1. National standard mark
Flanges should be marked according to nominal diameter, nominal pressure, sealing surface form code, matched steel pipe series code (matched with metric pipe code is "series 2", matched with imperial pipe is not marked) and standard number.
Marking example: convex face welded steel pipe flange with nominal diameter 80mm and nominal pressure 4.0MPa (25bar) (with metric pipe)
Flange DN80-PN40 M (series 2) GB/T9115.2-2000, nominal diameter 100mm, nominal pressure 5.0MPa (25bar) raised face neck flat welded steel pipe flange (with inch pipe) flange DN100-PN50 RF GB/T9116.1-2000.
2. Standard mark of the ministry of machinery
Marking example: Nominal diameter 500mm, nominal pressure 1.6MPa, series 2 raised face flat welded steel pipe flange
Flange 500-16 JB/T81-94
Nominal diameter 300mm, nominal pressure 6.4MPa, series 1 concave face welded steel pipe flange
Flange 300-64B (series 1) JB/T82.2-94
(Note: The standard default pipe outer diameter of the Ministry of Machinery is Series 2, butt welding flange classification: A-shaped convex surface, B-shaped concave surface, C-shaped tenon surface, D-shaped groove surface)
3. Standard mark of the ministry of chemical industry
Flanges should be marked according to the following regulations (this marking method is recommended)
a. Standard number: All types of pipe flanges are uniformly marked with the standard number of this standard: HG20592.
b. The flange type code shall be in accordance with the regulations in Table 5.0.1.
When the threaded flange adopts the tapered pipe thread specified in GB/T7306, it is marked as "Th(Rc)" or "Th(Rp)";
When the threaded flange adopts the tapered pipe thread specified in GB/T12716, it is marked as "Th(NPT)";
If the threaded flange is not marked with the thread code, it is Rp (GB/T7306.1).
c. Flange nominal diameter DN (mm) and applicable steel pipe outer diameter series:
Integral flanges, flange covers, lining flange covers, threaded flanges, the markings for the outer diameter of the applicable steel pipe can be omitted;
Suitable for flanges of international general series steel pipes (commonly known as British pipes), marked "DN(A)";
It is suitable for the flanges of the domestic steel pipes (commonly known as metric pipes), marked as "DN(B)".
d. The nominal pressure of the flange is PN, MPa.
e. The form code of the sealing surface shall be in accordance with the regulations in Table 6.0.1, and the raised face flange such as the car-made dense-grained waterline shall be marked as "RF(A)".
f. The wall thickness of the steel pipe shall be provided by the user.
Neck butt welding flanges and butt welding ring loose flanges should be marked with steel pipe wall thickness.
g. Material designation.
h. Others. Adopt requirements that are inconsistent with this standard series or additional requirements, such as the surface roughness of the sealing surface, etc.
Nominal diameter 1200mm, nominal pressure 0.6MPa, raised face plate flat welded steel pipe flange with metric pipe, material is Q235A
HG20592 flange PL1200(B)-0.6 RF Q235A
Nominal diameter 300mm, nominal pressure 2.5MPa, convex face neck flat welded steel pipe flange with inch pipe, material is 20 steel
HG20592 flange SO300(A)-2.5 M 20
The nominal diameter is 150mm, the nominal pressure is 16.0MPa, and the ring connection surface of the British pipe is equipped with a butt-welded steel pipe flange with a neck. The material is 16Mn, and the wall thickness of the steel pipe is 10mm.
HG20592 flange WN150(A)-16.0 RJ S=10mm 16Mn
The nominal diameter is 200mm, the nominal pressure is 1.0MPa, and the raised face of the metric pipe is equipped with a loose sleeve steel pipe flange with a welded ring. The material is: flange 20, butt weld ring 316, and the wall thickness of the steel pipe is 4mm
HG20592 flange PJ/SE200(B)-1.0 RF S=4m 20/316