bluuebunny/crossref_metadata_2025 huggingface dataset:
Designing for Metal Powder Injection Molding
Authors: German Randall M.
Published: December 2018

This article commences with a discussion on the qualitative and quantitative criteria for metal injection molding (MIM), including production quantities, shape complexity, material performance, and cost. It discusses geometric factors, such as surface finish, component size, and mass range, which help to identify a component for MIM. The article describes certain part features, including holes, undercuts, and flat faces. It concludes with a discussion on the common materials used in MIM; tensile properties of 17-4 PH stainless steel MIM, cast and wrought products; and attributes of the MIM process.
Magnetic Materials and Properties for Powder Metallurgy Part Applications
Authors: Narasimhan Kalathur S.
Published: December 2018

Powder metallurgy (PM) techniques are effective in making magnetically soft components for use in magnetic part applications. This article provides an account of the factors affecting magnetism, permeability, and hysteresis losses. It includes information on the magnetic properties of PM materials that are used in the magnetic part applications, namely, pure iron, phosphorus irons, ferritic stainless steels, 50 nickel-50 iron, and silicon irons. The article describes the factors that affect and optimize magnetic properties. It contains a table that lists the magnetic properties possible in metal injection molding parts. The article also discusses ferromagnetic cores used in alternating current applications and some permanent magnets, such as rare earth-cobalt magnets and neodymium-iron-boron (neo) magnets.
Powder Hot Pressing and Forging
Authors: Kuhn Howard A.
Published: December 2018

Successful application of forging and hot pressing involves careful consideration of powder preparation and forming process parameters. This article describes the important process features for powder forging and hot pressing, along with specific applications and materials used.
Atomization
Authors: Schade Chris , Dunkley John J.
Published: December 2018

Atomization is the dominant method for producing metal and prealloyed powders from aluminum, brass, iron, low-alloy steels, stainless steels, tool steels, superalloys, titanium alloys, and other alloys. The general types of atomization processes encompass a number of industrial and research methods. This article describes the key process variables and production factors for the industrial methods: two-fluid, centrifugal, vacuum or soluble-gas, and ultrasonic atomization. It also reviews the effect of atomization methods and process variables on key powder characteristics such as the average particle size, particle size distribution or screen analysis, particle shape, chemical composition, and microstructure.
Powder Metallurgy Electrical Contact Materials
Authors: Hu Bo
Published: December 2018

Electrical contacts are made of elemental metals, composites, or alloys that are made by the melt-cast method or manufactured by powder metallurgy (PM) processes. PM facilitates combinations of metals that ordinarily cannot be achieved by alloying. This article describes the processing, properties, and performance of electrical contacts based on PM or hybrid composite technologies with refractory metals and compounds. These metals and compounds include tungsten, molybdenum, carbide-based composites, and silver-base composites. The article explains composite manufacturing methods, namely, PM methods, internal oxidation, and hybrid consolidation. The availability of the refractory metals and compounds in various product forms are also reviewed.
Sampling and Classification of Powders
Authors: Pittenger Brian
Published: December 2018

This article summarizes sampling of powders, which includes the sampling of stored material and flowing streams, sample reduction and evaluation, and weight of sample required. It also summarizes the classification of powders. Classifiers are divided into two categories: counterflow equilibrium and crossflow separation. Classification methods are used to exclude certain powder sizes from a powder distribution and to obtain particular powder distributions. For example, sieving methods are used to obtain particular powder distributions and to obtain narrow size ranges of a powder. The article summarizes the sieving methods for powders. The sieving methods include hand sieving, machine sieving, manual wet sieving, air jet sieving, sonic sifter, wet sieving by machine, the Seishin robot sifter, automated systems, and ultrasonic machine sieving. The article outlines the sieve types and the process variables of the sieving process. An appendix reviews dispersion of powders in liquids.
Properties and Selection of Powder Metallurgy Refractory Metals
Authors: Ciulik James R. , Shields John A. , Kumar Prabhat , Leonhardt Todd , Johnson John L.
Published: December 2018

This article focuses on the selection, properties, and applications of powder metallurgy refractory metals and their alloys, including tungsten, molybdenum, tantalum, niobium, and rhenium.
Bulk and Surface Characterization of Powders
Authors: Tandon R. , Carson Charles
Published: December 2018

This article discusses the capabilities and limitations of various material characterization methods that assist in the selection of a proper analytical tool for analyzing particulate materials. Commonly used methods are microanalysis, surface analysis, and bulk analysis. The techniques used for performing microanalysis include scanning electron microscopy and electron probe X-ray microanalysis. The article describes surface analysis techniques, including Auger electron spectroscopy, X-ray photoelectron spectroscopy, and ion-scattering spectroscopy. Bulk analysis techniques, such as X-ray powder diffraction, inductively coupled plasma atomic emission spectroscopy, atomic absorption spectroscopy, and atomic fluorescence spectrometry, are also discussed.
Sintering Atmospheres
Authors: Nayar Harb S.
Published: December 2018

