Case Histories

Stress Corrosion Cracking of Various Alloys—Part 1

Stress corrosion cracking (SCC) can lead to rapid and catastrophic failure in many different metals and alloys. Failures often occur with little or no prior warning. A systematic approach is needed to evaluate any failure and identify its cause. The case histories in this article illustrate features that are commonly evident in various materials that experience SCC.

Stress Corrosion Cracking of Various Alloys—Part 2

Stress corrosion cracking (SCC) can lead to rapid and catastrophic failure. Failures often occur with little or no prior warning. A systematic approach is needed to evaluate any failure and identify its cause. This article continues the case histories begun in Part 1 and illustrate common features evident in SCC.

Effective Rehabilitation Planning for a Natural Gas Transmission Line—Part 2

This article outlines the results of a long-term pipeline integrity plan that was used to rehabilitate large segments of a natural gas pipeline over the past eight years. Part 1 of this article discussed the details to be followed in an effective rehabilitation plan to accomplish the goal of a well-maintained pipeline system.

Tuberculation Corrosion in Industrial Effluents

Tuberculation in waste water has long been a concern. Causes are an adverse mixture of water chemistry, construction materials, microbiological attack, and flow rate. Low velocity permits particulates and corrosion products to form deposits. Accumulated deposition leads to partial or complete blockage of pipelines, trapping of pigs, under deposit corrosion, and tuberculation. Tuberculation reduces flow rate. This article discusses tuberculation and presents a case study.

Caustic Treatment of Electric Utility Drum Boilers

Until recently, caustic water treatment was not used in high-pressure electric utility drum boilers in the United States because of concern over caustic gouging. Meanwhile, it was being used successfully in other countries. Many U.S. electric utilities have now converted their drum boilers to caustic treatment. This article describes the basics of caustic treatment and presents two case histories of successful use in the United States.

Long-Term Performance of a Fluoropolymer- Lined Process Vessel

An ethylene chlorotrifluoro-ethylene (ECTFE) lining of a process vessel handling alkaline-based fluids and active chlorine was examined after more than 23 years of service. The examination and tests showed that the ECTFE material was undamaged. Test procedures, data evaluation, and conclusions are presented.

Developing Welding Procedures for Sour Service

Controlling the hardness of the weld heat-affected zone (HAZ) in sour service is essential to help prevent sulfide stress cracking. It is important to evaluate HAZ properties when developing welding procedures. The behavior of specific alloys during welding presents roadblocks to HAZ hardness control. Two cases are presented to show that weld thermal simulation is an efficient tool for developing welding procedures for sour service.

Investigating Polyethylene-Encased Ductile Iron Pipelines

This article presents several case histories where ductile iron (DI) pipeline sections have been investigated to ascertain the corrosion control benefits of polyethylene (PE) encasement. The procedures and results of the investigations are evaluated and discussed. These investigations demonstrate the overall effectiveness of PE encasement as a corrosion control system for DI pipe.

Measurement of a Corrosion Inhibitor Through Online Monitoring

Typical repair of reinforced concrete structures showing corrosion damage involves removal of carbonated or chloride-contaminated concrete and subsequent retrofilling with new concrete. Corrosion inhibitors that can be applied by spraying onto the concrete surface are an alternative. These products are relatively new and only limited long-term monitoring results are available. The combination of an inhibitor with monitoring of the corrosion behavior provides evidence of protection. This article describes long-term monitoring results of protected highway gallery columns in the Swiss Alps.

Amine Blush in Epoxy Coatings

Carbonated amine material, often called amine blush, is the reaction product of the amine functional curatives in epoxy paint with carbon dioxide (CO2) and water vapor. This article explains the formation of amine blush and discusses factors controlled by the applicator and those controlled by the paint manufacturer.

Restoration of a Brick Chimney with a Dual Lining System and Polymer Concrete

A brick flue at a generating station was in need of rehabilitation because of the spalling and cracking of the brick. This caused a leakage of acid gases into the annulus. A typical flash coat system was not desired because of its relatively short life. A system of corrosion-resistant materials, which has shown excellent performance and durability, was chosen to make the repairs. The system consists of a combination of organic and ceramic-based lining materials. A case history is presented, with descriptions of the operating environment and materials selection criteria.

Designing Cathodic Protection for Power Plant Applications

Designing cathodic protection (CP) systems for buried piping in power plants and other similar industrial facilities offers several unique challenges. This article discusses these challenges and provides case histories to illustrate the impact they have on CP system design and operation.

Sampling Drinking Water: Methods and Problems

Water can acquire some aspect of every material it touches. Some of those materials are in such minute quantities, however, that they are virtually undetectable. This article discusses the importance of proper water sampling and analysis when investigating copper and lead concerns.

Lining Prevents Biogenic Sulfide Corrosion In Wastewater Systems

Faced with serious concrete deterioration from biogenic sulfide corrosion within collection systems, engineers and municipalities are extending the service life of wastewater conveyance structures with the use of 100% solids polyamine systems designed for hydrogen sulfide (H2S) permeation resistance. This article explains how sewer interceptors, manholes, and lift stations were protected using fluid-applied linings.

Hot Oil Aboveground Storage Tank Bottom Corrosion Failure and Cathodic Protection Upgrade—Part 2

Several types of anode installations for tank bottoms are possible, but the methods selected do not always produce the desired results. This two-part article discusses a case history in which existing cathodic protection (CP) was ineffective and testing methods did not identify system deficiencies. This led to the premature failure of the tank bottom. Part 1 covered the findings of an investigation conducted to identify the cause of the corrosion. Part 2 describes the remedial approach taken to enhance CP for effective corrosion control.