Corrosion
Corrosion is a subject that any Instrument Engineer should have knowledge in as selecting the correct equipment and process instruments for a plant is dependent on it. This page provides some excellent technical information about corrosion, forms of corrosion, corrosion effects, how to mitigate corrosion and corrosion monitoring and control. In addition there are Material Selection Guidelines and Corrosion Tables.
Corrosion Technical Information for Engineers
Dictionary of Metal Terminology - A searchable resource from Metalmart Inc..
Stainless Steel Types and their Selection
Chemical Compatibility Database - Use this site to help determine which materials are best suited for your applications. An excellent corrosion table source from Cole Palmer.
Online Problem Solver - The Corrosionsource.com CPS system provides assistance in the identification of the root cause of common corrosion problems through information obtained from simple visual examination of the corroding components or equipment. It also provides basic remedial action that can be taken immediately which should mitigate or at least reduce the severity of the problem.
Forms of Corrosion - This article covers Uniform Attack, Galvanic, Crevice, Pitting, Intergranular, Selective Leaching, Erosion, and Stress Corrosion.
Circle Seal Controls Corrosion Resistance Guide - This is a very useful tool.
The Corrosion Doctor - This site brings in focus new tools, events and concepts to quantify corrosion damage and the benefits of proposed solutions. It contains a series of modules that can be used for training in corrosion science and engineering.
Corrosion and its Effects - This technical data sheet briefly discusses some of the reasons why corrosion occurs and the problems that can result.
Stainless Steel Grade Selection Guidelines - Good information on Stainless Steel.
Copper & Copper Alloy Corrosion Resistance Database - For Copper and Copper Alloy data this is the site to visit.
Corrosion Tables - Searchable corrosion information and tables from Sandvik.
Corrosion Data Tables - This is a good table detailing materials against media, concentration and temperature - from OSECO.
The Corrosion Portal - A huge amount of information and links from corrosionsource.com.
Nickel Development Institute - There are 375 technical papers available here free of charge - A super site! NiDI has launched the first in a series of online training modules for the chemical process industry. These are online slide presentations accompanied by audio and scrolling text. The first module, entitled "Basics of Corrosion" was written by NiDI consultant Bud Ross and edited by NiDI Technical Director Gary Coates. Audio is provided by Scott Farlinger and the user interface was designed by Intelygis Inc. of Toronto. "Basics of Corrosion" is about 23 minutes in length and looks briefly at the various forms of corrosion (uniform, galvanic, pitting, crevice, erosion-corrosion, intergranular, corrosion fatigue, environmentally-assisted cracking, and stress corrosion cracking).
Corrosionpedia - The most widely read online journal dedicated to the corrosion industry. This is a very comprehensive Corrosion Resource.
Corrosion Technical Papers
NACE MRO175 Recommended Practice: Assuring Compliance in Sour Service Applications - Due to the hazardous nature of sour service applications which contain hydrogen sulfide (H2S), the National Association of Corrosion Engineers (NACE) has issued a standard recommended practice that includes minimum requirements to resist sulfide stress cracking. While not mandatory, many petroleum and natural gas producers are using the current NACE MRO175 guideline to improve the safety of their facilities and employees. Petroleum and natural gas facility operators cannot afford to take sour service applications lightly because H2S is extremely hazardous. Any type of failure in the pressure boundary area of a level control - such as a displacer switch - can result in the release of concentrated sour gas vapors, which can be fatal within only five minutes at a concentration of 800 ppm - from Magnetrol.
It’s Stainless Steel, it Shouldn’t Rust - This is often the kind of statements heard from individuals when discussing a failure of process piping or equipment. It is also an indication of how little is actually understood about stainless steel and the applications where it is used. For years industries have used stainless steels in their process piping systems. Most of the time stainless steel components provide satisfactory results. Occasionally a catastrophic failure will occur. The purpose of the information contained within this document is to bring an understanding to stainless steel, it’s uses, and why it will fail under certain conditions. This paper discusses the different classes of stainless steel, heat treatment, corrosion, welding, and finally material selection. As with any failure, it is imperative the cause of the failure be identified before a proper fix can be recognized. Most often the cause of the failure is identified as the wrong material being used in the wrong application - from CSI.
