This chapter discusses five forms of mechanically assisted degradation of metals: erosion, fretting, fretting fatigue, cavitation and water drop impingement, and corrosion fatigue. Emphasis is placed on the mechanisms and the factors affecting these forms of degradation.

This chapter presents the primary considerations and mechanisms for corrosion and how they are involved in the selection of materials for process equipment in petroleum refineries and petrochemical plants. In addition, specific information on mechanical properties, corrosion, sulfide stress cracking, hydrogen-induced cracking, stress-oriented hydrogen-induced cracking, hydrogen embrittlement cracking, stress-corrosion cracking, velocity-accelerated corrosion, erosion-corrosion, and corrosion control is provided.

Corrosion problems can be divided into eight categories based on the appearance of the corrosion damage or the mechanism of attack: uniform or general corrosion; pitting corrosion; crevice corrosion, including corrosion under tubercles or deposits, filiform corrosion, and poultice corrosion; galvanic corrosion; erosion-corrosion, including cavitation erosion and fretting corrosion; intergranular corrosion, including sensitization and exfoliation; dealloying; environmentally assisted cracking, including stress-corrosion cracking, corrosion fatigue, and hydrogen damage (including hydrogen embrittlement, hydrogen-induced blistering, high-temperature hydrogen attack, and hydride formation). All these forms are addressed in this chapter in the context of aqueous corrosion. For each form, a general description is provided along with information on the causes and the list of metals that can be affected, with particular emphasis on the recognition and prevention measures.

This chapter outlines the step-by-step processes by which materials are selected in order to prevent or control corrosion and includes information on materials that are resistant to the various forms of corrosion. The various forms of corrosion covered are general (uniform) corrosion, localized corrosion, galvanic corrosion, intergranular corrosion, stress-corrosion cracking, hydrogen damage, and erosion-corrosion. In addition, the economic importance of cost-effective materials selection is also considered.

Austenitic stainless steels exhibit a single-phase, face-centered cubic structure that is maintained over a wide range of temperatures. This chapter provides a basic understanding of grade designations, properties, and welding considerations of austenitic stainless steels. It also discusses general types of corrosive attack and their effects on service integrity as well as detection and control measures. The five corrosive attack mechanisms covered are intergranular corrosion, preferential attack associated with weld metal precipitates, pitting and crevice corrosion, stress-corrosion cracking, and microbiologically influenced corrosion.

Boilers are often classified based on the maximum operating temperature and pressure for which they are designed. Classifications, in ascending order, are subcritical, supercritical, ultra-supercritical, and to advanced ultra-supercritical. At each higher operating point comes greater efficiency, as well as greater demand on construction materials. This chapter discusses the primary requirements for boiler tube materials, including oxidation and corrosion resistance, fatigue strength, thermal conductivity, and the ability to resist creep and rupture. It also provides information on various steels and alloys, covering cost, engineering specifications, and ease of use.

This chapter discusses the corrosion behavior of titanium, the types of corrosion that can occur, and the effect of alloying on corrosion resistance. It explains that, due to its tenacious oxide film, titanium has excellent corrosion resistance in oxidizing environments and that the resistance can be extended into the “reducing-acid” region by adding a small amount of palladium. It describes how different grades of titanium respond to different forms of attack, including uniform, crevice, and galvanic corrosion. It also identifies applications where corrosion is often a concern.

The design process is the first and most important step in corrosion control. Major savings in operating costs are possible by anticipating corrosion problems so as to provide proper design for equipment before assembly or construction begins. This chapter describes the role of the design team in producing a successful final design, general considerations in corrosion-control design, and design details that accelerate corrosion. The details that must be considered when attempting to control corrosion by design include plant/site location, plant environment, component/assembly shape, fluid movement, surface preparation and coating procedures, and compatibility, insulation, and stress considerations. Design solutions for specific forms of corrosion, namely crevice corrosion, galvanic corrosion, erosion-corrosion, and stress-corrosion cracking, are then considered. A brief section is devoted to the discussion on corrosion allowance used for steel parts subject to uniform corrosion. Finally, the chapter describes the design considerations for using weathering steels.

Many metallic components, such as retorts in heat treat furnaces, furnace heater tubes and coils in chemical and petrochemical plants, waterwalls and reheater tubes in boilers, and combustors and transition ducts in gas turbines, are subject to oxidation. This chapter explains how oxidation affects a wide range of engineering alloys from carbon and Cr-Mo steels to superalloys. It discusses the kinetics and thermodynamics involved in the formation of oxides and the effect of surface and bulk chemistry. It provides oxidation data for numerous alloys and intermetallics in terms of weight gain, metal loss, depth of attack, and oxidation rate. It also discusses the effect of metallurgical and environmental factors such as oxygen concentration, high-velocity combustion gas streams, chromium depletion and breakaway, component thickness, and water vapor.

