Joining comprises a large number of processes used to assemble individual parts into a larger, more complex component or assembly. The selection of an appropriate design to join parts is based on several considerations related to both the product and the joining process. Many product design departments now improve the ease with which products are assembled by using design for assembly (DFA) techniques, which seek to ensure ease of assembly by developing designs that are easy to assemble. This chapter discusses the general guidelines for DFA and concurrent engineering rules before examining the various joining processes, namely fusion welding, solid-state welding, brazing, soldering, mechanical fastening, and adhesive bonding. In addition, it provides information on several design considerations related to the joining process and selection of the appropriate process for joining.

Arc welding applies to a large and diversified group of welding processes that use an electric arc as the source of heat to melt and join metals. This chapter provides a detailed overview of specific arc welding methods: shielded metal arc welding, flux cored arc welding, submerged arc welding, gas metal arc welding, gas tungsten arc welding, plasma arc welding, plasma-GMAW welding, electroslag welding, and electrogas welding. The basic characteristics of gases used for shielding during arc welding are briefly discussed.

Resistance welding is a group of processes in which the heat for welding is generated by the resistance to the flow of an electrical current through the parts being joined. This chapter discusses the processes, advantages, and limitations of specific resistance welding processes, namely resistance spot welding, resistance seam welding, projection welding, flash welding, and upset welding.

This chapter discusses the fusion welding processes, namely oxyfuel gas welding, oxyacetylene braze welding, stud welding (stud arc welding and capacitor discharge stud welding), high-frequency welding, electron beam welding, laser beam welding, hybrid laser arc welding, and thermit welding.

During fusion welding, the thermal cycles produced by the moving heat source causes physical state changes, metallurgical phase transformations, and transient thermal stresses and metal movement. This chapter begins by discussing weld metal solidification behavior and the solid-state transformations of the main classes of metals and alloys during fusion welding. The main classes include work- or strain-hardened metals and alloys, precipitation-hardened alloys, transformation-hardened steels and cast irons, stainless steels, and solid-solution and dispersion-hardened alloys. The following section provides information on the residual stresses and distortion that remain after welding. The focus then shifts to distortion control of weldments. Inclusions and cracking are discussed in detail. The chapter also discusses the causes for reduced fatigue strength of a component by a weld: stress concentration due to weld shape and joint geometry; stress concentration due to weld imperfections; and residual welding stresses. Inspection and characterization of welds are described in the final section of this chapter.

Solid-state welding processes are those that produce coalescence of the faying surfaces at temperatures below the melting point of the base metals being joined without the addition of brazing or solder filler metal. This chapter discusses solid-state welding processes such as diffusion welding, forge welding, roll welding, coextrusion welding, cold welding, friction welding, friction stir welding, explosion welding, and ultrasonic welding.

Brazing and soldering processes use a molten filler metal to wet the mating surfaces of a joint, with or without the aid of a fluxing agent, leading to the formation of a metallurgical bond between the filler and the respective components. This chapter discusses the characteristics, advantages, and disadvantages of brazing and soldering. The first part focuses on the fundamentals of the brazing process and provides information on filler metals and specific brazing methods. The soldering portion of the chapters provides information on solder alloys used, selection criteria for base metal, the processes involved in precleaning and surface preparation, types of fluxes used, solder joint design, and solder heating methods.

This chapter presents a comprehensive coverage of mechanical fastening methods. It begins with a discussion on the advantages and disadvantages of mechanical fastening followed by sections providing information on mechanically fastened joints and the selection of the correct fastener system. The chapter then describes important structural fasteners, namely bolts, screws, pins, collar fasteners, rivets, blind fasteners, machine pins, and spring clip fasteners. The following sections describe the process involved in presses, shrink fits, hole generation, and fastener installation. The chapter ends with information on miscellaneous mechanical fastening methods.

Adhesive bonding is a widely used industrial joining process in which a polymeric material is used to join two separate pieces (the adherends or substrates). This chapter begins with a discussion on the advantages and disadvantages of adhesive bonding, followed by a section providing information on the theory of adhesion. The chapter then describes the considerations for designing adhesively bonded joints and for testing or characterizing adhesive materials. The following section covers the characteristics of the most important synthetic adhesive systems and five groups of adhesives, namely structural, hot melt, pressure sensitive, water based, and ultraviolet and electron beam cured. The chapter ends with a discussion on some general guidelines for adhesive bonding and the basic steps in the adhesive bonding process.

This chapter reviews materials issues encountered in joining, including challenges involved in welding of dissimilar metal combinations; joining of plastics by mechanical fastening, solvent and adhesive bonding, and welding; joining of thermoset and thermoplastic composite materials by mechanical fastening, adhesive bonding, and, for thermoplastic composites, welding; the making of glass-to-metal seals; and joining of oxide and nonoxide ceramics to themselves and to metals by solid-state processes and by brazing. The classification, types, applications, and the mechanism of each of these methods are covered. The factors influencing joint integrity and the main considerations in welding dissimilar metal combinations are also discussed.

