This standard specifies the structural type and series size of Type B flat welding flanges for steel pressure vessels. This standard is applicable to Type B flat welding flanges for steel pressure vessels with nominal pressures of 0.25MPa to 6.40MPa and operating temperatures above -20℃ to 450℃. JB/T 4702-2000 Type B flat welding flange JB/T4702-2000 Standard download decompression password: www.bzxz.net

1 Scope
Industry Standard of the People's Republic of China
Btypesocket-weld flange
This standard specifies the structural type and series size of type B flat welding flange for steel pressure vessels. JB/T4702-2000
Replaces JB4702-1992
This standard applies to type B flat welding flanges for steel pressure vessels with a nominal pressure of 0.25~4.0MPa and a working temperature higher than 20~350℃.
This standard applies to corrosion allowances ≤2mm. When the corrosion allowance is 3mm, the thickness of the short section should be thickened by 2mm. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. JB/T4700—2000bZxz.net
JB/T47042000
JB/T 4705—2000
JB/T 4706—2000
JB/T4707—2000
3Structural types and dimensions
Classification and technical conditions of pressure vessel flanges
Non-metallic soft gaskets
Spiral wound gaskets
Metal clad gaskets
Equal length studs
The structural types and series dimensions of type B flat welding flanges with various sealing surfaces shall comply with the requirements of Figures 1 to 6 and Table 1. The qualities of flanges and bushings are listed in Table 2.
4 Selection regulations
4.1 The materials, maximum allowable working pressure, technical conditions and markings of flanges and matching gaskets, studs and nuts shall comply with the provisions of JB/T4700.
4.2 Non-metallic soft gaskets, spiral wound gaskets and metal-clad gaskets for flanges shall comply with the provisions of JB/T4704, JB/T4705 and JB/T4706 respectively.
4.3 Equal-length studs for flanges shall comply with the provisions of JB/T4707. 4.4 The thickness of the short section thickened to meet the corrosion allowance requirements shall be indicated in the remarks column of the drawing list: such as: 3, =××. State Bureau of Machinery Industry
State Bureau of Petroleum and Chemical Industry
Approved on April 24, 2000
Implemented on September 30, 2000
JB/T4702—2000
Figure 1 Flat sealing surface
Other academic subjects
JB/T4702—2000
Figure 2 Concave and convex sealing surface
JB/T47022000
Figure 3 Sample groove sealing surface
JB/T4702—2000
Figure 4 Flat sealing surface of liner ring Cover
Rest
JB/T4702—2000
Figure 5 Concave and convex sealing surface of liner ring
JB/T4702—2000
Figure 6 Ladder groove sealing surface of liner ring
Rest total
Nominal diameter
JB/T47022000
Flange, mm
PN=0.25MPa
PN=1.6MPa
Nominal diameter
JB/T4702-2000
Table 1 (End)
PN=2.5 MPa
Note: The welding groove type and size of the connection between the flange nipple and the container shell are determined by the design or manufacturing unit. Table 2
Nominal diameter
Flange mass,
PN = 0.25 MPa
PN=0.6MPa
Ring mass, kg
Nominal diameter
JB/T4702—2000
Table 2 (continued)
Flange mass, kg
PN=1.0 MPa
PN=1.6 MPa
PN=2.5 MPa
Ring mass,
Nominal diameter
JB/T4702—2000
Table 2 (Finish)
Flange mass, kg
Note: The mass of the flange body in the village ring flange
PN=4.0MPa
can be approximated to the mass of the flat flange.
Bushing ring mass,
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