Galvanized pipe and
seamless steel pipe are two areas of steel pipe. Galvanized refers to the surface of the steel pipe being galvanized. It may be a
welded steel pipe or a seamless pipe. Galvanized pipes are more corrosion-resistant, and seamless steel pipes can withstand greater pressure. Galvanized steel pipes are not easy to rust because of the protection of zinc. The difference between galvanized steel pipes and seamless steel pipes can be understood as galvanized seamless steel pipes and seamless steel pipes. Galvanized steel pipes refer to steel pipes with a layer of zinc applied to the surface of ordinary steel pipes. The zinc layer can form a protective film on the surface of the steel pipe, which can effectively extend the service life of the steel pipe and improve the corrosion resistance of the steel pipe. Galvanized steel pipes are divided into hot-dip galvanizing and electro-galvanizing. Hot-dip galvanizing has a thick galvanized layer, which has the advantages of uniform coating, strong adhesion and long service life. Electro-galvanizing has low cost, but the surface is not very smooth, and its own corrosion resistance is much worse than that of hot-dip galvanized pipes. Seamless steel pipes are made of a whole piece of metal, and steel pipes without seams on the surface are called seamless steel pipes.
Hot-dip galvanized pipe: Hot-dip galvanized pipe is to make molten metal react with iron matrix to produce alloy layer, so that the matrix and coating are combined. Hot-dip galvanizing is to pickle the steel pipe first. In order to remove the iron oxide on the surface of the steel pipe, after pickling, it is cleaned in an ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to the hot-dip galvanizing tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. Most processes in the north use the galvanized strip direct coiling zinc supplementation process.
Hot-dip galvanized seamless steel pipe: Galvanized seamless pipe sounds high-end. Galvanized seamless pipe generally adopts hot-dip galvanizing. The galvanizing layer is thick and the galvanizing amount is very small, only 10-50g/m2. Its own corrosion resistance is much different from that of hot-dip galvanized pipe. Therefore, it has stronger corrosion resistance and longer service life. With the improvement of building quality, the service life and strength requirements of pipeline systems are also improved. Products often replace galvanized steel pipes and are used in pipeline systems with higher requirements for fire protection, air conditioning and other circulating water and gas medium transportation. Regular galvanized pipe manufacturers are allowed to use cold-dip galvanized pipes as water and gas pipes. The galvanized layer of cold-dip galvanized steel pipes is an electroplated layer, and the zinc layer is independently layered from the steel pipe substrate. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe substrate and is easy to fall off. Therefore, its corrosion resistance is poor. In newly built houses, it is forbidden to use cold-dip galvanized steel pipes as water supply pipes.
What is the difference between galvanized seamless steel pipes and galvanized pipes?
The main difference between galvanized seamless steel pipes and galvanized steel pipes is:
① Different uses
Galvanized steel pipes are generally used to make fences, fences, guardrails, balcony guardrails, etc. Widely used in municipal engineering, roads, factories, campuses, development zones, garden squares, communities and other places.
Seamless steel pipes are very important in industry and can be used as fluid delivery pipelines. Seamless steel pipes are mainly used to make mechanical parts with moderate load capacity and speed, parts with large loads, moderate impact and moderate speed, and are widely used in industries such as petroleum, aviation, and automobiles.
② Different materials
Galvanized seamless steel pipe is made of seamless steel pipe after galvanizing. Generally, it is made of high-quality carbon structural steel such as 10, 20, 30, 35, 45, or low-alloy structural steel such as 16Mn, 5MnV, or bonding steel such as 40Cr, 30CrMnSi, 45Mn2, and is made by hot rolling or cold rolling.
Ordinary galvanized steel pipes are generally rolled into pipes by steel plates and then welded into shape, mostly Q195, Q215, Q235 ordinary carbon steel.
③ Different physical properties
Galvanized pipes are more corrosion-resistant, and seamless steel pipes can withstand higher pressures. Due to the protection of zinc, galvanized pipes are not easy to rust.
Galvanized pipes are lighter than seamless steel pipes. If used for balconies, it is best to use galvanized light pipes, and seamless steel pipes should not be used for balconies.
Because seamless steel pipes have thick walls and are naturally heavy, the cost of seamless steel pipes is higher than that of galvanized pipes, and galvanized pipes are very durable, and their service life is much longer than that of seamless steel pipes.
The above are some differences between galvanized pipe and seamless steel pipes. The so-called galvanized pipes are mainly used for gas transportation and heating. As a water pipe, galvanized pipes have a lot of rust inside after a few years of use. The yellow water flowing out not only pollutes sanitary ware, but also contains bacteria growing on the rough inner wall; the high content of heavy metals in the water causes corrosion, which seriously endangers human health.