What Is Galvannealed Steel Sheet?
Galvannealed steel sheet is a product of continuous hot-dip galvanizing followed by annealing. This process draws a portion of iron into the zinc coating, forming a unique zinc-iron alloy that enhances the material’s performance.
This enhanced performance makes galvannealed steel a favorite for automobile panels and frames, garage doors, highway signs and computer chassis. It also offers excellent corrosion resistance when painted.
Corrosion Resistance
While galvanized steel can offer some protection from corrosion, it’s not a complete solution. That’s why xometry customers often combine galvannealed sheet with a paint or satin finish, forming the metal into its final form and protecting it from harsh environments. This ensures that the corrosion resistance of galvannealed steel is fully utilized, reducing maintenance and replacement costs in the long run.
To get the benefits of corrosion resistance, galvannealed steel needs to undergo a two-step process: galvanization and annealing. During the first stage, the iron-based material is coated with zinc to create a barrier against environmental elements that could cause it to corrode or rust. The annealing stage is what differentiates galvannealed from standard galvanized steel: it converts the zinc coating into a stronger, more durable zinc-iron alloy.
This additional layer of durability allows the galvannealed steel to resist damage and withstand rough handling. For instance, the steel can be bent and formed into complex shapes without breaking or tearing. Similarly, it can withstand the pressure of large vehicles driving over it. It’s these properties that make galvannealed steel ideal for use in applications like automobiles where longevity is important, highway signs, computer chassis, and garage doors. To learn more about how to use the corrosion resistance of galvannealed sheet in your projects, speak with a xometry representative.
Paintability
The flat gray matte finish of galvannealed steel sheet has a uniform appearance and is very pleasing to the eye. This aesthetic makes it an excellent choice for projects where the finished product will be visible, such as buildings and bridges. Its durability also makes it a good choice for applications where the metal will be exposed to heavy traffic and other demanding environments.
Another benefit of using galvannealed metal is its paintability. Because the zinc coating on galvanneal is not spangled, it accepts paints more readily than other types of coated metal. In galvannealed steel sheet addition, the coating has more resilience and hardness because it is comprised of a zinc-iron alloy. This enables the galvanneal coating to resist scratching and other types of damage that could expose the steel underneath.
Galvanneal is also easy to form and weld, making it a popular choice for projects in need of strong, durable materials. The ductility and corrosion resistance of the material make it an ideal choice for applications such as making automotive panels and doors, household appliances, and electrical systems.
Phosphatized galvanized metal is a variant of galvanneal that has been treated with an electrochemical phosphate conversion process, known as phos-bond, in order to enhance its paintability. This treatment changes the surface of the zinc to a dull gray color and improves its ability to accept paint, without affecting its corrosion resistance or strength.
Ductility
Both galvanized and galvannealed steel offer excellent durability, but the annealing process that provides galvanneal metal with its zinc-iron alloy coating results in slightly better ductility than galvanized. This enhanced ductility allows galvannealed metal to bend and be formed into more complex shapes without the risk of damage to its protective layer or structural stability.
The coating on a galvanneal sheet of metal is also harder than standard galvanized steel, resulting in increased resistance to scratching or other types of damage that could expose the raw steel underneath and degrade its corrosion resistance. This improved ductility makes galvanneal metal ideal for use in products that will be exposed to high levels of physical stress.
Galvannealed steels that are used in automobile manufacturing can typically achieve tensile strength levels of up to 400 MPa. This ductility is crucial to the lightening of the vehicle’s weight, which helps improve fuel efficiency and crash resistance.
Other uses for galvanneal include household appliances and electrical systems, where the formability and corrosion resistance make it an ideal choice for enclosures and junction boxes. The metal’s ability to be easily painted gives it a natural look that blends well with its surroundings, which is important for products like solar panels and other highly visible components. Other industrial applications that commonly use galvanneal steel include the production of storage tanks and pipes for oil and gas extraction.
Aesthetics
The satin finish on galvannealed steel provides a beautiful aesthetic that is durable and easy to maintain. This combination of durability and beauty makes this type of sheet metal ideal for use in a variety of different applications, including car components, architectural elements, and household appliances. It is also a popular choice for manufacturing products that require hermetic protection from environmental factors like sunlight and moisture.
In addition to its corrosion resistance, satin finish galvannealed steel is extremely durable and has excellent paint adhesion qualities, making it an ideal choice for painting projects. However, applying a satin finish to galvannealed steel requires careful preparation and high-quality painting methods. This process involves sanding the surface of the metal to create a smooth, even surface and Q195 carbon steel plate cleaning it to remove any dust or debris. It is important to follow these steps in order to achieve a high-quality, durable satin finish that highlights the unique properties of galvannealed steel.
Although galvanized and galvannealed steel offer similar benefits, the latter is generally preferred if the product will be painted. This is because galvannealed steel offers a more uniform surface that better accepts paint and resists scratching and manufacturing damage. It also has a duller appearance than traditional galvanized steel, due to the fact that its zinc coating is made up of a mix of pure and metallic zinc with a small amount of iron (zeta, delta, and gamma). This coating is significantly harder than traditional galvanized steel, offering improved durability and surface protection.