Norfolk60 galv
San-RamonDN25 
HerediaDN25 gaNorfolkPrice of 1-inch galvanized water pipe,
Today, with the development of the world, all fields are coming rapidly, which makes the demand for square tube higher and higher, and the requirements of customers for square tube higher and higher. Now we are studying a new square tube. The following mainly introduces the performance of square tube in tensile strength.
Be sure to select special for square pipe cutting.
Norfolk.The square tube for fluid transportation (gbt8163-199) is a general square tube for transporting water, oil, gas and other fluids.
The normal process flow is as follows: the round steel is perforated to form a tube embryo, the black skin on the outer surface is washed off, and then grinding is carried out. After passing the inspection, the rolling mill or cold drawing and cold drawing are carried out. Annealing is required for wall reduction, but not for air drawing. After forming, annealing and straightening are carried out, and pickling is tested and stored in the warehouse. Basically these are the processes. Better manufacturers will perform whitening treatment during annealing to make the surface treatment more beautiful. The narrow blank of square pipe can produce welded pipe with larger diameter, and the blank of the same width can also produce welded pipe with different diameter. However, compared with the straight seam square pipe with the same length, the weld length increases by 60%, and the production speed is low. Square pipes with large or thick diameter are usually made of steel blank directly, while small welded pipes and thin-walled welded pipes only need to be directly welded with steel strip. Then after simple polishing, wire drawing is OK. Therefore, straight seam welding is mostly used for relatively welded pipes, and spiral welding is mostly used for large-diameter welded pipes.
.The iron filings and burrs on the cutting section shall be completely removed with a file or appropriate tools to prevent the iron filings and burrs from scratching the rubber O-ring and other accessories when connecting another part.
Dimensional stability for high-precision square tubes, the required accuracy is high, so the dimensional stability must be maintained. Due to straightening in the air and slow cooling speed, it has the effect of stabilization and will increase the number of residual square tubes in the, so it must be cooled; Reduce quenching deformation because the square tube is slender, it is easy to deform during quenching, so its deformation must be strictly controlled. Heat treatment is a key process. In the process of quenching and cooling, the cold plasticity shall be corrected in time, which is a key step to ensure the improvement of its qualification rate. Therefore, hot bath quenching or cooling in oil for a fixed time shall be carried out to propose thermal correction.
Electrochemical polishing: long specular gloss, stable process, it is mainly applied to high-grade products, also known as hollow cold-formed section steel. It is a section steel with square section shape and size made of hot-rolled or cold-rolled strip or coil plate after cold bending and high-frequency welding.
Square tubes for low and medium pressure boilers (gb3087-199) are high-quality carbon structural steel hot-rolled and cold drawn (rolled) square tubes for superheated steam tubes, large smoke tubes, small smoke tubes and arch brick tubes for locomotive boilers. Square tubes for high-pressure boilers (gb5310-199 is a high-quality carbon steel, alloy steel and stainless heat-resistant steel square tube for the heating surface of water tube boilers with high pressure and above. High pressure square tube for chemical fertilizer equipment (GB 79-200 is a high-quality carbon structural steel and alloy steel square tube suitable for chemical equipment and pipelines with working temperature of - 40 ~ 400 ℃ and working pressure of 10 ~ 30mA.
Tensile strength of square tube (& sigma; b): the stress (& sigma;) obtained by dividing the force (FB) borne by the sample during breaking by the original cross-sectional area (so) of the sample during stretching, which is called tensile strength (& sigma; b), and the unit is nmm2 (MPA). It represents the large capacity of metal materials under tension.
Industry management.In case of doubt about the strength of solid q355b square tube, it can be based on tb10426 & mdash; 200 the compressive strength of q355b square tube on the surface of the structure is indirectly measured by the post loading method. The measurement should be carried out at the age of about 56 days, and the measured average strength is required to be not lower than the design value or the specified value. When the requirements are not met, the core drilling sampling method can be used for verification.
Section shape classification square tube is classified according to section shape: simple section square tube: square tube, rectangular square tube.
