Many industries are using pipes that are made of carbon and carbon alloy. People are using these pipes to transport fluids and gases. Carbon steel pipes have high strength, which makes them suitable for use in construction, water systems, and even power plants. These pipes are durable, cheap, and resistant to damage. However, they have a major shortcoming known as Corrosion. When a carbon steel pipe is not dealt with care, it can lead to leaks, faults, and costly fixes. In this article, we will find out why carbon steel pipes are prone to Corrosion, what precautionary measures we can undertake, how to prevent it, and the best solution available.
Composition of Carbon Steel Pipes
Carbon steel pipes are mostly made of iron, containing small amounts of carbon (0.04-2.1% by weight). It makes carbon steel strong and tough. Pipes can also include manganese (0.30-1.60%), silicon, phosphorus, 2.6% chromium, or a small amount of sulfur, but these are kept at very low levels to prevent damage to the pipe’s quality. Different types of steel, as low, medium, and high carbon steel, change the strength and flexibility of the pipe. Low carbon steel is soft and bends easily, while high carbon steel is hard but less ductile.
Understanding Carbon Steel Pipe Corrosion
Exposure of the carbon steel pipes to chemicals, moisture, and high temperatures can lead to severe damage. It is normal that iron in steel interacts with oxygen present in the air and water and produces rust (iron oxide). This affects the brand of the carbon steel pipes. Corrosion can be evident (such as the rust on top of a pipe), and also unnoticeable (inside the pipe). The corroded wall may, over time, peel off the pipe and may result in leaks, pressure loss, or complete failure.
| Types of Corrosion | Impact on pipes |
| Uniform Corrosion | It corrodes the whole surface of the steel pipes and leads to overall deterioration of the iron in the presence of moisture and other chemicals. |
| Galvanic Corrosion | When the water is present, carbon steel behaves like an anode, and it may corrode very quickly once it makes contact with other metals like copper or stainless steel. |
| Pitting / Crevice Corrosion | Pitting is a form of Corrosion that creates deep holes. Cracking erosion occurs at close intervals and has low oxygen. They can be sublimated and are very toxic. |
| Microbial Corrosion | Some bacteria produce corrosive substances inside the pipe. This is called microbiologically affected war (Mic) and often affects industrial systems. Sulphate-reducing bacteria are agents of Corrosion in this case. |
It is imperative that people are aware that Corrosion does not happen all at once; instead, it takes time, but continuously, Corrosion occurs in cases such as on pipes that are being exposed to moisture, a chemical, or even high temperatures. In most cases, this Corrosion establishes itself above 0 °C and increases with a temperature rise. Rust cannot last long in closed systems, such as water, oil, or gas pipeline systems, and so on. When this internal damage bursts, everything ruins. This is because the pipeline is not observed regularly.
Common Causes of Corrosion and Their Effects
A lot of reasons exist that impact the quality of the carbon and carbon alloy steel pipes, some of them are as follows:
| Causes | How It Affects the Pipe |
| Exposure to Moisture or oxygen | Corrosion of steel occurs when it is in contact with water and oxygen. Indeed, in wet or moist conditions, it appears very quickly, especially near the sea. |
| Salt (Chloride Ions) | Salt, such as chlorides, can break the protective layer on steel from the seawater. It speeds up Corrosion and leads to dangerous beating. |
| Carbon Dioxide / Acidity | Carbon dioxide in the aerated water turns slightly into carbonic acid. It suppresses the pH and accelerates the process of Corrosion, and yet there is no oxygen. Likewise, the rate of Corrosion is accelerated by Sulfuric acid. |
| High Temperature | Hot pipes or large temperatures turn on moving chemical reactions, and stress makes cracks or weak spots where rust begins. |
| Improper Welding | The joints of the steel pipes must be welded. The Silver and the Construction of the seal of the joints are key steps in ensuring that the steel pipe is not readily susceptible to Corrosion. |
Preventive Strategies for Corrosion in Carbon Steel Pipes
To protect the surface area of the steel pipes to avoid Corrosion, there are a few methods, such as:
· Protective coating
The manufacturers use painting, epoxy layers, or zinc galvanization. These create a barrier between steel and corrosive elements.
· Cathodic protection
In this method, the steel pipe is usually attached to a sacrificial metal, such as zinc or magnesium, as a Corrosion inhibitor. This technique protects the buried or submerged pipes well.
· Erosion
Add chemicals inside the pipe fluid to create a protective film. It reduces inner war, especially in oil or water pipes.
· Design and material selection
Choose environmentally friendly carbon steel quality. Where necessary, use polyethylene-coated pipes or high-quality API quality pipes. Design the pipe layout to avoid stable areas and reduce stress points.
