The expression of steel pipe diameter should meet the following requirements:

1. For water and gas transportation steel pipes (galvanized or non-galvanized), cast iron pipes and other kinds line pipes, the pipe diameter should be expressed by the nominal diameter  DN (such as DN15, DN50);

2. For seamless steel pipes, welded steel pipes (straight seam or spiral seam), copper pipes, stainless steel pipes and other pipes, the pipe diameter should be expressed in terms of outer diameter D×wall thickness (such as D108×4, D159×4.5, etc.);

3. For reinforced concrete (or concrete) pipes, clay pipes, acid-resistant ceramic pipes, cylinder tile pipes, etc., the pipe diameter should be expressed by the inner diameter d (such as d230, d380, etc.);

4. For plastic pipes, the pipe diameter should be expressed accordance with the product standard method;

5. When the design uses the nominal diameter DN to indicate the pipe diameter, there should be a comparison table between the nominal diameter DN and the corresponding product specifications.

Changsha Xiangjia Metal Materical Co., Ltd. the Steel Pipe Division of ADTO GROUP, is one of the leading manufacturers of steel products in China. We specializes in manufacturing all kinds of steel pipe in various grades and sizes. Years of production experience and manufacturing facilities who have a capacity of 200,000 tons per annual will ensure the good quality and competitive duration of our products.