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Galvanized Steel Pipes

Date:2019-04-18    keywords:galvanized, steel pipes
Galvanized steel pipe, commonly known as "gi" steel pipe, is divided into hot-dip galvanized pipe and cold galvanized pipe

Hot dip galvanized pipe
The molten metal is reacted with an iron matrix to produce an alloy layer, thereby combining the matrix and the plating. In order to remove the iron oxide on the surface of the steel pipe, hot-dip galvanizing is to pickle the steel pipe first. After pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then fed into hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life. The steel pipe matrix and the molten plating solution undergo complex physical and chemical reactions to form a corrosion-resistant structure of a zinc-iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe base. Therefore, its corrosion resistance is strong.

Cold galvanized pipe
Cold galvanizing is electrogalvanizing. The amount of galvanizing is very small, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. In order to ensure quality, regular galvanized pipe manufacturers mostly do not use electro-galvanizing (cold plating). Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper. At present, the Ministry of Construction has officially laid down the cold-galvanized pipe with backward technology, and the cold-galvanized pipe is not allowed to be used as water and gas pipe in the future. The zinc layer is an electroplated layer, and the zinc layer and the steel pipe matrix are layered independently. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe base and is easy to fall off. Therefore, its corrosion resistance is poor. In new homes, the use of cold-galvanized steel pipes as water supply pipes is prohibited.

Use of galvanized steel pipe
The galvanized pipe and the galvanized pipe are often used. The iron pipe used for gas and heating is also a galvanized pipe. The galvanized pipe is used as a water pipe. After several years of use, a large amount of rust is generated inside the pipe, and the yellow water flowing out is not only polluted. Sanitary ware, and mixed with bacteria that grow on the inner wall of the slick, the rust causes the heavy metal content in the water to be too high, which seriously endangers the health of the human body. In the 1960s and 1970s, developed countries in the world began to develop new types of pipes and banned galvanized pipes. The Ministry of Construction and other four ministries and commissions also issued a document clarifying that galvanized pipes will be banned from 2000. At present, galvanized pipes are rarely used in cold water pipes in new residential areas. Some districts use galvanized pipes for hot water pipes.

Production Process

The production process of stainless steel has the following production steps: 

a. Round steel preparation; 

b. Heating; 

c. Hot rolling perforation; 

d. Cut head; 

e. Pickling; 

f. Grinding; 

g. Lubrication; 

h. Cold rolling processing; 

i. Degreasing; 

j. Solution heat treatment; 

k. Straightening; 

l. Cut tube; 

m. Pickling; 

n. Product testing.

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