Gasket

Flat gasket/rubber gasket:
Inner diameter (ID): usually 1~2mm larger than the outer diameter of the steel pipe (for socket connection) or matching the inner diameter of the flange.
Outer diameter (OD): determined by the size of the flange sealing surface, the common range is DN15~DN3000 (nominal diameter corresponds to 6mm~3000mm).
Thickness: non-metallic gaskets are usually 1~5mm, and metal gaskets are 0.5~3mm.

(2) Flange gaskets (such as spiral wound gaskets, metal ring gaskets)
Strictly match the flange standard (such as ANSI, DIN, JIS, etc.), the size is determined by the flange nominal diameter (DN) and pressure grade (PN/Class).
Example:
DN50 PN16 flange gasket: inner diameter ≈52mm, outer diameter ≈92mm (specific dimensions need to be checked in the flange standard table).
Class 150 spiral wound gasket (ASME B16.20): DN15~DN600 (1/2"~24").

1. Flange gasket
ASME B16.20
Application scope: metal spiral wound gasket, metal ring gasket (octagonal/oval), cover gasket.
Matching flange: ASME B16.5 (Class 150~2500), B16.47 (large diameter flange).
Key parameters: size range 1/2"~24", pressure level Class 150~2500.

EN 1092-1
Application scope: non-metallic flat gasket (PN series), metal composite gasket.
Matching flange: EN 1092-1 flange (PN6~PN100).

ISO 7483
Application scope: rubber/fiber gasket, suitable for ISO 7005 flange.

2. Ring gasket (special for high pressure)
API 6A
Application scope: metal ring gasket (R type/O type) for wellhead equipment and Christmas tree.
Pressure rating: 5000~15000 psi.

ASME B16.20 / API 6B
Ring gasket type: octagonal (RX), oval (BX), used for high-pressure oil and gas pipelines.

3. Non-metallic gasket
ASTM F104
Material: Performance test standard for non-metallic gaskets such as graphite and PTFE.

ASTM F146
Scope of application: compressed fiber gaskets (such as asbestos substitutes).

Accroding to the structure
Flat gasket: simple circular thin sheet, used for low-pressure static sealing.
Wound gasket: metal belt and non-metallic material (graphite, PTFE) are alternately wound, resistant to high pressure and high temperature.
Annular gasket (ring gasket): such as metal O-ring, octagonal ring gasket, used for high-pressure flange (such as API 6A standard).
Toothed gasket: metal surface with concentric teeth to enhance sealing.
Rubber gasket: used for low-pressure, corrosive media (such as NBR, EPDM).

Accroding to the material
Metal gasket: stainless steel (304/316), copper, aluminum, titanium, resistant to high temperature and high pressure.
Semi-metal gasket: metal + non-metal composite (such as wound gasket).
Non-metal gasket: rubber, graphite, PTFE, asbestos (gradually eliminated), suitable for corrosive media.

Petrochemical: Spiral wound gaskets or metal ring gaskets for high-pressure flanges.
Water supply system: EPDM rubber gaskets, rust-proof and water-resistant.
Food and medicine: PTFE gaskets, in line with hygiene standards.
Electricity/boiler: Graphite metal composite gaskets, resistant to high-temperature steam.