Two ways of galvanizing malleable iron pipe fittings

Malleable steel pipe fittings because of its material is iron, so when it is exposed to the air, it is easy to rust. In particular, malleable steel pipe fittings are mainly used in fire fighting and water supply projects, and pipe fittings are exposed to damp environment for a long time, which is more prone to rust. Therefore, malleable steel pipe fittings need to do anti-rust treatment on their surface.

The surface rust prevention treatment of malleable steel pipe fittings is generally divided into two kinds: hot galvanizing and cold galvanizing.

Hot dip galvanizing is an effective metal corrosion prevention method, which is mainly used in metal structure facilities in various industries. It is to immerse the steel parts after rust removal into the melting zinc liquid about 700 ° C, so that the surface of the steel member is attached to the zinc layer, so as to play the purpose of anti-corrosion. Hot-dip galvanizing process: finished product pickling - washing - adding plating solution - drying - hanging plating - cooling - medicine - cleaning - polishing - hot-dip galvanizing completed.

Cold galvanizing, also known as electrogalvanizing, relies on the electrophoretic phenomenon to transfer zinc hanging on the anode to the surface of the tube hanging on the cathode, and then forms a thin and uniform zinc layer.

The cost of hot-dip galvanizing is relatively high compared to cold galvanizing, but because the galvanized layer is relatively thick, and the zinc layer on the surface reacts with the iron matrix at high temperature, there is a transition layer between the zinc layer and the iron matrix, so the zinc layer and the pipe fitting matrix are particularly strong and not easy to fall off. Although the cost of cold galvanized layer is relatively low, the zinc layer is uniform and beautiful, but because electroplating is only to cover a layer of zinc metal film on the surface of the pipe fitting matrix, the galvanized layer is thin and easy to fall off. In addition, a large amount of toxic waste liquid will be produced in the production process of electrogalvanizing.