Ingot casting is the vital conduit between molten metal provided by primary production and recycling, and the manufacture of aluminum and aluminum alloy products. This article discusses various ingot forms, such as remelt ingot, billets, ingots for rolling, fabricating ingot, and particle ingot and powder. It describes the molten metal processing and ingot casting process in terms of open-mold casting and direct chill process. The article examines the continuous processes that provide commercial alternatives to conventional ingot casting. It reviews the postsolidification processes in terms of stress relief, homogenization, and scalping. The article concludes with a discussion on safety limited to ingot casting.

Ingot casting is the vital conduit between molten metal provided by primary production and recycling and the manufacture of aluminum and aluminum alloy products. A number of ingot casting processes have been developed to ensure the soundness, integrity, and homogeneity required by downstream manufacturing processes. This article starts with a review of the different forms of ingot and the molten-metal processing techniques involved in ingot casting. It then describes the open-mold casting and direct chill (DC) ingot casting processes. The process variations and solidification in the DC process are summarized. The article explains continuous processes, namely, twin-roll strip casting, slab casting, and wheel-belt processes. It concludes with information on postsolidification processes, including stress relief and scalping, and a discussion of safety practices for ingot casting.

The purpose of continuous casting is to bypass conventional ingot casting and to cast to a form that is directly rollable on finishing mills. The use of this process has resulted in improvement in yield, surface condition, and internal quality of product when compared to the ingot-made material. This article outlines the advantages of steel continuous casting, along with its developments and challenges for improvement. It provides a general description of the continuous casting process and the design and layout of a continuous casting steelmaking facility. It reviews process enhancements such as near-net shape casting, tundish metallurgy, and pouring stream protection. The article discusses the use and capabilities of different molds for steel continuous casting, including thin-wall tube-type molds, solid molds, and plate molds. The article explains the methods for enhancing productivity and improving quality in steel continuous casting. It evaluates the applications of horizontal continuous casting in casting steel. The article concludes by outlining priorities for future development such as enhanced control systems and automation.

When a heat of steel is melted and refined, it is necessary to solidify it into useful forms for further processing or final use. Ingot casting remains the preferred method for certain specialty, tool, forging, and remelted steels. This article discusses the methods, equipment, and theory for pouring, solidifying, and stripping steel ingots. It describes two basic types of pouring methods, top pouring and bottom pouring, and provides information on equipment such as hot tops, ingot molds, and stools. The design of the ingot is dictated by the application and type of steel involved. The article concludes with information on the applications of solidification simulation.

The primary purpose of this article is to describe general root causes of failure that are associated with wrought metals and metalworking. This includes a brief review of the discontinuities or imperfections that may be common sources of failure-inducing defects in the bulk working of wrought products. The article addresses the types of flaws or defects that can be introduced during the steel forging process itself, including defects originating in the ingot-casting process. Defects found in nonferrous forgings—titanium, aluminum, and copper and copper alloys—also are covered.

This article presents a detailed account on the process flow, composition, alternative sources, and the advancement of ironmaking, steelmaking and secondary steelmaking practices. Some steels, such as bearing steels, heat-resistant steels, ultrahigh strength missile and aircraft steels, and rotor steels have higher quality requirements and tighter composition control than plain carbon or ordinary low-alloy steels. The production of special-quality steels requires vacuum-based induction or electric remelting and refining capabilities. The article explores the types and characteristics of various steel manufacturing processes, such as ingot casting, continuous casting, and hot rolling. It provides an outline of specialized processing routes of producing ultralow plain carbon steels, interstitial-free steels, high strength low-alloy steels, ultrahigh strength steels, stainless steels, and cold-rolled products, and briefly explains the analytical techniques for liquid steels.

This article provides an overview of the studies on computational modeling of the vacuum arc remelting (VAR) and electroslag remelting (ESR) processes. These models involve the axisymmetric analysis of the electromagnetic, flow, heat-transfer, and phase-change phenomena to predict the pool shape and thermal history of an ingot using two-dimensional axisymmetric models for VAR and ESR. Analysis of segregation of alloying elements during solidification that gives rise to macrolevel compositional nonuniformity in titanium alloy ingots is also described. The article discusses the important features of the control-volume-based computational method to review the unique aspects of the processes. Measurement of the properties of alloys and slags is explained and an analysis of the process variants for improving the predictive accuracy of the models is presented.

Electroslag remelting (ESR) is commonly used to produce the highest levels of quality in plate steels, particularly in thick plates. This article provides an overview of the ESR and discusses the major components and operations of the ESR furnaces. It describes the principles of ingot solidification and the various defects of remelted ingot such as tree ring patterns, freckles, and white spots. The article explains several variations of ESR such as pressure electroslag remelting, remelting under reduced pressure, and electroslag rapid remelting. It also examines the features of steel ESR and superalloy ESR.

This article describes the zinc and zinc alloys for decorative and functional applications. It focuses on the types of zinc coatings, namely, hot dip galvanizing, electrogalvanizing, metallizing, and mechanical galvanizing. The article covers the uses of zinc alloy castings, including pressure die castings, and gravity castings. It details the wrought products of zinc and zinc alloys, including flat-rolled products, wire-drawn products, extruded products, and forged products. The article also describes various properties of zinc alloys, including mechanical, thermal, electrical, chemical, and magnetic properties. The listing for each alloy includes chemical compositions, relevant specifications, mass characteristics, and fabrication characteristics.

