What is the standard of pipe and what is the meaning of DN and Φ?
DN refers to the nominal diameter of the pipe. Note: This is neither the outer diameter nor the inner diameter; it should be related to the imperial unit in the initial stage of pipeline engineering development; it is usually used to describe the galvanized steel pipe and its correspondence with imperial units is as follows:
4 points: 4/8 inches: DN15;
6 points: 6/8 inches: DN20; 1 inch tube:
1 inch: DN25; inch 2 tube: 1 1/4 inch: DN32;
Inch half tube: 1 1/2 inch: DN40;
Two inch tube: 2 inches: DN50;
Three inch tube: 3 inches: DN80 (many places are also marked as DN75);
Four inch tube: 4 inches: DN100;
Φ means the outer diameter, such as Φ168×7 pipe, which means the outer diameter is 168mm, the wall thickness is 7mm, and the inner diameter is calculated to be 154mm, DN150. 
Editor in charge: Wang Zhen
At present, the bottleneck and disadvantage of large scale development and manufacturing of isotropic Graphite in China still exist: the design and manufacture of large, special cold and other static presses have not kept up with it. (2) other facilities not perfect, such as the large and super large (1200 mm) Φ graphite impregnated, roasting, graphitization, purification processing, special machine tools machining must be perfect.
Fortunately, there are now cold and other static press factory to start to design and manufacture the large specification (1200mm) cold isostatic pressing machine, if the successful two years can be put into production. At the same time, the development of large scale homogenated graphite is also used in the development of vibration-forming graphite, carbon/carbon composite materials, carbon fiber and other materials used in silicon crystal production.
In the face of such a huge graphite market prospect, and graphite profound understanding to the graphite pieces processing technology progress is the precondition that the future market share, the graphite with milling, car, plane, cutting, drilling, grinding and CNC (CNC), main products including graphite, graphite mold, such as thermal field static pressure graphite, High Purity Graphite, EDM graphite, graphite crucible, graphite flake, Graphite Powder for the SPD, all kinds of graphite profiled, etc., products are now widely used in solar photovoltaic (pv), mold, electronic semiconductor, electrical discharge machining, metallurgy, chemical industry, nuclear industry and quartz, etc. We hope to cooperate with you and develop together with you in the future.
Graphite Shaped Parts,Shaped Graphite,Brushed Graphite Milk,Forged Graphite Milk
Fengcheng Ruixing Carbon Products Co., Ltd , http://www.lnfcrxts.com