· Insulated Metal
In this procedure, the manufacturer uses linings, wear pads, or pipe shoes to separate carbon steel from other metals and prevent galvanic Corrosion.
· Supports the prevention of vibrations and friction
U-bolts, hugs, pipe shoes, and hangers reduce mechanical wear and cracking. This minimizes the risk at contact points.
· Environmental control
Keep the area dry, ensure drainage holes are clear, use sealant, and avoid contact with an acid or saltwater environment.
Existing Corrosion Management Solutions
Corrosion of carbon steel pipes is a serious problem, but many innovative solutions are available today to handle and reduce the effects.
1. Regular inspection and monitoring
Among the most effective measures of controlling Corrosion is to ensure it is fast. Due to frequent inspections, there is an opportunity to identify minor forms of Corrosion or damage before they escalate into more significant issues. The ultrasound tests, radiography (X-rays), and visual controls are the tools that professionals use to monitor the thickness and surface position. Some companies also use smart sensors or Corrosion monitoring controls inside the pipe to get real-time data.
2. Pipe wrap and sleeve
Packing pipes with protective tape, fiberglass, or resin-based sleeves helps you create a substantial barrier to moisture, salt, and air. This method is usually used for top countries and external pipes, especially in areas with high humidity or near the sea.
3. Cathodic Protective System
This is a very effective method for underground or underwater pipes. It works by using a sacrificial number (e.g., zinc or magnesium) or by sending a small electric current through the pipe. It protects carbon steel by preventing electrons from being lost (a significant portion of the Corrosion process).
4. Support and shoes for pipes
Mechanical wear and vibrations can cause damage where the pipe touches the metal surfaces. Exceptional support, such as pipe shoes, insulators, and clamps, reduces the movement, prevents rubbing, and prevents the moisture from getting stuck. This is especially useful in large industrial systems.
5. Corrosion-inhibiting chemical
In water, oil, or gas-carrying pipelines, the addition of inhibitory chemicals can help slow down the internal Corrosion. These chemicals coat the inside of the pipe and prevent reactions between the steel and the liquid.
6. Repair and replacement
In case a pipe is already damaged, it can be cleaned, or instead cleaned of its rust and repaired by replacing the damaged part. Nevertheless, when a rust goes deep or wide, a safer and trusty alternative is changing that part of the pipe most of the time.
Defensive Action Plans of Carbon Steel Pipe Manufacturers
There are specific strategies that a manufacturer can use to prevent the carbon steel pipe from getting corroded. Here in the table, the details of the benefits associated with these methods are:
| Strategy | Benefit |
| Steel of Low-Impurity Steel | The raw materials (low-imported) and the controlled carbon materials used should be low-impurity steel to reduce early Corrosion. |
| Adhere to International Standards | Take standards, e.g., ASTM A106/A53, ISO 3183, API, or ASME, to ensure the Corrosion meets the standard. |
| Coatings in the Factory | Coat the pipes with epoxy galvanization or polyethylene before shipment to prevent pipe deterioration. |
|
Provide Custom Options for Coating |
Recommends PE-left pipes, adapted lining, cathodic system, or specific coatings according to the customer’s case of use |
| Offer Maintenance instructions | Offer simple instructions on pipe shoes, maintenance, inspection, usage of obstacles, and the support team. |
FAQs
Which are the most popular Corrosion types on carbon steel pipes?
- Uniform Corrosion: It is even on the whole surface.
- Pitting rust: Deep and small holes are formed.
- Crevice Corrosion: This happens at joints and enclosed places.
- Galvanic Corrosion: This takes place when carbon steel comes in contact with another metal.
- Stress Corrosion Cracks (SCC): Stress Corrosion Cracks, which are not always visible
What is the best coating for carbon steel pipes?
The epoxy performs very well inside and out. Galvanization provides an anti-moisture and friction sink layer on the steel. Pipes that are coated with polyethylene fare well in complex chemical conditions or burial conditions in numerous situations.
What would be the symptoms of Corrosion on my carbon steel pipes?
Check for rust stains, leaks, low pressure, discolored water, or uncharacteristic odor. In the case of invisible or internal Corrosion, you will need to use ultrasound equipment, pigment equipment, or a non-destructive testing method.
Is it repairable, or should carbon steel pipes with Corrosion be replaced?
According to mild Corrosion, it can be cleansed, painted, and papered. However, if the wall is too thin or the hole is bottomless, it is safe to replace it, and it is cheaper in many cases.
What parameters should be met with carbon steel pipes to ensure rust resistance?
- ASTM A106 / A53 for regular pipe character
- ASME B36.10m for pipe dimensions
- ISO 3183 for oil and gas pipelines
- API 570 for inspection in service
- NACE SP0169 for cathodic protective guidance.