This article provides a discussion on the process descriptions, processing conditions, and processing variables of the most common chemical methods for metal powder production. These methods include oxide reduction, precipitation from solution, and thermal decomposition. Methods such as precipitation from salt solution and gas, chemical embrittlement, hydride decomposition, and thermite reactions are also discussed. The article also discusses the methods used to produce powders electrolytically and the types of metal powders produced. The physical and chemical characteristics of these powders are also reviewed.

The raw materials used in thermal spray processes are a critical parameter in the finished coating because the variations in their size, morphology, chemistry, and phase composition can significantly impact coating properties. Therefore, it is important to test and characterize the raw materials. This article discusses various characterization methods for powders. Topics discussed include: methods for determining particle size and/or size distribution; powder and coating stoichiometry; particle chemistry; and phase analysis by x-ray diffraction. This article discusses the characterization of thermal spray powders which involves the determination of particle size and/or size distribution and phase analysis by x-ray diffraction. It provides information on preferential volatilization and rapid solidification that influence compositional differences. Wet chemical methods, spectographic analysis, and atomic absorption spectrometry are also discussed.

The electrical discharge machining (EDM) process is used for machining dies because of its ability to machining difficult geometries or materials with poor machinability. This article provides a discussion on the fundamentals of electrical discharge erosion and the principles of EDM and orbital-movement EDM. It discusses various aspects of wire EDM in machining dies and provides an overview of the materials used in EDM electrodes. The article concludes with a discussion on electrochemical machining.

This article reviews the methods of machining and finishing forging dies. It illustrates different stages in die manufacturing. The article provides a brief description on requirements and characteristics of high-speed machining tools, including feed rates, spindle speed, surface cutting speeds, and high acceleration and deceleration capabilities. It discusses electrodischarge machining process and electrochemical machining process. The article concludes with information on die-making methods.

This article is a compilation of color etchants that have been developed for a limited number of metals and alloys. It describes the optical methods for producing color, such as polarized light and differential interference contrast, with illustrations. The article discusses film formation and interference techniques such as anodizing, chemical etching, and tint etching. It provides a description of reagents that deposit sulfide films and molybdate films. The article concludes with a discussion on the thermal and vapor deposition methods to produce color.

This article discusses four subsystems of the electrochemical machining (ECM) system: power source, electrolyte cleaning and supply system, tool and tool-feed system, and workpiece and workpiece-holding system. It describes the theory of ECM and provides information on the electrolytes used in ECM. The article reviews the methods associated with workpiece shape prediction. The procedures and integrated approach for the tool design in ECM are discussed. The article also explains the process control, capabilities, and the limitations of ECM. It concludes with information on the applications of ECM.

Specific machining processes that employ electrochemical machining technology include deburring and deep-hole drilling. This article describes the principle and applications of electrochemical deburring as well as the machine tools used in the process. The system, process capabilities, and applications of electrochemical deep-hole drilling are also discussed. The article also reviews the pulse electrochemical machining.

This article discusses the need of and the strain basis for residual stress measurements and describes the nature of residual stress fields. A generic destructive stress relief procedure is described along with the issues generally involved in each procedural step. The article presents the stress reconstruction equations to be used for computational reconstruction of the stress fields from the measured strains for the destructive methods. It provides information on the sectioning, material removal, strain measurement, and chemical methods of residual stress measurement. The article reviews the semidestructive methods of residual stress measurement: blind hole drilling and ring coring, spot annealing, and X-ray diffraction techniques. Nondestructive methods such as neutron diffraction, ultrasonic velocity, and magnetic Barkhausen noise techniques, are also discussed.

This article is a comprehensive collection of summary charts that provide data and information that are helpful in considering and selecting applicable processes alternative to the conventional material-removal processes. Process summary charts are provided for electrochemical machining, electrical discharge machining, chemical machining, abrasive jet machining, laser beam machining, electron beam machining, ultrasonic impact grinding, hydrodynamic machining, thermochemical machining, abrasive flow machining, and electrical discharge wire cutting.

Nontraditional finishing processes include electrochemical machining (ECM), electrodischarge machining (EDM), and laser beam machining. These processes belong to nonabrasive finishing methods where surface generation occurs with an insignificant amount of mechanical interaction between the processing tool and the workpiece surfaces. This article provides information on the equipment used, applications, process capabilities, and limitations of ECM and EDM.

