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When it comes to manufacturing projects within the oil and gas industry, one of the biggest challenges to overcome is tackling the different types of corrosion that parts are exposed to. It’s incredibly important to choose the right material for the right job. We take a look at the common corrosion issues and some of the best alloys to consider.  

Selecting materials for a project can be a difficult task, as there are so many factors to consider. In the oil and gas industry, an understanding of the corrosion issues that could present is critical, and knowing which materials to use to combat common problems will save time and money in the long run.

Given the extreme environments that materials are exposed to naturally within oil and gas extraction and refinement, corrosion is an inevitable consideration. Not only are external conditions corrosive – for example, placement in sea water or high operating temperatures – but the product being carried or processed through materials contains corrosive elements too, such as carbon dioxide, hydrogen sulphide and free water. These are all contributing factors towards the degradation of metal over time, which leads to a decline in a material’s mechanical properties like strength, ductility and impact strength. If left untreated, this corrosion can cause huge problems and a failure to continue to operate, which means stopping production – a costly result.

There are a number of different types of corrosion that you may need to consider for projects within the oil and gas industry. This includes (among others) CO2 corrosion, one of the main corroding agents in the sector, which can lead to pitting and mesa attack; sour corrosion, which is exposure to hydrogen sulphide in the presence of water causing uniform, pitting and stepwise corrosion; and oxygen corrosion, either on its own or accelerating the effects of acidic gases like those already mentioned.

Therefore, it is essential that the right materials are chosen at the manufacturing stage to offer the best protection against corrosion for the given environmental and product conditions. At Corrotherm, we specialise in corrosion-resistant alloys and supply a number of different grades to choose from to meet most needs.

For example, the popular INCONEL alloy 625 is often chosen for its outstanding corrosion resistance. This material is a high-quality mix of nickel, chromium, molybdenum and niobium, and it’s used for pipelines gathering sour gas and seawater heat exchangers due to its corrosion-resisting properties.

If a project requires high-temperature strength as well as corrosion resistance, INCONEL alloy 600 is worthy of consideration. By carefully controlling the compositional limits and through correct processing and thermal annealing, this alloy can help to avoid pitting and stress-corrosion cracking in some environments.

A good all-rounder, and an alloy that has been popular for over 50 years, proving its worth, is INCONEL alloy C-276. This super-alloy is resistant to general corrosion, stress corrosion cracking, pitting and crevice corrosion across a broad spectrum of environments, including seawater and reducing and oxidising acids.

You can see all of the alloys that we supply, along with detailed properties on our Grades page. If you want to discuss your project in more detail, our Sales team are ready to help. 

Topics: Corrotherm News

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