Dew-point corrosion occurs when gas is cooled below the saturation temperature pertinent to the concentration of condensable species contained by a gas. This article discusses dew-point corrosion problems in the susceptible areas of dry flue gas handling systems. The corrosion problems associated with the nitrate stress-corrosion cracking in heat-recovery steam generators are also discussed. The article presents general comments on the materials selection; plant operation; use of neutralizing additives; and maintenance, good housekeeping, and lagging (insulation). It concludes with information on guidance for maintaining specific sections of the plant.

This article briefly describes water and steam chemistry, which influence the effect of corrosion in boilers. The appropriate control measures to prevent corrosion in boilers are also presented. The article provides a discussion on the common causes of fluid-side corrosion such as flow-accelerated corrosion, oxygen pitting, chelant corrosion, caustic corrosion, acid corrosion, organic corrosion, phosphate corrosion, hydrogen damage, and corrosion-assisted cracking.

This article illustrates typical wear and friction issues encountered in gas and steam turbines and their consequences as well as commonly adopted materials solutions. It contains tables that present the summary of wear and friction related issues encountered in steam turbines and gas turbines. The article outlines the differences in the operating conditions and the nature of the components involved in gas and steam turbines. It discusses the constraints and applicable coating solutions for wear and friction issues, and concludes with a broad set of challenges that need to be addressed to improve performance and operability of gas and steam turbines.

This article discusses the methods of pulp production, pulp processing, pulp bleaching, and paper manufacturing. It describes various types of digesters, their construction materials, the corrosion problems encountered, and methods to protect these digesters from corrosion. The article examines the corrosion problems in high-yield mechanical pulping, sulfite process, neutral sulfite semichemical pulping, chemical recovery, tall oil plants, wastewater treatment, and recovery boilers. It explains the stages of chlorine-based and nonchlorine bleaching, process water reuse for elemental chlorine-free and nonchlorine bleaching stages, selection of material for bleaching equipment, developments in oxygen bleaching, and the use of highly corrosion-resistant materials for bleach plant equipment. The article reviews the materials used in the construction of paper machine components and specific corrosion problems that affect them. It discusses the composition and corrosive nature of white water. The article also addresses the corrosion and chemical recovery associated with kraft pulping liquors.

Failures in boilers and other equipment taking place in power plants that use steam as the working fluid are discussed in this article. The discussion is mainly concerned with failures in Rankine cycle systems that use fossil fuels as the primary heat source. The general procedure and techniques followed in failure investigation of boilers and related equipment are discussed. The article is framed with an objective to provide systematic information on various damage mechanisms leading to the failure of boiler tubes, headers, and drums, supplemented by representative case studies for a greater understanding of the respective damage mechanism.

Annealing is an essential treatment in the fabrication of metal parts and semiproducts. This article discusses the processes involved in annealing, namely, recovery, recrystallization, and grain coarsening. It lists the heat treatment conditions of processed aluminum alloys. It provides information on the types of heat treatment, which include preheating, full anneal, stabilization, and stoving. The article describes the steps involved for achieving the age-hardening effect and the strongest hardening effect in aluminum. The steps to increase the strength of aluminum alloys by extremely fine, dispersed second-phase particles are: solution heat treatment, quenching, and age hardening. Finally, the article also discusses the process parameters of annealing, including the effect of strain, effect of temperature, effect of heating rate, and the effect of alloy elements, and the effect of annealing on anisotropy.

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 begins with a discussion on the driving forces for recycling composites. It reviews the recycling process of thermoset-matrix composites and thermoplastic-matrix composites. The recycling of thermoset-matrix composites includes regrind, chemical, energy recovery, and thermal processes. Thermoplastic-matrix composites are recycled by regrinding, compounding/blending and reprocessing. The article concludes with discussion on the properties of recycled composite fibers.

This article explains the main types and characteristic causes of failures in boilers and other equipment in stationary and marine power plants that use steam as the working fluid with examples. It focuses on the distinctive features of each type that enable the failure analyst to determine the cause and suggest corrective action. The causes of failures include tube rupture, corrosion or scaling, fatigue, erosion, and stress-corrosion cracking. The article also describes the procedures for conducting a failure analysis.

This article discusses postconsumer plastics recyclate quantities, the classification of plastics recycling into primary, secondary, tertiary, and quaternary categories, and how the life cycle of plastics is affected by recycling. The recycling processes of polyethylene terephthalate (PET), which accounts for the largest percentage of plastic recycling, high-density polyethylene (HDPE) plastics, the other large-volume plastic recyclate, as well as vinyl resins and polycarbonate resins are described. The life cycle of plastics has four phases: poly formation, part fabrication, product service, and disposal. Landfilling is still the primary method of final disposal, and incineration is another option, but recycling has become a viable alternative. The article presents a comparison between secondary and tertiary recycling.