This article discusses the various categories of nontraditional machining processes that are subdivided according to the form of energy being harnessed. These include mechanical, electrical, thermal, and chemical methods.

Shaped tube electrolytic machining (STEM) is a modified electrochemical machining (ECM) process that uses an acid electrolyte so that the removed metal goes into the solution instead of forming a precipitate. This article lists some specific machining applications of the STEM process, including turbine blade cooling holes, turbine vane cooling holes, turbine disk cooling passages, oil passages, and fuel nozzles. It describes the limitations and advantages of the STEM process. The article discusses the various tool parts of the STEM system, including the holding fixture, guide for cathodes, cathodes, and cathode holder/manifold. The article concludes with information on the process parameters of the STEM system.

Nickel-base alloys can be machined by techniques that are used for iron-base alloys. This article discusses the effects of distortion and microstructure on the machinability of nickel alloys. It tabulates the classification of nickel alloys based on machining characteristics. The article describes the machining operations performed on nickel alloys, such as turning, planing and shaping, broaching, reaming, drilling, tapping and threading, milling, sawing, and grinding. It provides information on the cutting fluids used in the machining of nickel alloys. The article also analyzes nontraditional machining methods that are suitable for shaping high-temperature, high-strength nickel alloys. These include electrochemical machining, electron beam machining, and laser beam machining.

This article focuses on the machining of reactive metals which refer collectively to the elements titanium, hafnium, and zirconium. It provides guidelines for machining titanium and titanium alloys and describes machining operations, such as turning, milling, drilling, tapping, reaming, grinding, and sawing, performed on titanium and its alloys. The article also provides information on electrochemical machining (ECM), chemical milling (CHM), and laser beam machining (LBM) for titanium and titanium alloys. Guidelines for machining zirconium alloys and hafnium are also provided. The article provides a short description of turning, milling, and drilling operations performed on zirconium alloys and hafnium. It also discusses health and safety considerations related to zirconium and hafnium.

The machinability of stainless steels varies from low to very high, depending on the final choice of the alloy. This article discusses general material and machining characteristics of stainless steel. It briefly describes the classes of stainless steel, such as ferritic, martensitic, austenitic, duplex, and precipitation-hardenable alloys. The article examines the role of additives, such as sulfur, selenium, tellurium, lead, bismuth, and certain oxides, in improving machining performance. It provides ways to minimize difficulties involved in the traditional machining of stainless steels. The article describes turning, drilling, tapping, milling, broaching, reaming, and grinding operations on stainless steel. It concludes with information on some of the nontraditional machining techniques, including abrasive jet machining, abrasive waterjet machining electrochemical machining, electron beam machining, and plasma arc machining.

This article discusses the properties of beryllium metals that require special attention when machining. It provides information on the considerations of S65 and selects 65 beryllium materials that are used for conducting tool wear studies and surface damage studies. The article highlights some of the precautions to be followed while machining beryllium metals. Information on the cutting oils, cutting tools, and speeds and feeds used in turning the beryllium are also provided. The article describes the chemical milling and photochemical machining methods that are used for etching beryllium components.

Electrochemical machining (ECM) is the controlled removal of metal by anodic dissolution in an electrolytic cell in which the workpiece is the anode and the tool is the cathode. This article begins with a description of the ECM system and then discusses the primary variables that affect current density and the material removal rate in the ECM process. It reviews the various characteristics of electrolytes and considers tool material and design. It also provides an overview of the properties of the workpiece and defines the surface finish and accuracy of an electrochemically machined sample. The variety of work done by electrochemical machining is also exemplified in the article.

Photochemical machining (PCM), also known as chemical blanking, is a metal-etching process that uses a photoresist to define the locations where the metal will be etched. This article describes the major steps used in the PCM process, namely, the preparation of the phototool, selection of the metal, preparation of the workpiece, masking with photoresists, etching, and stripping and inspection. The article reviews various design considerations for the PCM process. These include dimensional limitations, tolerances, and edge quality. The article also discusses the advantages, disadvantages, and applications of the PCM process.