Engineered geometry and its microstructures impact casting performance. This chapter describes three interdependent disciplines that are needed to achieve product performance and cost targets, namely engineered geometry; target microstructure and chemistry; and optimum process for high integrity.

This chapter provides an overview of how the disciplines of design, material, and manufacturing contribute to engineering for functional performance. It describes the interaction of product designers and casting engineers in product development. It discusses the consequences of component failure, uncertainty in data and assumptions, and selection of the factor of safety. The chapter also presents an overview of the functional requirements for product performance and provides an overview of product design development. It also presents a partial list of the different tests that are performed on prototypes and examples of product testing. The chapter describes the requirements of a traceability system.

The casting engineer contributes to a successful component design by offering expertise in molding, core making, and material characteristics and by recommending the most suitable casting process to use to meet quality and cost targets. The casting engineer's responsibilities include recommending locator positioning; advising about lugs, hooks, or holes for casting handling through all processes; determining the choice of a parting plane and pouring orientation; designing cores for accurate positioning, suitable venting, and proper cleaning; guiding decisions about wall thicknesses and junctions; making suggestions about casting design to eliminate distortion; optimizing the gating design for slag-free metal; and establishing the feeding techniques to eliminate shrink porosity. This chapter provides the guidelines for these responsibilities. In addition, the guidelines for the use of chaplets and chills in cast iron castings; guidelines for drafts, machine stock, tolerances, and contraction or shrink rule; and guidelines for pattern layouts and nesting are also covered.

This chapter covers mechanical properties, microstructures, chemical compositions, manufacturing processes, and engineering of gating practices for several applications of gray, white, and alloyed cast irons. It begins with a description of material standards, followed by a section providing information on the practice of stress relieving. Next, the chapter details various ways of eliminating slag entrainment while designing gating and venting systems. Several factors related to the establishment of the optimum pouring rate and time are then covered. Further, the chapter discusses the technology of unalloyed or low-alloyed gray iron castings and white iron and high-alloyed cast irons. Finally, it describes the casting defects that are associated with cast iron and the processes involved in solving these defects. The article includes a number of figures illustrating the topics discussed.

Malleable iron has unique properties that justify its application in the metal working industry. This chapter discusses the advantages, limitations, and mechanical properties of malleable iron; provides a description of the malleabilization process; and presents manufacturing guidelines for malleable iron castings.

Ductile iron has far superior mechanical properties compared to gray iron as well as significantly improved castability and attractive cost savings compared to cast steel. This chapter begins with information on graphite morphology and matrix type. It then discusses the advantages and applications of ductile iron. Next, the effects of various factors on the grades, chemistry, matrix, and mechanical properties of ductile iron are covered. This is followed by a section detailing the ductile iron treatment methods and the quality control methods used. Guidelines for gating and feeder design are then provided. Further, the chapter addresses the technology of ductile iron castings, including the performance and geometric attributes, molding and core-making processes used, material grades, mechanical properties, and chemical compositions of a few applications. Finally, it describes ductile iron casting defects and presents practical cases of problem-solving.

Unlike conventional quench and temper heat treatment, austempering is an iron and steel heat-treatment process that enhances mechanical properties through the isothermal transformation of austenite with a minimum amount of quenching stresses. This chapter begins with a discussion of austemperability requirements. Then outlines of austenitizing and austempering cycles and resultant microstructures are presented. This is followed by sections discussing the mechanical properties, advantages, limitations, machinability, process variants, and applications of austempered ductile iron (ADI). Information on the growth of premachined ADI components is also provided. Further, the chapter describes two slightly different systems for austempering: atmospheric-salt and salt-salt systems. Finally, it presents general guidelines for component designers, casting manufacturers, and heat treaters to apply ADI more widely and with improved success.

Compacted graphite iron (GCI) is a cast iron grade that is engineered through graphite morphology modifications to achieve a combination of thermal and mechanical properties that are in between those of flake graphite iron and ductile iron. This chapter discusses the advantages of compacted graphite iron over gray iron and ductile iron. It presents examples of low- and high-frequency thermal cycling, both of which affect the thermal stresses that castings are exposed to during temperature fluctations. Information on optimum carbon and silicon ranges as well as mechanical property standards for CGI are provided. The chapter describes the critical factors that control CGI and discusses methods of CGI manufacturing.

