The national standard system GB for steel stainless steel flanges in China.
1. Nominal pressure: 0.25Mpa~42.0Mpa
Series 1: PN1.0, PN1.6, PN2.0, PN5.0, PN10.0, PN15.0, PN25.0, PN42 (main series)
Series 2: PN0.25, PN0.6, PN2.5, PN4.0
The flange sizes of PN0.25, PN0.6, PN1.0, PN1.6, PN2.5, and PN4.0 belong to the European flange system represented by German flanges, while the rest are stainless steel flanges of the American flange system represented by American flanges.
In the GB standard, the maximum nominal pressure level belonging to the European flange system is 4Mpa, and the maximum nominal pressure level belonging to the American flange system is 42Mpa.
2. Nominal diameter: 10mm~4000mm
3. The structural form of the flange:
① Integral flange ② Unit flange
Threaded flange;
Welding flange, butt welding flange;
Necked flat welding flange, neck socket welding flange, plate type flat welding flange: loose sleeve flange, welding ring loose sleeve with neck flange, welding ring loose sleeve plate flange, welding ring loose sleeve plate flange, plate type flip over loose sleeve flange
Flange cover (blind hole flange).
4. Flange sealing surface: flat, concave, convex, tenon groove, ring connection surface
Flange assembly
01、Before assembling the flange, it is necessary to clean the flange surface, especially the sealing surface.
02、When assembling flat welding flanges, the pipe end should be inserted into the inner diameter thickness of the flange 2 ≤ 3, and then the flange should be spot welded with the pipeline. If it is a horizontal pipe, the flange should be spot welded from above, and then the flange position should be checked and corrected from different directions using a 90 ° angle ruler, so that its sealing surface is perpendicular to the centerline of the pipeline. The second point under the spot welding is correct.
03、Use a 90 ° angle ruler to check and correct the position of the flange from the left and right directions, and complete the spot welding and fixation of the flange through the third and fourth points.
04、For the assembly of flange pairs, the bolt holes for installing the flange should be aligned with the corresponding bolt holes of the fixed flange and parallel to the fixed flange, with a deviation of not less than 1.5% of the outer diameter of each thousand flanges and not more than 2mm.
05、When selecting the matching flange for equipment or valve components, attention should be paid to whether the flange of the original equipment or valve component is consistent with the flange connection size used in the pipeline.