General Situation of the Ministry of Chemical Industry Standards for Pipeline Sealing Gaskets (European System):

1. HG20606-97 (non-metallic flat gasket for steel pipe flange) pressure grade: PN0.25Mpa, PN0.6Mpa, PN1.0Mpa, PN1.6Mpa, PN2.5Mpa, PN4.0Mpa. The sealing surface can be divided into FF (full plane), RF, MFM, TG (protrusion, concave and convex, mortise and groove), and RF-E (protrusion, wrapped edge).

2. HG20607-97 (PTFE gasket for steel pipe flange) pressure grade: PN0.6 Mpa, PN1.0 Mpa, PN2.5 Mpa, PN4.0 Mpa. The sealing surface can be divided into PMF (machined wing), PMS (machined rectangle), PFT (folded envelope).

3. HG20608-97 (Flexible Graphite Composite Gasket for Steel Pipe Flange) Pressure Grade: PN1.0Mpa, PN1.6Mpa, PN2.5Mpa, PN4.0Mpa, PN6.3Mpa. The sealing surface is divided into RF, MFM, TG (protrusion, concave and convex, mortise and groove), RF-E (protrusion, with inner wrapped edge).

4. HG20609-97 (metal-clad gasket for steel pipe flange) pressure grade: PN2.5 Mpa, PN4.0 Mpa, PN6.3 Mpa, PN10.0 Mpa. There are no forms of sealed surface.

5. HG20610-97 (winding gasket for steel pipe flange) pressure grade: PN1.6Mpa, PN2.5Mpa, PN4.0Mpa, PN6.3Mpa, PN10.0Mpa, PN16.0Mpa. Sealing surface form:

A (Basic Tenon Groove Surface Use)

B (Use of Inner Ring Concave and Convex Surface)

C (Use of Outer Ring Protrusion)

D (Use of Inner and Outer Ring Protrusions)