The meaning of Dn, De, D, d, Φ in steel pipe
The meaning of Dn, De, D, d, Φ in steel pipe
What do Dn, De, D, d, and Φ in seamless steel tubes represent? For example: DN200, De200, D200, d200, and Φ200
In general, the diameter of the pipe can be divided into the outer diameter (De), inner diameter (D), nominal diameter (DN). Let's distinguish the difference between these "dddddd" for everyone~
"DN" refers to the nominal diameter of the pipe
Note: This is neither the outer diameter nor the inner diameter. It is the average of the outer diameter and the inner diameter, which is called the average inner diameter.
When the design uses the nominal diameter DN to represent the pipe diameter, there should be a comparison table between the nominal diameter DN and the corresponding product specifications.
water. For gas transportation steel pipes (galvanized steel pipes or non-galvanized steel pipes), cast iron pipes, steel-plastic composite pipes and polyvinyl chloride (PVC) pipes, etc., the nominal diameter "DN" (eg DN15.DN20) should be marked
"De" mainly refers to the outer diameter of the pipe
Generally marked with De, all need to be marked in the form of outer diameter X wall thickness;
Mainly used to describe: seamless steel pipes, PVC and other plastic pipes, and other pipes that require a clear wall thickness.
Taking galvanized welded steel pipe as an example, the two marking methods of DN and De are as follows:
DN20 De25×2.5mm
DN25 De32×3mm
DN32 De40×4mm
DN40 De50×4mm
We are accustomed to using DN to mark welded steel pipes, and De is rarely used to mark pipes without involving wall thickness; but marking plastic pipes is another matter; it is still related to industry habits, and the actual construction process The 20, 25, 32 and other pipes we call simply refer to De rather than DN. There is a difference here. It is easy to cause losses in the procurement and construction process if it is not clear.
The connection method of the two pipe materials is nothing more than: screw connection and flange connection. Other connection methods are rarely used.
Both the galvanized steel pipe and the PPR pipe can be connected by the above two methods, but it is more convenient to use the thread buckle for the pipeline less than 50, and the flange is larger than 50 to be more reliable.
Note: If two metal pipes of different materials are connected, it is necessary to consider whether there will be a galvanic reaction, otherwise it will accelerate the corrosion rate of active metal material pipes. It is best to use flange connections and use rubber gaskets to insulate the two. All kinds of metals are separated, including bolts should be separated by gaskets to avoid contact.
"D" generally refers to the inner diameter of the pipeline
"d" is the inner diameter of the concrete pipe
"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 behind it.
Such as: Φ25×3, which means that the outer diameter is 25mm and the wall thickness is 3mm.
For seamless steel pipes or non-ferrous metal pipes, "outer diameter x wall thickness" shall be marked.
For example: Φ107×4, where Φ can be omitted.
Some steel pipes in China, ISO and Japan are marked with wall thickness to indicate the series of steel pipe wall thickness. For this type of steel pipe, the method is expressed as pipe outer diameter × wall thickness.
Such as: Φ60.5×3.8
Respective ranges of De, DN, d and ф!
De-- PPR, PE pipe, polypropylene pipe
DN-- nominal diameter of polyethylene (PVC) pipe, cast iron pipe, steel-plastic composite pipe, galvanized steel pipe
d - nominal diameter of concrete pipe
ф-- Seamless steel pipes or non-ferrous metal pipes should be marked "outer diameter x wall thickness"