Rust on Stainless Steel - Walter J. Sperko - Rust on stainless steel is ugly. Rust on stainless steel raises a lot of questions. Is the steel really stainless steel? If it’s stainless, why is it rusted? Where does the rust come from? Will it continue to rust? Will it spread? Will other forms of attack occur, such as pitting or stress-corrosion cracking? This paper addresses these questions for rust that occurs on a tank or pipe that is made from austenitic stainless steel such as Type 304, 304L, 316, 316L, 321, 317, etc. It covers the sources of rusting, the effect of rust on the performance of stainless steel and methods for prevention and removal of rust that appears on the surface of stainless steel components. It applies to rusting on external surfaces of piping and vessels that are exposed to the atmosphere, including rain, condensation, fog, etc. but are actually dry most of the time - from Sperko Engineering Services.
Corrosion Control And Treatment Manual - This manual provides guidelines for the control of corrosion of materials in facilities, systems, and equipment at the John F. Kennedy Space Center (KSC), Florida. It is very comprehensive - from NASA.
Corrosion Protection Of Metals - Two methods of combating corrosion which are widely used in New Zealand are cathodic protection and chemical inhibitors. Both methods depend on controlling the charge on the metal surface, and this can be monitored by measuring the potential of the metal. The conditions needed to stop corrosion can then be predicted from an electrochemical phase diagram - from NZIC.
Corrosion and Cathodic Protection Theory - James B. Bushman - This is an excellent reference on the subject - from Bushman and Associates.
Beginners Guide to Corrosion - Bill Nimmo and Gareth Hinds - This document gives an introduction to corrosion and its control in non-technical terms - from NPL.
Corrosion of Duplex Stainless Steels in Seawater - Bengt Wallén - In the following paper a review of most types of corrosion occurring in sea water applications is given. With just a few exceptions, only tests using real seawater have been taken into consideration. Whenever possible, the behaviour of superduplex steels is compared with that of super austenitic steels - from Avesta Sheffield.
Pitting and Crevice Corrosion of Offshore Stainless Steel Tubing - Gerhard Schiroky and Anibal Dam - Oil and gas platforms regularly use stainless steel tubing in process instrumentation and sensing, as well as in chemical inhibition, hydraulic lines, impulse lines, and utility applications, over a wide range of temperatures, flows, and pressures. Corrosion of 316 stainless steel tubing has been observed in offshore applications around the world. Corrosion is a serious development that can lead to perforations of the tubing wall and the escape, under pressure, of highly flammable chemicals. The two prevalent forms of localized corrosion are pitting, often readily recognizable, and crevice, which can be more difficult to see. Many factors contribute to the onset of localized corrosion - from the excellent offshore magazine.
Selecting Fluid System Components for use in Sour Oilfields - The conditions under which oil and gas are brought from their reservoirs to the surface can be outright hostile to many common materials used in fluid system components employed in industry. Potentially dangerous mechanisms include localised corrosion, stress corrosion cracking (SCC) and sulphide stress cracking (SSC). SSC has become increasingly common as more sour reservoirs are being developed - for example, those in the northern part of the Caspian Sea that contain up to 20% hydrogen sulphide (H2S). Ageing reservoirs can also turn sour as abiotic and biotic reactions take place. This article describes how to select the optimal materials of construction for components that need to perform reliably for many years in the demanding sour environments of oil and gas exploration and production - from Process Online and Swagelok.
Real-Time Corrosion Monitoring - Integrating Corrosion Data with other Process Variables - Russell Kane and Keith Briegel - Existing programs on the control system can assess, identify key plant relationships - The petrochemicals and pharmaceuticals sectors spend $2.5 billion annually to combat corrosion. Worldwide, the cost of corrosion in the process industries appears to be about $50 billion per year and will probably climb higher over the next five years. Many operators currently see corrosion on a “straight-line basis” in terms of repair, maintenance, and replacement during fixed interval turnaround inspections. New technology, however, is available that assesses corrosion deterioration in real time using the plant control and automation system. This makes linking corrosion to process conditions more direct and immediate. It also allows the assessment of corrosion in much shorter time intervals with the ability to control and mitigate the rate of damage and more accurately factor in its true economic impact on plant operations - from ISA and InTech.
Corrosion Monitoring: Breaking down the Misconceptions - Sridhar Srinivasan - The latest technology links corrosion to process conditions more directly and immediately. It also allows corrosion depreciation to be assessed in much shorter time intervals with the ability to control and mitigate the rate of damage and more accurately factor in its true economic impact on plant operations - from www.processonline.com.au.
