This chapter covers the tribological properties of different types of oil, greases, solid lubricants, and metalworking and traction fluids. It explains how lubricants are made, how they work, and how they are applied and tested. It also discusses the fundamentals of lubrication and friction control, the relationship between viscosity and breakaway friction, and the factors that affect load-carrying capacity and service life.

This chapter describes the properties and attributes of various classes of metalworking lubricants, including mineral oils; natural oils, fats, derivatives, and soaps; synthetic fluids (olefins, esters, polyglycols, ionic liquids); compounded lubricants (oils, greases, fats); aqueous lubricants (emulsions, synthetics, solutions); and a wide range of coatings and carriers. It also discusses solid-film lubricants (oxide films, polymer films, layer-lattice compounds) and environmental and safety concerns.

This chapter discusses the factors that must be considered when selecting a lubricant for sheet metal forming operations. It begins with a review of lubrication regimes and friction models. It then describes the selection and use of sheet metal forming lubricants, explaining how they are applied and removed and how their pressure and temperature ranges can be extended by performance enhancing additives. The chapter also explains how sheet metal forming lubricants are evaluated in the laboratory as well as on the production floor and how tribological tests are conducted to simulate stamping, deep drawing, ironing, and blanking operations.

This chapter discusses the effect of friction and lubrication on forgings and forging operations. The discussion covers lubrication mechanisms, the use of friction laws, tooling and process parameters, and the lubrication requirements of specific materials and forging processes. The chapter also describes several test methods for evaluating lubricants and explains how to interpret associated test data.

This chapter reviews the basic theory of lubrication in the context of metal forming applications. It discusses the rheological properties of fluids and their effect on fluid-film thickness at pressures, temperatures, and loading conditions typical of metal working processes. It describes the three lubrication regimes (boundary, mixed, and hydrodynamic) of a Stribeck curve and the forces that maintain surface separation. It also discusses mixed, elastohydrodynamic, plastohydrodynamic, and solid or semi-solid lubrication, the effects of starvation and frictional instabilities, and the role of elastic deflection and ultrasonic vibration.

This chapter reviews the knowledge of the field of gear tribology and is intended for both gear designers and gear operators. Gear tooth failure modes are discussed with emphasis on lubrication-related failures. The chapter is concerned with gear tooth failures that are influenced by friction, lubrication, and wear. Equations for calculating lubricant film thickness, which determines whether the gears operate in the boundary, elastohydrodynamic, or full-film lubrication range, are given. Also, given is an equation for Blok's flash temperature, which is used for predicting the risk of scuffing. In addition, recommendations for lubricant selection, viscosity, and method of application are discussed. The chapter discusses in greater detail the applications of oil lubricant. Finally, a case history demonstrates how the tribological principles discussed in the chapter can be applied practically to avoid gear failure.