The most common aluminum alloy systems are aluminum-silicon, aluminum-copper, and aluminum-magnesium. This article focuses on the grain structure, eutectic microstructure, and dendritic microstructure of these systems. It provides information on microsegregation and its problems in casting of alloys. The article also illustrates the casting defects such as macroporosity, microshrinkage, and surface defects, associated with the alloys.

This article describes the development of heat-resistant titanium-base alloys and their classification into several microstructure categories based on their strengthening mechanisms. It explains the phase transformation in titanium-aluminum-base alloys and two peritectic reactions that take place in the titanium-aluminum system. The article also describes two approaches for controlling the orientation of the high-temperature alpha phase to achieve the required lamellar orientation by directional solidification in order to improve the strength and ductility of titanium-aluminum alloys. One approach is by seeding the alpha phase in the alloys, and the other is without seeding, by controlling the solidification path of alloys through appropriate alloying. The article discusses the grain refinement technique used to improve the ductility of cast titanium-aluminum alloys to a level of above 1" at room temperature and reasonable room temperature ductility in the as-cast condition. Finally, it provides information on the microstructures produced through various near-net shape manufacturing processes.

Plasma melting is a material-processing technique in which the heat of thermal plasma is used to melt a material. This article discusses two typical design principles of plasma torches in the transferred mode: the tungsten tip design and the hollow copper electrode design. It describes the sources of atmospheric contamination in plasma melting furnaces and their control measures. The equipment used in plasma melting furnaces are also discussed. The article provides a detailed discussion on various plasma melting processes, such as plasma consolidation, plasma arc remelting, plasma cold hearth melting, and plasma casting.

The selection of the best material for a particular design is intimately associated with the decisions of how to process the material or manufacture a part. This article describes the basic characteristics of manufacturing processes such as material factors, shape factors, and process factors. The influence of materials on the manufacturing cost is described with a specific example. The article discusses the design for manufacturability to minimize the total number of parts, use readily processed materials, and eliminate machining and finishing operations. It reviews the factors influencing the selection of a material for production, including material composition, heat-treated condition, surface finish, and cost of material. The article describes the material characteristics, such as terms formability, workability, castability, machinability, and weldability, that aid or hinder the production of a part without defects.

This article reviews the melt processing and casting of non-ferrous alloys, such as nickel alloys, titanium alloys, and lead alloys. It describes the lead refining steps, namely, copper drossing, softening, desilvering, zinc removal, bismuth removal, and final refining.

This article presents conservation equations for heat, species, mass, and momentum to predict transport phenomena during solidification processing. It presents transport equations and several examples of their applications to illustrate the physics present in alloy solidification. The examples demonstrate the utility of scaling analysis to explain the fundamental physics in a process and to demonstrate the limitations of simplifying assumptions. The article concludes with information on the solidification behavior of alloys as predicted by full numerical solutions of the transport equations.

Macrosegregation refers to spatial compositional variations that occur in metal alloy castings and range in scale from several millimeters to centimeters or even meters. This article presents a derivative approach for understanding the mechanism of macrosegregation induced by flow of the liquid and movement of the solid with examples.

This article discusses various molten-metal treatments, namely fluxing, degassing, and molten-metal filtration. It focuses on various molten-metal handling systems for transporting, holding, or delivering molten metal to the mold/die system. These include launders, tundishes, holding furnaces or transport crucibles, molten-metal transfer pumps, teeming ladles, and dosing and pouring furnaces.

This article describes the general root causes of failure associated with wrought metals and metalworking. This includes a brief review of the discontinuities or imperfections that may be the common sources of failure-inducing defects in bulk working of wrought products. The article discusses the types of imperfections that can be traced to the original ingot product. These include chemical segregation; ingot pipe, porosity, and centerline shrinkage; high hydrogen content; nonmetallic inclusions; unmelted electrodes and shelf; and cracks, laminations, seams, pits, blisters, and scabs. The article provides a discussion on the imperfections found in steel forgings. The problems encountered in sheet metal forming are also discussed. The article concludes with information on the causes of failure in cold formed parts.

Aluminum casting alloys are the most versatile of all common foundry alloys and generally have the highest castability ratings. This article discusses the designation and classification of aluminum casting alloys based on their composition and the factors influencing alloy selection. Alloys discussed include rotor alloys, commercial duralumin alloys, premium casting alloys, piston and elevated-temperature alloys, general-purpose alloys, magnesium alloys, aluminum-zinc-magnesium alloys, and bearing alloys. Six basic types of aluminum alloys developed for casting include aluminum-copper, aluminum-copper-silicon, aluminum-silicon, aluminum-magnesium, aluminum-zinc-magnesium, and aluminum-tin. The article also describes the main casting processes for aluminum alloys, which include die casting, permanent mold casting, sand casting (green sand and dry sand), plaster casting, and investment casting. In addition, the article discusses factors affecting the mechanical and physical properties, microstructural features that affect mechanical properties, the effects of alloying, and major applications of aluminum casting alloys.