Sintering atmosphere protects metal parts from the effects of contact with air and provides sufficient conduction and convection for uniform heat transfer to ensure even heating or cooling within various furnace sections, such as preparation, sintering, initial cooling, and final cooling sections. This article provides information on the different zones of these furnace sections. It describes the types of atmospheres used in sintering, namely, endothermic gas, exothermic gas, dissociated ammonia, hydrogen, and vacuum. The article concludes with a discussion on the furnace zoning concept and the problems that arise when these atmospheres are not controlled.
Solidification Structures of Steels and Cast Irons
Authors: Stefanescu Doru M. , Ruxanda Roxana
Published: December 2018

The ferrous metals are the most significant class of commercial alloys. This article describes the solidification structures of plain carbon steel, low-alloy steel, high-alloy steel, and cast iron, with illustrations. The formation of nonmetallic inclusions in the liquid before and during solidification is also discussed.
Recovery, Recrystallization, and Grain-Growth Structures
Authors: Mankins William L.
Published: December 2018

Recovery, recrystallization, and grain growth are the stages that a cold worked metal undergoes when it is annealed. This article describes the changes in the structure and properties that occur on annealing a cold-worked metal. It summarizes the experimental recrystallization studies by Burke and Turnbull with six laws of recrystallization. Applications of these laws of recrystallization are discussed in detail with examples. The article reviews the classification of grain growth according to the growth behavior of grains, namely, normal or continuous grain growth and abnormal or discontinuous grain growth. The latter has also been termed exaggerated grain growth, coarsening, or secondary recrystallization.
Metallographic Sectioning and Specimen Extraction
Authors: Aliya Debbie
Published: December 2018

This article describes the sectioning process, some general practices, common tools, and guidelines on how to select a cutting tool for a given metallographic sectioning operation. It provides a discussion on the consumable-abrasive cutting and nonconsumable-abrasive cutting methods for metallographic sectioning. Other methods, including the use of hacksaws, shears, burning torches, wire saws, and electrical discharge machining, are also reviewed. The article reviews the issues related to the specimen test location for certification work as well as process troubleshooting and component failure analysis.
Light and Electron Microscopy
Authors: Goodhew Peter J. , Humphreys John , Beanland Richard
Published: December 2018

This article introduces the concepts of electron and light microscopy with some general features of imaging systems and the ideas of magnification, resolution, depth of field, depth of focus, and lens aberrations as they apply to simple and familiar light-optical systems. In addition, it describes the differences between electron and light in the context of their respective microscopy techniques.
Metallography and Microstructures of Titanium and Its Alloys
Authors: Gammon Luther M. , Briggs Robert D. , Packard John M. , Batson Kurt W. , Boyer Rodney , Domby Charles W.
Published: December 2018

This article describes the fundamentals of titanium metallographic sample preparation. Representative micrographs are presented for each class of titanium alloys, including unalloyed titanium, alpha alloys, alpha-beta alloys, and beta titanium alloys. The article provides information on the macroexamination and microexamination for these alloys. It concludes with a discussion on the several metallographic techniques developed for specific purposes, such as recrystallization studies and microstructure/fracture topography correlations.
Corrosion of Copper and Copper Alloys
Authors: Cohen Arthur
Published: December 2018

This article discusses the identifying characteristics of the forms or mechanisms of corrosion that commonly attack copper metals, as well as the most effective means of combating each. It tabulates the corrosion ratings of wrought copper alloys in various corrosive media. The article describes the corrosion behavior of copper alloys in specific environments. It reviews the corrosion characteristics of copper and copper alloys in various acids, alkalis, salts, organic compounds, and gases. The article provides information on the behavior of copper alloys that is susceptible to stress-corrosion cracking in various industrial and chemical environments. It concludes with information on various corrosion testing methods, including aqueous corrosion testing, dynamic corrosion tests, and stress-corrosion testing.
Corrosion of Zirconium and Zirconium Alloys
Authors: Yau Te-Lin , Sutherlin Richard C.
Published: December 2018