This article focuses on high-temperature corrosion in synthetic gas (syngas) coolers. Extensive laboratory corrosion studies on both model and commercial alloys are summarized. The article describes the material selection criteria for long-term performance of materials in service. It provides information on the fuels with chlorine contents used in gasification plants.

Heat exchangers are devices used to transfer thermal energy between two or more fluids, between a solid surface and a fluid, or between a solid particulate and a fluid at different temperatures. This article first addresses the causes of failures in heat exchangers. It then provides a description of heat-transfer surface area, discussing the design of the tubular heat exchanger. Next, the article discusses the processes involved in the examination of failed parts. Finally, it describes the most important types of corrosion, including uniform, galvanic, pitting, stress, and erosion corrosion.

This article describes various quenchants, namely, water and inorganic salt solutions, polymers (polyvinyl alcohol, polyalkylene glycol, polyethyl oxazoline, polyvinyl pyrrolidone and sodium polyacrylates), quench oils, and molten salts, which are used for heat treatment of ferrous alloys. It also provides information on the steps for controlling quenching performance for polymer quenchants and oils with an emphasis on measuring quenchant performance, safety measures, and oxidation.

Tantalum is one of the most versatile corrosion-resistant metals known. The outstanding corrosion resistance and inertness of tantalum are attributed to a very thin, impervious, protective oxide film that forms on exposure of the metal to slightly anodic or oxidizing conditions. This article provides a discussion on the mechanism of corrosion resistance and on the behavior of tantalum in different corrosive environments, namely, acids; salts; organic compounds; reagents, foods, and pharmaceuticals; body fluids and tissues; and gases. It contains several tables that summarize the effects of acids, salts, and miscellaneous corrosive reagents on tantalum and applications for tantalum equipment in chemical, pharmaceutical, and other industries. Finally, the article presents a discussion on hydrogen embrittlement, the galvanic effects, and cathodic protection of tantalum and describes the corrosion resistance of different types of tantalum-base alloys.

This article emphasizes short-term tension and compression testing of metals at high temperatures. It describes the effect of temperature on deformation and strain hardening, occurrence of high-temperature creep in structural alloys, and the performing of mechanical testing for high-temperature structural alloys. The article discusses hot tension testing and measurements of temperature and strain in the hot tension testing. It also provides an overview of hot compression testing.

Stress-corrosion cracking (SCC) is a form of corrosion and produces wastage in that the stress-corrosion cracks penetrate the cross-sectional thickness of a component over time and deteriorate its mechanical strength. Although there are factors common among the different forms of environmentally induced cracking, this article deals only with SCC of metallic components. It begins by presenting terminology and background of SCC. Then, the general characteristics of SCC and the development of conditions for SCC as well as the stages of SCC are covered. The article provides a brief overview of proposed SCC propagation mechanisms. It discusses the processes involved in diagnosing SCC and the prevention and mitigation of SCC. Several engineering alloys are discussed with respect to their susceptibility to SCC. This includes a description of some of the environmental and metallurgical conditions commonly associated with the development of SCC, although not all, and numerous case studies.

Gallium-base components can be found in a variety of products ranging from compact disk players to advanced military electronic warfare systems, owing to the factor that it can emit light, has a greater resistance to radiation and operates at faster speeds and higher temperatures. This article discusses the uses of gallium in optoelectronic devices and integrated circuits and applications of gallium. The article discusses the properties and grades of gallium arsenide and also provides information on resources of gallium. The article talks about the recovery techniques, including recovery from bauxite, zinc ore and secondary recovery process and purification. The article briefly describes the fabrication process of gallium arsenide crystals. Furthermore, the article gives a short note on world supply and demand of gallium and concludes with research and development on gallium arsenide integrated circuits.

This article focuses on the specific aspects of nitinol that are of interest to medical device designers. It describes the physical metallurgy, physical properties, and tensile properties of the nitinol. The article discusses the factors influencing superelastic shape memory effects, fatigue, and corrosion in medical device design. It reviews the biocompatibility of nitinol based on corrosion behavior. The article explains the general principles, potential pitfalls, and key properties for manufacturing, heat treatment, and processing of nitinol.

Control of temperature and furnace atmospheres has become increasingly critical to successful heat treating. Temperature instrumentation and control systems used in heat treating include temperature sensors, controllers, final control elements, measurement instruments, and set-point programmers. This article describes these items and discusses the classifications and control of furnace atmospheres. The article also describes the surface carbon control devices available for the wide variety of furnace atmospheres and evaluation of carbon control. Finally, the article provides a set of guidelines for safety procedures that are common to all industrial heat treating furnace installations.