Hotdipping

Hotdipping is a metal coating process that involves immersing a substrate, typically steel or iron, into a bath of molten metal, most commonly zinc. The molten metal adheres to the substrate, forming a protective layer. This coating provides corrosion resistance, enhances durability, and can improve the aesthetic appearance of the base material.

The hotdipping process begins with thorough cleaning of the substrate to remove any impurities such as oil, grease, rust, or scale. This cleaning is usually achieved through degreasing and pickling stages. Following the cleaning, the substrate is dipped into a bath of molten metal, which is maintained at a specific temperature. As the substrate is immersed, a metallurgical bond forms between the base metal and the coating metal. The thickness of the coating can be controlled by factors such as immersion time, withdrawal speed, and the composition of the molten bath.

The most common application of hotdipping is galvanizing, where steel is coated with zinc. Galvanized steel is widely used in construction, automotive manufacturing, and for producing items like guardrails, wire, and pipes due to its excellent protection against rust. Other hotdipping processes include tinning, which is used for food packaging, and aluminizing, which offers high-temperature corrosion resistance. The finished product is typically cooled and inspected for coating uniformity and adherence.