This article provides a description of the classification, industrial applications, microstructures, physical, chemical, corrosion, and mechanical properties of zirconium and its alloys. It discusses the formation of oxide films and the effects of water, temperature, and pH on zirconium. The delayed hydride cracking of zirconium is also described. The article provides information on the resistance of zirconium to various types of corrosion, including pitting corrosion, crevice corrosion, intergranular corrosion, galvanic corrosion, microbiologically induced corrosion, erosion-corrosion, and fretting corrosion. The article explains the effects of tin content in zirconium and effects of fabrication on corrosion. Corrosion control measures for all types of corrosion are also highlighted. The article concludes with information on the safety precautions associated with handling of zirconium.
Thermal Spray Coatings for Corrosion Protection in Atmospheric and Aqueous Environments
Authors: Kuroda Seiji , Sturgeon Andrew
Published: December 2018

This article provides a general technical description of thermal spray coatings used for corrosion protection in atmospheric and aqueous environments. It further discusses two basic coating approaches of corrosion protection, namely, the sacrificial coating of thermal spray aluminum (TSA) and thermal spray zinc (TSZ), and the barrier-type coating of corrosion-resistant materials. The emphasis is on sacrificial coatings. The article describes the steps involved in the application of TSA and TSZ: surface preparation, coating deposition, and postspray treatment. It discusses their field exposure tests and application history. The article also contains helpful information on the dense barrier coatings by high-velocity spraying processes along with their corrosion performance.
Corrosion of Electroplated Hard Chromium
Authors: Jones Allen R.
Published: December 2018

This article discusses the corrosion of chromium electrodeposits and the ways for optimizing corrosion resistance. It describes the processing steps and conditions for hard chromium plating. These steps include pretreatment, electroplating, and posttreatment. The article also provides information on duplex coatings and the applications of chromium electrodeposits.
Corrosion of Intermetallics
Authors: Datta P.K. , Du H.L. , Burnell-Gray J.S. , Ricker R.E.
Published: December 2018

This article reviews the corrosion behavior of intermetallics for the modeling of the corrosion processes and for devising a strategy to create corrosion protective systems through alloy and coating design. Thermodynamic principles in the context of high-temperature corrosion and information on oxidation; sulfidation; hot corrosion of NiAl-, FeAl-, and TiAl-based intermetallics; and silicides are included. The article explores the thermodynamic consideration, ordering influencing kinetics, stress-cracking corrosion, and hydrogen embrittlement of aqueous corrosion. It also explains the practical issues dealing with the corrosion problems.
Environmental Performance of Concrete
Authors: Panarese William C.
Published: December 2018

Portland cement concrete has low environmental impact, versatility, durability, and economy, which make it the most abundant construction material in the world. This article details the types and causes of concrete degradation. Concrete can be degraded by corrosion of reinforcing steel and other embedded metals, chlorides, carbonation, galvanic corrosion, chemical attack, alkali-aggregate reaction, abrasion, erosion, and cavitation as well as many other factors. The article addresses the durability of concrete by two approaches, namely, the prescriptive approach and the performance approach. In the former, designers specify materials, proportions, and construction methods based on fundamental principles and practices that exhibit satisfactory performance. In the latter, designers identify functional requirements such as strength, durability, and volume changes and rely on concrete producers and contractors to develop concrete mixtures to meet those requirements.
Radial Forging
Authors: Sizek H.W.
Published: December 2018

Radial forging is a process performed with four dies arranged in one plane that can act on a piece simultaneously. This article explains the types of radial forgings and describes the advantages and disadvantages of radial forging over open-die cogging/forging. The article discusses the parameters involved in product shape control. It also provides examples that illustrate the versatility and capabilities of the radial forge machine.
Forging of Stainless Steels
Authors: Mochnal George
Published: December 2018

Stainless steels, based on forging pressure and load requirements, are more difficult to forge because of the greater strength at elevated temperatures and the limitations on the maximum temperatures at which stainless steels can be forged without incurring microstructural damage. This article discusses the forging methods, primary mill practices (primary forging and ingot breakdown), trimming, and cleaning operations of stainless steels. It describes the use of forging equipment, dies, and die material in the forging operation. The article provides an overview of the forgeability of austenitic stainless steels, martensitic stainless steels, precipitation-hardening stainless steels, and ferritic stainless steels. It concludes with a discussion on the heating and lubrication of dies.
Flat, Bar, and Shape Rolling
Authors: Lahoti G.D. , Pauskar P.M.
Published: December 2018

The primary objectives of the rolling process are to reduce the cross section of the incoming material while improving its properties and to obtain the desired section at the exit from the rolls. This article illustrates a rolling sequence for the fabrication of bars, shapes, and flat products from blooms, billets, and slabs. It describes two methods for shapes or sections: universal rolling and caliber rolling. The article provides information on two-high mills and three-high mills. Specialty mills for thin sheets, namely, the Sendzimir mill and planetary mill, are discussed. The article analyzes the components of a computer controlled system for high-speed mills. Steels and nonferrous materials are also discussed. The article concludes with information on the defects in flat, bar, or shaped products due to heating and rolling practices.
Workability in Forging
Authors: Semiatin S.L.
Published: December 2018

