Are your pipes safe from corrosion? Chances are they’re not. According to the American Galvanizers Association, 85 percent of all steel produced is carbon steel. And carbon steel is susceptible to many kinds of corrosion.
Not that you should panic if your piping system includes this metal. There are ways to prevent carbon steel pipe corrosion without replacing your pipes altogether. Here’s why this metal is so vulnerable to corrosion and what you can do about it.
There are several factors that boost corrosion in carbon steel, but the overall cause is consistent. The biggest issue with carbon steel is that it contains a large amount of iron. This makes it strong, sturdy, and a solid option for building structures.
But iron comes with a downside. When it’s exposed to moisture, oxygen rushes to bond with iron. The result is iron oxide—otherwise known as rust.
When rust forms, it doesn’t just remain in one spot. It tends to spread quickly and eat away at metal. In a piping system, this can easily turn into leaks, pressure losses, and ruptures.
Carbon steel is inherently vulnerable to corrosion. But it won’t necessarily corrode at the same rate in every circumstance. Here are some common factors that increase carbon steel corrosion:
Galvanic corrosion is an electrochemical process that starts when two dissimilar metals are combined. For instance, if carbon steel and stainless steel are connected, your stainless steel could pull electrons from your carbon steel. As a result, it can eat away your carbon metal.
Pitting corrosion happens when chips or cavities form on your steel’s outer layer. Basically, this type of wear leaves little pits where water, chemicals, or other corrosive materials can pool. This type of concentrated corrosion can be hard to notice and can cause severe structural damage or leaks.
Exposure to moisture, grime, chemicals, and salt-heavy air can all speed up the corrosion process. At the same time, anything that wears down surface metal can give corrosive elements a chance to nestle in and corrupt metal.
In turn, when pipes scrape against harsh surfaces, it doesn’t just cause damage. It makes it easier for corrosion to set in.
Luckily, you don’t have to ditch carbon steel altogether to protect your pipes against corrosion. Here are a few ways to keep carbon steel from corroding:
Protective coatings reinforce metallic surfaces and make it less likely for cracks or other corrosion catchers to open up. Additionally, you can add galvanization to strengthen outer layers and protect against galvanic corrosion. The galvanizing process includes spreading a layer of liquid zinc over your carbon steel. Because zinc is more likely to give up electrons than carbon steel is, zinc strengthens the carbon steel beneath it.
Eliminating metal-to-metal contact strengthens pipes in two ways. First, it helps you avoid pairing up dissimilar metals. This protects pipes from galvanic corrosion.
Second, it stops metals from scraping against other metals and opening up surface scratches where corrosion can start. You can stop metal-on-metal contact by adding a buffer between pipes and other metals. For instance, you can use wear pads, rods, or other isolators to physically separate pipes from metal surfaces.
Generally, corrosion takes place when bacteria, corrosive chemicals, or moisture seeps into metal. This means you can lessen the effects of corrosion by keeping surfaces dry and even. There are a few ways to accomplish this:
You may already realize how pipe restraints like U-bolts, clamps, and straps can keep pipes from crashing into surrounding objects. But they can also reduce corrosion by controlling movement. Rather than pinning a pipe down to one spot, some pipe restraints use protective liners that minimize vibrations and encourage axial movement.
Additionally, you can use pipe shoes to lift your pipes off of surrounding beams or harsh surfaces. That way your pipes aren’t rubbing against other hard surfaces and wearing down.
Regardless of the final solution you choose, the end game should be the same. You can use pipe supports to reduce wear and eliminate weak spots where corrosive materials can creep in.