What's the actual size of the DN25?
Steel pipe is not only used to transport fluid and powder solid, exchange heat energy, and manufacture mechanical parts and containers, but also is an economic steel. It can reduce weight and save 20 to 40% of metal by using steel pipe to make building structure, network frame, prop and mechanical support. Moreover, it can realize factory mechanization construction. Using steel pipe to manufacture road bridge can not only save steel, simplify construction, but also greatly reduce the area of coating protective layer, save investment and maintenance cost.
Steel pipe production technology development began in the bicycle manufacturing industry rise, early nineteenth Century during the oil development, the two world war ships, boilers, aircraft manufacturing, manufacturing of power boiler after the Second World War, the development of chemical industry, petroleum and natural gas drilling and mining and transportation, are promoted in production the quality and variety, the development of steel tube industry.
Different materials of steel pipe, nominal diameter of the same, then its outer diameter is the same, diameter = outside diameter -2 times, wall thickness.
DN25 refers to the theoretical size of the inner hole of the pipe. That is to say, the theoretical dimension of the inner diameter of the pipe is 25 (the metric tube refers to the inner diameter, and the English tube is also to indicate the inner diameter, for example: 3/8, the inner diameter is 9.525, and the diameter of the 1/2 is 12.7, and the diameter of the 5/8 is 15.875). The outer diameter is theoretical in diameter, plus the wall thickness specified by the state (which is artificially specified and has no formula)The theoretical diameter of DN25 is 25, and the outer diameter is Phi 33.7 and phi 32(but there is also the outside diameter of the mark. The mark is: the outer diameter * wall thickness, such as: 32 * 2, that is to say, the outer diameter is 30, the inner diameter is 26)
