This article discusses the concepts of quality control (QC) and quality assurance (QA), and clarifies the differences and similarities in the roles and responsibilities of QC and QA personnel. It describes the inspection procedures used to verify proper surface preparation and installation of the protective coating/lining system. Prior to beginning surface-preparation operations, many specifications will require a presurface-preparation inspection to verify the correction of fabrication defects and removal of surface contamination such as grease, oil, cutting compounds, lubricants, and chemical contaminants. When inspecting concrete prior to coating installation, three areas of concern exist: surface roughness, moisture content in concrete, and acidity/alkalinity of the surface. The article provides information on the industry standards for assessing surface cleanliness. It details postcoating application quality requirements, including measuring of dry-film thickness, assessing intercoat cleanliness, verifying minimum and maximum recoat intervals, performing holiday/pinhole detection, conducting cure/hardness testing, and assessing adhesion of the applied coating system.

This article defines quality, quality assurance, quality control, and quality management of processes, products, and services. It describes the evolution of quality control and quality assurance in the coatings industry. The article also discusses the standards, quality programs, and certifications in the coatings industry.

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.

This article provides a discussion on the design, in-process, storage, and in-field problems and their considerations associated with armament corrosion with examples. Design considerations include geometry, material selection, assembly, pretreatment, coatings, and working and storage environments. In-process corrosion concerns include processing locations, in-process storage of parts, time between processing steps, and quality control of each processing step. The article also discusses the analysis of the in-field corrosion of the finished product, including physical environments, repair of corrosion-protective coatings, general corrosion-protection maintenance, and appropriate fixes and procedures that can be implemented by soldiers in-field to stop continued corrosion of armament equipment.

Temperature control in heat treating is of paramount importance in maintaining the quality and achieving the desired metallurgical results. This article provides a detailed account of the factors affecting temperature control in heat treating furnaces, with information on temperature control systems, including contact sensors, noncontact sensors, controllers, energy-flow regulators, measurement instruments, and set-point programmers. Common contact sensors include temperature scales, thermocouples, and resistance temperature detectors, whereas optical pyrometers and on-line radiation thermometers fall under the noncontact type. The article describes two types of instrumentation used in heat treating: field test instruments for temperature-uniformity surveys and system-accuracy tests; and controlling, monitoring, and recording instruments for digital instrumentation.

Microscopy is a valuable tool in materials investigations related to problem solving, failure analysis, advanced materials development, and quality control. This article describes the sample preparation techniques of composite materials. These techniques include mounting, rough grinding, and polishing. The preparation techniques of ultrathin sections are also summarized. The article explains the illumination methods used by reflected light microscopy to view a specimen. These consist of epi-bright-field illumination, epi-dark-field illumination, epi-polarized light, and epi-fluorescence. The article also provides information on transmitted light microscopy.

As additive manufacturing (AM) gains maturity as a manufacturing technique for production in many industrial sectors, inspection as a tool for quality control gains importance. This article is focused on the field of dimensional metrology, which is typically concerned with the verification of size, location, form, and surface topography of geometric features. This is split into two categories: geometric (size, location, form) and surface measurement (topography). The article also focuses on applicable inspection technologies, and it discusses the context within digital thread manufacturing. A case study on the Digital Inspection Requirements Enhancing Coverage and Traceability (DIRECT) is also presented.

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 discusses various molten-metal treatments, namely fluxing, degassing, and molten-metal filtration. It focuses on various molten-metal handling systems for transporting, holding, or delivering molten metal to the mold/die system. These include launders, tundishes, holding furnaces or transport crucibles, molten-metal transfer pumps, teeming ladles, and dosing and pouring furnaces.

This article addresses problems, such as “in spec” dilemma and on-target key, associated with traditional approaches to quality. It discusses major robust design techniques, tools, and concepts, such as quality loss function, parameter design, tolerance design, signal-to-noise ratio, technology development, and orthogonal arrays.

Inspection involves two types of testing, namely, destructive and non-destructive. This article provides an overview of the various inspection plans, such as first-article inspection and periodic tests done by destructive metallurgical testing and the final inspection done by the application of non-destructive technology. It describes the processes involved in destructive methods, such as surface hardness measurement, induction hardening pattern and heat-affected zone inspection, and the examination of microstructure before and after induction hardening. It also discusses non-destructive evaluation techniques for defect detection and microstructure characterization as well as non-destructive evaluation for real-time monitoring of induction process.

Concurrent engineering is product development that is done by concurrently utilizing all of the relevant information in making each decision. This article discusses the three aspects that must be taken into account for all product development decisions. The aspects include product functionality, production capability, and field-support capability. The concurrent process is carried out by a multifunctional team that integrates the specialties. The article schematically illustrates product design team configurations with subsystem teams and team of subsystem leaders. It discusses the three-step decision-making process, such as requirements, concepts, and improvement, followed by multifunctional product development teams. The article describes the two types of requirements development by multifunctional teams, namely, quality function deployment and functional analysis. It schematically illustrates the integration of product requirements and concept development. The article concludes with a discussion on the improvement of concepts in terms of robust design and mistake minimization.

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.

In situ process monitoring includes any technologies that monitor or inspect during an additive manufacturing (AM) process. This article presents the types, process considerations, and challenges of in situ monitoring technologies that can be implemented during an AM process. The types include system health monitoring, melt pool monitoring, and layer monitoring. The article discusses data analysis, and provides an overview of the integration of sensors into AM machines.

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.

Laser soldering uses a well-focused, highly controlled beam to deliver energy to a desired location for a precisely measured length of time. This article focuses on two types of laser soldering operations, namely, blind laser soldering and intelligent laser soldering. It discusses the function of the blind laser soldering and provides a brief description on key attributes of the blind laser soldering, including repeatability, speed, quality, safety, and flexibility. The article explores the function of the intelligent laser soldering and concludes with a section on key attributes of the intelligent laser soldering. The key attributes of the intelligent laser soldering include repeatability, speed, quality, safety, cost, and flexibility.

This article reviews weld quality monitoring considerations for two automotive materials, steel and aluminum, with a focus on photosensor technology. It provides an overview of the process description, process parameters, and weld characteristics of laser welding. The article discusses real-time or in-process monitoring, which is done with optical, acoustic, and/or charged-particle sensors. It highlights the advantages, applications, and selection criteria of weld monitoring system and concludes with examples of laser weld monitoring in the production of tailor-welded blanks.

This article provides a summary of the concepts discussed in the articles under the Section “Product Reliability, Maintainability, and Repair” in ASM Handbook, Volume 21: Composites. The Section covers a range of topics that include the general issues for reliability, maintenance, and repair of composite structures. Specific structural applications, including marine, infrastructure, and aircraft related issues, are discussed. Operators of equipment employing composite structures in primary load applications must understand the issues with respect to maintenance and repair action. The Section also provides information on these requirements.

Part quality in additive manufacturing (AM) is highly dependent on process control, but there is a lack of adequate AM control methods and standards. Laser powder-bed fusion (L-PBF) is one of the most-used metal AM techniques. This article focuses on the following laser control parameters: laser focus, laser power, laser position, and laser power-position synchronization. It then provides a discussion on laser scan strategies. The article also provides an overview of the AM control framework, the two major sections of which are software and hardware.