Forging is a deformation process achieved through the application of compressive stresses. During the stroke, pressures and velocities are continuously changing and the initial lubricant supply must suffice for the duration of the operation. Lubricant residues and pickup products also change with time, further complicating the analysis of friction and wear. This chapter provides a qualitative and quantitative overview of the mechanics and tribology of forging in all of its forms. It discusses the effects of friction, pressures, forces, and temperature on the deformation and flow of metals in open-die, closed-die, and impression-die forging and in back extrusion and piercing operations. It presents various ways to achieve fluid-film lubrication in upset forging processes and examines the cause of barreling, defect formation, and folding in the upsetting of cylinders, rings, and slabs. It also explains how to evaluate lubricants, friction, and wear under hot, cold, and warm forging conditions and how to extend die life and reduce defects when processing different materials.

This chapter covers the mechanics and tribology of sheet metalworking processes, including shearing, bending, spinning, stretching, deep drawing, ironing, and hydroforming. It explains how to determine friction, wear, and lubrication needs based on process forces, temperatures, and strains and the effects of strain hardening on workpiece materials. It presents test methods for evaluating process tribology, describes lubrication and wear control approaches, and discusses the factors, such as surface roughness, lubricant breakdown, and adhesion, that can lead to galling and other forms of wear. It also provides best practices for selecting, evaluating, and applying lubricants for specific materials, including steels, stainless steels, and aluminum and magnesium alloys.

In contrast to most plastic deformation processes, the shape of a machined component is not uniquely defined by the tooling. Instead, it is affected by complex interactions between tool geometry, material properties, and frictional stresses and is further complicated by tool wear. This chapter covers the mechanics and tribology of metal cutting processes. It discusses the factors that influence chip formation, including tool and process geometry, cutting forces and speeds, temperature, and stress distribution. It reviews the causes and effects of tool wear and explains how to predict and extend the life of cutting tools based on the material of construction, the use of cutting fluids, and the means of lubrication. It presents various methods for evaluating workpiece materials, chip formation, wear, and surface finish in cutting processes such as turning, milling, and drilling. It also discusses the mechanics and tribology of surface grinding and other forms of abrasive machining.

This appendix presents a table of definitions and conversion factors related to tribology and metalworking.

This chapter presents a qualitative and quantitative overview of the stresses, strains, forces, and energy associated with metalworking processes and the tribological behavior of metals. It covers key concepts necessary for understanding metalworking tribology, including plastic deformation, yield criteria, flow strength, and the application of flow rules. It explains how to calculate the work involved in deformation processes, how to assess the propensity for fracture, how to determine temperature rise and strain distribution in the workpiece, and how to classify metalworking processes based on related tribology.

This chapter examines the surface interactions that occur during metal forming operations at both the macroscopic and microscopic scale. It describes the measurement and characterization of surface profiles based on form error, waviness, and roughness. It explains how workpiece surfaces become rougher or smoother due to the effects of deformation, tooling interactions, and lubricant film thickness. It familiarizes readers with the concept of nominal contact, the role of asperities, and the effects of interface pressure, plasticity index, shear stress, and bulk strain rate. It also reviews the two basic friction rules applicable to metal forming and presents advanced friction models that account for the transition between Coulomb and Tresca behavior and the effects of lubrication.

Rolling is unique in that it cannot be conducted without friction. Friction draws the workpiece into the roll gap and facilitates its passage through the deformation zone. This chapter provides an overview of the mechanics and tribology of flat rolling processes and explains how various aspects of the theory apply to shape rolling as well. It derives numerous equations and models to help quantify the forces, torque, and power involved in rolling operations and the associated heating, slip, strain distribution, and deformation in both the workpiece and rolls. It describes the friction and wear that occur in hot and cold rolling under hydrodynamic and mixed-film lubrication; the influence of viscosity, film thickness, rolling speed, interface pressure, pass reduction, and lubricant breakdown; and the effect of surface finish and defects. The chapter also provides best practices for evaluating, applying, and treating lubricants for industrially important materials including iron-base, nickel-base, and aluminum alloys.

