Shandong Seamless Steel Tube Factory for everyone to explain the nominal diameter (DN) Nominal diameter, also known as the mean outside diameter. The nominal diameter is the dimension of all the pipeline accessories in the pipeline system. The nominal diameter is a convenient round integer for reference, and it has only a non-strict relationship with the processing dimensions. The nominal path is followed by the letter "DN" followed by a number sign. This is because the pipe rim from the metal pipe is very thin. The outer diameter of the pipe is almost the same as the inner diameter of the pipe. Therefore, the average value of the outer diameter of the pipe and the inner diameter of the pipe is called as the pipe diameter. DN is the nominal diameter, nominal diameter (or nominal diameter), and is the general caliber of various pipes and piping accessories. The pipes of the same nominal diameter and the pipeline accessories can be connected to each other and have interchangeability. It is not the actual outer diameter or inner diameter of the pipe, although its value is close to or equal to the inner diameter of the pipe. In order to make the pipe and pipe fittings uniform in size, nominal diameter (also called nominal diameter, nominal diameter) is used. For example, the thickness of welded steel pipe can be divided into thin-walled steel pipe, ordinary steel pipe and thicker steel pipe. Its nominal diameter is not the outside diameter, nor is it the inside diameter, but a nominal size that approximates the inside diameter of a normal steel pipe. Each nominal diameter corresponds to one outer diameter, and its inner diameter value varies with the thickness. The nominal diameter can be expressed in metric mm, or in inch. Pipe fittings are also represented by the nominal diameter, meaning that there is a seam pipe. The calculation method is: DN50 is 2 inches 1 inch = 25.4 DN50 = DN + (wall thickness * 2) Shandong seamless steel pipe plant Liaocheng Wanlihong Steel Pipe Factory is a professional manufacturer of seamless steel pipe, high quality and low price, spot supply of Shandong Seamless Steel Tube Factory Wanlihong Steel Pipe welcomes friends from all walks of life come to order negotiations, the hotline: 0635-2110045 2110345.