2021-12-03
1. Hot-dip galvanized pipes are widely used, mainly in curtain walls, construction, machinery manufacturing, solar power generation brackets, steel structure projects, etc., especially in curtain walls and buildings. So, how should we distinguish when buying?
Teach you a few points to distinguish between hot-dip galvanized square pipe and cold-dip galvanized square pipe.
First, look at the appearance. The cold galvanized square tube is smooth and bright in appearance. The appearance of the hot-dip galvanized square pipe is slightly rougher than that of the cold-dip galvanized square pipe.
Second, look at colors. The cold-galvanized square tube is yellowish-green, bluish-white or slightly colorful when the cold-galvanized square tube is at a certain angle to the sun. Galvanized square pipe is a kind of pipe that we have used a lot in recent years, so we really want to know what uses this pipe has in our lives? Let's briefly introduce the role of this kind of pipe in our lives.
Galvanized square pipe is a special pipe with a hollow cross section. It is precisely because of this special design that this pipe has a lot of expansion in the application of our lives. Especially in our shipbuilding and construction industries, but also in the military and aviation fields. The main function of galvanizing is to improve the service life and corrosion resistance of the square tube, which also makes the performance of the galvanized square tube further improved, and the quality of the galvanized layer is also directly affected. The quality of our galvanized square pipe and the price of galvanized square pipe. The color of the hot-dip galvanized square tube is silvery white at a certain angle to the sun.
Third, the thickness of the zinc layer. There is a big difference in the galvanizing process between cold galvanized pipe and hot-dip galvanized pipe. The corners of cold galvanized pipes are prone to "electric burning". The color of this part is dark and the zinc layer is thick. The current dead angle is easy to form at the internal corner, and the undercurrent area is generated. The zinc layer in this part is relatively thin, and there is no zinc layer on the inner wall of the cold galvanized pipe. The cold galvanized square tube has no zinc tumors or agglomeration as a whole, but the overall zinc layer is relatively thin, and the thickness of the outer wall zinc layer is 5μm-10μm. The inner and outer walls of the hot-dip galvanized square tube have zinc layers attached, and there will be water marks and a few zinc nodules, but the overall zinc layer is thicker, and the thickness of the inner and outer walls of the square tube is more than 70μm.
The above methods can also be used to identify galvanized steel products such as cold galvanized angle steel, hot-dip galvanized angle steel, cold galvanized channel steel, and hot-dip galvanized channel steel.
2. Standards and uses of galvanized pipes
First, the galvanized welded square pipe for low pressure fluid transportation, the standard number is GB/T3091-2008. Representative materials Q235A, Q235BQ345B, etc. It is mainly used to transport water, gas, air, oil and heating hot water or steam, and its use is limited to generally lower pressure fluids.
Second, the galvanized welded square pipe for low pressure fluid transportation, the standard number is GB/T3092-2008. The representative material is the same as above. It is mainly used to transport water, gas, air, oil, heating hot water or steam and other generally lower pressure fluids. The outer surface of the square tube adopts hot-dip galvanizing or cold-dip galvanizing anti-corrosion process.
Third, the welding square pipe for fluid transportation in mines, the standard number is GB/T14291-2000. The representative material is Q235A, grade B steel. It is mainly used for straight seam welding square pipes for mine air pressure, drainage, and shaft gas discharge.
Fourth, the large-diameter electric welded square pipe for low-pressure fluid transportation, the standard number is GB/T14980-1994. Representative material Q235AB level. Mainly used to transport low-pressure fluids such as water, sewage, gas, air, heating steam, etc.
Fifth, the mechanical structure uses stainless steel welded square pipe, the standard number is GB/T12770-1991. Representative materials 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc. Mainly used in machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical parts and structural parts.
Sixth, the stainless steel welded square tube for fluid transportation, the standard number is GB/T12771-1991. Representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc. Mainly used to transport low-pressure corrosive media.
Seventh, spiral square pipe for low-pressure transportation (standard of the Ministry of Petroleum)? The standard number is SY/T5037-2008. The representative material is carbon steel such as Q235BQ345B. Mainly used for low-pressure transportation of water, oil, natural gas, heating and other pipelines.
Eighth, square pipes for conveying flammable and non-flammable fluids, the standard number is GB/T9711.1 (GB/T9711.2)-1997. The representative material is L245-L415, and other pipeline steels. It is mainly used for conveying flammable and non-flammable fluids with low or high pressure square pipes, which require relatively high requirements. Mainly used in engineering construction, glass curtain wall, door and window decoration, steel structure, guardrail, machinery manufacturing, automobile manufacturing, home appliance manufacturing, shipbuilding, container manufacturing, electric power, agricultural construction, agricultural greenhouses, bicycle racks, motorcycle racks, shelves, fitness equipment , Leisure and tourism products, steel furniture, various specifications of oil casing pipes, oil pipes and line pipes, water, gas, sewage, air, heating and other fluid transportation, fire protection and support, construction industry and other fields