Workability in forging depends on a variety of material, process-variable, and die-design features. A number of test techniques have been developed for gaging forgeability depending on alloy type, microstructure, die geometry, and process variables. This article summarizes some common workability tests and illustrates their application in practical forging situations. Workability tests for open-die forging of cast structures, hot and cold open-die forging of recrystallized structures, fracture-controlled defect formation, establishing effects of process variables and secondary tensile stresses on forgeability, and flow-localization-controlled failure are some common tests. The workability test used for closed-die forging is also summarized.
Bulk Workability Testing
Authors: Dieter George E.
Published: December 2018

This article discusses a number of workability tests that are especially applicable to the forging process. The primary tests for workability are those for which the stress state is well known and controlled. The article provides information on the tension test, torsion test, compression test, and bend test. It examines specialized tests including plane-strain compression test, partial-width indentation test, secondary-tension test, and ring compression test. The article explains that workability is determined by two main factors: the ability to deform without fracture and the stress state and friction conditions present in the bulk deformation process. These two factors are described and brought together in an experimental workability analysis.
Introduction to Sheet-Forming Processes
Authors: Semiatin S.L.
Published: December 2018

Sheet forming comprises deformation processes in which a metal blank is shaped by tools or dies, primarily under the action of tensile stresses. This article discusses the classification of sheet-forming processes for obtaining desired dimensional features. It describes different process-related developments, namely, superplastic forming of aluminum, forming of tailor-welded blanks, rubber-pad forming, and high-velocity metal forming. The article explains cost-effective approaches of evaluating tooling designs prior to the manufacture of expensive steel dies and dieless forming techniques such as thermal forming and peen forming. It provides information on the application of advanced high-strength steels, magnesium alloys, and various ultrafine-grain materials for superplastic sheet forming. The article concludes with information on the development and application of simulation, design, and control of sheet-forming processes.
Fine-Edge Blanking
Authors: Lee T.C. , Tang C.Y. , Chan L.C.
Published: December 2018

Fine-blanking is a hybrid metal forming process that combines the technologies of stamping and cold extrusion. This article describes the three principal design features of the fine blanking process: the vee-ring, clearance between punch and die, and counterforce imposed by the ejector. It discusses the advantages and disadvantages of edge blanking and materials. The article reviews the classification of fine-blanking dies such as the moving-punch system and the fixed-punch system, and provides information on the mechanical and hydraulic fine-blanking presses.
Stretch Forming
Authors: Demeri Mahmoud Y.
Published: December 2018

Stretch forming is the forming of sheet, bars, and rolled or extruded sections over a die or form block of the required shape while the workpiece is held in tension. This article discusses the applicability, advantages, and machines and accessories of stretch forming. It provides a detailed discussion on four methods of stretch forming, namely, stretch draw forming, stretch wrapping, compression forming, and radial draw forming.
Peen Forming
Authors: Kopp R. , Schulz J.
Published: December 2018

Shot peen forming is a manufacturing process in which local compressive residual stresses form thin sheet metals and structural components in one or more dimensions. This article discusses the principle of the process with an emphasis on fundamental mechanisms. It presents the basic considerations in the simulation of shot peen forming and provides information on single impact and multiple-impact peening simulations. The article describes the equipment and tooling used in the process. It also analyzes the influence of process parameters on shot peen forming and illustrates possible shapes and contours, which are producible by shot peen forming. The article concludes with a table that presents typical peen forming applications in the aircraft and aerospace industries.
Forming of Nickel and Cobalt Sheet Alloys
Authors: Sizek Howard W.
Published: December 2018

This article tabulates the nominal compositions for nickel and cobalt alloys. It illustrates the comparison of strain-hardening rates of a number of alloys in terms of the increase in hardness with increasing cold reduction. The forming practice for age-hardenable alloys and the lubricants used in the forming processes of nickel and cobalt alloys are also discussed. The article summarizes the modification of tools and dies used for cold forming other metals, as the physical and mechanical properties of nickel and cobalt alloys frequently necessitate it. It discusses forming techniques for these alloys and provides several examples of these techniques, which include shearing, blanking, piercing, deep drawing, spinning, explosive forming, bending, and expanding/tube forming.
Computer-Aided Engineering in Sheet Metal Forming
Authors: Sa Chung-Yeh
Published: December 2018

