Galvanized steel is ordinary steel that has gone through a galvanizing process to apply a protective zinc coating, which greatly improves the corrosion resistance of the base metal. Galvanized steel is widely used where corrosion resistance is needed and has many advantages compared to untreated steel. Let’s take a look at some key knowledge about galvanized steel.
Basic information on galvanized steel
Firstly, the main methods of galvanizing are hot-dip galvanizing and electrogalvanizing. Hot-dip galvanizing is the most common industrial method, which forms the zinc layer by dipping steel into molten zinc. Electrogalvanizing utilizes electrolysis to deposit zinc on the steel surface through an electric current. No matter the method, the thickness of the zinc coating is generally 10-100 microns. Thicker coatings provide better corrosion protection but cost more.
Secondly, galvanized steel has excellent corrosion resistance because zinc is less noble than steel in the electrochemical series and will preferentially dissolve to protect the underlying steel. The cut edges of galvanized steel can also maintain corrosion resistance to some extent. In addition, zinc forms a strong mechanical interlock and metallurgical bond with the steel substrate, enhancing coating adhesion.
Thirdly, the service life of galvanized steel depends on many factors. Damage to the zinc coating will lead to premature failure, so collision and scratching should be avoided during handling and use. The corrosion nature of the environment also affects service life. For example, life is shorter in highly corrosive conditions like coastal areas. Generally, a 10-15 micron zinc coating can provide 2-8 years of protection in normal atmospheric environments.
Some limitations of galvanized steel should also be noted. The zinc coating can be oxidized at high temperatures and the bond strength is decreased. Chlorides and sulfides in corrosive media may also damage the coating. So galvanized steel should be used with caution in high-temperature or corrosive environments.
Applications of galvanized steel
The main applications of galvanized steel include construction structures, vehicles, appliance housings, pipes, etc. Specifically, H-beams, rebars for bridges and high-rises are often hot-dip galvanized. Vehicle bodies and parts extensively use galvanized steel sheets. Appliance housings like refrigerators and washing machines also commonly use galvanized steel. Piping systems for water supply, drainage, heating, and chemical transport also have galvanizing requirements.
Conclusion
In summary, galvanized steel has clear corrosion resistance advantages over untreated steel. However, the material should still be chosen wisely based on service conditions and properly maintained to maximize the protection of the zinc coating. With technological advancement, galvanized steel is expected to find wider applications in the future. Hopefully, this article has helped improve your understanding of galvanized steel. Feel free to search for more information to gain a deeper knowledge about this important engineering material.
