Search Results for underground environment

This article describes the various environments affecting corrosion performance, corrosion protection, and corrosion control. These include freshwater environments, marine environments, and underground environments. The article provides information on corrosion in military environments and specialized environments, representing less-well-known environments with more limited applications.

This article describes the test methods for evaluating the durability of a metal in soil. It provides useful information on soil characteristics such as soil electrical resistivity, pH value, and soil texture. Specimen design, preparation, burial, and retrieval techniques are discussed. The type of information sought during soil-induced corrosion evaluation controls the design configuration and the nature of the corrosion measurements. Consideration of these factors during the planning stage helps the corrosion engineer to obtain the maximum amount of information with the minimum number of problems.

This article describes the mechanisms of differential corrosion cells corrosion, microbiologically influenced corrosion, and stray direct current corrosion. It discusses the most common causes and contributing factors for corrosion and stress-corrosion cracking, as well as prevention, mitigation, detection, and repair processes.

Steel storage tanks are the primary means for storing large volumes of liquids and gaseous products. The stored fluid could be water, but it could also be volatile, corrosive, and flammable fluid requiring special precautions for storage as well. Corrosion is generally worst where the tank is in contact with the soil. This article describes the soil characteristics and addresses cathodic protection (CP) criteria for submerged metallic piping systems. It provides information on the data required for designing a CP system, alone or in conjunction with a protective coating system. These data are collected from predesign site assessments, tank electrical characteristics, and soil-resistivity measurements. The article addresses NACE Standard RP0169, which gives requirements and desired characteristics for coating in conjunction with CP. It also explains the methods of protecting aboveground storage tanks and underground storage tanks.

This article describes the coating materials, surface-preparation requirements, and application techniques used to protect underground pipelines. It provides a valuable insight into the types of polymer-based coatings that are both cost-effective and widely accepted in the pipeline industry.

This article provides information on predesign surveys and the various testing procedures associated with wastewater treatment plants. These include soil testing, atmospheric testing, and hydrogen sulfide testing. The primary parameters that influence the production of sulfides within the piping system that transports the wastewater to the treatment facility are discussed. The article describes the corrosion performance of various materials in the soil, fluid, and atmospheric exposures. These include concrete, steel, ductile iron, aluminum, copper, brass, stainless steel, and coatings used for wastewater facilities.

The major benefit of the implementation of the corrosion-control technologies at Army installations is the extension of the service life of buildings and other structures. This article reviews the exposure of military facilities and equipment to a wide variety of environmental conditions, including soils, waters, or atmospheres of varying corrosivity. It presents the case studies illustrating typical examples of the types of corrosion problems found on military installations. The article describes the various corrosion-control technologies used in military facilities. These include protective coatings and linings, cathodic protection, advanced materials selection and design, water treatment, equipment inspection and monitoring, and below-grade moisture mitigation.

A close-interval survey (CIS) is a series of structure-to-electrolyte direct current potential measurements performed at regular intervals for assessing the level of cathodic protection (CP) on pipelines and other buried or submerged metallic structures. This article describes the equipment required to perform the CIS. It provides a discussion on the activities that should be performed during the preparation and execution of the CIS. The dynamic stray current identification and compensation by CIS is discussed briefly. The article also explains various factors involved in the validation of CIS data. It concludes with information on CIS data interpretation.

The rate and form of corrosion that occur in a particular situation depend on many complex variables. This article discusses the rate of corrosion of lead in natural and domestic water depending on the degree of water hardness caused by calcium and magnesium salts. Lead exhibits consistent durability in all types of atmospheric exposure, including industrial, rural, and marine. The article tabulates the corrosion of lead in various natural outdoor atmospheres and the corrosion of lead alloys in various soils. It explains the factors that influence in initiating or accelerating corrosion: galvanic coupling, differential aeration, alkalinity, and stray currents. The resistance of lead and lead alloys to corrosion by a wide variety of chemicals is attributed to the polarization of local anodes caused by the formation of a relatively insoluble surface film of lead corrosion products. The article also provides information on the corrosion rate of lead in chemical environments.

