This article provides information on the salt baths used for a variety of heat treatments, including heating, quenching, interrupted quenching (austempering and martempering), case hardening, and tempering. It describes two general types of salt bath systems for steel hardening: the first type uses atmosphere austenitizing followed by salt quench and the second type employs austenitizing salt baths with rapid transfer to the quench salt. The article provides a detailed account on the construction, advantages and disadvantages, and limitations of isothermal quenching furnaces, submerged-electrode furnaces, immersed-electrode furnaces, and externally heated furnaces. It discusses the important applications of various furnace designs, including the austempering of ductile iron, the hardening of tool steels, and the isothermal annealing of high-alloy steels.

This article begins with a discussion on the environmental factors that induce corrosion in magnesium alloys. It reviews the factors that determine the severity of different forms of localized corrosion, namely, galvanic corrosion, corrosion fatigue, and stress-corrosion. The article discusses the corrosion protection in magnesium assemblies and the protective coating systems used in corrosion protection practices. The protection schemes for specific applications and production of novel magnesium alloys with improved corrosion resistance are also described. The article concludes with a discussion on corrosion of bulk vapor-deposited alloys and magnesium-matrix composites.

Electrodeposits of cadmium are used to protect steel and cast iron against corrosion. This article provides an overview of the surface preparation of, and brighteners used in, cyanide baths. It focuses on the anode system, current density, deposition rates, and bath temperature of cadmium plating with attention to the materials of construction and equipment used. The article provides a description of the selection of plating method with examples, applications, and several postplating processes of cadmium plating.

Polyaspartic coating technology has found utility in a variety of coating applications, including corrosion protection and flooring topcoats, as these coatings are based on aliphatic polyisocyanates and aliphatic diamines. This article describes the chemistry of polyaspartic esters and curing characteristics and performance properties of polyaspartic coatings. It also provides information on curing corrosion protection coating systems, polyaspartic floor coatings, and safe-use recommendations for handling isocyanates.

Radiography is the process or technique of producing images of a solid material on a paper/photographic film or on a fluorescent screen by means of radiation particles or electromagnetic waves of short wavelength. This article reviews the general characteristics and safety principles associated with radiography. There are two main aspects of safety: monitoring radiation dosage and protecting personnel. The article summarizes the major factors involved in both and discusses the operating characteristics of X-ray tubes. It describes the various methods of controlling scattered radiation: use of lead screens; protection against backscatter and scatter from external objects; and use of masks, diaphragms, collimators, and filtration. The article concludes with a discussion on image conversion media, including recording media, lead screens, lead oxide screens, and fluorescent intensifying screens.

This article discusses the occupational health hazards related to industrial protective coating application and removal. It explains the health hazards associated with coating constituents such as lead, cadmium, chromium, arsenic, silica, and asbestos. The article also discusses hazard evaluation, hazard controls, Occupational Safety and Health Administration standards, and industry consensus standards. It concludes with a description of containment systems to prevent environmental exposures from industrial paint removal projects.

Polyurethane is any polymer consisting of a chain of repeating organic units joined by urethane linkages. Polyurethane polymers are formed through step-growth polymerization by making a monomer containing at least two isocyanate functional groups to react with another monomer containing at least two hydroxyl (alcohol) groups. This article provides a detailed account of the protective coatings used in the building, infrastructure, and architectural markets. It focuses on the various types of polyurethane coatings used in these applications: moisture-cure and two-pack aromatic coatings as primers and topcoats, moisture-cure aromatic elastomeric high-build coatings, moisture-cure aliphatic topcoats, two-pack aliphatic polyurethane coatings as topcoats, and one- and two-pack polyurethane dispersion coatings as sealers and topcoats. It also includes a section on the health effects of isocyanates.

This article reviews the steps involved in presurface-preparation inspection: substrate replacement; removal of weld spatter, rounding of sharp edges, and grinding of slivers/laminations; and removal of rust scale, grease, oil, and chemical (soluble salt) contamination. It focuses on surface preparation methods that range from simple solvent cleaning to hand and power tool cleaning, dry and wet abrasive blast cleaning, centrifugal wheel blast cleaning, chemical stripping, and waterjetting for the application of the coating system. In addition, the article provides a description of the Society for Protective Coatings' (SSPC) standards and NACE International standards as well as the International Organization for Standardization (ISO) standards and International Concrete Repair Institute (ICRI) guidelines for surface cleanliness.

Two-component polyurea elastomeric coating/lining systems are the newest technology in the protective coating/lining industry and a wide variety of applications have been developed. These include coating/lining applications over concrete, geotextile membranes, various metals for corrosion and decorative areas, and some plastics. This article discusses the formulation basics of polyurea technology and compares the technology to that of polyurethane and polyurethane/polyurea systems. It addresses performance issues and describes application processing considerations and safety practices of polyurea coating/lining systems.

