Search Results for metalworking 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 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 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.

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.

This chapter provides a practical overview of the tools and techniques used to assess the tribological aspects of metal forming processes. It describes test methods that have been developed to evaluate bulk deformation and sheet metal forming processes along with lubricant rheology, friction forces, and stress and strain distributions. It explains how to measure temperature between tooling and workpiece surfaces as well as surface topography and composition, film thickness, and wear. It also discusses the benefits of reduced-scale and simulation testing and the transfer of results from one process to another.

This chapter presents a qualitative and quantitative overview of the stresses, strains, forces, and energy associated with metalworking processes and the tribological behavior of metals. It covers key concepts necessary for understanding metalworking tribology, including plastic deformation, yield criteria, flow strength, and the application of flow rules. It explains how to calculate the work involved in deformation processes, how to assess the propensity for fracture, how to determine temperature rise and strain distribution in the workpiece, and how to classify metalworking processes based on related tribology.

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 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 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.

This chapter describes the general characteristics of two commonly classified metalworking processes, namely hot working and cold working. Primary metalworking processes, such as the bulk deformation processes used to conduct the initial breakdown of cast ingots, are always conducted hot. Secondary processes, which are used to produce the final product shape, are conducted either hot or cold. The chapter discusses the primary objectives, principal types, advantages, and disadvantages of both primary and secondary metalworking processes. They are rolling, forging, extrusion, sheet metal forming processes, blanking and piercing, bending, stretch forming, drawing, rubber pad forming, and superplastic forming.

This chapter examines the surface interactions that occur during metal forming operations at both the macroscopic and microscopic scale. It describes the measurement and characterization of surface profiles based on form error, waviness, and roughness. It explains how workpiece surfaces become rougher or smoother due to the effects of deformation, tooling interactions, and lubricant film thickness. It familiarizes readers with the concept of nominal contact, the role of asperities, and the effects of interface pressure, plasticity index, shear stress, and bulk strain rate. It also reviews the two basic friction rules applicable to metal forming and presents advanced friction models that account for the transition between Coulomb and Tresca behavior and the effects of lubrication.

This chapter provides a brief history of powder metallurgy from its earliest known uses to present day applications.

This appendix presents a table of definitions and conversion factors related to tribology and metalworking.

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.

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.

Rolling is unique in that it cannot be conducted without friction. Friction draws the workpiece into the roll gap and facilitates its passage through the deformation zone. This chapter provides an overview of the mechanics and tribology of flat rolling processes and explains how various aspects of the theory apply to shape rolling as well. It derives numerous equations and models to help quantify the forces, torque, and power involved in rolling operations and the associated heating, slip, strain distribution, and deformation in both the workpiece and rolls. It describes the friction and wear that occur in hot and cold rolling under hydrodynamic and mixed-film lubrication; the influence of viscosity, film thickness, rolling speed, interface pressure, pass reduction, and lubricant breakdown; and the effect of surface finish and defects. The chapter also provides best practices for evaluating, applying, and treating lubricants for industrially important materials including iron-base, nickel-base, and aluminum alloys.

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 article presents six case studies of failures with steel forgings. The case studies covered are crankshaft underfill; tube bending; spade bit; trim tear; upset forging; and avoidance of flow through, lap, and crack. The case studies illustrate difficulties encountered in either cold forging or hot forging in terms of preforge factors and/or discontinuities generated by the forging process. Supporting topics that are discussed in the case studies include validity checks for buster and blocker design, lubrication and wear, mechanical surface phenomenon, forging process design, and forging tolerances. Wear, plastic deformation processes, and laws of friction are introduced as a group of subjects that have been considered in the case studies.

This chapter discusses the processes of isothermal and hot-die forging and their use in producing aerospace components. It explains how isothermal forging was developed to provide a near-net shape component geometry and well-controlled microstructures and properties with accurate control of the working temperature and strain rate. It describes the materials typically used as well as equipment and tooling, die heating procedures, part separation techniques, and postforging heat treatment.