This article describes the safety precautions required for using laboratory equipment. It reviews the various personal protective equipment specified on the Material Safety Data Sheets (MSDS) for laboratory chemicals and products. The article provides information on the storage and handling of etchants, solvents, acids, bases, and other chemicals. It describes the safety precautions and procedures for handling concentrated and dilute hydrofluoric acid. The article concludes with a discussion on the precautions to be followed in the event of spills and cleanup.

The liquid nitriding process has several proprietary modifications and is applied to a wide variety of carbon steels, low-alloy steels, tool steels, stainless steels, and cast irons. This article discusses the applications, subclassifications, operating procedures, and maintenance procedures, as well as the equipment used (salt bath furnaces) and safety precautions to be undertaken during the liquid nitriding process. It describes the different types of liquid nitriding process, namely, liquid pressure nitriding, aerated bath nitriding, and liquid nitrocarburizing. Environmental considerations and the increased cost of detoxification of cyanide-containing effluents have led to the development of low-cyanide salt bath nitrocarburizing treatments. The article reviews the wear and antiscuffing characteristics of the compound zone produced in salt baths with the help of Falex scuff test.

This article describes the advantages of martempering and the use of oil and salt as quenchants in the martempering process. It also discusses safety precautions to be followed by an operator and reviews the steels that are suitable for martempering. The article provides information on the importance of controlling process variables in martempering, including austenitizing temperature, temperature of the martempering bath, time in the bath, salt contamination, water additions to salt, agitation, and the rate of cooling from the martempering bath. It also describes specific situations in which distortion problems have been encountered during martempering. The article contains tables that indicate typical applications of martempering in salt and oil by listing commonly treated steel parts and giving details of martempering procedures and hardness requirements. The article also lists equipment requirements for oil and salt martempering of steel.

This article summarizes the terminology for gas reactions, and discusses low-temperature nitriding and nitrocarburizing of stainless steels. It describes the various nitriding processes, namely, high- and low-pressure nitriding, oxynitriding, sulfonitriding, oxysulfonitriding, ferritic nitrocarburizing and austenitic nitrocarburizing. The article includes a discussion on the difficulties in specimen cleaning, importance of furnace purge, uses of pre and post oxidation, depassivation, or activation, and requirements for perfect nucleation in nitriding process. In nitriding, the successful atmosphere control depends on various potentials. The article summarizes the methods of measuring potentials in nitriding and nitrocarburizing, provides useful information on the furnaces used, and the safety precautions to be followed in the nitriding process. It also describes the sample preparation procedures and testing methods to ensure the quality of the sample.

This article addresses dies and die materials used for hot forging in vertical presses, hammers, and horizontal forging machines (upsetters). It reviews the properties of die materials for hot forging, including good hardenability, resistance to wear, plastic deformation, thermal fatigue, and mechanical fatigue. The article describes heat treating practices commonly employed for chromium- and tungsten-base AISI hot-work tool steels. It discusses the fabrication of impression dies, and the advantages and disadvantages of cast dies. The article concludes with a discussion on the factors that affect die life and safety precautions to be considered during die construction.

This article describes various machining techniques of refractory metals, namely, niobium, molybdenum, tantalum, and tungsten. These include turning, boring, trepanning, reaming, milling, tapping, drilling, and sawing. Parameters for the machining of the refractory metals are also tabulated. In addition, the article provides information on cutting fluids and tools that are used in machining of the refractory metals as well as on the safety precautions to be followed in the machining process.

Sawing is the process of cutting a workpiece with power band saws, hacksaws, and circular saws. This article discusses the process capabilities and limitations of band sawing. It provides information on band sawing machines, their fixtures and attachments, band construction and materials, blade design, and cutting fluids associated with the band sawing process. The article also discusses the variables considered in band saw machining. In addition, it presents examples representing the comparison of contour band sawing with milling and shaping in various applications. The article concludes with a discussion on the safety precautions to be followed during band sawing and on friction band sawing, circular sawing, and hacksawing.

This article serves as a basic information source for those interested in accomplishing one-sided, no-hole attachment of metal fasteners. The stud arc-welding process is a substitute for fastening procedures such as drilling and tapping, bolting, and self-tapping screws. The article describes the operating principle of, and the tooling and equipment used for, the welding process. It contains tables that present information on the mechanical properties of aluminum, stainless steel, and low-carbon steel stud arc welded fasteners. The article details the different tests conducted to ensure the quality of stud arc-welded fasteners. It concludes with information on safety precautions to be followed in the welding process.

Resistance spot welding (RSW) is the most widely used joining technique for the assembly of sheet metal products. This article discusses the process description, evaluation methods, and applications of RSW. It describes the equipment needed for RSW and explicates the major functions of electrodes in RSW and effect of surface condition on the technique. The article concludes with information on the safety precautions to be followed during the welding process.

The gas tungsten arc welding (GTAW) process derives the heat for welding from an electric arc established between a tungsten electrode and the part to be welded. This article provides a discussion on the basic operation principles, advantages, disadvantages, limitations, and applications of the process. It describes the equipment used for GTAW, namely, power supplies, torch construction and electrodes, shielding gases, and filler metals as well as the GTAW welding procedures. The article concludes with a review of the safety precautions to avoid possible hazards during the GTAW process: electrical shock, fumes and gases, arc radiation, and fire and explosion.

