Search Results for case

This chapter discusses hardening processes that involve changes in surface composition. These case hardening treatments are broadly classified into four groups: carburizing, carbonitriding, nitriding, and nitrocarburizing. Key parameters and operating considerations for each treatment are discussed.

This chapter presents various case histories that illustrate a variety of failure mechanisms experienced by the high-strength steel components in aerospace applications. The components covered are catapult holdback bar, AISI 420 stainless steel roll pin, main landing gear (MLG) lever, inboard flap hinge bolt, nose landing gear piston axle, multiple-leg aircraft-handling sling, aircraft hoist sling, internal spur gear, and MLG axle. In addition, the chapter provides information on full-scale fatigue testing, nondestructive testing, and failure analysis of fin attach bolts.

This chapter provides an outline of the failure modes and mechanisms associated with most boiler tube failures in coal-fired power plants. Primary categories include stress rupture failures, water-side corrosion, fire-side corrosion, fire-side erosion, fatigue, operation failures, and insufficient quality control.

This chapter provides details on powder-binder processing for three materials, namely precipitation-hardened 17-4 PH stainless steel, cemented carbides, and alumina. The types of powders, binders, feedstock, shaping processes, debinding, sintering cycles, compositions, microstructure, distortion, postsintering treatments, and mechanical properties are presented for each. The shaping options include powder-binder approaches such as binder jetting, injection molding, extrusion, slip and slurry casting, centrifugal casting, tape casting, and additive manufacturing. Sintering options are outlined with respect to attaining high final properties.

Examining and evaluating the nitrided case is generally accomplished by hardness testing and microscopic examination. This chapter discusses both characterization methods, as well as sample preparation. The chapter also discusses the processes involved in the etching of the sample after microhardness testing and provides practices that contribute to the safe preparation of specimens. Examples of nitrided case microstructures, using optical light microscopy, are also presented.

The design of case-hardened components is an iterative process, requiring the consideration of multiple interrelated factors. This chapter walks readers through the steps involved in selecting an appropriate material and assessing the influence of alloy composition and cooling rate on core properties including hardenability, microstructure, tensile and yield strength, ductility, toughness, and fatigue resistance. It likewise explains how carbon affects case hardenability, surface hardness, and case toughness and how case depth influences residual stresses and bending and contact fatigue. It also discusses the effect of quenching methods and addresses the issue of distortion.

This chapter analyzes four gearbox failures, in each case identifying the underlying failure mechanism and recommending changes to reduce vibration. These include failure of an offset parallel gearbox due to gear tooth geometry error; high vibration on high-speed offset parallel gearbox; failure of an epicyclic gearbox; and vibration due to tooth wear.

This chapter explores case studies on using induction heating for joining applications, encompassing both soldering and brazing to demonstrate versatility. Each study focuses on inductor coil design, workpiece geometry, and production quantities, emphasizing optimization due to the interplay between material geometry, coil configuration, and process parameters like generator frequency and power. The case studies provide real-world data on effectively implementing induction heating in joining processes.