1. Overview of galvanized pipe
In order to improve the corrosion resistance of the steel pipe, galvanized the general steel pipe. Galvanized pipes (galvanized steel pipes) are divided into two types: hot -dip galvanized and cold -dip galvanized. The hot -dip galvanized galvanized layer is thick, has the advantages of uniform galvanization, strong adhesion, and long service life. The cost of cold galvanized pipes is low, and the surface is not very smooth. The corrosion resistance of itself is much different than the hot -dip galvanized pipe, and it has been gradually eliminated.
Most of the old houses in my country are used in galvanized pipes. The iron pipes commonly used in gas and heating are also galvanized pipes. As a water pipe, as a water pipe, with the accumulation of the use period, a large amount of rust is generated in the pipe. This not only pollutes the sanitary ware, but also is mixed with bacteria breeding in the smooth inner wall. Health. In the 1960s and 1970s, some developed countries began to develop new pipes and disabled galvanized pipes. The four ministries and commissions of the Ministry of Construction of China also explicitly stipulated that the galvanized galvanized pipes have been disabled from 2000. At present, the cold water pipes in the newly -built communities have rarely used the galvanized pipes. The heat water pipes in some communities use galvanized pipes.
Galvanized pipes are divided into heat -galvanized steel pipes and cold -galvanized steel pipes, of which cold galvanized steel pipes have been gradually eliminated.
1. Hot -dip galvanized pipe/hot -dip galvanized steel pipe
The hot -dip galvanized metal reacts with the iron -based reaction to generate the alloy layer, which combines the substrate and the coating. The manufacturing of hot -dip galvanized pipes is to pick up the steel pipes first to remove iron oxide on the surface of the steel pipe. After pickling, cleaning through ammonium chloride or chloride water chloride or ammonium chloride and zinc chloride hybrid water grooves for cleaning , And then send it to the hot immersion groove.
The hot -dip galvanized steel pipe is a complicated physical and chemical reaction between the steel pipe matrix and the melting plating fluid, forming a tight zinc iron alloy layer with corrosion resistance. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix. Therefore, the hot -dip galvanized steel pipe has the advantages of uniform plating, strong adhesion, and long service life.
2. Cold galvanized pipe/cold galvanized steel pipe
Cold galvanized is electroplating. The amount of galvanizing is very small, only 10-50g/m2. Its corrosion resistance itself is much different than hot -dip galvanized pipes. In order to ensure the quality, the formal galvanized pipe manufacturers are mostly not used in electroplating (cold galvanized). Only those small and old -fashioned small companies use electroplating, of course, their prices are relatively cheap. The zinc layer and steel pipe matrix of cold galvanized steel pipes are layered independently. Because the zinc layer is thin, the zinc layer is simply attached to the steel pipe matrix and is easy to fall off. Therefore, the corrosion resistance of cold galvanized steel pipes is poor. Therefore, in the newly built houses, cold galvanized steel pipes have been prohibited as water supply and gas pipes.
