Corrosion Mechanisms

Corrosion of Embedded Ferrous Metals in Woods

Timber is the most widely utilised natural materials in human history. It is a renewable material and readily available. Ferrous metal fasteners and fixtures are often used in the timber structure. They are generally reliable and maintenance free.  However, the pre-mature corrosion failures are identified in the history [1].  Field experience and test even suggested higher corrosion risk for outdoor applications [2]. If not attending carefully, it will lead to serious consequence.  Corrosion scientists also believe that wood provides a corrosive environment through permeable structure acting as an electrolyte sponge.  Recent research is not only focusing on understanding the corrosion…
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Metal Dusting: recent progress and industrial experience

The metal dusting is one of major failure mechanisms of equipment in producing process of hydrogen, ammonia, and syngas, as well as methanol reforming.  Although it has been recognized for the decades, there are still controversies in its mechanism.  With the recent development in metal dusting research, industries are having better understanding and may develop practical approaches to combat this type of failure. In this report, the recent research of metal dusting mechanism is summarized. It is reasonable to group these mechanisms in 3 types per Szakálos’ proposal: Type 1: decomposition of metastable carbides (e.g. cementite), Type 2: decomposition of…
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Hydrotest Water Specification and Integrity Considerations

The pipeline and pressure vessel are required by code to perform hydrotest after their construction, maintenance to demonstrate the strength and integrity. Water is the most common media to be used in this test. There are several standards and code of practice in place for the quality of hydrotest water.  Nevertheless, there is still multiple case of failure while the inappropriate water was used for the hydrotest, which has been proven costly in rectification.

Corrosion of ASTM 304 Grade Stainless Steel for Drinking Water Service

Grade 304  Stainless Steel Grade 304 is the standard “18/8” austenitic chromium-nickel stainless steel. It is the most versatile and most widely used stainless steel, available in the widest range of products, forms and finishes. It has excellent forming and welding characteristics. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures. 304 and its variant are general purpose stainless steel grade with good atmospheric corrosion resistance and many corrosive media. It subjects to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C.  Considered resistant to pitting corrosion in…
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Guadalajara Sewer Explosion by Stray Current Corrosion

Stray Current Corrosion of Ductile Iron Pipe (DIP) Near Steel Pipeline The most notorious incidents is catastrophe of  Guadalajara Sewer Explosion.The sewer network in Guadalajara, Mexico was exploded in April 1992. The official toll was: 206 dead, 500 to 600 missing, 1 800 injured and, in all, 4 500 disaster victims. Associations estimate that the catastrophe actually caused at least 1000 deaths. The catastrophe caused damage worth 200 billion pesos (76 million Euros 2006), which included ~13 km of streets, 1500 houses, 1224 buildings and 637 vehicles. The scientific investigation found the stray current corrosion is the blame. According to…
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