The galvanized elbow has a small amount of galvanizing, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. Regular galvanized elbow manufacturers are allowed to use cold galvanized pipes for water and gas pipes.
Cold galvanized elbow: The galvanized layer of the cold galvanized elbow is an electroplated layer, and the zinc layer and the elbow base 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, it is forbidden to use cold galvanized elbows as the water supply pipe connection parts.
Hot-dip galvanized elbow: A hot-dip galvanized elbow is a combination of a molten metal and an iron matrix to produce an alloy layer, thereby combining the substrate and the plating. Hot-dip galvanizing is to first pickle the elbow, in order to remove the iron oxide on the surface of the elbow, 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 Feed into the hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life.
The use of galvanized elbows: the use of galvanized elbows. The iron pipe connection for gas and heating is now a galvanized elbow. The galvanized elbow is used as a water pipe connection. After a few years of use, a large amount of rust is generated inside the pipe. The yellow water that flows out not only pollutes the sanitary ware, but also is mixed with the bacteria that grow on the uneven inner wall. 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 successively banned galvanized pipes and galvanized elbows. The Ministry of Construction and other four ministries also issued a document clarifying that galvanized elbows will be banned from 2000. At present, cold water pipes in newly built communities have rarely used galvanized elbows to connect pipe fittings. In some districts, hot water pipes use galvanized bends. Head connection.