Stainless Steel Pipe from Corrosion Causes

The time of issue:2014-6-25 9:50:25       Author:

The corrosion causes of stainless steel pipe are as follow.
Firstly, same with the corrosion of API steel pipe, there is also chemical corrosion on the surface of stainless steel pipe. The chemical corrosion of the stainless steel pipe include the oil attached on the surface of the workpiece, dirt, acid, salt and other which can be changed into a corrosive medium under certain special conditions, such as the chemical reaction with some elements and chemical corrosion and rust. If the surface of the steel pipe is scratched, then it is easy for stainless steel pipe to react with the chemical media. What is worse, if the pipe is scratched, the passive film will be broken, which in turn decreases the ability to protect the stainless steel pipe. When we do not clean the pipe clearly, there is some residue retention, and then the electrochemical corrosion carbon pollution will be caused.

In the meanwhile, the corrosion of the stainless steel pipe may be generated during the process of cutting. In the cutting process, it is inevitable to form cut slag, rust and other substances, and then the electrochemical corrosion is produced when those substances adhere and form the galvanic corrosion medium. The electrochemical corrosion can be also caused by the changes and uneven of the composition and microstructure of the flame heating zone. When the stainless steel pipe is in the welding process, we should ensure the welding area complete, because the physical defects of welding area, such as undercut, cracks, pores and so on, and the chemical defects such as coarse grains and penetration, can react with corrosive media so that electrochemical corrosion will be caused. Besides, the electrochemical corrosion can form because of the passivation. When the pickling passivation effect of stainless steel pipe is not good, the surface of the passivation film will be uneven and thin, which in turn lead to electrochemical corrosion.

On the summary, even though it is difficult for the stainless steel pipe to react with the common corrosion media because of its special microstructure and the passivation film on the surface of the pipe, it still can react under certain special conditions. And sometimes, the corrosion may be very fast, especially pitting and crevice corrosion.

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