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Case Histories

Prevention of Micro-Flow Marks in Cathodic Electrodeposited Primer Coating in Automotive Industries

There was a defect of severe micro-flow mark lines in cathodic electrodeposited (CED) primer coating on car components. This problem was highlighted after final painting. This article describes the tests performed to determine the root cause of the defect. Tests included a surface profile of the CED coating and the determination of the microstructure and nickel content of the phosphate coating beneath the CED coating. The investigation identified the optimum concentration of nickel in the coating to refine phosphate grain size and create a unity crystal aspect ratio. It also found that the triple point junction of phosphate crystals determines the porosity to provide a uniform CED coating surface finish.

Centrifugally Cast Fiberglass-Reinforced Polymer Mortar Pipe for a Large-Diameter Interceptor Sewer

This article discusses one city’s approach to preserving the integrity of its infrastructure through the use of corrosion-resistant piping systems. Technological developments in centrifugally cast fiberglass pipes have provided installation advantages and lifelong benefits to municipalities.

Recent Fiberglass-Reinforced Plastic Applications: Radome and Hybrid Bridge System

This article describes two case histories: construction and installation of a fiberglass-reinforced plastic (FRP) radome and the design, construction, and utilization of composite FRP/concrete bridge beams. The shape, structural requirements, and radar transmission requirements of the radome are discussed, as are the design, fabrication, and testing of the composite beams.

Role of Nonmetallic Composites in Gas Plants

Several factors cause deterioration of critical process equipment in process plants. The options widely utilized for restoration include conventional repair or replacement. Nonmetallic composite materials can be utilized as an option to restore equipment integrity. This article discusses the material degradation aspects in critical streams such as the cooling water system and hydrocarbon pipelines at a Saudi Arabian gas plant. Nonmetallic composite coating materials play a vital role in corrosion protection and life extension of core components.

Advanced Coatings for Water Treatment Plant Components

Components of water treatment plants (WTPs) are susceptible to corrosion from constant immersion in water and proximity to chlorine. A case history of corrosion problems and their treatment at an Army WTP is presented. Solutions included using high micro-silica restoration mortar and advanced coal tar epoxy coatings.

Enhancing Asset Value Through Corrosion Management

The relative value of an aging asset depends on many parameters, among which are production rate/ continuity and integrity management (IM) costs. Reducing unplanned shutdowns and IM costs can maintain or even improve the relative asset value. This article describes—using data collected over a five-year period—how having asset corrosion management and risk-based inspection systems in place may achieve the above.

Interference Problems and Nonuniform Potentials in Cathodic Protection of a Complex Installation

After being in operation for some time, cathodic protection (CP) systems at compressor stations, refineries, and other industrial plants can experience problems. For example, the CP potential distribution can change for various reasons, because of isolating flange failures, alterations in pipeline systems, grounding systems, or reinforced concrete foundations. Some areas become underprotected and others overprotected. The extent of CP current required may exceed the capacity of rectifiers, and may also increase interference on foreign pipelines. This article describes the results of corrective measures for these problems.

Premature Coating Disbonding on Ships and Offshore Structures

Epoxy/urethane coating systems are widely used for ships and offshore structures because of their excellent resistance to ultraviolet radiation and protection against corrosion. Recently, some of these coating systems used in Korea experienced premature failure. This work investigated the root cause of the failures using pH tests and Fourier transform infrared spectroscopy.

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.