This chapter gives an overview of how steel castings may be effectively adapted to modern concurrent engineering processes. The chapter discusses computer aided design programs, solid modeling, solidification simulation programs, and rapid prototyping.

This chapter summarizes the progress that has been made in the study of high-entropy alloy (HEA) systems and the process-structure-property relationships that define them. It describes the various ways HEAs can be strengthened and explains how alloying elements influence tensile and yield strength, fracture toughness, and fracture strength. It discusses the stages of plastic deformation in HEAs and the role of dislocations and twinning in the evolution of microstructure. It reviews some of the work that has been done on fatigue behaviors and the methods developed to assess fatigue performance. It discusses the influence of defects on fatigue life, the effect of temperature and grain size on fatigue-crack propagation, and the role of nanotwinning in crack-growth retardation. It describes the methods used to produce HEAs in bulk and powder form and to apply them as protective coatings and films. It also identifies potential applications based on properties such as strength, hardness, density, wear resistance, high-temperature stability, and biocompatibility.

This chapter compares and contrasts surface-engineering processes based on process availability, corrosion and wear performance, distortion effects, penetration depth or attainable coating thickness, and cost. It provides both quantitative and qualitative information as well as measured property values.

This chapter is intended to identify materials, processes, and designs that will lead to great advances in powder-binder forming technologies. It discusses some of the structures obtained through these advances in powder-binder technologies such as binder jetting and extrusion-based additive manufacturing, including bound-metal deposition and fused-filament fabrication: oxidation-resistant high-temperature alloys, anisotropic structures, submicrometer-scale structures, surface hard materials, and artist metallic clays. Some of the advances discussed include the developments in process involving plastics, emulsions, ceramics, and porous structures and foams. Improvements in the design processes have led to the development of functional structures, controlled porosity, and bioinspired structures.

This chapter provides details on several specific binder formulations and a discussion of basic binder design concepts. The focus is on customization of the feedstock response to heating, pressurization, or solvent exposure for a specific shaping process. The discussion starts with the requirements of a binder system, the historical progression of binder formulations, and the use of binder alternatives to adapt to specific applications. The importance of binder handling strength to shape preservation is emphasized. The chapter provides information on the binders used for room-temperature shaping, namely slurry and tape casting systems.

This chapter describes secondary processes employed in the production of powder-metal stainless steel parts, including various machining operations, welding, brazing, sinter bonding, resin impregnation, re-pressing and sizing, and surface finishing. It also discusses the factors that affect the machinability and weldability of sintered stainless steels.

This chapter discusses the advantages of using powder metallurgy to produce magnetic materials, particularly its ability to control chemistry and near-net shape. It also explains how process parameters and powder characteristics influence the physical and magnetic properties of common stainless steels.

After shaping and first-stage binder removal, the component (with remaining backbone binder) is heated to the sintering temperature. Further heating induces densification, evident as dimensional shrinkage, pore rounding, and improved strength. This chapter begins with a discussion on the events that are contributing to sintering densification, followed by a discussion on the driving forces, such as surface energy, and high-temperature atomic motion as well as the factors affecting these processes. The process of microstructure evolution in sintering is then described, followed by a discussion on the tools used for measuring bulk properties to monitor sintering and density. The effects of key parameters, such as particle size, oxygen content, sintering atmosphere, and peak temperature, on the sintered properties are discussed. Further, the chapter covers sintering cycles and sintering practices adopted as well as provides information on dimensional control and related concerns of sintering. Cost issues associated with sintering are finally covered.

This chapter begins with a brief review of the different types of surface treatments and coatings used in industry and their effect on properties and performance. It then discusses the importance of corrosion and wear treatments and the consequences of failing to properly implement them in critical industries such as mining, energy production, transportation, and mineral and chemical processing. The chapter also describes basic approaches to dealing with corrosion and wear in steel.

This chapter introduces the key powder fabrication attributes to assist in the identification of the right powders for an application. First, it describes the characteristics of engineering powders such as particle size distribution, powder shape and packing density, surface area, powder flow and rheology, and chemical analysis. The chapter then describes the general categories of powder fabrication methods, namely mechanical comminution, electrochemical precipitation, thermochemical reaction, and phase change and atomization. It provides information on the two largest contributors to powder price, namely raw material cost and conversion cost. The applicability of various processes to specific material systems is mentioned throughout this chapter.

