Radiography is the process or technique of producing images of a solid material on a paper/photographic film or on a fluorescent screen by means of radiation particles or electromagnetic waves of short wavelength. This article reviews the general characteristics and safety principles associated with radiography. There are two main aspects of safety: monitoring radiation dosage and protecting personnel. The article summarizes the major factors involved in both and discusses the operating characteristics of X-ray tubes. It describes the various methods of controlling scattered radiation: use of lead screens; protection against backscatter and scatter from external objects; and use of masks, diaphragms, collimators, and filtration. The article concludes with a discussion on image conversion media, including recording media, lead screens, lead oxide screens, and fluorescent intensifying screens.

Digital radiography is a technique that uses digital detector arrays (linear or area) to capture an X-ray photonic signal and convert it to an electronic signal for display on a computer. This article begins with an overview of real-time radiography and provides a schematic illustration of a typical radioscopic system using an X-ray image intensifier. It discusses the advantages and limitations of real-time radiography. Computed radiography (CR) is one of the radiography techniques that utilizes a reusable detector comprised of photostimuable luminescence (PSL) storage phosphor. The article provides a schematic illustration of a typical storage phosphor imaging plate. It concludes with a discussion on the benefits of digital radiography.

Radiography is a nondestructive-inspection method that is based on the differential absorption of penetrating radiation by the part or test piece (object) being inspected. This article discusses the fundamentals and general applications of radiography, and describes the sources of radiation in radiographic inspection, including X-rays and gamma rays. It deals with the characteristics that differentiate neutron radiography from X-ray or gamma-ray radiography. The geometric principles of shadow formation, image conversion, variation of attenuation with test-piece thickness, and many other factors that govern the exposure and processing of a neutron radiograph are similar to those for radiography using X-rays or gamma rays.

Film radiography requires the development of the exposed film so that the latent image becomes visible for viewing. It describes the general characteristics of film, including speed, gradient, and graininess, and the factors affecting film selection and exposure time. The article discusses the three major inspection techniques for tubular sections, namely, the double-wall, double-image technique; the double-wall, single-image technique; and the single-wall, single-image technique. It illustrates the arrangements of penetrameters and identification markers for the radiography of plates, cylinders, and flanges. The article discusses various control methods, including the use of lead screens; protection against backscatter and scatter from external objects; and the use of masks, diaphragms, collimators, and filtration. The radiographic appearance of specific types of flaws is also discussed. The article concludes with a discussion on two methods of radiographic film processing: manual and automatic processing.

The commonly used nondestructive testing of cast products include liquid penetrant inspection, radiographic inspection, fluoroscopic inspection and automated defect recognition, ultrasonic inspection, eddy current inspection, process-controlled resonant testing (PCRT), leak test, and electrical conductivity measurements. This article summarizes the application of these nondestructive tests to castings. It also tabulates a partial list of automotive part types and materials amenable to PCRT and lists the potential limitations to the use of PCRT.

Nondestructive testing (NDT), also known as nondestructive evaluation (NDE), includes various techniques to characterize materials without damage. This article focuses on the typical NDE techniques that may be considered when conducting a failure investigation. The article begins with discussion about the concept of the probability of detection (POD), on which the statistical reliability of crack detection is based. The coverage includes the various methods of surface inspection, including visual-examination tools, scanning technology in dimensional metrology, and the common methods of detecting surface discontinuities by magnetic-particle inspection, liquid penetrant inspection, and eddy-current testing. The major NDE methods for internal (volumetric) inspection in failure analysis also are described.

This article describes the applications, methods, and limitations of five principal nondestructive test methods, namely, penetrant testing, magnetic-particle testing, eddy current testing, radiographic testing, and ultrasonic testing. The article also provides guidance for the method selection for respective applications.

This article focuses on the aspects associated with inspection related to pressure vessels and pipework. These aspects include inspection policy, inspection planning and procedures, inspection strategy, inspection methodology, preparation for inspection, invasive inspection, internal visual inspection, and non-invasive inspection. Inspection execution, risk-based inspection, competence assurance of inspection personnel, inspection coverage, inspection periodicity, inspection anomaly criteria, assessment of fitness, and reporting requirements, are also discussed. The article addresses the data acquisition, reporting and trending, and review and audit for the inspection. It reviews inspection techniques, including visual inspection, ultrasonic inspection, and radiographic inspection.