This article focuses on the technology breakthroughs that make forming simulation a routine work throughout the industry. It discusses many forms of the computer-aided engineering (CAE) methodology. The article describes several failure criteria to predict the failure of sheet metal. It explains the numerical procedure for sheet metal forming and reviews the important technical issues in CAE simulations. The article provides information on the applications and process of metal-forming simulation. It also reviews the capabilities of major systems that are popular among sheet metal forming users worldwide.
Forming of Carbon Steels
Authors: Demeri Mahmoud Y. , Lampman Steve
Published: December 2018

This article reviews the selection and formability characteristics of steels, with an emphasis on low-carbon steels and some coverage on the forming of high-carbon steels. It describes the key factors that affect the formability of steels in terms of steelmaking practices, surface finishes, metal thicknesses, and alloying. The article explains the bending and forming operations with some examples. It also describes the formation of various shells, including doubly contoured shells, deep recessed shells, and deep circular shells.
Troubleshooting Formability Problems Using Strain Analysis
Authors: Schaeffler Daniel J. , Vineberg Evan J.
Published: December 2018

This article describes strain analysis techniques for troubleshooting formability and process discrepancies throughout a tooling development and production stamping cycle. The techniques include strain calculations of a flat blank, forming limit curve, and forming limit diagram. The article describes the types of strain analysis, namely, thinning strain analysis and circle grid strain analysis. It also provides information on the applications of the thinning strain analysis.
Constitutive Equations
Authors: Ghosh Amit
Published: December 2018

Constitutive relations for metal-working include elements of behavior at ambient temperature as well as high-temperature response. This article presents the equations for the strain hardening and strain-rate-sensitive flow, with alternate sections on empirically determined properties, followed by models of constitutive behavior. These models include the isothermal constitutive model and the physical model for superplastic flow. A formal description of the superposition of the operative mechanisms for dynamic recovery at hot-working strain rates is also provided. The article describes creep mechanisms that are useful for illustrating the strong stress dependence of dislocation and diffusional flow.
Shape Casting Processes—An Introduction
Authors: Jorstad J.L.
Published: December 2018

This article discusses the categories and subcategories of shape casting processes. These include single-use processes, such as sand, plaster, ceramic, and graphite molding; essentially unpressurized multiuse processes, such as permanent mold; and high-pressure metal mold methods, such as die casting, squeeze casting, and semisolid processing. The article contains tables that compare some of the typical capabilities of shape casting processes.
Investment Casting
Authors: Horton Robert A.
Published: December 2018

This article reviews the pattern materials used in investment casting. It describes patternmaking process, pattern tooling, and pattern and cluster assembly. The article provides information on melting equipment, casting methods, and the inspection and testing of investment casted materials. It presents recommendations that which serve as a useful guide to the design of investment castings. The article tabulates the applications of the process and illustrates the Shellvest system for investment casting of small parts. It explains the manufacturing process of ceramic shell molds and cores. Binders and materials used for ceramic shell molds; slurry and cluster formulation; and pattern removal methods in the manufacturing process are summarized. The article discusses the coating and drying process of clusters and slurries.
Low-Pressure Metal Casting
Authors: Woycik Gregory G. , Peters Gordon
Published: December 2018

This article provides an overview of conventional low-pressure casting and describes types of furnaces, tooling, and cores. It discusses the casting cycle steps, advantages, mechanical properties, and considerations of counterpressure casting. The article describes the vacuum riserless/pressure riserless casting process for casting aluminum.
Semisolid Casting—Introduction and Fundamentals
Authors: Pan Q.Y. , Apelian Diran , Jorstad John
Published: December 2018

Semisolid metal (SSM) processing, also known as semisolid metal casting, semisolid forming, or semisolid metal forging, is a special die casting process. This article discusses the origin and advantages of the SSM processing. It describes three major semisolid processing routes: thixocasting, rheocasting, and thixomolding.
Steel Ingot Casting
Authors: Hurtuk Donald J.
Published: December 2018

This article discusses the methods, equipment, and theory for pouring, solidifying, and stripping steel ingots. It describes the two basic types of pouring methods: top pouring and bottom pouring. The equipment includes hot tops, ingot molds, and stools. The design of the ingot is dictated by the application and type of steel involved. The article concludes with information on the applications of solidification simulation.
Patterns and Patternmaking
Authors: Voigt Robert C.
Published: December 2018

This article discusses the types of patterns used for a specific application such as loose patterns, match plate patterns, cope and drag patterns, and special patterns. It describes the principles of the patternmaking techniques used to make expendable molds and for metal casting processes such as die casting and permanent mold casting. The article reviews the pattern features and mold production considerations used in pattern design, namely, parting line considerations, addition of gates and risers, core prints, and locating points. It discusses the pattern allowances for ensuring a dimensionally correct final pattern. A wide variety of materials and advanced composite materials used in the manufacture of patterns are discussed. The article reviews the factors influencing the selection of type of patterns for specific castings.
Introduction to Cast Irons
Authors: Goodrich George M.
Published: December 2018

