Search Results for lubrication

This article introduces process factors that influence die wear and lubrication for metal forming operations such as bending, spinning, stretching, deep drawing, and ironing. It discusses the effects of part shape, sheet thickness, tolerance requirements, sheet metal, and lubrication on shallow forming dies. The article describes the wear of material for dies to draw round and square cup-shaped metal parts in a press. It also discusses the effect of process conditions on the shallow forming dies.

This article is concerned with gear tooth failures influenced by friction, lubrication, and wear, and especially those failure modes that occur in wind-turbine components. It provides a detailed discussion on wear (including adhesion, abrasion, polishing, fretting, and electrical discharge), scuffing, and Hertzian fatigue (including macropitting and micropitting). Details for obtaining high lubricant specific film thickness are presented. The article describes the selection criteria for lubricants, such as oil, grease, adhesive open gear lubricant, and solid lubricants. It discusses the applications of oil and gear lubricants and the types of standardized gear tests. The article presents some recommendations for selecting lubricants and lubricant viscosity for enclosed gear. It provides some examples of failure modes that commonly occur on gears and bearings in wind turbine gearboxes.

Strategies for the lubrication of mechanical systems operating in extreme environments must exclude the liquid lubricants and greases and rely on alternative methods of lubrication, such as gases and solids. This article provides a survey of some of the more effective alternative methods of lubrication. It provides a discussion on the solid materials that have been most commonly used as lubricants: carbon-base materials, transition metal dichalcogenides, polymers, and soft metals.

This article provides a brief introduction to lubrication as a method to reduce friction between two surfaces. It discusses the surface characteristics of parts and explores how lubrication helps separate two contacting surfaces and thereby decreases the coefficient of friction. The article details the classifications of lubrication regimes, namely, boundary, mixed, hydrodynamic, and elastohydrodynamic lubrications. It discusses the various types of lubricant materials and additives, including liquid lubricants, solid lubricants, gaseous lubricants, greases, green lubricants, and nanomaterials. The article also reviews the properties of lubricants. It describes the tribological evaluation of lubricants, including stribeck test, four-ball test, block-on-ring test, pin-in-vee test, and reciprocating motion test.

This article discusses the fundamentals of electroplating processes, including pre-electroplating and surface-preparation processes. It illustrates the four layers of a plating system, namely, top or finish coat, undercoat, strike or flash, and base material layers. The article describes various plating methods, such as pulse electroplating, electroless plating, brush plating, and jet plating. It reviews the types of electrodeposited coatings, including hard coatings and soft coatings. The article also details the materials available for electroplating, including electroplated chromium, electroplated nickel, electroless (autocatalytic) nickel, electroless nickel composite coatings, electroplated gold, and platinum group coatings. These are specifically tailored toward plated coatings for friction, lubrication, and wear technology. The article concludes with a discussion on the common issues encountered with electroplating.

Both hot and cold forgings are batch-type processes in which steady-state conditions are never fully achieved and the initial lubricant supply must perform adequately for the duration of the operation. This article discusses methods to measure lubricant effectiveness and wear. It describes the mixed-film lubrication and solid film lubrication in cold forging, as well as solid film lubrication and thick film lubrication in hot forging. The article reviews the factors affecting abrasive wear: die hardness, workpiece temperature, and lubrication and die temperature. It concludes with information on ways to improve resistance to abrasive wear.

Pumps and compressors are representative fluid machineries, which are indispensably important industrial equipment for water supply systems, chemical processing and reactions, and fluid power systems. This article addresses friction, lubrication, and wear of components in several types of machines such as positive displacement pumps including hydraulic pumps, turbo-pumps including centrifugal pumps, vacuum pumps, and compressors including the positive displacement type and turbo type.

This article discusses the tribology of three main sheet forming processes: deep drawing, bending, and shearing. For each process, the basic principle of the forming process is briefly explained. Tribological phenomena observed in each process, such as wear and galling, are presented. Common methods of using lubricants and coatings in sheet forming processes are also described.

Rolling is the process of reducing the thickness or changing the cross section of a workpiece by compressive forces applied through a set of rolls. This article emphasizes flat rolling and illustrates basic flat-rolling process used to reduce the thickness of a rectangular cross section. It provides a discussion on hot rolling, cold rolling, and warm rolling, as well as lubrication in rolling. The article reviews the lubrication for iron-base and nickel-base materials, light metals, copper-base alloys, and titanium alloys. It discusses the wear mechanism in rolling: abrasion, adhesion, and fatigue, as well as oxidative and corrosive wear. Surface modification techniques, such as hardening by induction heat treating, weld overlay, thermal spray coating, coating via physical vapor deposition (PVD), and laser surface treatment, are also discussed for improving roll service life.

This article focuses on friction, lubrication, and wear of internal combustion engine parts, improvements in which provide important gains in energy efficiency, performance, and longevity of the internal combustion (IC) engine systems. It discusses the types, component materials, and Friction and Wear Control of IC engine. The article explains the process of friction reduction by surface textures or coatings. It provides information on surface hardening of iron and steel, which is commonly employed for engine and powertrain components such as crankshafts, cams, and cylinder liners. The article also discusses advanced surface engineering technologies, such as diamondlike carbon coatings and surface texture technology. Information on thermal-spray methods that have led to improvements in engine components is also provided. The article describes IC engine-components wear, namely, piston assembly wear, valvetrain wear, cylinder-bore wear, and engine bearing wear. It concludes with information on inlet valve and seat wear of IC engine.

Drawing is a process by which a workpiece is pulled against a die to produce a wire, bar, or tube with smaller cross sectional area compared with the initial stock. This article discusses the variables that affect the drawing process and the parameters that influence friction, lubrication, and wear. These parameters include process, lubricant, workpiece, and tooling. The article provides information on dry and wet lubrication in wire drawing. The dry lubrication refers to use of solid lubricants while wet lubrication refers to the practice of providing a liquid lubricant to the workpiece-die interface. The article describes the most common types and causes of die wear: abrasive wear, adhesive wear, surface fatigue wear, thermal fatigue wear, and catastrophic failure. It concludes with a discussion on the surface treatment and texturing that are used to reduce die wear in drawing operations.

This article is a compilation of terms related to friction, lubrication, and wear technology.

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.

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.