This chapter provides an overview of the blanking process and the forces and stresses involved. It discusses the factors that affect part quality and tool life, including punch and die geometry, stagger, clearance, and wear as well as punch velocities, misalignment, and snap-thru forces. It also discusses ultra-high-speed blanking, fine blanking, and shearing, and the use finite-element simulations to predict part edge quality.

A pair of bearings mounted side by side in an aircraft engine failed in service. Photographs show that the inner rings were either broken or deformed, the balls were worn and flattened, and the cages severely damaged. The bearing races were damaged as well, but only on one side indicating a directional thrust. In addition to their examination, investigators also conducted metallographic studies and hardness tests, which indicated that the balls and inner rings reached temperatures above 825 °C (1520 °F). Based on their findings, investigators concluded that the bearings failed due to overheating, possibly as a result of misalignment compounded by insufficient lubrication and high speeds.

This chapter focuses on what can cause a system to fail and addresses the challenge in approaching a system failure. It then examines the steps involved in the four-step problem-solving process: defining the problem, identifying all potential failure causes and evaluating the likelihood of each, identifying the potential solutions, and identifying the best solution. The chapter concludes by describing the responsibilities of a failure analysis team.

This article addresses critical aspects in bond testing of thermal spray coatings and provides step-by-step guidance for obtaining representative and reproducible test results based on ASTM C633 and other applicable industry standards. It clarifies details of ASTM C633 requirements and provides examples of the best practice confirmed by hundreds of tests performed worldwide, adopted by numerous industrial standards, and requested to comply with international technical standardization and certification organizations such ISO, AS, SAE, and Nadcap.

This article discusses the various options for controlling fatigue and fracture in welded steel structures, the factors that influence them the most, and some of the leading codes and standards for designing against these failure mechanisms. The two most widely used approaches discussed for fatigue control in welded joints are the S-N curve approach and the fracture mechanics assessment methods.

Combustion byproducts such as soot, ash, and abrasive particulates can inflict significant damage to boiler tubes through the cumulative effect of erosion. This chapter examines the types of erosion that occur on the fire side of boiler components and the associated causes. It discusses the erosive effect of blowing soot, steam, and fly ash as well as coal particle impingement and falling slag. It also includes several case studies.

Nitriding is a case-hardening process used for alloy steel gears and is quite similar to case carburizing. Nitriding of gears can be done in either a gas or liquid medium containing nitrogen. This chapter discusses the processes involved in gas nitriding. It reviews the effects of white layer formation in nitrided gears and presents general recommendations for nitrided gears. The chapter describes the microstructure, overload and fatigue damage, bending-fatigue life, cost, and distortion of nitrided gears. Information on nitriding steels used in Europe and the applications of nitrided gears are also provided. The chapter presents case studies on successful nitriding of a gear and on the failure of nitrided gears used in a gearbox subjected to a load with wide fluctuations.

The testing of plastics includes a wide variety of chemical, thermal, and mechanical tests. This chapter reviews the tensile testing of plastics, which has been standardized in ASTM D 638, "Standard Test Method for Tensile Properties of Plastics," and other comparable standards. It describes the fundamental factors that affect data from tensile tests, examines the stipulations in standardized tensile testing, and discusses the utilization of data from tensile tests.

This chapter identifies the primary causes of service failures and discusses the types of defects from which they stem. It presents more than a dozen examples of failures attributed to such causes as design defects, material defects, and manufacturing or processing defects as well as assembly errors, abnormal operating conditions, and inadequate maintenance. It also describes the precise usage of terms such as defect, flaw, imperfection, and discontinuity.

This chapter discusses the fatigue behavior of bolted, riveted, and welded joints. It describes the relative strength of machined and rolled threads and the effect of thread design, preload, and clamping force on the fatigue strength of bolts made from different steels. It explains where fatigue failures are likely to occur in cold-driven rivet and friction joints, and why the fatigue strength of welded joints can be much lower than that of the parent metal, depending on weld shape, joint geometry, discontinuities, and residual stresses. The chapter also explains how to improve the fatigue life of welded joints and discusses the factors that can reduce the fracture toughness of weld metals.

Gears can fail in many different ways, and except for an increase in noise level and vibration, there is often no indication of difficulty until total failure occurs. This chapter begins with the classification of gear failure modes, followed by sections discussing the characteristics of various fatigue failures. Then, it provides information on the modes of impact fractures, wear, scuffing, and stress rupture. Next, the chapter describes the causes of gear failures and discusses the processes involved in conducting the failure analysis. Finally, the chapter presents examples of gear failure analysis.

Nitriding is a surface hardening heat treatment that introduces nitrogen into the surface of steel while it is in the ferritic condition. Gas nitriding using ammonia as the nitrogen-carrying species is the most commonly employed process and is emphasized in this chapter. Nitriding produces a wear- and fatigue-resistant surface on gear teeth and is used in applications where gears are not subjected to high shock loads or contact stress. It is useful for gears that need to maintain their surface hardness at elevated temperatures. Gears used in industrial, automotive, and aerospace applications are commonly nitrided. This chapter discusses the processes involved in gas, controlled, and ion nitriding.