Search Results for castability

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.

Aluminum casting alloy compositions parallel those of wrought alloys in many respects. However, because work hardening plays no significant role in the development of casting properties, the use and purposes of some alloying elements differ in casting alloys versus wrought alloys. This chapter provides information on specifications and widely used designation systems and alloy nomenclature for aluminum casting alloys. It describes the composition of seven basic families of aluminum casting alloys: aluminum-copper, aluminum-silicon-copper, aluminum-silicon, aluminum-silicon-magnesium, aluminum-magnesium, aluminum-zinc-magnesium, and aluminum-tin. The chapter discusses the effects of alloying elements on the properties of cast aluminum. It provides information on various alloys that are grouped with respect to their applications or major performance characteristics.

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.

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.

This chapter instructs the metallographer on the basic skills required to prepare a polished metallographic specimen. It is organized in a chronological sequence starting with the information-gathering process on the material being investigated, then moving on to sectioning, mounting, grinding, and polishing processes, and ending with methods used to properly store metallographic specimens. The discussion covers the preparation procedures, the materials being investigated, and equipment used to perform these procedures.

This chapter is a collection of tables listing: cast alloy designations of Aluminum Association, along with their general applications; the chemical compositions of the frequently used alloys for gravity permanent molds, low-pressure permanent molds, squeeze castings, and die castings; the typical tensile properties of die cast alloys; and the designations of different heat treatments and their description. The tables also list the temperatures and times of typical heat treatment cycles for different permanent mold cast alloys; typical components in sand, gravity, and low-pressure permanent mold castings and die castings, the functional requirements of each process, and the corresponding suitable alloys and heat treatments; and alloys that are high vacuum die cast for structural castings. The chapter also presents examples of photomicrographs of some alloys cast by different processes.

This chapter begins with information on the historical development of aluminum alloy castings. It then covers the basic factors involved in the selection of a casting process. This is followed by sections describing the various categories of casting processes and their variants: expendable mold gravity-feed casting, nonexpendable (permanent) mold gravity feed casting, and pressure die casting. Next, the chapter describes the technologies used to produce premium engineered castings and when such castings may be relevant. The chapter concludes with descriptions of other process technologies used with castings, including metallurgical bonding, metal-matrix composites, and hot isostatic pressing.

This article examines the composition and properties of magnesium and its alloys. It discusses alloy and temper designations, applications and product forms, and commercial alloy systems, and explains how alloying elements affect physical and mechanical properties, processing characteristics, and corrosion behaviors.

This chapter first introduces the various factors that may alter the physical and mechanical properties of aluminum castings that are addressed in the other chapters in the book. Then, it presents the historical development of aluminum castings, followed by a discussion on the advantages and limitations of aluminum castings. Next, the chapter describes the major trends that are influencing the increased use of aluminum castings. Finally, it introduces the considerations involved in the selection of an appropriate aluminum alloy and casting process for a given application.

This article discusses the general purpose of alloying and identifies some of the material properties and behaviors that can be improved by adding various elements to the base metal. It explains how alloying can make metals stronger and more resistant to corrosion and wear as well as easier to cast, weld, form, and machine. It also discusses some of the alloying techniques that have been developed to address problems stemming from dissimilarities between the base metal and alloying or inoculate material.

This chapter describes the processes and alloys used in the casting of aluminum components, the advantages and disadvantages of the different shape-casting methods, and the major factors that influence alloy selection for shape-casting applications. An overview of the heat treatment of cast products is also included.

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.