technique using a power supply signature analysis.

After the failure analysis team hypothesizes failure causes, prepares a failure mode assessment and assignment, and evaluates all potential failure causes, it may find in some cases that several causes are still suspect but cannot be confirmed. In this situation, an experiment is necessary to confirm or rule out suspected causes. This chapter discusses two predominant methods for doing this, namely analysis of variance (ANOVA) and Taguchi methods (a more powerful technique based on ANOVA).

Tensile tests are performed for several reasons related to materials development, comparison, selection, and quality control. The properties derived from tensile tests are used in selecting materials for engineering applications. Tensile properties often are used to predict or estimate the behavior of a material under forms of loading other than uniaxial tension. This chapter provides a brief overview of tensile specimens and test machines, stress-strain curves, true stress and strain, and test methodology and data analysis.

Semiconductor memories are superb drivers for process yield and reliability improvement because of their highly structured architecture and use of aggressive layout rules. This combination provides outstanding failure signature analysis possibilities for the entire design, manufacturing, and test process. This article discusses five key disciplines of the signature analysis process that need to be orchestrated within the organization: design for test practices, test floor data collection methodology, post-test data analysis tools, root cause theorization, and physical failure analysis strategies.

Root cause of failure in automotive electronics cannot be explained by the failure signatures of failed devices. Deeper investigations in these cases reveals that a superimposition of impact factors, which can never be represented by usual qualification testing, caused the failure. This article highlights some of the most frequent early life failure types in automotive applications. It describes some of the critical things to be considered while handling packages and printed circuit board layout. The article also provides information on failure anamnesis that shows how to use history, failure signatures, environmental conditions, regional failure occurrences, user profile issues, and more in the failure analysis process to improve root cause findings.

This chapter presents an overview of microprocessor and application specific integrated circuit (IC) testing. It begins with a description of key industry trends that will impact how ICs will be tested in the future. Next, it provides a brief description of the most common tests applied in the IC industry, where technical issues that are causing methodology changes are emphasized. These include functional testing, structural testing, scan-based delay testing, built-in self-testing, memory testing, analog circuit testing, system-on-a-chip testing, and reliability testing. Trends discussed have driven the development of novel focus areas in test and the chapter discusses several of those areas, including test data volume containment, test power containment, and novel methods of defect-based test.

A product pedigree describes its design and how it was built and shows that it was built in accordance with the drawings and other documentation defining the product configuration. Evaluating the pedigree of a failed product can help to rule in or rule out hypothesized failure causes. This chapter describes various areas that can be examined by the failure analysis team to assess the pedigree of the failed system. If the failure analysis team suspects product pedigree anomalies it should confirm conformance through independent means.

This chapter describes some common pitfalls encountered in failure investigations and provides guidance to help engineers recognize processes and “quick fixes” that companies often try to substitute for failure analysis. It discusses three important skills and characteristics that a professional engineer must improve to conduct an effective and successful failure investigation, namely technical skills, communication skills, and technical integrity. The chapter also provides information on the additional basic tools available for failure investigation and root cause determination: the Kepner-Tregoe structured problem-solving method, PROACT software for root cause analysis developed by the Reliability Center, Inc., and other processes and methods developed by the Failsafe Network, Inc., and Shainin LLC.

The inspection of castings normally involves checking for shape and dimensions, coupled with aided and unaided visual inspection for external discontinuities and surface quality. This chapter discusses methods for determining surface quality, internal discontinuities, and dimensional inspection. Casting defects including porosity, oxide films, inclusions, hot tears, metal penetration, and surface defects are reviewed. Liquid penetrant inspection, magnetic particle inspection, eddy current inspection, radiographic inspection, ultrasonic inspection, and leak testing for castings are discussed. The chapter provides information on the procedures involved in the inspection of castings that are limited to visual and dimensional inspections, weight testing, and hardness testing. It also discusses the use of computer equipment in foundry inspection operations.