Corrosion of marine- and land-based infrastructure is of major concern and its control forms an important objective. Thermal spray coatings (TSCs) are widely used for corrosion protection. This article focuses on two types of TSCs: cathodic or noble coatings and anodic or sacrificial coatings. It describes the factors affecting the performance of sacrificial TSCs in atmospheric and immersion environments. The article provides information on the applications of sacrificial TSCs, non-sacrificial coatings, and sealants/top coats, and exemplifies the use of sacrificial TSCs on structures for corrosion protection.

This article describes the major issues involved in designing systems with acceptable cold-climate corrosion performance. It discusses the methods used to control corrosion in external and internal environments. The article provides information on the various common causes of corrosion in cold climates. These include improper transportation and storage practices; improper operations and maintenance practices; and construction practices.

This article provides a summary of the concepts discussed in the article under the section "Corrosion Testing and Evaluation" in ASM Handbook, Volume 13A: Corrosion: Fundamentals, Testing, and Protection. This section presents fundamental information on step-by-step instructions for techniques, examples of actual test data, and hints to help in interpretation. The topics covered include planning corrosion tests and evaluating results, laboratory corrosion testing, simulated service corrosion testing, in-service techniques for damage detection and monitoring, and evaluating forms of corrosion.

This article presents the fundamentals of stray-current corrosion caused by electric rail transit systems. It describes the various corrosion-control design elements for the electric rail system. These design elements include substation spacing and grounding, track and track slab design, and construction acceptance criteria. The impacts of the electric rail construction in underground utilities are discussed. Direct physical interferences, maintenance access encroachments, stray-current effects, and utility relocation design considerations, are discussed. The article also reviews construction issues such as funding, sequencing, and working clearances. It concludes with information on the post-construction monitoring and maintenance for stray-current corrosion control.

This article explores the use of the electrochemical and nonelectrochemical techniques for measuring the corrosion behavior of buried metals and the types of probes used. The electrical resistance technique is the main nonelectrochemical technique used for measuring corrosion rate. Electrochemical techniques discussed include linear polarization resistance, electrochemical noise, harmonic distortion analysis, electrochemical impedance spectroscopy, and hydrogen permeation. The principles of operation for the corrosion measuring techniques are described along with examples of their use in soils.

This article provides a detailed discussion on the various devices by which cathodic protection (CP) can be applied to pipe-type power transmission cables. These devices include the resistor rectifier, isolator-surge protector, polarization cells, and field rectifiers. The article describes the interference created by stray currents on CP and associated remedial actions.

Coating of cast irons is done to improve appearance and resistance to degradation due to corrosion, erosion, and wear. This article describes inorganic coating methods commonly applied to cast irons. The coating methods include plating, hot dip coating, conversion coating, diffusion coating, cladding, porcelain enameling, and thermal spray. Organic coatings have a wide variety of properties, but their primary use is for corrosion resistance combined with a pleasing colored appearance. The article discusses the various types of organic coatings applied to cast irons. Practically any degree of smoothness or roughness and requirement for color and gloss can be filled by organic coatings. The article describes abrasive blast cleaning, abrasive waterjet cleaning and finishing, vibratory finishing, barrel finishing, and shot peening for processing iron castings.

This article details factors that have been used for evaluating the susceptibility of alloys to stress-corrosion cracking. Many considerations impacting the validity and accuracy of information gathered from laboratory testing programs are reviewed. The article highlights the main characteristics of probability distributions, such as normal distribution, log-normal distribution, exponential distribution, Poisson distribution, and extreme-value distribution. It also provides information on the statistical concepts to produce effective test programs.

This article describes the corrosion of principal parts of mining equipment such as mine shafts, wire rope, rock bolts, and pump and piping systems. It discusses the diagnosis and prevention of various types of corrosion including uniform corrosion, pitting corrosion, crevice corrosion, erosion-corrosion, and intergranular corrosion. The article explains the corrosion in tanks, reactor vessels, cyclic loading machinery, and pressure leaching equipment.