There are many types of steel on the market and when it comes to carbon steel, these metals are classified by their carbon content: low, medium, and high carbon. Each of these varieties possesses unique properties that make them best suited for certain applications. High-carbon steels are often used when strength and durability are important, such as in tools. Low carbon is typically favored in applications that require flexibility and precision. Low-carbon steel is also commonly used for fasteners like screws and hinges.
The lower carbon content in low-carbon steel makes it more resistant to corrosion, but it is not impervious. When relative humidity exceeds 60% within the environment, even low-carbon steel can begin to rust and corrode. Thus, many thin coatings have been developed to protect the metal and prevent this from happening. The most common coatings are made from zinc, but they can be made from a variety of different compounds to protect the metal from corrosion.
Common Steel Coatings
Steel can be coated in many ways. These include:
- Galvanizing: Steel is immersed in a molten bath of zinc. The coating then reacts with atmospheric oxygen and carbon dioxide to form zinc carbonate. Galvanized steel typically has a dull gray appearance that can be unattractive for some use cases.
- Electroplating: An electrical current is used to deposit a thin layer of a metal onto the surface of another. This greatly improves corrosion resistance and is typically aesthetically pleasing as well. However, it can produce uneven coats which can be a drawback for applications that require high precision.
- Powder Coating: In an electrically charged process, a powder is deposited onto the surface of a metal. Powder coats are durable, but can be thicker than some applications demand.
- Painting: Steel can also be painted to reduce corrosion, but the durability is lower than that of other coating methods.
There is also research being done to identify coatings that could be more effective or environmentally friendly when compared to these traditional methods. One such coating is corundum-based paint. Corundum is an aluminum oxide crystal that could potentially protect steel by providing a barrier and galvanic protection while forming corrosion-inhibiting products.
The purpose of these coatings is to protect the underlying steel from corrosion, expanding its lifespan and increasing durability. For fasteners, this ensures that fasteners used in harsh environments don’t prematurely corrode and require replacement or maintenance too soon. At Electronic Fasteners, we have a wide range of coated fasteners to choose from. If you have questions about our inventory or need help selecting the right product, contact our experienced team today.