Square tube classification
1. process classification
Square pipes are divided into hot-rolled seamless square pipes, cold-drawn seamless square pipes, extruded seamless square pipes and welded square pipes according to the production process.
Welded square pipes are divided into:
(a) according to the process is divided into arc welding square tube, resistance welding square tube (high frequency and low frequency), gas welding square tube and furnace welding square tube.
(b) Weld the square pipe and spiral weld the square pipe according to the weld seam.
2. Material classification
Square pipes are divided into plain carbon steel square pipes and low alloy square pipes according to materials. Plain carbon steel is divided into: Q 195, Q2 15, Q235, SS400, 20# steel, 45# steel, etc. Low alloy steel is divided into Q345, 16Mn, Q390, ST52-3, etc.
3. Classification of production standards
Square pipes are divided into national standard square pipes, Japanese standard square pipes, British standard square pipes, American standard square pipes, European standard square pipes and non-standard square pipes according to production standards.
4. Section shape classification
Square tubes are classified according to the cross-sectional shape:
(1) Square pipes have simple section square pipes and rectangular square pipes.
(2) Square pipes with complex cross sections, such as flower-shaped square pipes, open square pipes, corrugated square pipes and irregular square pipes.
5. Classification of surface treatment
Square pipes are divided into hot-dip galvanized square pipes, electro-galvanized square pipes, oiled square pipes and pickled square pipes according to surface treatment.
6. Classification of uses
Square pipes are divided into decorative square pipes, square pipes for machine tools and equipment, square pipes for mechanical industry, square pipes for chemical industry, square pipes for steel structure, square pipes for shipbuilding, square pipes for automobiles, square pipes for steel beams and columns, and square pipes for special purposes.
7. Classification of wall thickness
Square pipes are divided into super-thick-walled square pipes, thick-walled square pipes and thin-walled square pipes according to their wall thickness.
Characteristic use
1, square tube product description
Square tube is a kind of light thin-walled steel tube with hollow square section, also known as cold-formed steel. It is made of Q235 hot-rolled or cold-rolled strip or coil as the base material, which is processed by cold bending and then welded by high frequency. In addition to the thickening of the wall thickness, the corner size and edge flatness of hot-rolled extra-thick-walled square tubes reach or even exceed the level of resistance welding cold-formed square tubes. Good comprehensive mechanical properties, weldability, cold and hot workability and corrosion resistance, and good low temperature toughness.
2. The use of square tube
Square pipes are used for high-load welded structural parts such as construction, machinery manufacturing, steel structure engineering, shipbuilding, solar power generation bracket, steel structure engineering, power engineering, power plant, agricultural and chemical machinery, glass curtain wall, automobile chassis, airport, boiler construction, highway railings, housing construction, pressure vessels, oil storage tanks, bridges, power station equipment, lifting and transportation machinery.
Square pipe quotation
The price of a square pipe is generally around 8000 tons, and a variety of materials can form a square pipe body, which is medium, what is the use and where it is used. Square pipes are mostly made of steel pipes, which are disassembled, flattened, curled and welded into round pipes, then rolled into square pipes, and then cut into required lengths. Generally, 50 square tubes per package are mostly large in size from the spot, ranging from10 *10 * 0.8-1.5 ~ 500 * 500 *10-25. Square pipes are divided into structural square pipes, decorative square pipes, architectural square pipes and mechanical square pipes according to their uses.
Square tube identification method
With the development of economy, there are more and more counterfeit products in society. In order to prevent ourselves from being deceived when buying square pipes, we need to know some knowledge about how to judge the authenticity of square pipes: "We can judge by observing the surface smoothness and flatness of square pipes. If the surface of the square tube is relatively flat, it can reflect that the square tube is good. On the contrary, if the surface is not so flat and the size and thickness are not standardized, it can reflect the inferior quality of the square pipe.
Square tube storage method
1. Select the appropriate site and warehouse.
(1) The site or warehouse for storing steel pipes should be in a clean and well-drained place, away from factories and mines that produce harmful gases or dust. Remove weeds and all sundries on site and keep steel pipes clean;
(2) Materials corrosive to steel pipes such as acid, alkali, salt and cement shall not be stacked in the warehouse. Different kinds of steel pipes should be stacked separately to prevent confusion and contact corrosion;
(3) Large section steel, rails, humiliating steel plates, large-diameter steel pipes and forgings can be stacked in the open air;
(4) Small and medium-sized steel bars, wire rods, steel bars, medium-diameter steel pipes, steel wires and wire ropes can be stored in a well-ventilated shed, but they must be covered and padded;
(5) The warehouse can store some small steel pipes, thin steel plates, steel belts, silicon steel sheets, small-caliber or thin-walled steel pipes, all kinds of cold-rolled and cold-drawn steel pipes and metal products with high price and easy corrosion;
(6) The warehouse should be selected according to the geographical conditions, and the common closed warehouse is generally adopted, that is, the warehouse with walls on the roof, tight doors and windows and ventilation devices;
(7) The warehouse should be ventilated in sunny days, closed and moisture-proof in rainy days, and always maintain a suitable storage environment.
2. Reasonable stacking, first in first out
(1) The principle requirement of stacking is to pile up according to varieties and specifications under the condition of stable stacking and ensuring safety, and different varieties of materials should be piled up separately to prevent confusion and mutual corrosion;
(2) It is forbidden to store items corrosive to steel pipes near the crib;
(3) The bottom of the crib should be padded high, solid and flat to prevent the material from being affected with damp or deformed;
(4) The same materials are stacked separately according to the warehousing order, so as to facilitate the implementation of the first-in first-out principle;
(5) There must be wooden mats or stones under the steel beams piled in the open air, and the stacking surface is slightly inclined to facilitate drainage, and pay attention to the straightness of materials to prevent bending deformation;
(6) The stacking height for manual operation shall not exceed 1.2m, and the stacking width for mechanical operation shall not exceed12.5m；:
(7) There should be a certain passage between stacks. The inspection passage is generally O.5m, and the access passage depends on the size of materials and transportation machinery, generally1.5 ~ 2.om;
(8) Pad the bottom of the chimney. If the warehouse is on Chaoyang cement floor, it can be raised by O.1m; If it is silt, it must be raised by 0.2 ~ 0.5m. If it is an open field, the cement floor should be raised by 0.3 ~ 0.5m, and the sand surface should be raised by 0.5 ~ 0.5 ~ O.7m9) Angle steel and channel steel piled in the open air should be put down, that is, I-beams should be placed vertically, and the groove surface of I-beams of steel pipes should not be upward, so as to avoid water rusting.
3. Packaging and protective layer of protective materials
Coating preservatives or other electroplating and packaging before leaving the factory is an important measure to prevent materials from rusting, which should be protected during transportation and loading and unloading to avoid damage and prolong the storage period of materials.
4. Keep the warehouse clean and tidy, and strengthen material maintenance.
(1) Before warehousing, materials should be rain-proof or impurity-proof. Wet or soiled materials should be wiped by different methods according to their properties, such as wire brushes with higher hardness and cloth and cotton with lower hardness.
(2) After the materials are put into storage, they should be checked frequently. If there is corrosion, the corrosion layer should be removed;
(3) Generally, after the surface of steel pipe is cleaned, there is no need to apply oil, but for high-quality steel, alloy sheet steel, thin-walled pipe, alloy steel pipe, etc. After rust removal, the internal and external surfaces should be coated with antirust oil before storage;
(4) The seriously corroded steel pipe should not be stored for a long time after derusting, and should be used as soon as possible.