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The first difference in the process is that hot-dip galvanizing involves removing oil from the workpiece, acid washing, dipping in a chemical solution, drying, and then immersing it in molten zinc for a certain period of time before removing it. Hot-dip galvanizing is an effective method of metal corrosion prevention, mainly used in metal structural facilities in various industries. It involves immersing the rust-removed steel parts in molten zinc at around 500°C to form a zinc layer on the surface of the steel components, thereby achieving the purpose of corrosion prevention. The zinc layer is relatively firm.

Cold galvanizing, generally speaking, does not require heating and has a very small amount of zinc coating. Such galvanized parts are prone to zinc layer detachment in humid environments.

The differences between hot-dip galvanizing and cold galvanizing:
Hot-dip galvanizing, also known as hot-dip zinc plating, involves melting zinc ingots at high temperatures and adding some auxiliary materials, then immersing metal structural components in the zinc plating bath to form a zinc layer on the surface of the metal components. The advantage of hot-dip galvanizing lies in its strong corrosion resistance and good adhesion and hardness of the zinc layer.

“Cold galvanizing” is also known as “electro-galvanizing”, which involves electroplating a zinc layer on the surface of the part by electrolyzing a zinc salt solution. Generally, it does not require heating and has a very small amount of zinc coating, which is prone to detachment in humid environments.

Hot-dip galvanizing is a chemical process and belongs to an electrochemical reaction.
Cold galvanizing is a physical process, merely applying a layer of zinc on the surface, so the zinc layer is prone to detachment. In construction, hot-dip galvanizing is more commonly used.

Continuous hot-dip galvanizing process: steel → heating → cooling to galvanizing temperature → galvanizing → cooling

Cold galvanizing is electro-galvanizing, with only 10-50g/m2, and its inherent corrosion resistance is much lower than that of hot-dip galvanizing. The price of electro-galvanizing is relatively cheaper.

Hot-dip galvanizing is the process of galvanizing the surface of steel under hot-dip conditions. It has strong adhesion and is not easy to fall off. Although hot-dip galvanized pipes may also show signs of rust, they can meet technical and hygiene requirements for a long period.