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.

This article compares and contrasts mechanical joining techniques used in the manufacture of aluminum assemblies, including seaming, swaging, flanging, crimping, clinching, dimpling, interference and snap fits, and interlocking joints. It provides basic illustrations of the various methods and summarizes the advantages and disadvantages of each. The article also discusses the use of staples, nails, rivets, and threaded fasteners and provides relevant property and performance data.

This article discusses different types of mechanical fasteners, including threaded fasteners, rivets, blind fasteners, pin fasteners, special-purpose fasteners, and fasteners used with composite materials. It describes the origins and causes of fastener failures and with illustrative examples. Fatigue fracture in threaded fasteners and fretting in bolted machine parts are also discussed. The article provides a description of the different types of corrosion, such as atmospheric corrosion and liquid-immersion corrosion, in threaded fasteners. It also provides information on stress-corrosion cracking, hydrogen embrittlement, and liquid-metal embrittlement of bolts and nuts. The article explains the most commonly used protective metal coatings for ferrous metal fasteners. Zinc, cadmium, and aluminum are commonly used for such coatings. The article also illustrates the performance of the fasteners at elevated temperatures and concludes with a discussion on fastener failures in composites.

This article discusses the classifications, specifications, applications and methods for producing welded and seamless steel tubular products, including pipes and tubes. Common types of pipes include standard pipe, conduit pipe, piling pipe, pipe for nipples, transmission or line pipe, water main pipe, oil country tubular goods, water well pipe, and pressure pipe. Pipes in suitable sizes, and most of the products classified as tubing, both seamless and welded, may be cold finished. Pressure tubes are given a separate classification by both the American Society for Testing and Materials (ASTM) and producers. The term tube covers three groups, including pressure tubes, structural tubing, and mechanical tubing.

Magnesium and magnesium alloys have been employed in a wide variety of structural applications because of their favorable combination of tensile strength, elastic modulus, and low density. Providing a brief section on occurrence, production, and uses of magnesium, this article describes alloy and temper designations of cast and wrought magnesium alloys. The role of mechanical properties and fabrication characteristics in selection of product forms for structural applications is covered. The article explores the use of magnesium alloys as a substitution for heavier metals such as steel and aluminum alloys to reduce weight in structural parts.

This article focuses on the factors to be considered for selecting fasteners for joining carbon fiber composites. These considerations include corrosion compatibility, fastener materials, strength, stiffness, head configurations, importance of clamp-up, hole fit, and lightning protection.

This article provides a discussion on adhesively bonded joints and elastic-plastic mathematical model for an adhesive in shear. It discusses the design rules for thin bonded structures and reviews computer programs for the highly loaded stepped-lap joints. The article describes the two-dimensional effects associated with load redistribution around flaws and with damage tolerance. The elastic-isotropic geometric stress-concentration factors and empirically established correlation factors of mechanically fastened joints are discussed. The article provides information on the identification of optimal joint proportions for single-row joints, and the design and analysis of the stronger multirow joints, with particular regard to the bearing-bypass interaction.

Fretting is a special wear process that occurs at the contact area between two materials under load and subject to slight relative movement by vibration or some other force. During fretting fatigue, cracks can initiate at very low stresses, well below the fatigue limit of nonfretted specimens. This article describes the mechanisms of fretting and fretting fatigue; stress analysis, modeling, and prediction of fretting fatigue; fretting fatigue testing; and fretting prevention methods. Three general geometries and loading conditions for fretting fatigue, along with their remedies, are reviewed.

Fretting is a special wear process that occurs at the contact area between two materials under load and subject to slight relative movement by vibration or some other force. This article focuses on measures to avoid or minimize crack initiation and fretting fatigue. It lists the factors that are known to influence the severity of fretting and discusses the variables that contribute to shear stresses. These variables include normal load, relative displacement (slip amplitude), and coefficient of friction. The article describes the general geometries and loading conditions for fretting fatigue. It presents the types of fretting fatigue tests and the effect of variables on fretting fatigue from different research test programs. The article also lists the general principles and practical methods for the abatement or elimination of fretting fatigue.

Magnesium and magnesium alloys are used in a wide variety of structural and nonstructural applications. This article provides information on selection and application of magnesium and magnesium alloys, mainly, casting alloys and wrought alloys. It also provides tabulated data for the composition, properties of these alloys, including compressive strength, bearing strength, shear strength, hardness, wear resistance, and fatigue strength. The article describes the selection of product forms (castings, extrusions, forgings) for structural applications which is based on mechanical property requirements, cost, availability, and fabricability. It also discusses the types of inserts used in magnesium. The article also deals with the joining of magnesium alloys by welding, adhesive bonding, and riveting. It concludes by describing the formability and machinability of magnesium and magnesium alloys, and explains the role of magnesium in design and weight reduction.

This article presents information regarding the use of protective coatings in municipal potable water systems, including raw water collection and transmission, water treatment plants, and treated water distribution. It provides useful guidance for the selection and use of protective coatings in these municipal water systems. The most commonplace corrosion-damage mechanisms are highlighted. The article describes the most common materials of construction found in municipal water systems, namely, cast iron, ductile iron, carbon steel, precast concrete cylinder pipe and reinforced concrete pipe, prestressed concrete tanks, and stainless steel. It provides information on the most common generic coating systems used for new steel tanks and water storage tanks. It concludes with a discussion of quality watch-outs when selecting or using protective coatings in municipal water systems.

