The biggest difference between American standard pipe fittings and national standard pipe fittings is the size. American standard is commonly referred to as A series, while national standard is B series.

For example, elbow: DN100*6, the nominal diameter is DN100, the diameter of national standard DN100 is 108 MM, the thickness is 6 MM, the inch of American standard DN100 is 4 ", the outer diameter is 114.3 MM, the thickness is 6 MM, and the length of American standard elbow is slightly longer than that of national standard. It also means that pipe fittings with the same nominal diameter (including elbows, tees, big and small heads, pipe caps). The caliber sizes of American and national standards are different.

The national standard is divided into A series and B series, which are two outer diameter sizes. Series A corresponds to the size of the American Standard. At present, most of the steel pipe mills in China can produce materials according to two standards.

1. Chemical Constituents, China's S, P Content Requirements are Stricter

2. The mechanical property requirements are slightly different and roughly equivalent.