Drawing is a process by which a workpiece is pulled against a die to produce a wire, bar, or tube with smaller cross sectional area compared with the initial stock. This article discusses the variables that affect the drawing process and the parameters that influence friction, lubrication, and wear. These parameters include process, lubricant, workpiece, and tooling. The article provides information on dry and wet lubrication in wire drawing. The dry lubrication refers to use of solid lubricants while wet lubrication refers to the practice of providing a liquid lubricant to the workpiece-die interface. The article describes the most common types and causes of die wear: abrasive wear, adhesive wear, surface fatigue wear, thermal fatigue wear, and catastrophic failure. It concludes with a discussion on the surface treatment and texturing that are used to reduce die wear in drawing operations.

Many nonferrous metals, including aluminum, nickel, copper, and others, are among the few materials that do not degrade or lose their chemical or physical properties in the recycling process. As a result, these metals can be recycled an infinite number of times. This article focuses on the recycling of nonferrous alloys, namely, aluminum, copper, magnesium, tin, lead, zinc, and titanium, providing details on the sources, consumption and classification of scrap, and the technological trends and developments in recycling.

This article focuses on different aspects of wear particle analysis. It discusses the different wear regimes in the wear rate versus time (bathtub) curve. The article explains the essence of condition monitoring and how to properly sample lubricants for condition monitoring. It also discusses in-service lubricant analysis for condition monitoring, focusing on the spectrometric oil analysis program. The article describes the characteristics of wear particles and analytical techniques for characterizing them. It also describes the characteristics of different types of wear particles and the mechanisms by which they are generated. The article concludes with a summary of the major applications of wear particle analysis.

This article commences with a discussion on the characteristics of stress-corrosion cracking (SCC) and describes crack initiation and propagation during SCC. It reviews the various mechanisms of SCC and addresses electrochemical and stress-sorption theories. The article explains the SCC, which occurs due to welding, metalworking process, and stress concentration, including options for investigation and corrective measures. It describes the sources of stresses in service and the effect of composition and metal structure on the susceptibility of SCC. The article provides information on specific ions and substances, service environments, and preservice environments responsible for SCC. It details the analysis of SCC failures, which include on-site examination, sampling, observation of fracture surface characteristics, macroscopic examination, microscopic examination, chemical analysis, metallographic analysis, and simulated-service tests. It provides case studies for the analysis of SCC service failures and their occurrence in steels, stainless steels, and commercial alloys of aluminum, copper, magnesium, and titanium.

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 is a compilation of definitions for terms related to engineering materials, including plastics, elastomers, polymer-matrix composites, adhesives and sealants, ceramics, ceramic-matrix composites, glasses, and carbon-carbon composites.

Induction hardening of steel components is the most common application of induction heat treatment of steel. This article provides a detailed account of electromagnetic and thermal aspects of metallurgy of induction hardening of steels. It describes induction hardening techniques, namely, scan hardening, progressive hardening, single-shot hardening, and static hardening. The article discusses the techniques used to control the heat pattern, and provides a brief review of quenching techniques used in the induction hardening. It provides guidelines for selecting the frequency and power for induction hardening, and describes common methods for measuring case depth, such as optical and microhardness, and surface hardness. It provides information on some complications and ambiguities associated with these measurements. The article also discusses the commonly used non-destructive testing methods, namely, magnetic particle testing, ultrasonic testing, and eddy current testing to evaluate induction-hardened components.

Advanced thermoplastics are stiff, moldable plastics that compete with traditional engineering thermoplastics and thermosets owing to their good tensile, compressive, impact, and shear strength, electrical properties, and corrosion resistance. This article discusses commercial forms, family characteristics, properties and applications of the following advanced thermoplastics: homopolymer and copolymer acetals, fluoropolymers, ionomers, polyamides, polyamide-imides, polyarylates, polyketones, polyaryl sulfones, polybutylene terephthalates, polycarbonates, polyether-imides, polyether sulfones, polyethylene terephthalates, thermoplastic polyimides, liquid crystal polymers, polyphenylene ether blends, polyphenylene sulfides, and polysulfones.

This article describes some of the welding discontinuities and flaws characterized by nondestructive examinations. It focuses on nondestructive inspection methods used in the welding industry. The sources of weld discontinuities and defects as they relate to service failures or rejection in new construction inspection are also discussed. The article discusses the types of base metal cracks and metallurgical weld cracking. The article discusses the processes involved in the analysis of in-service weld failures. It briefly reviews the general types of process-related discontinuities of arc welds. Mechanical and environmental failure origins related to other types of welding processes are also described. The article explains the cause and effects of process-related discontinuities including weld porosity, inclusions, incomplete fusion, and incomplete penetration. Different fitness-for-service assessment methodologies for calculating allowable or critical flaw sizes are also discussed.