This chapter introduces basic extrusion concepts, including types, processes, mechanics, and the principal variables and their effects on extrusion. The chapter defines the two basic types of extrusion commonly used in the aluminum extrusion industry, direct and indirect. The chapter discusses the mechanics of extrusion including plastic deformation and metal flow, plastic strain and strain rate, extrusion pressure, and extrusion force. The principal variables of extrusion, including billet material flow stress, extrusion ratio, dead-metal zone semiangle, speed of deformation, and extrusion temperature are discussed.

Tribology plays a critical role in extrusion. This chapter provides an overview of tribology in extrusions including a discussion about the friction models at various locations of the extrusion tooling/die material interfaces and a discussion about wear and lubrication in extrusion die and tooling. The chapter shows a flow diagram highlighting the significant input variables necessary for computer simulation using the fundamentals of friction and thermodynamics models. The chapter explains the influence of principal variables on temperature rise in extrusion. It describes the most common industrial methods of isothermal extrusion of aluminum alloys.

This chapter discusses how aluminum and other alloying constituents are added to prepare a furnace charge for the melting process, and how it is cast into billets of various aluminum alloys. Fundamental aspects of billet casting are covered to give an overview of the casting process. The melting practice is discussed, as well as grain refining and degassing. Charge material, grain refining, degassing, filtration of melt, casting systems, and casting variables are discussed. The chapter concludes with a discussion of casting defects.

This chapter discusses the extrusion technology of soft- and medium-strength aluminum alloys. The relative extrudability ratings of some soft- and medium-grade alloys are given. The chapter presents useful extrusion parameters and their relationships associated with day-to-day production practices in the aluminum extrusion industry. Useful parameters discussed include: extrusion runout; extrusion pressure; ram or extrusion speed control; and butt or extrusion discard thickness control. The chapter provides fundamental approaches to introducing and developing the design of experiments (DOE) for the aluminum extrusion plant to improve overall productivity. It also focuses on heat treatment of aluminum alloys.

This chapter discusses the extrusion technology of hard alloys. The chapter provides an overview of hollow extrusion for aerospace application. It presents extrusion defects related to hard alloys. The chapter describes the extrusion quality requirements for aerospace applications. It also discusses extrusion of aluminum-matrix composites. The chapter outlines the powder metallurgy process for making billets for extrusion.

Variables affecting the cost of aerospace extrusions, including extrusion geometry, billet alloy, press size, order quantity, and the length of extrusion and final temper, are discussed in this chapter. Energy and labor inputs at various stages for aerospace extrusions are shown. The chapter offers insights into the economics of producing aerospace extrusions in a highly competitive global business market.

In this chapter, process control of each operational stage is discussed, with a detailed process-control flow diagram to provide a better understanding and to create a process-control document of each operational process stage. This chapter also presents fundamental ideas of a complete process- and quality-control framework system of an aluminum extrusion plant, starting from alloy and billet making to the final heat treatment process parameters required to bring the extrusion to the final alloy and temper designation to meet product requirements.

This chapter discusses the scope of research and development in aluminum extrusion technology. Research in the key technology areas of friction, thermodynamics, and die wear are discussed. The chapter also highlights future developments in extrusion technology.

This chapter presents a brief review of the history of brazing and soldering. It illustrates complicated soldering techniques and masterful goldsmith work, as demonstrated by the famous gold mask of the Egyptian Pharaoh Tutankhamun. The chapter includes the image of a painting from Egypt circa 1475 B.C. that shows a goldsmith soldering with a blowpipe. Numerous similar images have been found in the tombs of ancient Egypt that offer insight into the practices of gold workers from the period, including the use of processes such as smelting, forging, and joining with both brazing and soldering.

This chapter reviews the experience-based guidelines that were developed for forming and welding AHSS.

The increased use of advanced high-strength steels (AHSS) to achieve weight reduction in automobiles has led to the development of tool designs and innovative manufacturing processes. These technologies and processes include: real-time process control, active drawbeads, active binders, flexible binders, flexible rolling, and additive manufacturing. This chapter focuses on these processes and technologies.

This chapter discusses ultra-high-strength steels (UHSS) and gigapascal (GPa) steels and discusses the global formability diagram.

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.