The term galvanizing broadly refers to an electro-deposition process where a thin layer of another metal is added to an item made of steel. The purpose of galvanizing is to protect the base steel by preventing rusting. However, one of the most effective galvanizing methods does not employ any electrochemical deposition. It is distinguished as hot dip galvanized coils or simply HDGC.
Usage of galvanized coils:
Hot-dip galvanizing has become widely popular owing to its effectiveness when it comes to corrosion protection. In fact, in recent times, the term “galvanizing” is being used to refer to hot-dip galvanizing. In this method, a four-layer corrosion-resistant finish or surface is produced on a steel base using zinc by an electrochemical process. The metal (usually steel and iron) to be protected from corrosion is passed through a molten bath of zinc at a temperature of 460-degree centigrade—zinc bonds to steel at the molecular level. Of four layers created, while the top layer is zinc, the three layers underneath are made up of zinc-iron alloy. Hot-rolled coils are being extensively used for industrial applications requiring the strength of steel and active resistance to corrosion.
Hot-dip galvanizing has proven to be far more superior when compared to other methods like the use of paint, metallizing, mechanically galvanized steel coils or electroplate galvanizing. It has appeared as one of the numerous result-oriented and reliable techniques that meets all your galvanizing requirements. Unlike electroplate galvanizing (which is considered to be the original form of galvanizing), HDG produces a much thicker, durable coating, which makes it suitable for even outdoor applications. On the other hand, the thin layer produced by electroplating is much more quickly consumed, exposing the steel base to corrosion.
HDG results in superior protection from corrosion or rusting. The hard zinc-steel alloy layers offer an effective barrier. If this barrier is damaged, zinc acts as a sacrificial anode; the electrons in the zinc coating will sacrifice themselves to prevent corrosion. Also, the topmost layer comprising only zinc, when reacts with the oxygen, moisture and carbon dioxide in the air, forms a thin but hard film called the zinc patina (which is an impermeable layer of zinc carbonate). It acts as an effective barrier over the galvanized coils zinc coating and protects it from corrosion. Zinc is higher reactive than iron or steel, and so the zinc galvanized sheet corrodes first, protecting the base metal.
Because hot-dip galvanizing leads to bonding of zinc to steel at a molecular level, the galvanized coating quickly covers the entire surface, including joints, scratched and holes. HDG is widely used in several applications ranging from automotive body parts, handrails, consumer appliances to roofing and walling. Because of its superior corrosion resistant properties, HDG is increasingly used to protect the exterior automotive parts and panels. Hot-dip galvanized metal sheets is also commonly used in metal pails and heating and cooling duct systems in buildings.
Pros of hot-dip galvanized metal sheets:
Hot rolled coils is a process of corrosive coating metals like iron, steel and aluminum with a thin zinc layer. This particular form of galvanization is widely used for industrial applications. The metal to be protected from rust is passed through a molten bath of zinc at a temperature of 460-degree centigrade.
There are several rust prevention techniques available. Of all, paint is widely used to prevent rust formation on metal surfaces. However, hot-dip galvanizing is far more superior to colours when it comes to effectiveness. It is not a coating on the metal surface like paint. When exposed to the atmosphere, the zinc on the surface reacts with oxygen to form zinc oxide. On further reacting with carbon dioxide present in the atmosphere, zinc oxide forms zinc carbonate, a durable material that effectively protects the steel or iron beneath from corrosion.
The major drawback of paint is its failure to ensure 100% protection from corrosion. What if the paint coating gets damaged, exposing the bare steel or iron surface? The exposed surface will immediately start corroding. If left unchecked, the rust will increase, growing under the remaining paint coating. Once rust forms between the paint coating and the metal surface, it will cause the paint to fade. And once rust forms, applying a new coat of paint becomes extremely difficult and expensive. Galvanized steel suppliers is free from such problems and offers 100% protection from rust.