Steel pipe specification size

In general, the diameter of the pipe can be divided into outer diameter, inner diameter and nominal diameter. The outer diameter of seamless steel pipe is indicated by the letter D, followed by the outer diameter size and wall thickness. For example, a seamless steel pipe with an outside diameter of 108 and a wall thickness of 5MM is indicated by D108*5. Plastic pipe is also indicated by the outer diameter, such as De63. others such as reinforced concrete pipe, cast iron pipe, galvanized steel pipe and so on. Expressed in DN, generally expressed in nominal diameter in the design drawings. The nominal diameter is artificially specified to facilitate design, manufacture and maintenance. The nominal diameter of a pipe is not equal to its inner diameter and outer diameter. For example, the nominal diameter of 100MM seamless steel pipe, there are 102 * 5, 108 * 5 and so on. 108 is the outer diameter of the pipe, 5 represents the wall thickness of the pipe. So the inner diameter of the tube is (108*5-5)=98MM, but it is not exactly equal to twice the difference between the outer diameter of the tube and the wall thickness. It can also be used. However, the pipe diameter is not equal to the inner diameter of the specification name should be used in the design drawings of the nominal diameter in order to pipe, fittings, valves, flanges, gaskets and other structural dimensions and connection dimensions. Can be determined based on the nominal diameter. The nominal diameter is indicated by the symbol DN. If the outer diameter is indicated in the design drawings, a pipe specification comparison table should also be made to indicate the nominal diameter and wall thickness of a particular pipe. Pipe series standards in the design and construction of pressure piping, should first consider the selection of pressure piping and its components standard series. Although there are many standard systems applied internationally, they can be roughly divided into two categories. Pipe pressure standards are shown in Table 3. flange standards are shown in Table 4. table 3 Pressure piping standard classification of large outer diameter series small outer diameter series specification DN - nominal diameter ф - outer diameter DN15 - ф22 mm, DN20 - ф27 mm DN25 - ф34 mm, DN32 - ф42 mm DN40 - ф48 mm, DN50 - ф60 mm DN65 - ф76 (73) mm. DN80-ф89 mm dn100-ф114 mm, dn125-ф140 mm dn150-ф168 mm, dn200-ф219 mm dn250-ф273 mm, dn300-ф324 mm dn350-ф360 mm, dn400-ф406 mm dn450-ф457 mm, dn500-ф 508mm dn600-ф610mm, dn15-ф18mm, dn20-ф25mm dn25-ф32mm, dn32-ф38mm dn40-ф45mm, dn50-ф57mm dn65-ф73mm, dn80-ф89mm dn100-ф108mm, dn125-ф133mm dn150-ф159mm, dn200-ф219mm dn250-ф273mm, dn300-ф325mm dn350-ф377mm, dn400-ф426mm dn450-ф480mm, dn500-ф530mm DN600-ф630mm, 3. What are the specifications for the length of scaffolding steel pipe? According to "JGJ Safety Technical Specification for Fastened Steel Pipe Scaffolding for Building Construction" 130-2011, the scaffolding shall be made of Q235 common steel pipe as stipulated in the current national standard "Straight Sewing Welded Steel Pipe" GB/T13793 or "Welded Steel Pipe for Low-Pressure Fluid Conveyance" GB/T3091; the steel quality of the steel pipe shall be in line with the current national standard "Carbon Structural Steel" GB/T700 in the provisions of Q235 grade steel. The scaffolding shall be made of the scaffolding pipe specifications provided by the Square Pipe Association:There are generally two kinds of steel pipes for scaffolding, one with an external diameter of 48mm and a wall thickness of 3.5mm; the other with an external diameter of 51mm and a wall thickness of 3mm. The scaffolding shall be made of φ48.3*3.6 steel pipe. The maximum mass of each steel pipe should not be greater than 25.8 kg ...