Treatment Methods for Corrosion Pits on The Outer Wall of Boiler Tubes

Causes of corrosion pits on the outer wall of boiler tubes

The outer wall of the boiler tube is often affected by high temperature, high pressure and chemical reactions, which leads to corrosion and pits. The main reasons are as follows:

1. Acid corrosion

The steam, water and chemical substances contained in the boiler tube will corrode the outer wall of the pipe to a certain extent, especially in an acidic environment. For example, in some industrial production, if the carbon steel pipe is in an acidic medium environment, it is easy to be corroded by acid.

2. Oxidation corrosion

High-temperature oxidation corrosion is an inevitable phenomenon. Under long-term high temperature, the outer wall of the boiler tube forms an oxide layer with uneven thickness, which is prone to pits, oxidation cracks, etc.

3. Discharge corrosion

Static discharge will occur in the boiler pipeline, and there will be electrolytic corrosion on the metal surface, which is also a reason for the corrosion pits on the outer wall of the boiler.

Treatment methods for corrosion pits on the outer wall of boiler tubes

1. Cleaning treatment

If the outer wall of the boiler tube is only slightly corroded, the corrosion can be removed by cleaning. Usually, cleaning agents or grinding tools are used to clean the boiler tube surface to make it smooth without affecting the normal operation of the pipe. For some small hydraulic tubes or precision tubes, cleaning can effectively restore their surface condition and extend their service life.

2. Active protection

When corrosion is just found on the outer wall of the boiler tube, active protection can be used to prevent the expansion of pits. Active protection technology is formulated according to the principle of anodic protection. By adding different potentials to the outer wall of the pipe, the outer wall of the boiler tube is in a protected state, thereby preventing the formation and expansion of pits. This method is of great significance for some high-value heat exchanger tubes or drill pipes, etc., and can reduce the cost of repair.

3. Repair welding method

If there are large pits or deep pits on the outer wall of the boiler tube, repair welding can be used. When repairing, it is necessary to select welding materials of the same material as the outer wall of the pipe, and carry out comprehensive pretreatment to ensure the quality of welding.

4. Replacement method

If there is serious corrosion on the outer wall of the boiler tube, the pits are large and deep, and cannot be completely solved by repair, then replacement operation is required. When replacing, you need to choose the same specifications and materials as the original pipe. After installation, you need to conduct a comprehensive inspection to ensure the quality of pipe installation.

Summary

In short, in order to ensure the safe operation of the boiler, it is very important to deal with the corrosion pits on the outer wall of the pipe in a timely manner. The above methods are used for different situations and can help maintenance personnel solve this problem. At the same time, regular maintenance should also be carried out to promptly detect and deal with problems with boiler tubes.

Read more: How To Weld Boiler Tubes? or Material of Boiler tube