This article focuses on marine coatings associated with protecting commercial and military vessels. It provides detailed information on the common issues and requirements encountered when coating ballast tanks, freeboard, topside, and decks of the vessel. The article describes the advent of ultra-high solids coatings technology, and reviews the marine-specific coatings such as antifouling and their mechanisms and common failure modes.

Acrylic coatings are one of the major generic classes of organic coatings and are prevalent in both architectural and industrial applications. This article provides information on the chemistry of acrylic polymers, the methods used in their manufacture, the relationship between structure and properties when they are formulated into coatings, and how they are being used in coatings. The main discussion points are the differences between solventborne and waterborne technologies and some of the challenges in formulating and applying waterborne acrylic coatings. The article describes the mechanism of film formation of acrylic latex polymers and its effect on final coating properties. It discusses the types of waterborne acrylic latex coatings based on chemical properties and based on applications such as primers, intermediate coats, topcoats, stains, and direct-to-substrate finishes. The article concludes with a description of the advances in the development of waterborne acrylic coatings for maintenance and protective applications.

This article presents a simple cost/pricing system that is reasonably accurate and could easily be recalculated if the yearly cost of any of the basic cost components change. Using the example of a commercial heat treating facility, the operational details are categorized as atmosphere processes, induction processes, aluminum processes, high-heat processes, and secondary processes. For the purpose of calculating the heat treatment processing cost per hour and the selling price for a piece of equipment, the costs are separated into direct costs, allocated costs, capitalized cost, and general and administrative costs. The article discusses the techniques involved in allocating costs to the group of equipment, and presents a description on the cost analysis of endothermic gas.

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.

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.

Solvent cleaning is a surface preparation process that can be accomplished in room temperature baths (cold cleaning ) or by condensing vapors of a solvent on a workpiece (vapor degreasing). This article provides a detailed discussion on solvents, equipment, process limitations and applications, and safety and health hazards of cold cleaning and vapor degreasing. It also includes information on control of contamination, conservation and recovery of solvent, and disposal of solvent wastes.

This article provides an insight into the cost estimation of painting projects for both contractors and others. The cost estimating methods include benchmarking, unit price estimating, developed pricing, market pricing, and critical path scheduling. The first step in developing an accurate estimate for an industrial painting contract is determining the scope of work. The article describes the method of calculating quantities of materials and labor, surface area takeoff, and equipment costs. It concludes by listing the forgotten costs and presenting information on coating condition assessment and determining selling cost.

Alkaline cleaning is a commonly used method for removing a wide variety of soils from the surface of metals. This article focuses on the composition, operating conditions, and test and control of alkaline cleaners, as well as equipment used and their application methods. It describes the mechanisms of alkaline cleaning, such as saponification, displacement, emulsification and dispersion, and metal oxide dissolution. The article concludes with information of the safety and environmental considerations in the usage of alkaline cleaners.

Heat treating furnaces require different control systems and integration for achieving optimum technical results and enabling safe operation. This article focuses on atmosphere furnaces, with some coverage on controls for vacuum furnaces. Heat treating operations require reliable monitoring and control of motion and position of various mechanical components with the help of mechanical limit switches, proximity sensors, and distance- and position-measuring devices. Using inputs from both flow meters and sensors, such as thermocouples and oxygen sensors, flow measurement control systems must be able to adjust the flow of gases for process optimization. The operator interface of a furnace-control system displays critical information such as the furnace temperature, atmosphere status, alarms, electronic chart recorders, recipe, and maintenance. A supervisory control and data-acquisition (SCADA) system is used to monitor, collect, and store data from multiple pieces of equipment.

This article describes the methods and equipments involved in the preparation of specimens for examination by light optical microscopy, scanning electron microscopy, electron microprobe analysis for microindentation hardness testing, and for quantification of microstructural parameters, either manually or by the use of image analyzers. Preparation of metallographic specimens generally requires five major operations: sectioning, mounting, grinding, chemical polishing, and etching. The article provides information on the principles of technique selection in mechanical polishing, and describes the procedures, advantages, and disadvantages of electrolytic and chemical polishing. It also provides a detailed account of procedures, precautions, and composition for preparation and handling of etchants.

Bitumen for coating usage can best be categorized as two fundamental but very different types: asphalts and coal tars. This article provides a detailed discussion on asphalt and coal tar hot-melt applications; asphalt and coal tar emulsions; asphalt and coal tar cutbacks; and coal tar epoxies. It reviews the similarities between asphaltic and coal tar coatings and discusses the health and environmental concerns of these materials.