Corrosion allowance for pressure pipelines
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I’ve been troubled by this issue lately: how should the corrosion allowance for pressure pipelines be determined? ? ? Arigawa Tomo said that in order to prevent container components from losing thickness due to corrosion or mechanical wear, a corrosion margin should be taken into account (there are three types of corrosion margins: 1.5mm, 3mm, 4.5mm). The specific requirements are as follows: a) For components that are subject to corrosion or wear, the corrosion margin should be determined based on the expected service life of the container and the rate at which the medium corrodes the metal material ； b) When the corrosion levels experienced by various components of the container differ, different corrosion margins can be employed ； c) For containers made of carbon steel or low-alloy steel, with a medium of compressed air, water vapor, or water, the corrosion allowance must be at least 1 mm; this allowance is determined based on the service life and corrosion rate. There are certain prerequisites for these three possible scenarios. Is any specification or standard followed? Let’s discuss it together.
I’m not sure if there are any standards for this, but in our engineering work, the corrosion allowance is generally determined based on the pipe material and the type of process medium. For carbon steel, it’s 1.5 mm for normal process media; 2.0 mm for mildly corrosive process media; and 3.0 mm for highly corrosive process media. For alloy steel, it’s 1.0 mm, and so on. These values are determined based on specific operating conditions and engineering experience
I encountered a condition where corrosion was extremely severe, with a remaining corrosion thickness of over 3 mm. Is it possible to calculate exactly how much that is?