The primary market for metal powder is the production of powder metallurgy (PM) parts, which are dominated primarily by iron and copper powders. This article reviews the chemical and pyrotechnics applications of ferrous and nonferrous powders. It describes the characteristics of iron powder used in oxygen scavengers and chemical reactive warmers and heaters. Metal powders used as fuels in solid propellants, pyrotechnic devices, explosives, and similar applications are reviewed. Atomized aluminum, magnesium, tungsten, and zirconium powders are also discussed.

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.

Vacuum heat treating consists of thermally treating metals and alloys in cylindrical steel chambers that have been pumped down to less than normal atmospheric pressure. This article provides a detailed account of the operations and designs of vacuum furnaces, discussing their pressure levels, resistance heating elements, quenching systems, work load support, pumping systems, and temperature control systems. It describes the classification of instruments used for measuring and recording pressure inside a vacuum processing chamber. Common devices include hydrostatic measuring devices and devices for measuring thermal and electrical conductivity. The article also describes the applications of the vacuum heat treating process, namely, vacuum nitriding and vacuum carburizing. Finally, it reviews the heat treating process of tool steels, stainless steels, Inconel 718, and titanium and its alloys.

This article provides a rough estimate of the basic parameters, including coil efficiency, power, and frequency in induction heating of billets, rods, and bars. It focuses on the frequency selection for heating solid cylinders made of nonmagnetic metals, frequency selection when heating solid cylinders made from nonmagnetic alloys, and frequency selection when heating solid cylinders made from magnetic alloys. The article describes several design concepts that can be used for induction billet heating, namely, static heating and progressive/continuous heating. It presents the four major factors associated with the location and magnitude of subsurface overheating: frequency, refractory, final temperature, and power distribution along the heating line. The article summarizes the pros and cons of using a single power supply. It also reviews the design features of modular systems, and concludes with information on the temperature profile modeling software.

Thermal spray processes involve complete or partial melting of a feedstock material in a high-temperature flame, and propelling and depositing the material as a coating on a substrate. This article describes the properties of sprayed electronic materials, including dielectrics, conductors, and resistors, and discusses their implications and associated limitations for device applications and potential remedial measures. The article presents specific examples of electrical/electronic device applications, including electromagnetic interference/radio-frequency interference shielding, planar microwave devices, waveguide devices, sensing devices, solid oxide fuel cells, heating elements, electrodes for capacitors and other electrochemical devices.

This article addresses the major heat-transfer components of the water-steam loop of a power plant. It describes the various types of condensers, including water-cooled condensers and air-cooled condensers. The article explains the corrosion mechanisms encountered in the condensers, including erosion-corrosion, galvanic corrosion, and pitting corrosion. It discusses the types of deaerators and deals with their corrosion problems. The article provides a discussion on two types of feedwater heaters: channel feedwater heaters and header feedwater heaters. It summarizes the corrosion problems associated with common feedwater heater tube materials.

This article provides an overview of the capabilities of closed-die forging. One of the most important aspects of closed-die forging is proper design of preforming operations and of blocker dies to achieve adequate metal distribution. The article describes the effects of friction and lubrication in forging. It discusses the types of closed-die forgings, namely, blocker-type, conventional, and close-tolerance. The article illustrates the classification of forging shapes and explains how to predict the forging pressure and the control of die temperature during closed-die forging. It explains the use of heating equipment for closed-die forging and tabulates the maximum safe forging temperatures for carbon and alloy steels. The article concludes with a discussion on a trimming method used for closed-die forgings.

This article describes the phenomena of crack initiation and early growth. It examines specimen design and preparation as well as the apparatus used in crack initiation testing. The article provides descriptions of the various commercially available fatigue testing machines: axial fatigue testing machines and bending fatigue machines. Load cells, grips and alignment devices, extensometry and strain measuring devices, environmental chambers, graphic recorders, furnaces, and heating systems of ancillary equipment are discussed. The article presents technologies available to accomplish closed loop control of materials testing systems in performing standard materials tests and for the development of custom testing applications. It explores the advanced software tools for materials testing. The article includes a description of baseline isothermal fatigue testing, creep-fatigue interaction, and thermomechanical fatigue. The effects of various variables on fatigue resistance and guidelines for fatigue testing are also presented.

This article reviews the common methods of shear and multiaxial testing for the evaluation of engineering components such as fasteners and mill products. It discusses shear test methods, including through-thickness tests, in-plane shear tests, and double-notched shear test. The article provides information on torsional (rotational shear) tests as well as the basic equipment and setup of torsion testing. Motors, twist and torque transducers, torque sensors, and heating systems as well as the specimen preparation procedure are also discussed.

Batch furnaces and continuous furnaces are commonly used in heat treating. This article provides a detailed account of various heat treating equipment and its furnace types, including salt bath equipment (externally heated, immersed-electrode and submerged-electrode furnaces), and fluidized-bed equipment (external-resistance-heated fluidized beds). It describes various auxiliary equipment used in cold-wall furnaces, namely, heating elements and pumping systems. Five types of heat-resistant alloys are used for furnace parts, trays, and fixtures: Fe-Cr alloys, Fe-Cr-Ni alloys, Fe-Ni-Cr alloys, nickel-base alloys and cobalt-base alloys. The article lists the recommended applications for alloys for parts and fixtures for various types of heat treating furnaces.