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Authors: Richard Mahn
This article helps those who work with aluminum in the many varieties of applications of such products. It describes the two main categories of cleaning that can be used with most any metal, namely, mechanical cleaning and chemical cleaning. The article provides a discussion on the laboratory evaluation of cleaners, field testing of cleaners, and cleaner types and procedures. It also describes the special cleaning procedures for aluminum alloys, such as steam cleaning and rotary wire-brush cleaning. The article reviews the use of temporary coatings and the use of maintenance coatings on aluminum. It provides information on the handling and storage procedures of aluminum alloys and the cleaning of specific applications of aluminum.
Authors: Jude Mary Runge, John Weritz
This article discusses the properties of aluminum surface and the applications of aluminum alloys. It explains the effects of trace elements on aluminum alloys. The article considers microstructural development of aluminum in terms of the surface and explains how it will impact corrosion resistance and surface treatment. It describes the thermodynamics of equilibrium oxidation processes and non-equilibrium corrosion processes. The article provides a discussion on aluminum oxidation under atmospheric and dynamic conditions. It presents the potential/pH (Pourbaix) diagram for aluminum under atmospheric and dynamic conditions. The article also explains the polarization effects during the formation of stable aluminum oxide under dynamic conditions. It concludes with information on the designation system for aluminum finishes.
Authors: Michael E. Finn
This article reviews general machining factors as well as specific cutting tool and cutting parameters for the six basic chip-forming processes. Best practices for each of the six chip-forming processes are suggested for optimized machining of aluminum alloys. The article lists the inherent disadvantages of machining processes that involve compression/shear chip formation. It discusses the machining of aluminum metal-matrix composites and nontraditional machining of aluminum.
Authors: D. Scott MacKenzie
This article provides an overview of the factors used to determine a suitable cooling rate and the appropriate quenching process to develop a suitable cooling rate. It discusses the three distinct stages of quenching and reviews the factors that affect the rate of cooling in production operations. It discusses the quenchants that are used in quenching aluminum alloys. The article also describes the racking practices for controlling distortion and the level of residual stresses induced during the quench.
Authors: Geoffrey K. Sigworth
This article presents a discussion on the heat treatment of aluminum alloy castings, with a focus on the fundamental technical aspects involved in each process step. The intent is to convey a good understanding of the fundamental aspects of heat treatment. Typical heat treatments of aluminum casting alloys are presented in a table. The article describes the solution heat treatment, quenching, and preaging of Al-Si-Mg alloys, as well as the solution heat treatment and artificial aging of Al-Si-Cu-Mg casting alloys.
Authors: D.S. MacKenzie
This article summarizes a typical solution and aging heat treatments of 2xxx (Al-Cu), 6xxx (Al-Mg-Si), and 7xxx (Al-Zn-Mg) wrought alloys. It discusses the general aging characteristics and the effects of reheating of aluminum alloys. Typical examples of hardness and conductivity values for various aluminum alloy tempers are listed in a table. The article also describes the age hardening of Al-Cu (Mg) alloys, Al-Mg-Si alloys, and Zn-Mg-(Cu) aluminum alloys.
Authors: Michael E. Finn
This article describes the two types of grinding used in mechanical finishing. It reviews the binders and fluid carriers used in buffing, and discusses satin finishing and barrel finishing. It also describes lapping and honing techniques that are of special interest in treating aluminum parts that have received hard anodic coatings. Honing recommendations for aluminum alloys are presented in a table.
Authors: Mangesh V. Pantawane, Sameehan S. Joshi, and Narendra B. Dahotre
This article focuses on a variety of laser beam machining (LBM) operations of aluminum and its alloys. It presents different approaches for carrying out machining operations, laser processing parameters, efficiency and accuracy of the process, and the effect of laser processing parameters on the quality of the machined surface. The article provides an overview of the various conventional (chip forming) and nonconventional machining techniques employed for aluminum-based materials. A comparison of the various aspects of LBM with other non-conventional techniques is also presented. The article also describes the features of LBM techniques employed for aluminum and its alloys for different types of machining.
Authors: Alton T. Tabereaux
This article describes the Bayer process for the purification of alumina. It discusses the aluminum electrolytic process in terms of aluminum electrolysis cell design, magnetohydrodynamic forces, and cathode lining. It reviews the electrochemical reactions and thermodynamics for aluminum electrolysis. It also describes the cell operations and cell stability, as well as the key indicators of cell performance. It schematically illustrates the typical costs producing aluminum in an aluminum smelter. The article also discusses various environmental issues, such as fluoride recovery; perfluorocarbons, polycyclic aromatic hydrocarbons, and sulfur emissions; spent pot lining; and development of inert anodes and carbon dioxide emissions.
Authors: Geoffrey Sigworth
This article provides an overview of the common methods of aluminum shape casting. It discusses the designations of aluminum casting alloys categorized by the Aluminum Association designation system. The article summarizes the basic composition groupings of aluminum casting alloy and discusses the effects of specific alloying elements and impurities. The characteristics of the important casting processes are summarized and compared in a table. The article presents the advantages and disadvantages of green sand casting, permanent mold casting, semipermanent mold casting, and high-pressure die casting. A discussion on other casting processes is also included.