Leak testing is used to determine the rate at which a liquid or gas penetrates from inside a component or assembly to the outside, or vice versa. This article discusses the type of leaks, namely real leaks, and virtual leaks. It describes the leak testing of fluid systems at pressure through acoustic method and bubble testing. The article gives a short note on types of leak detectors, sulfur hexafluoride detectors and mass-spectrometer. It tabulates the pressure and vacuum system leak-testing methods and discusses the application of gas detectors in leak testing.

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 inspection (NDI) methods for cast iron are used to ensure that the parts supplied perform as required by the purchaser. This article focuses on the principal nondestructive methods used to inspect for anomalies in cast irons and to determine if the volume, shape, size, or number of these anomalies exceeds the maximum allowed by the purchaser. The nondestructive methods include visual inspection, dimensional inspection, liquid penetrant inspection, magnetic-particle inspection, eddy-current inspection, radiographic inspection, ultrasonic inspection, resonant testing, and leak testing. The technique, strengths, and weaknesses of each of the nondestructive methods are also discussed.

This article reviews nondestructive testing (NDT) and inspection techniques, namely liquid penetrant, magnetic particle, ultrasonics, X-ray, eddy current, visual and radiography that are commonly used to detect and evaluate flaws or leaks in an engineering system. This article compares the merits and limitations of these techniques and describes the various uses of NDT, including leak detection, metrology, structure or microstructure characterization, stress-strain response determination, and rapid identification of metals and alloys.

This article outlines the requirements and methods associated with the inspection of brazements. It emphasizes the incorporation of these requirements into the overall quality system. The article reviews the acceptance limits, design limitations, and nondestructive and destructive inspection techniques involved in the brazement inspection. Selected case studies are also provided for further reference.

Welded connections are a common location for failures for many reasons, as explained in this article. This article looks at such failures from a holistic perspective. It discusses the interaction of manufacturing-related cracking and service failures and primarily deals with failures that occur in service due to stresses caused by externally applied loads. The purpose of this article is to enable a failure analyst to identify the causative factors that lead to welded connection failure and to identify the corrective actions needed to overcome such failures in the future. Additionally, the reader will learn from the mistakes of others and use principles that will avoid the occurrence of similar failures in the future. The topics covered include failure analysis fundamentals, welded connections failure analysis, welded connections and discontinuities, and fatigue. In addition, several case studies that demonstrate how a holistic approach to failure analysis is necessary are presented.

Acoustic-emission inspection detects and analyzes minute acoustic-emission signals generated by discontinuities in materials under applied stress. This article discusses the types of acoustic emissions (continuous-type emissions and burst-type emissions) and applications, including laboratory testing, production testing, and structural testing. The article includes a section in which the characteristics of acoustic emission inspection are compared with other nondestructive testing methods. Further, it briefly reviews the key elements of the acoustic-emission instrumentation, which includes the acoustic-emission resonant sensor.

This article discusses the failure analysis of several steel transmission pipeline failures, describes the causes and characteristics of specific pipeline failure modes, and introduces pipeline failure prevention and integrity management practices and methodologies. In addition, it covers the use of transmission pipeline in North America, discusses the procedures in pipeline failure analysis investigation, and provides a brief background on the most commonly observed pipeline flaws and degradation mechanisms. A case study related to hydrogen cracking and a hard spot is also presented.

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 provides a discussion on general nondestructive evaluation (NDE) science and considerations for specific technique selection. It explains the basic concept of flaw detection and evaluation and probability of detection. The article provides an overview of NDE methods with their applications, limitations, and advantages. It includes details on NDE codes, calibration standards, inspection frequency, guidance on how to perform inspections, applicability, and mandatory and nonmandatory practice. The article also provides tips on where to focus inspections in order to align with the likely areas of damage or degradation and a number of other aspects of inspection.

This article describes the physical properties of powder metallurgy (PM) stainless steels. These include thermal diffusivity, conductivity, thermal expansion coefficient, Poisson's ratio, and elastic modulus. The article contains a table that lists the characteristics of various grades of PM stainless steels. It discusses the applications of various PM stainless steels such as rearview mirror brackets, anti-lock brake system sensor rings, and automotive exhaust flanges and sensor bosses.

Acoustic emission is the generation of stress waves by sudden movement in stressed materials. This article begins with a comparison of acoustic emission from most other nondestructive testing (NDT) methods, and discusses the range of applicability of acoustic emission. It describes the instrumentation principles of acoustic emission and reviews the role of acoustic emission in materials studies. The article illustrates the testing of metal-matrix composites (MMCs) using acoustic emission and the use of acoustic emission inspection in production quality control. It concludes with information on the structural test applications of acoustic emission inspection to find defects and to assess or ensure structural integrity.

This article discusses the principle, coil design, types and operation of a vacuum induction furnace. It describes the operation parameters that should be considered during the functioning of the induction furnace.

This article provides members of the thermal spray community with practical recommendations for the safe installation, operation, and maintenance of gas equipment used in the thermal spray process. It focuses on safety issues concerning gas equipment used in conjunction with thermal spray equipment at consumer sites. The article covers the gas sources (bulk or gaseous), the piping (hard and soft) leading to the gas console or the torch, and the specific safety devices used to help ensure safe operation. It discusses the characteristics and safety hazards of gases such as oxygen, compressed air, nitrogen, helium, argon, carbon dioxide, hydrogen, acetylene, kerosene, propylene, propane, and natural gas. The article also provides information on the maintenance and safety practices involved in the plumbing configurations of cylinder gas supply units and bulk gas supply units.

Both nondestructive testing (NDT) and nondestructive evaluation (NDE) use noninvasive measurement techniques to gain information about defects and various properties of materials, components, and structures. This article begins with a discussion on the historical development of quantitative measurement techniques, evaluation reliability, and quantitative interpretation of nondestructive inspection methods. The common nondestructive evaluation methods, along with their uses and limitations, are summarized in a table. The article conceptually illustrates the interplay of NDE and fracture mechanics in the damage tolerant approach. It concludes with information on pressure vessel applications that can be separated into three protocols used by military nuclear power, commercial nuclear power, and non-nuclear pressure vessels and/or fired boilers.

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.

Corrosion of carbon steel weldments can be due to metallurgical effects, such as preferential corrosion of the heat-affected zone (HAZ) or weld metal, or it can be associated with geometrical aspects, such as stress concentration at the weld toe, or creation of crevices due to joint design. This article describes the issues related to corrosion of carbon steel weldments and the remedial measures that have proven to be successful in specific cases. It provides useful information on preferential HAZ corrosion, preferential weld metal corrosion, and galvanic corrosion.