Metal corrosion is the main cause of metal failure, which seriously affects industrial production. Hot-dip galvanizing is one of the most basic and extensive methods of steel corrosion  prevention in the world,it has been widely used in various fields of the national economy.

zinc pot
At present, there are three main methods for hot dip galvanized zinc pot heating:

· heat the outside of the zinc pot

· heat the zinc pot

· induction heating of zinc pot with working frequency

Zinc pot is strongly corroded by zinc liquid, which is one of the main reasons for high cost of hot galvanizing.Silicon and carbon are the main elements that promote the reaction of iron and zinc.The silicon content has the greatest influence on the life of the zinc pot, so the performance of the zinc pot depends on the silicon content.There are two kinds of hot galvanizing bath: one is to improve the fluidity of zinc and add aluminum bath, the other is to improve the development of zinc flower and add tin, antimony, made of gold alloy bath.Due to the strong corrosion of molten zinc solution on equipment materials,it has brought a series of problems to heat zinc production:

· low service life of zinc pot equipment

· abnormal zinc consumption is high:

A. zinc iron reaction

B. zinc liquid surface volatilization and oxidation

C.  due to zinc temperature is not allowed, not uniform, so that the product coating uniformity is poor caused by the waste of pure zinc

The following three protection processes of zinc pot are commonly used in industry:

1. Zinc-corrosion resistant coating: it has the characteristics of non-wetting with zinc solution, high melting point and zinc-corrosion resistance.To improve the corrosion resistance of materials by separating metals from corrosive media

2. Zinc corrosion resistant layer is treated on the metal surface

· seepage layer: make the seepage paste for boron agent, solution and binder filler into chips, place it on the side of the cavity, and use gray iron as the master material for casting

· surface alloying

Main defects: thin protective layer, brittle, uneven composition, high porosity, easy peeling.As a result of the above reasons long life of the overall material has more important significance.In industry, inorganic and metal integrated zinc-corrosion resistant materials and metal integrated zinc-corrosion resistant materials are usually used, including brittle metal corrosion resistant materials and ductile metal corrosion resistant materials.

Researching on reducing and preventing zinc corrosion at home and abroad generally include:

· keep the temperature of zinc solution as low as possible as conditions permit

· minimize silicon and carbon content in steel

· select the appropriate heating technology: ceramic and zinc pot heating technology.

3. Plasma arc spraying ceramic coating technology: it can be divided into gas-stable plasma arc spraying and water-stable plasma arc spraying.Gas stability is generally more extensive in the industrial sector.Plasma spraying technology can make the surface of zinc pot with wear resistance, corrosion resistance, high temperature oxidation resistance, etc. The use of plasma arc spraying technology to prepare ceramic coating, which has certain limitations in the density of the coating porous in some occasions seriously affect the service life of the coating.As long as the appropriate process and measures are selected, plasma arc spraying ceramic coating can play a role in zinc corrosion resistance layer, so as to increase the time of zinc corrosion resistance, improve the life of zinc pot, and thus get a good application in production.

Eternal Bliss Alloy Casting & Forging Co, Ltd.

Technical Dept.

Tel:0086-130 930 23772