Drawing is a bulk deformation process that involves significant surface generation and high pressures. This chapter provides an overview of the mechanics and tribology of wire, bar, tube, and shape drawing. It presents important equations for calculating stresses, forces, friction, heat, strain, and distortion for different tooling configurations and geometries. It explains how to select and apply lubricants based on drawing speed, die design, and other factors and how to maintain sufficient film thickness for hydrodynamic, mixed, and solid-film lubrication conditions. It also discusses the use of vibrating dies, the influence of surface finish and defects, and lubrication practices for specific materials.

This chapter deals with the mechanics and tribology associated with the extrusion of bars, sections, and tubes. It covers direct and indirect extrusion processes in detail and demonstrates the use of important equations, relationships, and measurements for determining pressure, force, material flow, friction, die wear, heat generation, and lubrication requirements. The chapter also provides information on hydrostatic, friction-assisted, and severe plastic deformation extrusion processes, discusses the cause of instabilities and defects, and explains how to select and apply lubricants to minimize friction and die wear when extruding steel, aluminum, copper, and refractory metals.

This chapter describes the process steps in the production of smelter grade aluminum, the environmental issues with aluminum production, and the importance of recycling. It also provides a discussion on the refining, or Bayer, process and the smelting, or Hall-Héroult, process.

This chapter provides an overview of the alloy and temper designations adopted for aluminum cast and wrought products. It explains the naming system and how to identify the main alloying elements and basic strengthening mechanism from any given alloy and temper designation. The chapter provides additional detail on the strengthening and softening mechanisms that allow aluminum alloys to attain a range of engineering properties. The strength of aluminum alloys can be controlled by three methods: solid-solution hardening by alloying, work hardening by plastic deformation, and precipitation hardening with appropriate alloying and heat treatment.

The manufacture of all aluminum wrought products begins with an ingot or a continuous strip solidified from the liquid state. During molten metal processing (MMP), aluminum undergoes a series of operations that are described in this chapter including melting and alloying, recycling, molten metal treatment, control of inclusions, ingot grain refinement, and direct chill (DC) or continuous casting.

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.

This chapter provides an overview of the rolling and finishing processes required to create a sheet, plate, or foil product from a direct chill (DC) cast ingot. The flow paths, equipment, and operations are described with a view to the basic evolution of the microstructure, surface characteristics, and dimensions.

Aluminum shapes, rod, bar, tubes, and wire may be produced directly as extrusions or by subsequent processing of continuous cast stock. This chapter describes the key aspects of aluminum extrusion and wire production focusing on the more common hot extrusion process and presenting the general types of aluminum extrusion alloys. An overview of free-machining alloys and products, and weldable 6xxx and 7xxx high-strength structural alloys is also provided.

Forged aluminum products vary widely in their production methods and applications. The forging process allows for control of microstructure and directional properties, and their fatigue and fracture resistance are superior to shape castings. This chapter presents the types, equipment, process steps, alloys, and products of aluminum forging.

This chapter provides basic concepts and background for customer-related manufacturing processes applied to aluminum products including forming, joining and welding, surface treatments, and machinability. It reviews the selection criteria, key testing regimes, and original equipment manufacturer (OEM) requirements. The chapter also presents examples that demonstrate the importance of choosing the correct alloy and temper to successfully meet the OEM fabrication criteria.

This chapter presents the theory and practice associated with the application of thin films. The first half of the chapter describes physical deposition processes in which functional coatings are deposited on component surfaces using mechanical, electromechanical, or thermodynamic techniques. Physical vapor deposition (PVD) techniques include sputtering, e-beam evaporation, arc-PVD, and ion plating and are best suited for elements and compounds with moderate melting points or when a high-purity film is required. The remainder of the chapter covers chemical vapor deposition (CVD) processes, including atomic layer deposition, plasma-enhanced and plasma-assisted CVD, and various forms of vapor-phase epitaxy, which are commonly used for compound films or when deposit purity is less critical. A brief application overview is also presented.