Galvanized steel pipes are divided into cold galvanized steel pipes and hot-dip galvanized steel pipes. Cold galvanized steel pipes are strictly prohibited from being used, and the latter one is advocated for temporary use in my country. In the 1960s and 1970s, the international bourgeoisie in my country slowly developed designs and designs for new pipes, and successively banned galvanized pipes. In 2000, the use of galvanized pipes as water supply pipes was gradually prohibited. The cold water pipes of newly created residential areas have long been rarely used galvanized pipes, and some heating pipes in residential areas use galvanized pipes.
Hot-dip galvanized steel pipes are widely used in fire safety, power installation projects and highways. Hot-dip galvanized steel pipes are widely used in construction engineering, industrial equipment, coal mining industry, pharmaceutical factory, power installation engineering, rolling stock, automobile industry, road surface, road and bridge, container, sports and cultural field equipment, agricultural machinery, machinery manufacturing, prospecting industry Equipment and other production and processing industrial production. The surface of the galvanized steel pipe has a hot-dip or hot-dip galvanized layer arc-welded electric-welded steel pipe. Hot-dip galvanizing can improve the corrosion resistance of steel pipes and increase the service life. Galvanized pipes are widely used, in addition to being used as pipelines for pressure testing, liquefied petroleum gas, oil and other general low-pressure liquid pipelines, but also as oil and gas well pipes, oil pipelines, and coking equipment in pharmaceutical factories in the petroleum industry, especially in submarine oil fields. High-temperature heat-conducting oil electric heater, glass fiber reinforced plastic cooling tower, coal distillation oil washing network switch pipe, its suspended plank road cast-in-place pile, mining tunnel supporting frame pipe, etc.
The hot-dip galvanized pipe produces an aluminum alloy profile layer by reflecting the molten metal composite material and the iron matrix, so that the matrix and the coating are closely connected. Hot dip galvanizing is to first carry out phosphating treatment on the steel pipe. In order to better remove the chemical substances on the surface of the steel pipe, after the phosphating treatment, it is carried out according to the ammonium chloride or magnesium oxide aqueous solution or the mixed aqueous solution tank of ammonium chloride and magnesium oxide. Cleaned and then sent to the hot-dip bath. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot-dip galvanized steel pipe matrix and the molten plating solution cause complicated physical and chemical reactions, resulting in a zinc rare metal layer with a tight corrosion-resistant structure. The aluminum alloy profile layer is integrated with the pure zinc layer and the steel pipe matrix, and the anti-corrosion work is diligent.
The cold galvanized pipe is phosphating treatment, and the amount of hot dip galvanizing is very small, only 10-40g/m2, and its corrosion resistance is far better than that of the hot dip galvanized pipe. Reliable galvanized pipe factory quality, most reliable galvanized pipe manufacturers do not choose hot-dip galvanizing (cold galvanizing). Only such small and dilapidated small and medium-sized enterprises choose hot-dip galvanizing, and naturally their prices are relatively cost-effective. Secondly, to replace the cold galvanized pipes that started later, it is strictly forbidden to use cold galvanized pipes as water and gas pipes. The hot-dip galvanized layer of cold galvanized steel pipe is an electroplating layer, and the zinc layer is layered with the steel pipe substrate. The zinc layer is thin, and the zinc layer is very easy to adhere to the steel pipe substrate, and it is very easy to explode. Poor corrosion resistance. Cold galvanized steel pipes are prohibited from being used as sewage pipes in newly created housing.