Search Results for compounded lubricants

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 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.

A pair of bearings mounted side by side in an aircraft engine failed in service. Photographs show that the inner rings were either broken or deformed, the balls were worn and flattened, and the cages severely damaged. The bearing races were damaged as well, but only on one side indicating a directional thrust. In addition to their examination, investigators also conducted metallographic studies and hardness tests, which indicated that the balls and inner rings reached temperatures above 825 °C (1520 °F). Based on their findings, investigators concluded that the bearings failed due to overheating, possibly as a result of misalignment compounded by insufficient lubrication and high speeds.

Generally, binders consist of at least three ingredients: a backbone to provide strength (compounds such as polyethylene, polypropylene, ethylene vinyl acetate, and polystyrene); a filler, such as polyacetal and paraffin wax, to occupy space between particles; and additives, such as stearates, stearic acid, or magnesium stearate, as well as phosphates and sulfonates, to adjust viscosity, lubricate tooling, disperse particles, or induce binder wetting of the powder. In the case of binders deposited via ink jet printing, the binder contains solvents to lower the viscosity for easier jetting. The chapter provides a detailed description of these constituents. The requirements of a binder as well as the factors determining the physical and thermal properties of polymers are discussed. Then, two factors associated with solvation of polymers, namely solubility parameter and wetting, are covered. The chapter ends with information on the specification of polymers used in binders.

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 provides a detailed discussion of salt bath nitrocarburizing. Process variations discussed include low-cyanide salt bath ferritic nitrocarburizing, salt bath nitrocarburizing plus post treatment, and the Kolene Nu-Tride process.

This chapter provides an overview of environmental factors when studying a gear failure. Environmental factors discussed are lubrication, temperature, and mechanical stability.

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.

Plastic gears are continuing to displace metal gears in applications ranging from automotive components to office automation equipment. This chapter discusses the characteristics, classification, advantages, and disadvantages of plastics for gear applications. It provides a comparison between the properties of metals and plastics for designing gears. The chapter reviews some of the commonly used plastic materials for gear applications including thermoplastic and thermoset gear materials. The chapter also describes the processes involved in plastic gear manufacturing.

This chapter covers the mechanics and tribology of sheet metalworking processes, including shearing, bending, spinning, stretching, deep drawing, ironing, and hydroforming. It explains how to determine friction, wear, and lubrication needs based on process forces, temperatures, and strains and the effects of strain hardening on workpiece materials. It presents test methods for evaluating process tribology, describes lubrication and wear control approaches, and discusses the factors, such as surface roughness, lubricant breakdown, and adhesion, that can lead to galling and other forms of wear. It also provides best practices for selecting, evaluating, and applying lubricants for specific materials, including steels, stainless steels, and aluminum and magnesium alloys.

Drawing is a bulk deformation process that involves significant surface generation and high pressures. This chapter provides an overview of the mechanics and tribology of wire, bar, tube, and shape drawing. It presents important equations for calculating stresses, forces, friction, heat, strain, and distortion for different tooling configurations and geometries. It explains how to select and apply lubricants based on drawing speed, die design, and other factors and how to maintain sufficient film thickness for hydrodynamic, mixed, and solid-film lubrication conditions. It also discusses the use of vibrating dies, the influence of surface finish and defects, and lubrication practices for specific materials.

This chapter covers the different types of wear encountered in metalworking processes. It discusses the mechanisms involved in adhesive, abrasive, chemical, and fatigue wear and key contributing factors, including the composition and structure of tool and workpiece materials, the characteristics of contact surfaces, and loading forces imposed by the process. It describes the nature of metal transfer between tool and workpiece surfaces and the role of lubricants, coatings, and textures. It also discusses the use of wear maps, the effects of adhesion, and material-lubricant interactions.

Cleaning procedures serve to remove scale, tarnish films, and other contaminants that form or are otherwise deposited on the surface of titanium during processing operations such as hot working and heat treatment. This chapter explains what makes titanium susceptible to the formation of scale and how it can be removed via belt grinding, abrasive blasting, and molten salt descaling baths. It also discusses the role of acid pickling, barrel finishing, polishing, and buffing as well as the use of chemical conversion coatings and protective platings.

This chapter provides a brief review of the history of metal working processes, the use of lubricants, and the study of friction and wear. It also explains how the book is organized and describes the method of treatment used by the authors.

Forging is a deformation process achieved through the application of compressive stresses. During the stroke, pressures and velocities are continuously changing and the initial lubricant supply must suffice for the duration of the operation. Lubricant residues and pickup products also change with time, further complicating the analysis of friction and wear. This chapter provides a qualitative and quantitative overview of the mechanics and tribology of forging in all of its forms. It discusses the effects of friction, pressures, forces, and temperature on the deformation and flow of metals in open-die, closed-die, and impression-die forging and in back extrusion and piercing operations. It presents various ways to achieve fluid-film lubrication in upset forging processes and examines the cause of barreling, defect formation, and folding in the upsetting of cylinders, rings, and slabs. It also explains how to evaluate lubricants, friction, and wear under hot, cold, and warm forging conditions and how to extend die life and reduce defects when processing different materials.

This chapter covers coatings and treatments that are used to improve the friction and wear behaviors of materials. It describes modifications that work by hardening contacting surfaces, including heat treating, vacuum coating, thermal spray, and plating, and those that separate or lubricate surfaces, including solid film, chemical conversion, and vacuum coatings, surface oiling and texturing, and lubricating platings. It compares and contrasts methods based on thickness and depth and their relative effect on friction, erosion, and wear.