This chapter is a detailed account of major sources of stray current that can cause corrosion and discusses several ways to prevent damage from stray-current corrosion.

This chapter discusses three related corrosion mechanisms, galvanic, deposition, and stray-current corrosion, explaining why they occur and how they affect the corrosion process. It includes information on testing and prevention methods along with examples of the type of damage associated with these corrosion mechanisms.

This chapter discusses the most common causes and contributing factors for external corrosion and stress-corrosion cracking on oil and natural gas pipelines, as well as describes procedures for prevention, mitigation, detection, assessment, and repair. The forms of external corrosion covered include differential cell corrosion, microbiologically influenced corrosion, and stray current corrosion.

Corrosion can be defined as a chemical or electrochemical reaction between a material and its environment that causes the material and its properties to degrade. In most cases, it refers to the electrochemical oxidation of metals accompanied by the production of oxides or salts of the base material. This chapter discusses the process of corrosion and how to prevent or mitigate its effects. It describes several forms of corrosion, including uniform, intergranular, pitting, crevice, and stray-current corrosion, and the effects of stress-corrosion cracking, corrosion fatigue, and selective leaching. It discusses the use of corrosion inhibitors, cathodic and anodic protection, pH control, and Pourbaix diagrams.

This article describes in detail the process of corrosion control by cathodic and anodic protection. The discussion covers the basic concept of cathodic and anodic protection systems, their types and equipment used, and the advantages, limitations, and applications of these protection systems. The types of cathodic protection systems include sacrificial cathodic protection and impressed-current cathodic protection systems. Some of the technical problems associated with cathodic protection include the effects of stray currents on the corrosion of adjacent metal structures, the effects of the chemical reactions occurring at the surface of the protected structure, and the effects of cathodic protection on coatings.

Corrosive environments can be broadly classified as atmospheric, underground/soil, water, acidic, alkaline, and combinations of these. Complicating matters is the fact that there are important variables, for example, pH, temperature, and the presence of biological organisms, that can significantly alter the response of the material in a given environment. This chapter provides a detailed account of all these types of corrosion affecting various industries, pointing out the connection between the characteristics of the corrosive environment that control corrosion behavior, the corrosion characteristics of various metals and materials systems, and the subsequent corrosion response.

This chapter provides an introduction to various forms of corrosion, namely uniform corrosion, localized corrosion, mechanically assisted degradation, environmentally induced cracking, microbiologically influenced corrosion, and metallurgically influenced corrosion.

This chapter focuses on various factors to be considered at design stage to minimize corrosion. It begins by providing information on design considerations and general corrosion awareness. This is followed by a description of several factors influencing materials-component failure. Details on design and materials selection, which assist in controlling corrosion, are then provided. The chapter ends with a discussion on the design factors that influence corrosion.

This appendix is a compilation of terms and definitions related to corrosion.

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.

Aluminum generally has excellent resistance to corrosion and gives years of maintenance-free service in natural atmospheres, fresh waters, seawater, many soils and chemicals, and most foods. This chapter explains why aluminum and aluminum alloys are naturally resistant to corrosion and describes the conditions and circumstances under which their natural defenses break down. It discusses the causes and forms of corrosion observed in aluminum alloys and the effect of composition, microstructure, processing history, and environmental variables such as impurities, fluid flow, surface area, pressure, and temperature.

This chapter provides a brief account of galvanic corrosion, which occurs when a metal or alloy is electrically coupled to another metal or conducting nonmetal in the same electrolyte. It begins by describing the galvanic series of metals and alloys useful for predicting galvanic relationships, followed by a brief section on polarization of metals or alloys. The effects of area, distance, and geometric shapes on galvanic-corrosion behavior are then discussed. Various alloys susceptible to galvanic corrosion are briefly reviewed. The chapter also discusses various modes of attack that lead to galvanic corrosion, along with methods for predicting and controlling galvanic corrosion.

This chapter discusses the particular corrosion problems encountered and the methods of control used in petroleum production and the storage and transportation of oil and gas up to the refinery. It begins by describing those aspects of corrosion that tend to be unique to corrosion as encountered in applications involving oil and gas exploration and production. This is followed by a section reviewing the methods of corrosion control, namely the proper selection of materials, protective coatings, cathodic protection systems, use of inhibitors, use of nonmetallic materials, and control of the environment. The chapter ends with a discussion on the problems encountered and protective measures that are based on the state-of-the-art as practiced daily by corrosion and petroleum engineers and production personnel.