This article provides a description of the classification, industrial applications, microstructures, physical, chemical, corrosion, and mechanical properties of zirconium and its alloys. It discusses the formation of oxide films and the effects of water, temperature, and pH on zirconium. The delayed hydride cracking of zirconium is also described. The article provides information on the resistance of zirconium to various types of corrosion, including pitting corrosion, crevice corrosion, intergranular corrosion, galvanic corrosion, microbiologically induced corrosion, erosion-corrosion, and fretting corrosion. The article explains the effects of tin content in zirconium and effects of fabrication on corrosion. Corrosion control measures for all types of corrosion are also highlighted. The article concludes with information on the safety precautions associated with handling of zirconium.

Brazing technology is continually advancing for a variety of metals including aluminum and its alloys and nonmetals. This article discusses the key physical phenomena in aluminum brazing and the materials for aluminum brazing, including base metals, filler metals, brazing sheet, and brazing flux. It describes various aluminum brazing methods, such as furnace, vacuum, dip, and torch brazing. Friction, flow, induction, resistance, and diffusion brazing are some alternate brazing methods discussed. The article reviews the brazing of aluminum to ferrous alloys, aluminum to copper, and aluminum to other nonferrous metals. It also discusses post-braze processes in terms of post-braze heat treatment and finishing. The article concludes with information on the safety precautions considered in brazing aluminum alloys.

This article reviews the performance of power electronics components, namely, power rectifiers, insulated-gate bipolar transistors, metal-oxide semiconductor field-effect transistors, diodes, and silicon-controlled rectifiers. It provides information on induction heating power supplies with multiple heat stations, such as switching units and multiple (zone) outputs. The article describes power supply operational control and power supply protection circuits. It details duty cycle, power factor, and harmonics of power supplies. The article also describes system parameters, software analysis-calculations, human analysis-decisions, multiple system arrangements, and zone control systems for power supply selection. It provides information on the maintenance of induction power supplies, detailing the safety precautions to be taken and the need for routine inspection and servicing.

Aluminum, a commonly used base material for brazing, can be easily fabricated by most manufacturing methods, such as machining, forming, and stamping. This article outlines non-heat-treatable wrought alloys typically used as base metals for the brazing process. It highlights chloride-active and fluoride-active types of fluxes that are used for torch, furnace, or dip brazing processes. The article explains the steps to be performed, including the designing of joints, preblaze cleaning, assembling, brazing techniques (dip brazing, furnace and torch brazing, fluxless vacuum brazing), flux removal techniques, and postbraze heat treatment processes. It concludes with information on the safety precautions to be followed during the brazing process.

This article describes the dip brazing process and the principal types of furnaces used for molten-salt-bath dip-brazing applications. It provides information on equipment maintenance, which is divided into temperature control, control of the liquid, and maintenance of the vessel. The article presents the typical salts used for molten-salt dip brazing of carbon and low-alloy steels with selected filler metals in tabular form. It concludes with information on dip brazing of stainless steels, cast irons, and aluminum alloys and safety precautions of the process.

Mechanical cleaning systems are used to remove contaminants of work surface by propelling abrasive materials through any of these three principal methods: airless centrifugal blast blade- or vane-type wheels; compressed air, direct-pressure dry blast nozzle systems; or compressed-air, indirect-suction (induction) wet or dry blast nozzle systems. This article focuses on the abrasive media, equipment, applications, and limitations of dry and wet blast cleaning. It discusses the health and safety precautions to be taken during mechanical cleaning.

This article focuses on the types, composition, and applications of phosphate coatings and describes the characteristics of phosphate-coated ferrous and nonferrous materials, including steel and aluminum. It addresses five successive process fundamentals: cleaning, rinsing, phosphating, rinsing after phosphating, and chromic acid rinsing. The article describes the techniques for controlling the chemical composition of various phosphating solutions. It discusses the equipment and factors that influence equipment requirements in immersion and spray systems. The article also describes the controlling procedures of coating weight and crystal size. It provides guidelines for choosing phosphate coatings based on application, coating weight requirements, and recommended process parameters. The article concludes with a discussion on safety precautions and the treatment of effluents from phosphating plants.

Mass finishing normally involves loading components to be finished into a container together with abrasive media, water, and compound. This article focuses on basic mass finishing processes, including barrel finishing, vibratory finishing, centrifugal disc and barrel finishing, spindle finishing, and drag finishing. It describes the various factors considered in selecting the most suitable mass finishing process. The article also provides information on consumable materials, process considerations, safety precautions, and waste disposal of mass finishing processes.

Surface treatments are applied to magnesium parts primarily to improve their appearance and corrosion resistance. Mechanical and chemical cleaning methods are used singly or in combination, depending on the specific application and product involved to ensure repetitive reliability. This article focuses on mechanical finishing methods, namely, barrel tumbling, polishing, buffing, vibratory finishing, fiber brushing, and shot blasting. It provides useful information on process control and difficulties with chemical and anodic treatments of magnesium alloys. The use and applications of plating and organic finishing of magnesium alloys are also reviewed. The article concludes with a description of health and safety precautions to be followed during the surface treatment process.

This article provides information on the liquid lithium systems that are exposed to liquid metal. It discusses the forms in which liquid-metal corrosion is manifested. The influence of several key factors on the corrosion of metals and alloys by liquid-metal systems or liquid-vapor metal coolants is described. Some information on safety precautions for handling liquid metals, operating circulating systems, dealing with fire and spillage, and cleaning contaminated components, are also provided.