The conversion of feedstock into a shape involves the application of heat and pressure, and possibly solvents. This chapter discusses the operating principle, advantages, limitations, and applications of such shaping processes, namely additive manufacturing, cold isostatic pressing, die compaction, extrusion, injection molding, slip casting, slurry processes, and tape casting. Information on equipment setup, requirements, and the various factors influencing these processes are described. In addition, the chapter provides information on novel approaches and processing costs applicable to these shaping processes.

This chapter discusses the application of investment casting to nickel- and cobalt-base superalloys. It describes the production of polycrystalline and single crystal castings, the materials normally used, and the part dimensions and tolerances typically achieved. It explains how patterns, molds, and shells are produced, discusses the practice of directional solidification, and examines an assortment of turbine components cast from nickel- and cobalt-base alloys. The chapter also addresses casting problems such as inclusions, porosity, distortion, core shift, and leaching and explains how to avoid them.

Ceramics normally have high melting temperatures, excellent chemical stability and, due to the absence of conduction electrons, tend to be good electrical and thermal insulators. They are also inherently hard and brittle, and when loaded in tension, have almost no tolerance for flaws. This chapter describes the applications, properties, and behaviors of some of the more widely used structural ceramics, including alumina, aluminum titanate, silicon carbide, silicon nitride, zirconia, zirconia-toughened alumina (ZTA), magnesia-partially stabilized zirconia (Mg-PSZ), and yttria-tetragonal zirconia polycrystalline (Y-TZP). It also provides information on materials selection, design optimization, and joining methods, and covers every step of the ceramic production process.

This chapter discusses some of the promising developments in the use of titanium, including titanium aluminides, titanium matrix composites, superplastic forming, spray forming, nanotechnology, and rapid solidification rate processing. It also reports on efforts to increase the operating temperature range of conventional titanium alloys and reduce costs.

Binder removal approaches involve various combinations of heat, solvents, vacuum, and pressure. In each variant, the goal is binder removal without component damage. This chapter addresses the factors that control success, showing how process decisions depend on the powder and binder characteristics. The chapter starts with a comparison of binder-, lubricant-, and polymer-removal situations that arise after powder shaping and then describes the general principles of binder removal in powder-binder techniques. The subsequent sections discuss in detail characteristics, operating procedure, equipment setup, advantages, limitations, and applications of first- and second-stage binder removal processes, as well as the factors influencing these processes. Cost issues associated with binder-removal technologies are also discussed.

This chapter describes the processes involved in the fabrication of wrought and cast metal products. It discusses deformation processes including bending and forming, material removal processes such as milling, cutting, and grinding, and joining methods including welding, soldering, and brazing. It also discusses powder consolidation, rolling, drawing and extrusion, and common forging methods.

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.

This chapter provides helpful guidelines for selecting a surface treatment for a given application. It identifies important design factors and applicable treatments for common design scenarios, materials, and operating conditions. It explains why heat treatments and finishing operations may be required before or after processing and how to estimate or predict coating thickness, case depth, hardness, and the likelihood of distortion. It also addresses related issues and considerations such as part handling and fixturing, surface preparation and cleaning requirements, processability, aesthetics, and the influence of design features.

This chapter discusses the factors that affect die steel selection for hot forging, including material properties such as hardenability, heat and wear resistance, toughness, and resistance to plastic deformation and mechanical fatigue. It then describes the relative merits of various materials and the basic requirements for cold forging dies. The chapter also covers die manufacturing processes, such as high-speed and hard machining, electrodischarge machining, and hobbing, and the use of surface treatments.

This chapter begins with a review of some of the terms used in the gear industry to describe the design of gears and gear geometries. It then discusses the types of gears that operate on parallel shafts, intersecting shafts, and nonparallel and nonintersecting shafts. Next, the processes involved in the selection of gear are discussed, followed by information on the basic stresses applied to a gear tooth, the strength of a gear tooth, and the most widely used gear materials. Further, the chapter briefly reviews gear manufacturing methods and the heat treating processing steps including prehardening processes, through hardening, and case hardening processes.