This article discusses tubular products made from wrought carbon or alloy constructional steels, particularly pipe, specialty tubing, and oil country tubular goods. The article covers product classifications, available specifications, chemical compositions, sizes, and other dimensional attributes. Some of the common types of pipe are standard pipe, conduit pipe, piling pipe, pipe for nipples, transmission or line pipe, water main and water well pipe, and pressure pipe. Pipe in suitable sizes and most products classified as tubing, both seamless and welded, may be cold finished. Pressure tubes, a separate classification, include double-wall brazed tubing, structural tubing, welded mechanical tubing, continuous-welded cold-finished mechanical tubing, and seamless mechanical tubing.

Aluminum, the second most plentiful metallic element, is an economic competitor in various applications owing to its appearance, light weight, fabricability, physical properties, mechanical properties, and corrosion resistance. This article discusses the primary and secondary production of aluminum and classification system for cast and wrought aluminum alloys. It talks about various manufactured forms of aluminum and its alloys, which are classified into standardized products such as sheet, plate, foil, rod, bar, wire, tube, pipe, and structural forms, and engineered products such as extruded shapes, forgings, impacts, castings, stampings, powder metallurgy parts, machined parts, and metal-matrix composites. The article also reviews important fabrication characteristics in the machining, forming, forging, and joining of aluminum alloys. It concludes with a description of the major industrial applications of aluminum, including building and construction, transportation, consumer durables, electrical, machinery and equipment, containers and packaging, and other applications.

Hot-rolled steel bars and other hot-rolled steel shapes are produced from ingots, blooms, or billets converted from ingots or from strand cast blooms or billets and comprise a variety of sizes and cross sections. Most carbon steel and alloy steel hot-rolled bars and shapes contain surface imperfections with varying degrees of severity. Seams, laps, and slivers are probably the most common defects in hot-rolled bars and shapes. Another condition that could be considered a surface defect is decarburization. Hot-rolled steel bars and shapes can be produced to chemical composition ranges or limits, mechanical property requirements, or both. Hot-rolled carbon steel bars are produced to two primary quality levels: merchant quality and special quality. Merchant quality is the least restrictive descriptor for hot-rolled carbon steel bars. Special quality bars are employed when end use, method of fabrication, or subsequent processing treatment requires characteristics not available in merchant quality bars.

The structural efficiency of a composite structure is established by its joints and assembly. Adhesive bonding, mechanical fastening, and fusion bonding are three types of joining methods for polymer-matrix composites. This article provides information on surface treatment and the applications of adhesive bonding. It discusses the types of adhesives, namely, epoxy adhesives, epoxy-phenolic adhesives, condensation-reaction PI adhesives, addition-reaction PI adhesives, bismaleimide adhesives, and structural adhesives. The article provides information on fastener selection considerations, including corrosion compatibility, fastener materials and strength, head configurations, importance of clamp-up, interference fit fasteners, lightning strike protection, blind fastening, and sensitivity to hole quality. Types of fusion bonding are presented, namely, thermal welding, friction welding, electromagnetic welding, and polymer-coated material welding.

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.

This article aims to identify and illustrate the types of overload failures, which are categorized as failures due to insufficient material strength and underdesign, failures due to stress concentration and material defects, and failures due to material alteration. It describes the general aspects of fracture modes and mechanisms. The article briefly reviews some mechanistic aspects of ductile and brittle crack propagation, including discussion on mixed-mode cracking. Factors associated with overload failures are discussed, and, where appropriate, preventive steps for reducing the likelihood of overload fractures are included. The article focuses primarily on the contribution of embrittlement to overload failure. The embrittling phenomena are described and differentiated by their causes, effects, and remedial methods, so that failure characteristics can be directly compared during practical failure investigation. The article describes the effects of mechanical loading on a part in service and provides information on laboratory fracture examination.

This article describes the commonly observed forms of airplane corrosion, namely: general corrosion, exfoliation corrosion, pitting corrosion, microbiologically induced corrosion, galvanic corrosion, filiform corrosion, crevice corrosion, stress-corrosion cracking, and fretting. It discusses the factors influencing airplane corrosion from the manufacturing perspective: design, manufacturing, and service-related factors. The article explains the collection of corrosion data and provides an overview of the implementation and evolution of airline corrosion prevention and control programs and directions being considered in the design for corrosion prevention of airplanes.

Forging machines use a wide variety of hammers, presses, and dies to produce products with the desired shape, size, and geometry. This article discusses the major types of hammers (gravity-drop, power-drop, high speed, and open-die forging), and presses (mechanical, hydraulic, screw-type, and multiple-ram). It further discusses the technologies used in the design of dies, terminology, and materials selection for dies for the most common hot-forging processes, particularly those using vertical presses, hammers, and horizontal forging machines. A brief section is included on computer-aided design in the forging industry. Additionally, the article reviews specific characteristics, process limitations, advantages, and disadvantages of the most common forging processes, namely hot upset forging, roll forging, radial forging, rotary forging, isothermal and hot-die forging, precision forging, and cold forging.

This article discusses the most important factors required for cutoff methods. It explains the operations of machines used for the punching, shearing, notching, or coping of plates, bars, and structural sections. The article describes the effects of the blade angle and speed on the shear blade life. It reviews the design requirements and best practices for the production of blades. The article compares double-cut dies with single-cut dies used for shearing of structural and bar shapes. The shearing of specific forms, such as angle iron and flat stock, is also discussed. The article describes the advantages of hydraulic bar and structural shears. It concludes with information on the principle and construction of impact cutoff machines.