The galvanized square tube is a hollow square section steel tube with a square cross-sectional shape and a shape obtained by hot-rolling or cold-rolling galvanized steel strip or galvanized coil as a blank after cold bending forming and then high-frequency welding. Or a galvanized square tube made of cold-formed hollow steel pipe which has been prepared in advance and then hot-dip galvanized .
Classification of galvanized square tubes:
The galvanized square tube is divided into a hot-dip galvanized square tube and a cold-galvanized square tube from the production process. It is precisely because of the different processing of these two galvanized square tubes that they have many different physical and chemical properties. In general they have many differences in strength, toughness and mechanical properties.
1.Hot-dip galvanized square tube
Hot-dip galvanized square tube: a square tube welded by using a steel plate or a steel strip after crimp forming, and the square tube is placed in a hot-dip galvanizing bath after a series of chemical reactions on the basis of the square tube A square tube formed. The production process of hot-dip galvanized square tube is relatively simple, and the production efficiency is very high, and there are many varieties and specifications. The square tube requires little equipment and funds, and is suitable for the production of small galvanized square tube manufacturers. But in terms of strength, the strength of this steel pipe is much lower than that of a seamless square tube.
2. Cold galvanized square tube
The cold-galvanized square tube uses the principle of cold-galvanizing on the square tube used to make the square tube have anti-corrosion properties. Different from hot-dip galvanizing, cold-galvanized coatings are mainly anti-corrosion by electrochemical principle. Therefore, it is necessary to ensure sufficient contact between the zinc powder and the steel to produce an electrode potential difference, so the surface treatment of the steel is very important.
Hot and cold galvanizing difference:
Galvanized square tubes are available in two categories: hot-dip galvanized square tubes and galvanized square tubes. The hot-dip galvanized square tube has a wet method, a dry method, a lead-zinc method, a redox method, and the like square tube manufacturer. The main difference between different hot-dip galvanizing methods is how to activate the surface of the pipe to improve the galvanizing quality after the acid pipe is cleaned. The dry process and the redox process are mainly used in production, and their characteristics are shown in the table. The zinc-plated zinc layer has a very smooth and compact surface and uniform structure; it has good mechanical properties and corrosion resistance; zinc consumption is 60% to 75% lower than that of hot-dip galvanizing. Electro-galvanizing has certain technical complexity, but it must be applied to single-sided coatings, double-sided coatings with different thicknesses on the inner and outer surfaces, and thin-walled tubes.
The purpose of galvanized square tube:
Since the galvanized square tube is galvanized on the square tube, the application range of the galvanized square tube is greatly expanded compared with the square tube. It is mainly used in curtain wall, construction, machinery manufacturing, steel construction projects, shipbuilding, solar power brackets, steel structure engineering, power engineering, power plants, agriculture and chemical machinery, glass curtain walls, automobile chassis, airports, etc.
Characteristics of galvanized square tubes:
Zinc plating has stronger protection and strong corrosion resistance. The entire structure consists of zinc, forming a dense quaternary crystal that forms a barrier on the steel sheet, thus effectively preventing the penetration of corrosion factors. Corrosion resistance comes from the barrier function of zinc. When zinc is sacrificed in trimming, scratching and scratching of the coating, zinc forms an insoluble oxide layer and acts as a barrier.