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.

This article reviews photographic principles, namely, visual examination, field photographic documentation, and laboratory photographic documentation, as applied to failure analysis and the specific techniques employed in both the field and laboratory. It provides information on the photographic equipment used in failure analysis and on film and digital photography. The article describes the basics of photography and the uses of different types of lighting in photography of a fractured surface. The article also addresses the techniques involved in macrophotography and microscopic photography as well as other special techniques.

Failure analysis is an investigative process in which the visual observations of features present on a failed component and the surrounding environment are essential in determining the root cause of a failure. This article reviews the basic photographic principles and techniques that are applied to failure analysis, both in the field and in the laboratory. It discusses the processes involved in visual examination, field photographic documentation, and laboratory photographic documentation of failed components. The article describes the operating principles of each part of a professional digital camera. It covers basic photographic principles and manipulation of settings that assist in producing high-quality images. The need for accurate photographic documentation in failure analysis is also presented.

This article focuses on the heat removal stages involved in quenching, and on the experimental setup used for measuring temperature and detecting sound signals with the help of illustrations and curves. The quenching process generates acoustic signals, which are the consequences of the phase transformation of steel and of the boiling process at the interface during the cooling process. The sound-pressure signal is captured by the hydrophone through sound-emission measurements that occur during steel quenching in different quenching media. The analysis of the results offers an interesting approach to evaluation and, more importantly, to monitoring, controlling, and optimizing the entire quenching process.

Failure analysis is an investigative process that uses visual observations of features present on a failed component fracture surface combined with component and environmental conditions to determine the root cause of a failure. The primary means of recording the conditions and features observed during a failure analysis investigation is photography. Failure analysis photographic imaging is a combination of both science and art; experience and proper imaging techniques are required to produce an accurate and meaningful fracture surface photograph. This article reviews photographic principles and techniques as applied to failure analysis, both in the field and in the laboratory. The discussion covers the processes involved in field and laboratory photographic documentations, provides a description of professional digital cameras, and gives information on photographic lighting and microscopic photography. Special techniques can be employed to deal with highly reflective conditions and are also described in this article.

This article focuses on the corrosion-wear synergism in aqueous slurry and grinding environments. It describes the effects of environmental factors on corrosive wear and provides information on the impact and three-body abrasive-corrosive wear. The article also discusses the various means for combating corrosive wear, namely, materials selection, surface treatments, and handling-environment modifications.

This article reviews the fundamentals of electrochemical corrosion test methods. The features and requirements of the instrumentation needed for an electrochemical test are briefly discussed. The article provides a discussion on the various electrochemical techniques and tests available for laboratory studies of corrosion phenomena. The techniques and tests include no-applied-signal tests, small-signal polarization tests, large-signal polarization tests, scanning electrode techniques, and miscellaneous techniques.

Transmission electron microscopy (TEM) approach enables essentially simultaneous examination of microstructural features through imaging from lower magnifications to atomic resolution and the acquisition of chemical and crystallographic information from small regions of the thin specimen. This article discusses fundamentals of the technique, especially for solving materials problems. Background information is provided to help understand basic operations and principles, including instrumentation, the physics of signal generation and detection, image formation, electron diffraction, and spectrometry techniques with data analysis.

Tribocorrosion is the subject dealing with complex, synergistic effects of chemical and mechanical conditions that cause wear. This article begins with a discussion on oxidative wear and corrosive wear, as well as quantitative measurements of corrosion, mechanical wear, and wear-corrosion effects. It illustrates the mechanism of corrosive-abrasive wear and discusses the factors affecting two-body wear. These factors include particle shape, size, density, and hardness; slurry velocity; slurry particle angle of attack; solids concentration in the slurry; hydrodynamic factors; corrosion products and the mass transfer of oxygen. The article describes slurry particle impingement tests and grinding tribocorrosion tests, as well as the factors to be considered for mitigating corrosive wear, such as materials selection, surface treatments, and environment modifications.

This article focuses on the cooling process and related transformation behavior of steel wires during patenting to identify a physical metallurgical basis for the development of nontoxic alternatives to molten lead for wire patenting. It describes the materials required, the procedures, and the results of cooling curve analysis. The article schematically summarizes the cooling behaviors of the various cooling media and the microstructure of the pearlite transformation in a lead bath.