Steel is broadly classified as plain-carbon steels, low-alloy steels, and high-alloy steels. This chapter begins by describing microconstituents of low- and medium-carbon steel, including bainite and martensite. This is followed by a section discussing the effect of alloying elements on steel. Then, it provides an overview of steel casting applications. Next, the chapter reviews engineering guidelines for steel castings and feeder design. The following section provides information on feeding aids. Further, the chapter describes the elements of gating systems for steel castings. It also describes the alloys, properties, applications, and engineering details of steel. Finally, the chapter explains defects in steel castings and presents guidelines for problem solving with examples.

This chapter provides an overview of key elements in controlling the casting process, systems to confirm the quality of outgoing components, and the steps needed to launch a novel product. The discussion also provides information on process control tools and techniques; incoming material control; process control of sand preparation and system maintenance; metallic charge materials; product quality control; and melting, metallurgical, and mechanical testing.

This chapter discusses the crystal structures of steel and cast iron, the iron-iron carbide equilibrium diagram, microconstituents or phases in the iron-iron carbide phase diagram, the iron-carbon carbide-silicon equilibrium diagram of cast irons, and the influence on microstructure by base elements and alloying elements. Graphitization, cooling rates, and heat treatment effects are covered. There also is discussion on inoculation benefits, flake graphite types and typical applications, evolution of cast iron types, ASTM specification A247 for graphite shapes, and selection of the best molding process. A large table lists typical material choices for various applications.

Iron and steel have been the most useful materials to meet the needs of several industries for many decades. Each iron and steel alloy offers unique attributes that make them the best choice for an application. This chapter provides an overview of each ferrous alloy—gray iron, malleable iron, compacted graphite iron (CGI), ductile iron, austempered ductile iron (ADI), and carbon steel and low-alloy steel; its versatile attributes; and its individual applications. A large section of the chapter covers the impact of electric vehicles on the future of the iron and steel castings industry, including discussion on electric vehicle categories and weights; impact of center of gravity on stability and steering; lightweighting incentives; and engineering for improved suspension.

This chapter provides a brief overview of iron and steel manufacturing and the major equipment involved in the process as well as identifying where casting fits into the overall process. In addition, it provides an overview of cast iron manufacturing, including the processes involved in converting pig iron into cast iron and steel.

Most iron and steel castings are produced by casting into sand molds. Sand cores are needed primarily to form hollow cavities in castings for collapsibility and ease of cleaning. This chapter begins with an overview of the classification of molding and core-making systems. This is followed by a section discussing the process involved in shell molding, along with its applications. A brief description of the special casting processes is then presented. Next, the chapter discusses the processes involved in core making. Further, it provides an overview of casting manufacturing. Finally, the chapter provides information on the factors that influence a casting facility layout.

Product design requires an understanding of the mechanical properties of materials, much of which is based on tensile testing. This chapter describes how tensile tests are conducted and how to extract useful information from measurement data. It begins with a review of the different types of test equipment used and how they compare in terms of loading force, displacement rate, accuracy, and allowable sample sizes. It then discusses the various ways tensile measurements are plotted and presents examples of each method. It examines a typical load-displacement curve as well as engineering and true stress-strain curves, calling attention to certain points and features and what they reveal about the test sample and, in some cases, the cause of the behavior observed. It explains, for example, why some materials exhibit discontinuous yielding while others do not, and in such cases, how to determine when yielding begins. It also explains how to determine other properties via tensile tests, including ductility, toughness, and modulus of resilience.

This appendix provides readers with worked solutions to 25 problems involving calculations associated with tensile testing and the determination of mechanical properties and variables. The problems deal with engineering factors and considerations such as stress and strain, loading force, sample lengthening, and machine stiffness, and with mechanical properties and parameters such as elastic modulus, Young’s modulus, strength coefficient, strain-hardening exponent, and modulus of resilience. They also cover a wide range of materials including various grades of aluminum and steel as well as iron, titanium, brass, and copper alloys.

This chapter provides an overview of the production and use of titanium and its significance as an engineering material. It begins by identifying important deposits and ores and assessing current and future production capacities and how they align with global consumption trends. It then describes the physical and mechanical properties of pure titanium and numerous grades of wrought titanium alloys and explains how they compare with other aerospace materials in terms of processing complexity and cost. The chapter also includes information on extractive metallurgy, current and emerging processes, product forms, and related costs.

This chapter discusses the equipment and processes used to convert titanium billet and bar into useful shapes or more refined product forms. These secondary working operations include open-die, closed-die, hot-die and isothermal forging as well as ring rolling and extruding. The chapter describes each method in detail and how it affects the microstructure and mechanical properties of various titanium alloys. It also discusses the propensity of titanium to react with oxygen and hydrogen when heated and explains how to mitigate the effects.