The advantages of real bending are small reverse, accurate forming and as long as the roll shape is accurate, the R of inner corner forming is more accurate. The disadvantage of solid bending is that it has tensile thinning effect. The actual bending will produce tension at the bending point, and the tensile effect will shorten the longitudinal length of the bending line; The metal at the real bend will become thinner due to stretching.
The welding sequence is to reduce deformation. The welding sequence of rectangular butt welding shall adopt layered and symmetrical skip welding from the middle to both sides according to the following principles. The welding deformation is smaller than that of straight through welding, which is conducive to the dispersion and release of stress and avoid complex stress in weldments. During straight through welding, the narrow plastic deformation zone formed at the beginning of welding only occurs once. Moreover,NorfolkConnection mode of galvanized square pipe, due to continuous welding, the heat input is large, the heating area is large, so the shrinkage deformation after welding is very large. In case of layered and segmented skip welding, the section of each layer is very small, and the heat required is small, and each layer is divided into several sections for skip welding. Each welding section basically re establishes the secondary temperature field on the cold steel plate, and a narrow plastic deformation zone appears each time. Therefore, the average width of the plastic deformation zone (i.e. the size of transverse shrinkage) is smaller than that of the corresponding layered straight through welding and the longitudinal shrinkage is also smaller, The welding deformation is smaller than that of continuous filling.
knowledge.The general delivery length of square pipe is 3200mm-13000mm, mostly 65000mm and 13000mm. The square tube is allowed to deliver short and non fixed length products not less than 2300mm, or in the form of interface tube, but the Demander shall cut off the interface tube when using it. The allowable deviation of the wall thickness of square pipe shall not exceed plus or minus 10% of the nominal wall thickness when the wall thickness is not greater than 10mm, plus or minus 8% of the wall thickness when the wall thickness is greater than 10mm, except for the wall thickness of corners and weld areas. The weight of short gauge and non fixed gauge products shall not exceed 8% of the total delivery. For square tubes with a theoretical weight greater than 20kgm, it shall not exceed 5% of the total delivery. We have many different ways in square tubes. Different ways make square tubes have different characteristics. According to these characteristics, we can correctly select the appropriate application field, In this way, the use efficiency of square tube can be improved. Next, we will mainly explain the characteristics of pipe cooling technology below. What are the main characteristics of square tubes? Square tube parts have accurate dimensions and smooth surfaces: the dimensional accuracy of cold parts developed at present can reach grade 8 ~ 9. If ideal ones are adopted, their accuracy is second only to that of fine polished surfaces. Therefore, cold parts generally do not need to be reprocessed, and a small amount only need finishing (grinding).
Stage (1978 & mdash; 1992)
The calculation method theory of square tube mechanics is feasible to calculate static structures, such as warehouses houses and bridges, but it is not suitable for moving components such as wheels. At this time, people often use the plastic theory. The research of the plastic theory can be traced back to 1914. In 1975, the European Design Association formulated D plastic design code which is mainly used for plane beams under static load and bending stress For the frame structure with stress, the requirements are as follows:% 26sigma; B% 26sigma;% 26zeta;% 26ge;% 26delta;% 26ge; 15% for high-rise buildings, more detailed calculation is required. In the case of plastic design, the allowable stress is usually calculated according to the safety factor that the allowable stress is not less than the dynamic load and multiplied by the allowable stress. In the case of bending of an axis, the formula a = w can be used Using plasticity instead of calculated strength can improve the bearing capacity of members by 14%.
Norfolk.Q355b square pipe for mining fluid transportation, Standard No.: gbt14291-2000. The representative material is Q235 grade B steel. It is mainly used for straight seam q355b square pipe for mine air pressure, drainage and shaft gas drainage.
The researcher's test before using the strip thinning drawing also confirmed that using the strip thinning drawing can greatly reduce the large value of tangential residual stress of the drawn parts and effectively prevent the occurrence of longitudinal cracking. According to different deformation degree and original sheet thickness, the appropriate thinning coefficient & psi is selected; N (generally 0.9t ~ 0.95t), if & psi; If n is too small, the deformation stress will increase sharply, resulting in the fracture of the bottom of the drawing part.
It seems that preheating the q355b square tube can avoid a lot of problems, and there will be a better guarantee that the q355b square tube itself is a quality problem.