This standard specifies the product classification of marine lap-welded steel ring loose-fitting steel flanges (hereinafter referred to as flanges). This standard applies to flanges with a nominal pressure not exceeding 1.6 MPa and a working temperature not exceeding 300°C. GB 2508-1989 Marine lap-welded steel loose-fitting steel flanges (four-digit) GB2508-1989 Standard download decompression password: www.bzxz.net

UDC 621.643.4 : 629.4
National Standard of the People's Republic of China
GB 10745~10751—89
GB2501-250B-89
Moon flange
(four-position）
Marine pipe flauges
1989-03-31 Issued
1989-12-01 Implementation
State Administration of Technical Supervision Issued
National Standard of the People's Republic of China
Marine lap-welded steel ring loose-sleeve steel flange
(four-position）
Marine combinatioo pipe flanges, slip onsteel outer flanges, rillet weld-on steel inner flanges1 Subject content and scope of application
This standard specifies the product classification of marine lap-welded steel ring loose-fitting steel flanges (hereinafter referred to as flanges). This standard applies to flanges with a nominal force of less than 1.6MPa and a working temperature not exceeding 300°C. 2 Reference standards
GB2501 Marine flange connection dimensions and sealing surfaces (four-in-one) GB2502 Marine flange soft-lift ring (four-in-one) GB700 Carbon structural steel
GB3098.1 Mechanical properties of fasteners Bolts, screws and studs G series 3098.2 Mechanical properties of fasteners Nuts
GB5312 Carbon steel seamless steel pipes for cabins
YB242 Diameter 5-152mm cut electric welded steel pipes
3 Product classification
Basic parameters of method 8.1 are as shown in Table 1.
FWorking temperature, C
Number of forces, EPM
3.2 Flange dimensions are as per Figure 1 and Table 2.
Maximum working force, Ma
Approved by China State Shipbuilding Corporation on March 27, 198952bzxZ.net
GB25D8-89
Replaced GB 2508-86
Nominal diameter TN
198912-01 implemented
Outer diameter of the spring a
333334
GB 250889
PV -8.6MPa
End distance of the blasting seam
Side width
Light blasting effect and through hole
Outer diameter of the pipe D
GB 250B-89
Continued Table 2
Ph = 0.6 MPa
Pp=1.0.1.6MPa
IN-1.0MPa
Good end distance
Bolt thread and through hole
［Warning outer light
323.9! 525
5131 541
333364
366 1 887
GB 2508--89
Continuation 2
t% =1.0MPa
Pn -1.6 MPa
Depth and
Diameter of thread and
Jiang: Calculate, the first series of pipe connection dimensions are international universal dimensions, and the second series of arrow connection dimensions are our universal dimensions. a.3 Name examples
3.3.f Lead lap-welded steel ring loose-sleeve steel flange with nominal pressure of 0.6M.Pt and nominal diameter of 5Umm 6050GB2508-89
3.3.2 Lap-welded steel ring loose-sleeve steel flange with nominal pressure of 1.6MPa and nominal diameter of 400mm 16400GB 25U8-89
Technical requirements
4.1 The materials of flanges, steel rings, bolts and nuts shall be as per Table 3.18
Tai Xue Multi-Name
GB 250889
4.2 Seamless steel pipes shall be as per GB5312 and welded steel pipes shall be as per YB242. Brand or performance level
Q235-A
Level 4 or 5
Standard Guide
GB 70—88
GH 3098.182
GR 3098.2—82
4.3 The mechanical properties of the welding rod shall be lower than the lower limit of the mechanical properties of the welded parts (steel ring or pipe) with lower strength. 4.4 The surface of the flange and steel ring shall be smooth and shall not have defects that reduce strength and affect sealing. 4.5 The end face of the steel ring shall be perpendicular to its axis, and the deviation shall not exceed 30°. 4.6 The inner diameter of the pin ring is plus the actual outer diameter of the pipe, and the allowable deviation of the diameter is +1mm. The allowable negative deviation of the flange thickness is 0.5mm.4.7
4.8. The soft gasket used for the flange shall comply with GB.2502.4.9 The connection dimensions and sealing surfaces of the flange shall comply with GB2501. Inspection rules
The flange and steel ring shall be inspected and accepted by the technical inspection department of the manufacturer and a certificate of conformity shall be issued.5.1
5.2 The inspection contents during acceptance include material certificates, dimensions and appearance.6. Marking, packaging
6.1 Flange and steel ring The following marks shall be printed on the outer cylindrical cover: a. Manufacturer's trademark; b. Model and standard number specified in this standard; c. Production batch number: d. Inspection pass stamp. 6.2 The processed surface of flanges and steel rings shall be coated with industrial vaseline before packaging. Additional remarks: This standard was proposed by the Sixth Institute of China Shipbuilding Industry Corporation. This standard is under the jurisdiction of China Shipbuilding Industry Corporation. This standard was drafted by China Shipbuilding Industry Corporation. The main drafters of this standard are Yu Weihai, Sun Jingming and Wu Shaozeng. The technical specifications are provided by the unified construction sample.
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