This article provides an overview of the interfacial interactions with a lubricant film between a die and a metal, lubricant mechanisms, chemistry, qualification testing, application methods, and property test methods. It focuses on sheet metal-forming operations, although the discussions are relevant to metal-forming operations in general. The article also deals with lubricant selection as influenced by the metal to be formed and particular sheet-metal forming operations. The article also discusses some aspects of microbiology and toxicity in lubricants.

This article lists functions of lubricants common to the majority of applications and processes. It discusses the lubricant candidates widely used in forging: conversion coatings with soaps (stearate compounds) and molybdenum disulfide for cold forging; oil-based thick, film oil or polymerbased lubricants and molybdenum disulfide for warm application; graphite suspensions in oil or water for hot forging steels; and glass films for titanium and superalloys hot forgings. The article describes the applications of lubricants in warm extrusion and forging, hot forging of steel, hot forging of aluminum, isothermal and hot die forging, and the extrusion of steel.

This article introduces the structure, tribological properties, advantages, and applications of ionic liquids (ILs) as lubricating media. It discusses the mechanisms of IL lubrication for different contacts. The advances in studies focusing on tribological properties of a wide range of ILs are reviewed. The article concludes with the challenges that limit the applications of ILs in tribology engineering.

This article discusses the functions of lubricants to prevent premature failure of rolling element bearings and the advantages of fluid lubrication. It describes the composition of refined mineral oil for rolling bearing applications. The article reviews the types and properties of nonpetroleum oils, such as polyglycols, phosphate esters, silicone fluids, dibasic acid esters, and fluorinated polyethers. It discusses the properties of greases, including grease speed limits, grease composition, relubrication intervals, corrosion prevention behavior, and grease compatibility. The article concludes with a discussion on polymeric lubricants and solid lubricants.

This article addresses the impact of emerging technologies on future lubricant and tribology requirements. The connection between lubricant and tribological requirements is shown by briefly describing basic lubrication and friction processes in major engine components incorporating emerging technologies. The article introduces automotive lubricant development activities and the foundation of future automotive engine-lubricant trends. It discusses how emerging powertrain technology impacts future automotive lubricant and technology requirements, focusing on the effects of engine oils and additives on engine performance to meet powertrain performance requirements. A detailed overview of automotive engine oil performance evaluation methods and specifications, and their impact on the types of advanced lubricants being developed as well as future automotive engine testing requirements, is provided.

Solid lubricants consist of materials placed at the interface between moving bodies to mitigate friction and wear. This article begins with a historical overview of solid lubricants and discuses the characteristics and fundamental aspects of solid lubricants. It describes the material categories of solid lubricant coatings, including graphite, graphite fluoride, transition metal dichalcogenides, diamond-like-carbon, polymeric materials, and metallic films. The article presents a description of deposition methods from the simplest processes involving burnishing and impingement in open air to modern vacuum-based methods for solid lubricants. It concludes with a discussion on metrics that can be used to qualify solid lubricants in high-consequence applications.

The function of lubricants is to control friction and wear in a lubricating system containing machine elements such as gears and bearings. This article discusses the basic properties of lubricants to help scientists and engineers understand the principles behind lubricant selection. It reviews the functions of additives, such as friction modifiers, antiwear additives, viscosity modifiers, corrosion inhibitors, oxidation inhibitors, dispersants, and detergents. The article discusses the physical properties of liquid lubricants and the performance characteristics of lubricants. It describes the most common lubricant categories and provides information on the health and safety aspects of using liquid lubricants. The article concludes with a discussion on the lubricant-application method that plays a vital role in how the lubricant functions.