Pipe Corrosion – Causes and Prevention Techniques

Metal pipes are essential in our day-to-day lives and in industry for transporting and distributing liquids (e.g., oil, water etc.) from one point to the other. When corrosion takes place, the impacted pipe starts disintegrating and the distribution of liquids is impacted. For pipes transporting water, corrosion may also impact the color, taste, and odor of water. This may be harmful in cases where the water is meant for human consumption. Along with the pipe itself, pipe fabrication connections are seriously impacted by corrosion. So, what are the causes of corrosion and how can it be prevented? This blog will look to discuss this interesting topic going forward.

Causes of Pipe Corrosion

• Acidity and Alkalinity – Acidity is one of the factors that cause corrosion in metal pipes. Water has a low PH if it is untreated because of the presence of carbonic acid or other acids. The presence of these acids in water causes corrosion as they will react with pipes. This reaction will go on for a while and eventually the pipes get corroded. Alkalinity refers to bases which are contained in water. These bases are not good for pipes since they are anti-corrosive.
• Electric Current – It is well known that most of the water pipes are underground. Hence, the electric current will come from earthing. The excess electricity is damped to the ground to prevent accidents in electrical appliances. This electric current that goes to the ground will cause corrosion in these pipes.
• Material and Organic Constituents – Water contains minerals and organic constituents. These dissolved minerals have a great chance of causing corrosion in pipes if they are not eliminated. For instance, dissolved oxygen in water facilitates corrosion in pipes. The only way to eliminate the minerals and organic constituents in water is by treating that water before entering the pipes.

Prevention of Pipe Corrosion

• Cathodic Prevention – Cathodic protection is the use of electrical current to prevent corrosion. This is done by connecting the pipe to the negative pole of a DC generator or the anode metals like magnesium so the entire pipe acts as a cathode. The cathodic protection method is very effective for metal pipes that are buried. When the pipe is made to be a cathode, then this will greatly prevent corrosion simply because corrosion only occurs at the anode and not the cathode since corrosion is an electrochemical process.
• Proper Pipe Material – The type of pipe material used for welding pipes also has a great influence on preventing corrosion. There are pipe materials that are resistant to corrosion, these kinds of pipe materials will do a great job of preventing corrosion. The best pipe materials that one should consider using are the alloys of iron or steel with chromium, copper, or nickel. They are quite expensive, but they are the best pipe materials for prevention of corrosion and also helps in reducing scrap during the pipe manufacturing process.
• Water Treatment – Water treatment involves adjusting the pH value. The moment the PH value is low or high that will facilitate the corrosion of the pipes. So, the water must be treated and the PH should be between 6.5 to 8.5, this is the PH that will prevent the pipes from corroding. Also, treating water tends to take control of calcium carbonate which increases the alkalinity of water. Removal of oxygen from water also aids in the prevention of corrosion in metal pipes, since oxygen is one of the factors that increase corrosion in pipes. The addition of sodium silicate in water when treating it also prevents corrosion in pipes.

The Last Word

It is important to note that corrosion of pipes cannot be eliminated since oxygen will always be available unless the earth is filled with inert gases. However, corrosion needs to be managed to the maximum extent possible else it will impact pipes in the long run and replacement of pipes will be an additional expense. Thus, pipe corrosion is an ongoing phenomenon and the management of corrosion by heavy steel fabrication companies needs to be an ongoing practice as well!