Q235B Carbon Steel Pipe Supplier-GNEE
- 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 units in the early days of the development of pipeline engineering; it is usually used to describe galvanized steel pipes, and its correspondence to the imperial units is as follows:
4 branches: 4/8 inch: DN15;
6 branches: 6/8 inch: DN20;
1 inch pipe: 1 inch: DN25;
Inch tube: 1 and 1/4 inches: DN32;
Half pipe: 1 and 1/2 inches: DN40;
Two-inch pipe: 2 inches: DN50;
Three-inch pipe: 3 inches: DN80 (also marked as DN75 in many places);
Four-inch pipe: 4 inches: DN100;
Water and gas transportation steel pipes (galvanized steel pipes or non-galvanized steel pipes), cast iron pipes, steel-plastic composite pipes, polyvinyl chloride (PVC) pipes and other pipes should be marked with the nominal diameter "DN" (such as DN15, DN20)
Hot Rolled Steel Pipe
- De mainly refers to the outer diameter of the pipe
Generally, De marks need to be marked in the form of outer diameter
Taking galvanized welded steel pipes as an example, the two marking methods of DN and De are as follows: DN20 De25×2.5mm
DN25De32×3mm
DN32De40×4mm
DN40De50×4mm
We are accustomed to using DN to mark welded steel pipes, and rarely use De to mark pipes when the wall thickness is not involved; but marking plastic pipes is another matter; it still depends on industry habits. In the actual construction process The 20, 25, 32 and other pipes we abbreviate refer to De, not DN. There is one specification difference here. Failure to understand it can easily cause losses during the procurement and construction processes.
The connection methods of the two pipe materials are nothing more than: threaded connection and flange connection. Other connection methods are rarely used.
Both galvanized steel pipes and PPR pipes can be connected using the above two methods. However, it is more convenient to use screw threads for pipes smaller than 50 mm, while flanges are more reliable for pipes larger than 50 mm.
Note: If two metal pipes of different materials are connected, consider whether there will be a galvanic reaction, otherwise it will accelerate the corrosion rate of the active metal pipe. It is best to use a flange connection and use an insulating material such as a rubber gasket to separate the two. Separate the two metals, including bolts, with washers to avoid contact.
Carbon Steel Pipe
- D generally refers to the inner diameter of the pipe, d represents the inner diameter of the concrete pipe, and Φ represents the diameter of an ordinary circle.
Of course, Φ can also represent the outer diameter of the pipe, but at this time it should be multiplied by the wall thickness.
For example: Φ25×3 means a pipe with an outer diameter of 25mm and a wall thickness of 3mm.
For seamless steel pipes or non-ferrous metal pipes, "outer diameter × wall thickness" should be marked.
For example: Φ107×4, where Φ can be omitted.
Some steel pipe labels in China, ISO and Japan use wall thickness dimensions to indicate the steel pipe wall thickness series. For this type of steel pipe, the expression method is pipe outer diameter × wall thickness.
Such as: Φ60.5×3.8
