A number of nondestructive evaluation (NDE) methods, such as radiography, ultrasound, and eddy current, are available to detect flaws in solid materials. This article describes the fundamental aspects of these NDE methods in terms of operation principles. It presents some examples of the methods performed on various types of flaws resulting from solid-state welding processes.

This article provides information on the application of nondestructive examination (NDE) technologies to tube and pipe products. These include modeling and simulation methods, eddy-current methods, magnetic methods, acoustic methods, and physical methods. A summary of nondestructive examination methods based on flaw type and product stage is presented in a table. The article also discusses in-service inspection of tubular products and presents an example that illustrates the importance of nondestructive testing (NDT) for welds in austenitic stainless steel tubing.

Adhesive-bonded joints are extensively used in aircraft components and assemblies where structural integrity is critical. This article addresses the problem of how to inspect bonded assemblies so that all discrepancies are identified. It describes several inspection techniques and presents drawbacks and limitations of these techniques. Generic flaw types and flaw-producing mechanisms are listed in a table. The article discusses metal-to-metal defects, adherend defects, honeycomb sandwich defects, repair defects, and in-service defects. It reviews the methods applicable to the inspection of bonded structures, including visual inspection, ultrasonic inspection, X-ray radiography, and neutron radiography. The evaluation and correlation of inspection results are also discussed. The article concludes with information on the effects of ultrasonic wave interference in the ultrasonic inspection of adhesive-bonded joints.

Cast nickel-base alloys are used extensively in corrosive-media and high-temperature applications. This article briefly reviews the common types of heat treatments of nickel alloy castings: homogenization, stress relieving, in-process annealing, full annealing, solution annealing, quenching, coating diffusion, and precipitation. It describes the three general strengthening mechanisms, namely, solid-solution hardening, age hardening, and carbide precipitation. The article summarizes the typical heat treatment of the general families of nickel-base castings used in industrial applications. It focuses on the solution treatment and age hardening of cast nickel-base superalloys and the heat treatment of cast solid-solution alloys for corrosion-resisting applications. The article also discusses the typical types of atmospheres used in annealing or solution treating: exothermic, endothermic, dry hydrogen, dry argon, and vacuum.

Polyvinylidene fluoride (PVDF)-based coatings are typically used in outdoor applications that require exceptionally high performance and excellent long-term exterior durability with little maintenance. This article provides a background of three fluoropolymers most commonly used for coatings, namely, PVDF, polyvinyl fluoride, and polytetrafluoroethylene. It focuses on general properties, polymerization, resin types, coating formulation, technology of organic coatings, coating properties, and health and related safety considerations of PVDF. The article describes the application and typical end uses of PVDF-based coatings and the opportunities for improvement in PVDF-based coatings as with all organic coatings.

This article discusses the standard conduct of coating failure investigation. As each failure is different, a specific coating failure may require increased emphasis on a given step, or additional work and/or steps may be required. This article covers the following topics: obtaining and analyzing background information, preliminary determination of site conditions, inspection equipment requirements, coating failure site investigation, sampling techniques, sample chain of custody, coordination with the coatings laboratory, report preparation, and sample retention.

Functional fusion-bonded epoxy (FBE) coatings are used as external pipe coatings, base layer for three-layer pipe-coating systems, internal pipe linings, and corrosion coatings for concrete reinforcing steel (rebar). This article provides information on the chemistries of FBE, and discusses the application procedures for internal and external FBE pipe coating. The procedures involve pipe inspection, surface preparation, heating, powder application, curing, cooling, coating inspection, and repairing. It describes the problems and solutions for FBE external pipe coatings, girth weld FBE application, FBE custom coatings, internal FBE pipe linings, and FBE rebar coatings.

Microjoining methods are commonly used to fabricate medical components and devices. This article describes key challenges involved during microjoining of medical device components. The primary mechanisms used in microjoining for medical device applications include microresistance spot welding (MRSW) and laser welding. The article illustrates the fundamental principles involved in MRSW and laser welding. Most multicomponent medical devices implement microjoining techniques to join various forms of materials and geometries. The article presents examples of various microjoining methods used in medical device applications, including pacemaker and nitinol microscopic forceps.

