This chapter opens with a discussion of the classification of rod and tube extrusion processes. The standard processes involve hot working (extrusion at temperatures above room temperature), but some specialized cold working processes are also used for rod and tube extrusion. The next section reviews principles, variations, thermal conditions, axial load calculation, material flow, and applications of direct extrusion and indirect extrusion, with examples provided for extrusion of aluminum and copper alloys. Next, the chapter focuses on the process principles, advantages, and applications of conventional hydrostatic extrusion and thick film processes. This is followed by sections providing information on the special extrusion processes, namely conform process and cable sheathing. The chapter ends with a discussion on direct and indirect tube extrusion.

Tube hydroforming is a material-forming process that uses pressurized fluid to plastically deform tubular materials into desired shapes. It is widely used in the automotive industry for making exhaust manifolds, catalytic converters, shock absorber housings, and other parts. This chapter discusses the basic methods of tube hydroforming and the underlying process mechanics. It explains how to determine if a material is a viable candidate and whether it can withstand preforming or bending operations. It describes critical process parameters, such as interface pressure, surface expansion and contraction, and sliding velocity, and how they influence friction, lubrication, and wear. The chapter also provides information on forming presses and tooling, tube hydropiercing, and the use of finite elements to determine optimal processing conditions and loading paths.

This chapter describes the metallurgy, composition, and properties of steels and other alloys. It provides information on the atomic structure of metals, the nature of alloy phases, and the mechanisms involved in phase transformations, including time-temperature effects and the role of diffusion, nucleation, and growth. It also discusses alloying, heat treating, and defect formation and briefly covers condenser tube materials.

Water chemistry is a factor in nearly all boiler tube failures. It contributes to the formation of scale, biofilms, and sludge, determines deposition rates, and drives the corrosion process. This chapter explains how water chemistry is managed in boilers and describes the effect of impurities and feedwater parameters on high-pressure boiler components. It discusses deposition and scaling, types of corrosion, and carryover, a condition that occurs when steam becomes contaminated with droplets of boiler water. The chapter also covers water treatment procedures, including filtration, chlorination, ion exchange, demineralization, reverse osmosis, caustic and chelant treatment, oxygen scavenging, and colloidal, carbonate, phosphate, and sodium aluminate conditioning.

Boilers are often classified based on the maximum operating temperature and pressure for which they are designed. Classifications, in ascending order, are subcritical, supercritical, ultra-supercritical, and to advanced ultra-supercritical. At each higher operating point comes greater efficiency, as well as greater demand on construction materials. This chapter discusses the primary requirements for boiler tube materials, including oxidation and corrosion resistance, fatigue strength, thermal conductivity, and the ability to resist creep and rupture. It also provides information on various steels and alloys, covering cost, engineering specifications, and ease of use.