This article considers the two primary methods used for ultrasonic inspection: pulse-echo and the transmission methods. Pulse-echo inspection can be accomplished with longitudinal, shear, surface (Rayleigh), or Lamb (plate) waves using a diverse range of transducers. The article discusses the principles of each of these inspection methods. It describes the applications and the basic data formats for single-element transducer-based systems, including A-scans, B-scans, and C-scans. The article provides information on electronic equipment used for ultrasonic inspection. It also describes how specific material conditions produce and modify A-scan indications. The article provides information on the controls and their functions for the display unit of the electronic equipment. It describes the techniques used for the identification and characterization of flaws, namely, surface (Rayleigh) wave and ultrasonic polar scan techniques.

This article provides an insight into the cost estimation of painting projects for both contractors and others. The cost estimating methods include benchmarking, unit price estimating, developed pricing, market pricing, and critical path scheduling. The first step in developing an accurate estimate for an industrial painting contract is determining the scope of work. The article describes the method of calculating quantities of materials and labor, surface area takeoff, and equipment costs. It concludes by listing the forgotten costs and presenting information on coating condition assessment and determining selling cost.

This article explains how ceramic powders are made. It begins by briefly describing the raw materials used in structural clay products, whitewares, refractories, and advanced ceramics. It then examines various additives that promote uniformity at different stages of the process. After a description of the comminution process (wet and dry milling methods), it discusses batching and mixing operations and granulation methods. The article also deals with the effect of process variables and the steps involved in chemical synthesis, including preparation from solution and gas-phase reactions, filtration and washing, and powder recovery techniques. It concludes with a discussion on characterization, centering on size distribution analysis, specific surface area, density, porosity chemical composition, phase, and surface composition.

As a failure investigation progresses, the time arrives when the data and results of the various testing and analyses are compiled, compared, and interpreted. Data interpretation should be relatively straightforward for results that align well. However, interpretation can be challenging when results from various tests seem contradictory or inconclusive. Regardless, conclusions must eventually be drawn from the data. This article discusses the processes involved in reviewing data, formulating conclusions, failure analysis report preparation and writing, and providing recommendations and follow-up with appropriate personnel to prevent future failures.

Inverse hardening a steel of adequate hardenability requires a workpiece of sufficiently large cross section, an appropriate cooling medium, and the right quenching conditions. This article explains the Temperature Gradient Quenching Analysis System (TGQAS), which can measure, record, and evaluate all quenching processes in common use, describing their heat extraction dynamics by corresponding thermodynamic functions. It discusses the metallurgical aspects of steels with an emphasis on two different processes, namely, heat extraction (a thermodynamic process) and microstructural transformation (a metallurgical process) that are initiated at the moment when the austenitized workpiece is immersed in the quenchant. The article describes the uses of polyalkylene glycol copolymer and the effect of hardness and fatigue resistance on AISI 4140 type steel.

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.

Scanning electron microscopy (SEM) has unique capabilities for analyzing fracture surfaces. This article discusses the basic principles and practice of SEM, with an emphasis on its applications in fractography. The topics include an introduction to SEM instrumentation, imaging and analytical capabilities, specimen preparation, and the interpretation of fracture features. SEM can be subdivided into four systems, namely, illuminating/imaging, information, display, and vacuum systems. The article also describes the major criteria and techniques of SEM specimen preparation, and the general features of ductile and brittle fracture modes.

Ultrasonic inspection is a nondestructive method in which beams of high-frequency acoustic energy are introduced into a material to detect surface and subsurface flaws, to measure the thickness of the material, and to measure the distance to a flaw. This article provides a detailed account of ultrasonic flaw detectors, including ultrasonic transducers and types of search units and couplants. The article describes pulse-echo and transmission inspection methods and data interpretation. The general characteristics of ultrasonic waves and the factors influencing ultrasonic inspection are also addressed. The article concludes with a review of the advantages and disadvantages of ultrasonic inspection compared with other methods applications of the technique.

This article provides a background of the complex relationship between titanium and its alloys with aqueous environments, which is dictated by the presence of a passivating oxide film. It describes the corrosion vulnerability of titanium and titanium oxides by the classification of oxide failure mechanisms. The mechanisms are spatially localized oxide film breakdown by the ingress of aggressive anions; spatially local or homogenous chemical dissolution of the oxide in a strong reducing-acid environment; and mechanical disruptions or depassivation such as scratching, abrading, or fretting. Titanium alloys can be classified into three primary groups such as titanium alloys with hexagonal close-packed crystallographic structure; beta titanium alloys with body-centered cubic crystallographic structures; and alpha + beta titanium alloys including near-alpha and near-beta titanium alloys. The article also illustrates the effects of alloying on active anodic corrosion of titanium and repassivation behavior of titanium and titanium-base alloys.