This article provides an overview of curing techniques, adhesive chemistries, surface preparation, adhesive selection, and medical applications for adhesives. The curing techniques are classified into moisture, irradiation, heat, and anaerobic. The article highlights the common types of curable adhesives used for medical device assembly, including acrylics, cyanoacrylates, epoxies, urethanes, and silicones. Other forms of adhesives, such as hot melts, bioadhesives, and pressure-sensitive adhesives, are also discussed. Adhesives are used for medical device assembly, hard-tissue attachment in the fields of orthopedics and dentistry, and soft-tissue attachment such as wound closure. The typical characteristics and applications of biocompatible medical device adhesives are listed in a table. The article concludes with a section on selection of materials for medical adhesives.

Die castings is the process most often used for shaping zinc alloys. This article tabulates the compositions of zinc casting alloys and comparison of typical mechanical properties of zinc casting alloys. It discusses additions of alloys to the zinc, including aluminum, magnesium, copper, and iron. The article illustrates a characteristic five-layer microstructure of zinc alloy casings. It discusses the various methods of finishing of zinc alloy die castings, including chromium plating, polishing, painting, and electropainting. The article describes the casting of inserts and their uses in the zinc. It concludes with information on applications for zinc die castings.

The combination of high strength-to-weight ratio, excellent mechanical properties, and corrosion resistance makes titanium the best material choice for many critical applications. This article begins with a description of the historical perspective of titanium casting technology. It discusses the types of molding methods, such as rammed graphite molding and lost-wax investment molding. The article provides information on the casting design, melting, postcasting, and pouring practices. It describes the microstructure and mechanical properties of Ti-6AI-4V alloy. The article examines the product applications of titanium alloy castings. The tensile properties, standard industry specifications, and chemical compositions of various titanium alloy castings are tabulated.

This article describes typical foundry practices used to commercially produce zirconium castings. The foundry practices are divided into two sections, namely, melting and casting. The article discusses various melting processes, such as vacuum arc skull melting, induction skull melting, and vacuum induction melting, and various casting processes, such as rammed graphite casting, static and centrifugal casting, and investment casting. It explains the evaluation and testing of the process. The article provides information on the mechanical and chemical properties of zirconium castings.

Repair welding is a necessary operation for most fabricators and can cost more than the price of the original component if performed improperly. This article provides a discussion on the repair welding of castings for ferrous and nonferrous materials. The discussion focuses on surface preparation, weld repair process selection, joint selection, filler metal selection, weld repair considerations, deposition techniques, postweld heat treatment, and verification of weld repair quality.

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.

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.

Corrosion is often thought of as rusting, the process of deterioration undergone by a metal when it is exposed to air or water. This article provides the fundamentals of joints corrosion and primarily addresses the various forms of corrosion observed in brazed and soldered joints and their causes. It describes the role of proper brazing procedures in controlling corrosion. The article concludes with information on the corrosion resistance of various brazing alloy systems.

Precision forging is defined as a closed-die forging process in which the accuracy of the shape, dimensional tolerances, and surface finish exceed normal expectations to the extent that some of the postforge operations can be eliminated. This article provides an overview of the key factors that impact the precision forging process. It provides information on the achievable tolerances and presents examples of precision forging. A discussion on forging of bevel gears/spiral bevel gears is also presented.

This article addresses the cobalt and cobalt-base alloys most suited for aqueous environments and those suited for high temperatures. The performance of cobalt alloys in aqueous environments encountered in commercial applications is discussed. The article provides information on the environmental cracking resistance of the cobalt alloys. Three welding processes that are used for hardfacing with the high-carbon Co-Cr-W alloys, namely, oxyacetylene, gas tungsten arc, and plasma-transferred arc are also discussed. The article examines the effects of various modes of high-temperature corrosion. It describes the applications and fabrication of cobalt alloys for high-temperature service.