Corrosion Detection Methods for Stainless Steel Pipe

The time of issue:2014-7-2 9:37:06       Author:

Different from API steel pipe, there are usually two forms of corrosion that can have a great influence on stainless steel pipe, including pitting and stress corrosion cracking. What is worse, the two forms of corrosion may even lead to other bad problems. In this article, we will tell some popular detection methods to detect corrosion in stainless steel pipe.

1 Visual Inspection
This kind of method to corrosion is the simplest method of all, whose detecting theory is visually inspecting. If the number of your pipe is very small, you had better choose this method for cost-saving. On the contrary, if you have a large amount of stainless steel pipes, this method is not suitable, because when you detect your pipe with this method, you will need enormous amount of labor. Besides, with this method, those you cannot see cannot be detected, especially those you do not cut off. Under the circumstances, the non-uniform corrosion will be very difficult for you to detect, such as cracking. In addition, when detecting stress corrosion cracks, our eyes may be inept so that some problems may be caused. In summary, we should not only depend on visual inspection.

2 X-Ray
X-ray, which is also known as radiography, can be used even if there is no insulation removal. However, there are also some disadvantages of this method. As we all know, X-ray can produce radiation. Even though we are careful when conduction X-ray testing, the precautions may be still impractical in many environments. In addition, we cannot use X-ray to detect the two forms of corrosion of stainless steel pipe, cracking and pitting. But we can use it to detect other kinds of defects.

3 Eddy Current Technique
It is said that this kind of corrosion detection method for stainless steel pipe is becoming one of the most common one. This technique is used to detect corrosion by applying alternative “Eddy” currents to pipe with electromagnetic induction. When interacting the electromagnetic field with the material, the changes during the test of the impedance of the coil will occur.

4 Conventional Eddy Current
Even though the Eddy current methods are relatively few, the conventional eddy current is often used on stainless steel pipe. There are many advantages of this method, such as versatile, fast, and cost-effective and so on. But only when the tested pipe is accessible to the probe can this method be useful.

5 Pulsed Eddy Current
The most fantastic advantage of this method is that we can use it to detect stainless steel pipe without contacting the material being tested. The disadvantage of this method is that it may be unreliable when we use it to detect such corrosion as pitting.

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