The hot-working process extrusion is used to produce semifinished products in the form of bar, strip, and solid sections, as well as tubes and hollow sections. The first part of this chapter describes the composition, properties, and applications of tin and lead extruded products with a deformation temperature range of 0 to 300 deg C and magnesium and aluminum extruded products with a working temperature range of 300 to 600 deg C. The second part focuses on copper alloy extruded products, extruded titanium alloy products, and extruded products in iron alloys with a working temperature range of 600 to 1300 deg C.

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.

Compared with other deformation processes used to produce semifinished products, the hot-working extrusion process has the advantage of applying pure compressive forces in all three force directions, enhancing workability. The available variations in the extrusion process enable a wide spectrum of materials to be extruded. This chapter focuses on the processes involved in the extrusion of semifinished products in various metals and their alloys, namely tin, lead, lead-base soft solders, tin-base soft solders, zinc, magnesium, aluminum, copper, titanium, zirconium, iron, nickel, and powder metals. It discusses their properties and applications as well as suitable equipment for extrusion. It further discusses the processes involved in the extrusion of semifinished products in exotic alloys and extrusion of semifinished products from metallic composite materials.

This chapter begins with a description of the requirements of tooling and tooling material for hot extrusion. It covers the processes of designing tool and die sets for direct and indirect extrusion. Next, the chapter provides information on extrusion tooling and die sets for direct external and internal shape production and tools for copper alloy extrusion. Further, it addresses design, calculation, and dimensioning of single-piece and two-part containers and describes induction heating for containers. Information on static- and elastic-based analysis and dimensioning of containers loaded in three dimensions is provided. Examples of calculations for different containers, along with their stresses and dimensions, are presented and the manufacture, operation, and maintenance of containers are described. The chapter further discusses the properties and applications of hot working materials for the manufacture of extrusion tooling and of different extruded materials for the manufacture of extrusion tooling for direct and indirect forming.

This appendix contains tables listing the approximate composition of materials for the extrusion process. The materials covered are aluminum alloys, magnesium and magnesium alloys, copper and copper alloys, cobalt alloys, nickel and nickel alloys, iron alloys, steels, lead, tin, zinc alloys, molybdenum, niobium, tantalum, zirconium alloys, titanium, and titanium alloys.

This chapter provides an overview of the basic principles and historic development of metal extrusion processes. It starts by illustrating the two major process categories: direct extrusion and indirect extrusion. It then briefly defines hydrostatic extrusion and the conform process. The history coverage addresses early patents for extrusion of lead at the turn of the 17th century up through the major process innovations in the 20th century.

This chapter explains the basic terminology and principles of metallurgy as they apply to extrusion. It begins with an overview of crystal structure in metals and alloys, including crystal defects and orientation. This is followed by sections discussing the development of the continuous cast microstructure of aluminum and copper alloys. The discussion provides information on billet and grain segregation and defects in continuous casting. The chapter then discusses the processes involved in the deformation of pure metals and alloys at room temperature. Next, it describes the characteristics of pure metals and alloys at higher temperatures. The processes involved in extrusion are then covered. The chapter provides details on how the toughness and fracture characteristics of metals and alloys affect the extrusion process. The weld seams in hollow profiles, the production of composite profiles, and the processing of composite materials, as well as the extrusion of metal powders, are discussed. The chapter ends with a discussion on the factors that define the extrudability of metallic materials and how these attributes are characterized.

The machinery and equipment required for rod and tube extrusion is determined by the specific extrusion process. This chapter provides a detailed description of the design requirements and principles of machinery and equipment for direct and indirect hot extrusion. It then covers the presses and auxiliary equipment for tube extrusion, induction furnaces for billet processing, handling systems for copper and aluminum alloy products, extrusion cooling systems, and age-hardening ovens. Next, the chapter describes the principles and applications of equipment for the production of aluminum and copper billets. Then, it focuses on process control in both direct and indirect hot extrusion of aluminum alloys without lubrication. The chapter describes the technology of electrical and electronic controls in the extrusion process. It ends with a discussion on the factors that influence the productivity and quality of the products in the extrusion process and methods for process optimization.

The aim of every extrusion plant is the efficient production of competitive products that meet the appropriate quality requirements. This chapter discusses the processes involved in the selection and introduction of a quality management system, along with its application, advantages, and disadvantages. It describes the process chain for order processing within the quality circle and provides information on product liability legal issues. In addition, the chapter discusses the processes involved in quality control, along with its organization, responsibilities, audits, and testing.