The term cast iron designates a group of materials that contain more than one constituent in their microstructure due to excess carbon that result in unique characteristics such as the fracture appearance and graphite morphology. This article discusses the classification of cast iron and the various metallurgical aspects, such as composition, alloying element, solidification, and graphite morphologies, of different types of cast iron. It describes the physical properties for various cast irons and the influence of microstructure and chemical composition on each property. The article provides a detailed account on thermal properties, conductive properties, magnetic properties, and acoustic properties of cast iron. It also discusses heat treatment, namely, stress relieving, annealing, normalizing, through hardening, and surface hardening. The article presents a discussion on the welding, machining and grinding, and coating of the types of cast iron.
Magnesium and Magnesium Alloys
Authors: Savage Ken
Published: December 2018

This article focuses on the variety of alloys, furnaces, and associated melting equipment and on the casting methods available for manufacturing magnesium castings. The casting methods include sand casting, permanent mold casting, die casting, thixomolding, and direct chill casting. The article discusses the flux process and fluxless process for the melting and pouring of magnesium alloys. It describes the advantages and disadvantages of green sand molding and tabulates typical compositions and properties of magnesium molding sands. The article provides information on the machining characteristics of magnesium and the applications of magnesium alloys.
Synthesis and Processing of Cast Metal-Matrix Composites and Their Applications
Authors: Rohatgi Pradeep K. , Gupta Nikhil , Daoud Atef
Published: December 2018

Metal matrix composites (MMCs) can be synthesized by vapor phase, liquid phase, or solid phase processes. This article emphasizes the liquid-phase processing where solid reinforcements are incorporated in the molten metal or alloy melt that is allowed to solidify to form a composite. It illustrates the three broad categories of MMCs depending on the aspect ratio of the reinforcing phase. The categories include continuous fiber-reinforced composites, discontinuous or short fiber-reinforced composites, and particle-reinforced composites. The article discusses the two main classes of solidification processing of composites, namely, stir casting and melt infiltration. It describes the effects of reinforcement present in the liquid alloy on solidification. The article examines the automotive, space, and electronic packaging applications of MMCs. It concludes with information on development of select cast MMCs.
Wear of Stainless Steels
Authors: Lindgren Mari
Published: December 2018

Stainless steels are characterized as having relatively poor wear resistance and tribological properties, but they are often required for a particular application because of their corrosion resistance. This article describes the classification of stainless steels and wear. Stainless steels have been classified by microstructure and are categorized as austenitic, martensitic, ferritic, or duplex. The main categories of wear are related to abrasion, erosion, adhesive wear, and surface fatigue. The article presents a list that proposes the alloy family that could be the optimal selection for a particular wear mode. The corrosion modes include dry sliding, tribocorrosion, erosion, erosion-corrosion, cavitation, dry erosion, erosion-oxidation, galling and fretting.
Adhesion, Friction, and Wear in Low-Pressure and Vacuum Environments
Authors: Miyoshi Kazuhisa , Abel Phillip B.
Published: December 2018

This article discusses the adhesion behavior of materials in low-pressure and vacuum environments and provides a schematic illustration of an apparatus for measuring adhesion and friction in ultrahigh vacuum. It describes the effects of low-oxygen pressures and vacuum environments on adhesion and friction, as well as the effects of defined exposure to oxygen on friction. The article discusses the wear of various metals in contact with ceramics, and alloying element effects on friction, wear, and transfer of materials. It also describes studies that characterize the contributions of surface contamination and chemical changes to tribology in low-pressure and vacuum environments.
Liquid Impingement Erosion
Authors: Wood Robert J.K.
Published: December 2018

Liquid impingement erosion has been defined as progressive loss of original material from a solid surface due to continued exposure to impacts by liquid drops or jets. This article focuses on the core nature of erosion by liquid impingement, due to the greater appreciation of the distinctions between the different forms of erosion. It discusses steam turbine blade erosion, aircraft rain erosion, and rain erosion of wind turbine blades. The article describes the mechanisms of liquid impact erosion and time dependence of erosion rate. It reviews critical empirical observations regarding both impingement variables (velocity, impact angle, droplet size, and physical properties of liquids) and erosion resistance of materials, including the correlation between erosion resistance and mechanical properties and the effects of alloying elements and microstructure. The article also provides information on the ways to combat erosion.
Fundamentals of Lubrication
Authors: Kuiry Suresh C.
Published: December 2018

