DN stands for welded steel pipe. DN refers to the nominal diameter of the pipeline, which is the average of the outer diameter and inner diameter. For example, water and gas transmission steel pipes, cast iron pipes, steel plastic composite pipes and PVC pipes, the nominal diameter 'dn' shall be marked on them. What is DN? Pipe is very common in industry, and the diameter of pipe can be divided into outer diameter, inner diameter, nominal diameter, etc. it is usually expressed in English letters, so we should also find out when using it, so as not to cause wrong use.
Most habitually use DN to mark welded steel pipes. DN refers to the nominal diameter of the pipeline, which is the average value of outer diameter and inner diameter. Generally, DN = de - 0.5 & times; Pipe wall thickness.
For pipes such as water and gas transmission steel pipes, cast iron pipes, steel plastic composite pipes and PVC pipes, the nominal diameter 'dn' shall be marked on them, such as DN15, DN50, etc., which will be more concise and clear.