The diameter of the spiral pipe is also learned

In general, the diameter of the spiral pipe can be divided into diameter, diameter, nominal diameter. The outer diameter of the pipe for the spiral pipe is indicated by the letter D, followed by the additional outer diameter of the size and wall thickness, for example, the outer diameter of 108 seamless steel pipe, wall thickness of 5MM, with D108 * 5 said, plastic pipe also With the outer diameter, such as De63, other such as reinforced concrete pipe, cast iron pipe, galvanized pipe and other DN said, in the design drawings are generally used to represent the nominal diameter, nominal diameter is designed to manufacture and maintenance of the convenience of man-made A standard, also more nominal diameter, is the pipe (or pipe) specification name.
The nominal diameter of the pipe and its inner diameter, the outer diameter is not equal, for example: nominal diameter of 100mm spiral steel pipe 102 * 5,108 * 5 and so on several, 108 for the pipe diameter, 5 pipe thickness, Therefore, the diameter of the steel pipe is (108 * 5-5) = 98MM, but it is not exactly equal to the difference between the wall thickness of the steel pipe minus two times. It can also be said that the nominal diameter is close to the inner diameter, but it is not equal to the inner diameter The name of a pipe diameter, in the design drawings to use the nominal diameter, the purpose is to be based on the nominal diameter can be determined pipe, pipe, valve, flange, gasket and other structural size and connection size, nominal diameter using symbol DN , If the design drawings in the use of outer diameter, it should also make a pipe specification table, indicating the nominal diameter of a pipe, wall thickness.

Abstract from Tianjin Xinyue Steel Group