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.
Introduction to Tribology and Tribological Parameters
Authors: Czichos Horst , Woydt Mathias
Published: December 2018

Tribology is the science and technology of interacting surfaces in relative motion. This article describes in detail the basic structural, operational, and interaction parameters of a tribosystem. The interaction parameters, which characterize the action of the operational parameters on the structural components in the system, consist of three important aspects: contact parameters, friction parameters, and wear parameters. These three aspects embody the complex mechanisms and relationships between the constituents of a tribosystem. The article concludes with information on the selection criteria of a material for wear applications.
Lubrication and Wear in Rolling
Authors: Wei Dongbin , Xia Wenzhen , Jiang Zhengyi , Hao Liang
Published: December 2018

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.
Fatigue and Fracture
Authors:   ASM Handbook Committee
Published: December 2018

Volume 19 is a resource for basic concepts, alloy property data, and the testing and analysis methods used to characterize fatigue and fracture behavior of structural materials. Contents include fatigue mechanisms, crack growth and testing; fatigue strength prediction and analysis; fracture mechanics, damage tolerance, and life assessment; environmental effects; and fatigue and fracture resistance of ferrous, nonferrous, and nonmetallic structural materials. Statistical aspects of fatigue data, the planning and evaluation of fatigue tests, and the characterization of fatigue mechanisms and crack growth are also covered. Practical applications and examples of fracture control in weldments, process piping, aircraft systems, and high-temperature crack growth and thermos-mechanical fatigue are also included. For information on the print version of Volume 19, ISBN 978-0-87170-385-9, follow this link.
Fatigue of Mechanically Fastened Joints
Authors: Reemsnyder Harold
Published: December 2018

This article discusses the effect of thread design, preload, tightening, and mean stress on the fatigue strength of bolt steel. It describes the factors influencing fatigue failures in cold-driven and hot-driven riveted joints. The factors affecting the fatigue resistance of bolted friction joints are also discussed. The article reviews stress concentrations in pin joints and discusses stress-intensity factors for mechanically fastened joints.
Contact Fatigue
Authors: Glaeser W.A. , Shaffer S.J.
Published: December 2018

Contact fatigue is a surface-pitting-type failure commonly found in ball or roller bearings. This article discusses the mechanisms of contact fatigue found in gears, cams, valves, rails, and gear couplings. It discusses the statistical analysis of rolling contact bearing-life tests. The article concludes with information on various approaches that improve the contact fatigue resistance of rolling contact systems.
The Role of the Materials Engineer in Design
Authors: Boardman Bruce , Williams James C. , Bridenbaugh Peter R.
Published: December 2018

This article discusses the various roles and responsibilities of materials engineers in a product realization organization and suggests different ways in which materials engineers may benefit their organization. It also provides a summary of the concepts discussed in the articles under the Section “The Role of the Materials Engineer in Design” in ASM Handbook, Volume 20: Materials Selection and Design.
Conceptual and Configuration Design of Products and Assemblies
Authors: Otto Kevin N. , Wood Kristin L.
Published: December 2018

A concise and quantified specification is essential to developing suitable product concepts. This article describes an integrated set of structured methods for identifying the customer population for the product and developing a representation of feature demands. The structured methods include design task probing, customer needs analysis, functional decomposition, and competitive benchmarking for directly mapping customer statements to functional requirements.
Statistical Aspects of Design
Authors: Rice Richard C.
Published: December 2018

This article discusses some of the statistical aspects of design from an engineer's perspective. It reviews the commonly used statistical terms and distributions for providing some guidance on the practical engineering applications of these distributions. The article describes the basic statistical procedures that can be used to address variability and uncertainty in an engineering analysis. It contains a table that lists the relevant statistics standards published by the American Society of Testing and Materials.
Computer-Aided Materials Selection
Authors: Weiss Volker
Published: December 2018

This article provides a description of various systems for computer-aided materials selection that deals primarily with promising prototypes that have emerged for various applications. These include expert systems, quantitative selection systems, qualitative and experiential selection systems, and object-oriented systems.
Introduction to the Effects of Composition, Processing, and Structure on Materials Properties
Authors: Heckel Richard W.
Published: December 2018

Materials are selected and used as a result of a match between their properties and the needs dictated by the intended application. This article provides information on how the composition and structure determine the properties of materials. It describes common structural elements that are most important in materials. The article presents a historical perspective of the use of materials and illustrates the evolution of engineering materials.
Design for Oxidation Resistance
Authors: Smialek James L. , Barrett Charles A. , Schaeffer Jon C.
Published: December 2018

