In recent years, with the continuous improvement of material durability requirements in construction and manufacturing industries, the application of galvanized steel pipes has become increasingly widespread. Among them, hot-dip galvanized pipes and cold-dip galvanized pipes, as two common galvanized process products, have significant differences in performance, service life, and applicable fields.
Hot dip galvanized pipe: alloy layer bonding, strong corrosion resistance
Hot dip galvanized pipes are formed by immersing steel pipes in molten zinc solution, causing zinc to react with the iron substrate to form a dense zinc iron alloy layer, thereby achieving a strong bond between the substrate and the coating. During the production process, steel pipes are first pickled to remove surface iron oxide, then cleaned in ammonium chloride or zinc chloride solution, and finally sent to a hot-dip galvanizing tank for galvanizing.
The hot-dip galvanizing process has the advantages of uniform coating, strong adhesion, and long service life. Due to the integration of the alloy layer with the pure zinc layer and the steel pipe matrix, forming a tight structure, hot-dip galvanized pipes exhibit excellent corrosion resistance and are widely used in engineering environments with high durability requirements.
Cold galvanized pipe: electroplating process, poor corrosion resistance, has been restricted from use
Cold galvanized pipes, also known as electroplated galvanized pipes, have a galvanizing amount of only 10-50g/m ², much lower than hot-dip galvanized pipes. The galvanized layer is formed by electroplating and is in an independent layered state with the steel pipe substrate, with weak adhesion and easy detachment, resulting in significantly insufficient corrosion resistance.
According to industry knowledge, most legitimate galvanized pipe production enterprises do not use electroplating technology to ensure product quality. At present, only some small-scale and outdated equipment enterprises are still producing cold galvanized pipes. Although their prices are relatively low, the product quality is difficult to meet engineering standards.
It is worth noting that the national construction department has officially issued a document to eliminate technologically outdated cold galvanized pipes and prohibit their use in water and gas pipelines. Cold galvanized steel pipes are also explicitly prohibited from being used as water supply pipes in new residential projects.
summary comparison
Hot dip galvanized pipe: uniform coating, strong adhesion, long service life, suitable for high standard engineering.
Cold galvanized pipe: low galvanizing amount, easy peeling of coating, poor corrosion resistance, and has been restricted from use by policies
Hot dip galvanized pipe: alloy layer bonding, strong corrosion resistance
Hot dip galvanized pipes are formed by immersing steel pipes in molten zinc solution, causing zinc to react with the iron substrate to form a dense zinc iron alloy layer, thereby achieving a strong bond between the substrate and the coating. During the production process, steel pipes are first pickled to remove surface iron oxide, then cleaned in ammonium chloride or zinc chloride solution, and finally sent to a hot-dip galvanizing tank for galvanizing.
The hot-dip galvanizing process has the advantages of uniform coating, strong adhesion, and long service life. Due to the integration of the alloy layer with the pure zinc layer and the steel pipe matrix, forming a tight structure, hot-dip galvanized pipes exhibit excellent corrosion resistance and are widely used in engineering environments with high durability requirements.
Cold galvanized pipe: electroplating process, poor corrosion resistance, has been restricted from use
Cold galvanized pipes, also known as electroplated galvanized pipes, have a galvanizing amount of only 10-50g/m ², much lower than hot-dip galvanized pipes. The galvanized layer is formed by electroplating and is in an independent layered state with the steel pipe substrate, with weak adhesion and easy detachment, resulting in significantly insufficient corrosion resistance.
According to industry knowledge, most legitimate galvanized pipe production enterprises do not use electroplating technology to ensure product quality. At present, only some small-scale and outdated equipment enterprises are still producing cold galvanized pipes. Although their prices are relatively low, the product quality is difficult to meet engineering standards.
It is worth noting that the national construction department has officially issued a document to eliminate technologically outdated cold galvanized pipes and prohibit their use in water and gas pipelines. Cold galvanized steel pipes are also explicitly prohibited from being used as water supply pipes in new residential projects.
summary comparison
Hot dip galvanized pipe: uniform coating, strong adhesion, long service life, suitable for high standard engineering.
Cold galvanized pipe: low galvanizing amount, easy peeling of coating, poor corrosion resistance, and has been restricted from use by policies