This chapter describes two types of auxiliary equipment required in most induction heating installations: cooling systems and device timers. Water- and vapor-based systems used for cooling the power supply and the induction coil are described. The chapter concludes with a brief discussion of timers, with emphasis on open-loop timing systems.

Water chemistry is a factor in nearly all boiler tube failures. It contributes to the formation of scale, biofilms, and sludge, determines deposition rates, and drives the corrosion process. This chapter explains how water chemistry is managed in boilers and describes the effect of impurities and feedwater parameters on high-pressure boiler components. It discusses deposition and scaling, types of corrosion, and carryover, a condition that occurs when steam becomes contaminated with droplets of boiler water. The chapter also covers water treatment procedures, including filtration, chlorination, ion exchange, demineralization, reverse osmosis, caustic and chelant treatment, oxygen scavenging, and colloidal, carbonate, phosphate, and sodium aluminate conditioning.

This article discusses the composition, properties, and behaviors of copper and its alloys. It begins with an overview of the characteristics, applications, and commercial grades of wrought and cast copper. It then discusses the role of alloying, explaining how zinc, tin, aluminum, silicon, and nickel affect the physical and mechanical properties of coppers and high-copper alloys as well as brasses, bronzes, copper-nickels, and nickel silvers. It also explains how alloying affects electrical conductivity, corrosion resistance, stress-corrosion cracking, and processing characteristics.

The challenge of materials selection is to achieve adequate performance at the lowest possible cost. Corrosion resistance is not the only property to be considered in making materials selections. Typical requirements and some of the procedures involved in making a selection and some of the factors that must be considered when determining the corrosion performance of a given material are listed in this chapter. The various steps that might be included in a materials selection process are then examined. These include a review of operating conditions and design, the selection of candidate materials, the in-depth evaluation of each candidate material, fabrication requirements, follow-up monitoring, and final materials selection. Material considerations such as cost, materials properties, and processing and fabrication requirements are subsequently covered. Finally, the chapter provides information on materials selection under general corrosion conditions and under conditions of localized corrosion forms such as pitting, crevice corrosion, and stress-corrosion cracking.

This chapter explains how mechanical processes, including erosion, cavitation, impingement, and fretting, contribute to the effects of corrosion in aluminum alloys. It describes the two main types of erosion-corrosion and the factors involved in cavitation and liquid impingement erosion along with testing and prevention methods. It also provides information on fretting corrosion and fretting fatigue.

This chapter describes the advanced ceramic materials that include both noncomposite, or monolithic, ceramics (for example, oxides, carbides, nitrides, and borides) and ceramic-matrix composites (CMCs). It describes the rationale for use of ceramics and intrinsic limitations of ceramics. The chapter presents four key considerations that must be taken into account when carrying out tensile tests on advanced monolithic ceramics and CMCs. These include effects of flaw type and location on tensile tests, separation of flaw populations, design strength and scale effects, and lifetime predictions and environmental effects. The chapter discusses the advantages, problems, and complications of four basic categories of tensile testing techniques as applied to ceramics and CMCs. These categories are true direct uniaxial tensile tests at ambient temperatures, indirect tensile tests, tests where failure is presumed to result from tensile stresses, and high-temperature tensile tests.

The hot-working process extrusion is used to produce semifinished products in the form of bar, strip, and solid sections, as well as tubes and hollow sections. The first part of this chapter describes the composition, properties, and applications of tin and lead extruded products with a deformation temperature range of 0 to 300 deg C and magnesium and aluminum extruded products with a working temperature range of 300 to 600 deg C. The second part focuses on copper alloy extruded products, extruded titanium alloy products, and extruded products in iron alloys with a working temperature range of 600 to 1300 deg C.

This chapter discusses the maintenance needs of major components in induction heat-treating systems, including power supplies, heat stations, capacitors, high-frequency output stages, induction coils, water systems, quench systems, and fixturing.

This chapter addresses the general effects of composition, mechanical treatment, surface treatment, processing, and fabrication operations on the corrosion resistance of aluminum and its alloys. Different types of surface treatments covered include claddings, anodizing, and conversion coatings. The processing steps that can have relatively significant impact on corrosion resistance are homogenization, rolling, extrusion, quenching, aging, and annealing.

This chapter examines boiler tube failures attributed to operation-related causes. It discusses failures due to rapid start-ups, excessive load swing, excessive heat inputs, poor water chemistry control, and water-treatment methods.