Alloys intended for use in high-temperature environments rely on the formation of a continuous, compact, slow-growing oxide layer for oxidation, and hot corrosion resistance. This article focuses on the issues related to high-temperature oxidation of superalloys used in gas turbine engine applications. It discusses the general methodologies used to evaluate oxidation resistance of materials. The article describes the performance characteristics of superalloys, single-crystal superalloys, and other high-temperature materials such as refractory metals and ceramics. It discusses hot corrosion of superalloys and airfoil degradation due to deposits resulting from ingested particles or sand. The article concludes with a discussion on the limitations of testing techniques and life prediction.
Design for Manufacture and Assembly
Authors: Boothroyd Geoffrey
Published: December 2018

Product design for manufacture and assembly can be the key to high productivity in all manufacturing industries. This article discusses the use of design for manufacture and assembly (DFMA) software in the evaluation of proposed designs. It summarizes the steps taken when using DFMA software during design. The article describes the use of design for analysis tool in reducing the number of separate parts, estimating assembly time, and determining design efficiency. It reviews assembly analysis methods such as the assemblability evaluation method, the assembly-oriented product design method, the Lucas method, and the design-for-assembly cost effectiveness method. The article explains the design for manufacture in terms of cost estimation and principal cost drivers. It provides information on the applications of DFMA and roadblocks in the implementation of DFMA. The article concludes with a discussion on the design for automatic assembly.
Manufacturing Processes and Their Selection
Authors: Schey John A.
Published: December 2018

This article explores the possibilities and limitations imposed by manufacturing processes and materials. Detailed design rules for the processes are presented. The article lists the main features of process groups in a tabular form. The physical characteristics and ratings of relative cost and production factors are also tabulated. The process groups include casting; deformation; powder processing; machining; noncutting; joining; ceramic, glass, and polymer processing; and composites manufacturing.
Design for Ceramic Processing
Authors: Greenhut Victor A.
Published: December 2018

This article provides an overview of the steps that are used in ceramics processing and related mechanical design considerations. It discusses various design approaches, such as the empirical design, the deterministic design, and the probabilistic design. The article presents a general process design flowchart for ceramic processing. Information on traditional ceramics and advanced ceramics is also provided. The article describes various ceramic forming processes, such as wet processing, plastic forming, dry processing, and machining. The factors for evaluating different ceramic forming processes are summarized in a table. The article discusses vitrification and sintering that generally pertain to ceramic firing and concludes with a discussion on firing process factors.
Design for Plastics Processing
Authors: Muccio Edward A.
Published: December 2018

This article describes key processing methods and related design, manufacturing, and application considerations for plastic parts. The methods include injection molding, extrusion, thermoforming, blow molding, rotational molding, compression molding/transfer molding, composites processing, and casting. The article describes principal features incorporated into the design of plastic parts. It concludes with a discussion on the materials selection methodology for plastics.
Metallic Matrices
Authors: Pandey Awadh B.
Published: December 2018

Metallic matrices are essential constituents for the fabrication of metal-matrix composites (MMCs). This article describes three different classes of aluminum alloys, namely, commercial aluminum alloys, low-density and high-modulus alloys, and high temperature alloys. It presents typical tensile properties and fracture toughness of the selected heat treatable aluminum alloys in a table. Titanium alloys are very attractive for MMC applications, due to their higher strength and temperature capability compared to aluminum alloys. The article tabulates the effect of heat treatment on room-temperature properties and tensile properties of Ti-25Al-17Nb alloy sheet.
Lightweight Structural Cores
Authors: Kindinger Jim
Published: December 2018

Lightweight structural cores are used on aircrafts to reduce weight and increase payload and fight distance. This article discusses the classification of lightweight structural cores, namely, honeycomb, balsa, and foam. It reviews the four primary manufacturing methods used to produce honeycomb: adhesive bonding and expansion, corrugation and adhesive bonding, corrugation and braze welding, and extrusion. The article describes cell configuration and properties of honeycomb. It discusses the factors influencing specification of structural cores, including materials, size, density, mechanical properties, environmental compatibility, formability, durability, and thermal behavior. The article provides information on the benefits and concepts of a sandwich panel containing lightweight structural cores.
Fracture Mechanics of Composite Delamination
Authors: O'Brien T. Kevin
Published: December 2018

Delamination is one of the most commonly observed failure modes in composite materials. This article describes the three fundamental fracture failure modes of composite delamination, namely, opening, in-plane shearing, and tearing or scissoring shearing modes. It discusses the characterization and analysis of delamination. The article also reviews the prediction of delamination factors, such as flexbeam fatigue life, and skin/stiffener pull-off strength and life.