Different Corrosion Detection Methods for Stainless Steel Pipe

This article will introduce the method of stainless steel corrosion detection，and we will briefly overview some of the more popular detection techniques.

Visual Inspection

Visual inspection is a simple, cost-effective approach for smaller systems, such as those made of stainless steel tubes and pipes. However, for larger systems, the labor required for visual inspection can become too costly. Additionally, if there is insulation, visual inspection becomes impossible. This makes it difficult to detect non-uniform corrosion, such as cracking and stress corrosion cracks, which are notoriously difficult to spot with the human eye. Therefore, it is recommended to not rely solely on visual inspection.

X-Ray

X ray (radiography) is a non-destructive testing technique that can be used to detect corrosion in materials without requiring insulation removal. However, it does have some disadvantages. One disadvantage is that X-rays produce radiation, so the proper safety measures and precautions must be taken in order to conduct X-ray testing. Additionally, X-ray cannot detect cracking and pitting; however, it can be useful for detecting other kinds of defects.

Eddy Current Technique

Eddy Current Technique is a corrosion detection method for stainless steel that uses electromagnetic induction to apply alternating "Eddy" currents to the pipe or tube. The impedance of the coil in the testing probe changes as the electromagnetic field interacts with the material, providing a picture of the defect in the tube.

Conventional Eddy Current is the most commonly used method for corrosion detection of stainless steel. It is versatile, fast, and cost-effective, but requires direct contact with the material being tested - meaning insulation must sometimes be removed.

Pulsed Eddy Current is a specialized Eddy Current method that does not require direct contact with the material being tested. Therefore, no insulation needs to be removed, making it a popular method for detecting corrosion under insulation. However, it may not be as reliable in detecting ultra-localized corrosion like pitting.

Corrosion Under Insulation (CUI) is a common issue for stainless steel piping systems. It can cause severe problems, such as deterioration or even failure of the piping system. Therefore, it is important to consider corrosion detection methods before installing piping and insulation.

There are a wide range of detection methods for CUI, such as ultrasonic testing, temperature monitoring, and visual inspection. Each of these techniques has its own advantages and disadvantages, and none of them can work perfectly in all scenarios. Therefore, it is recommended to combine different methods to better suit the inspection needs.

In addition, it is important to choose the right insulation system based on corrosion detection and prevention needs. For example, removable insulation is a great choice if frequent inspection and maintenance are required. Finally, consulting with corrosion detection experts can be beneficial in making the best detection plans.