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 describes how forces and temperatures generated during sintering influence particle bonding, grain growth, shrinkage, and densification as well as bulk material properties. It explains how density, a good predictor of mechanical and electrical properties, can be controlled by proper selection of sintering time, temperature, and particle size for various steels, ceramics, and tungsten and titanium alloys.

This appendix provides a brief review of thin film deposition methods and their uses in a question and answer format. The questions deal with recommended practices, process conditions, terminology, and classifications.

This appendix provides tempering curves for common grades of steel, including 1045, 1144, 4140, 4150, and E52100.

This appendix provides hardenability curves for several H-steels (1045H, 4130H, 4140H, 4142H, 4145H, 4340H, 5160H, 8620H) and one alloy steel (E52100).

This chapter discusses the alloy composition, metallurgy, mechanical behavior, stabilization, texture, anisotropy, high-temperature properties, and corrosion and oxidation resistance of ferritic stainless steels.

This appendix contains a temperature conversion table listing the temperature readings (in deg F) to be converted and equivalent Celsius temperature values.

Annealing, a heat treatment process, is used to soften metals that have been hardened by cold working. This chapter discusses the following three distinct processes that can occur during annealing: recovery, recrystallization, and grain growth. The types of processes that occur during recovery are the annihilation of excess point defects, the rearrangement of dislocations into lower-energy configurations, and the formation of subgrains that grow and interlock into sub-boundaries. The article also discusses the main factors that affect recrystallization. They are temperature and time; degree of cold work; purity of the metal; original grain size; and temperature of deformation. The types of grain growth discussed include normal or continuous grain growth and abnormal or discontinuous grain growth.

Fracture is the separation of a solid body into two or more pieces under the action of stress. Fracture can be classified into two broad categories: ductile fracture and brittle fracture. Beginning with a comparison of these two categories, this chapter discusses the nature and causes of these failure modes. Some body-centered cubic and hexagonal close-packed metals, and steels in particular, exhibit a ductile-to-brittle transition when loaded under impact and the chapter describes the use of notched bar impact testing to determine the temperature at which a normally ductile failure transitions to a brittle failure. The discussion then covers the Griffith theory of brittle fracture and the formulation of fracture mechanics. Procedures for determination of the plane-strain fracture toughness are subsequently covered. Finally, the chapter describes the effects of microstructural variables on fracture toughness of steels, aluminum alloys, and titanium alloys.

Temperature is a critical process parameter in the heat treatment and forging of steel and must be accurately measured to properly control it. This appendix discusses the operating principles of thermocouples and infrared pyrometers, describing the various types as well as advantages and applications.

This chapter discusses the factors that influence temperature in forging operations and presents equations that can be used to predict and control it. The discussion covers heat generation and transfer, the effect of metal flow, temperature measurement, testing methods, and the influence of equipment-related parameters such as press speed, contact time, and tooling geometries.

This chapter details low-temperature test procedures and equipment. It discusses the role temperature plays in the properties of typical engineering materials. The effect that lowering the temperature of a solid has on the mechanical properties of a material is summarized for three principal groups of engineering materials: metals, ceramics, and polymers (including fiber-reinforced polymers). The chapter describes the factors that influence the selection of tensile testing procedures for low-temperature evaluation, along with a comparison of tensile and compression tests. It covers the parameters and standards related to low-temperature tensile testing. The chapter discusses the factors involved in controlling test temperature. Finally, the chapter discusses the safety issues concerning the use of cooled methanol, liquid-nitrogen, and liquid helium.

Ion nitriding equipment can be categorized into two groups: cold-wall continuous direct current (dc) equipment and hot-wall pulsed dc equipment. This chapter focuses on these two categories along with other important considerations for ion (plasma) nitriding equipment and processing. Other important considerations discussed include the hollow cathode effect, sputter cleaning, furnace loading, pressure/voltage relationships, workpiece masking, and furnace configuration options. The chapter describes five methods of cooling parts from the process temperature to an acceptable exposure temperature after plasma nitriding. The chapter also presents some of the advantages of the pulsed plasma process.