1. Description:
The metal ring gasket refers to the metal gasket of octagonal-shaped, oval-shaped, RX-shaped or BX-shaped section by processing metal materials. It is self-tightening in diameter direction and has good sealing as the contact between gasket and the inside and outside surface of terracing glove is pressed tightly and keepgood sealing performance.

The gasket is installed inside the terracing ring glove of flange surface. When the connection bolt is fastened, it is compressed in axis direction and sticks tightly to the upper and lower terracing glove.As a result, the plastic deformation is yielded and a ring-shaped sealing strap is formed. After pressure is raised, the ring gasket expands in diameter direction under the force of media pressure. The gasket sticks more tightly to the sloping surface of terracing glove, thus becoming self-tightening. However, the rise of media pressure will deform the flange and connection bolt, and lead to the relevant separation from sealing surface, and the sealing ratio of gaskets reduce accordingly, and the ring gasket can be regarded as semi-self-tightening.
The octagonal-shaped ring gasket matches with flange glove in the form of surface contact. Compared with oval-shaped ring gasket, the octagonal-shaped ring gasket can not seal closely with flange glove, but can be used again and is easy to be process as its section constitute different lines. The oval-shaped ring gasket contacts the flange glove in linear form, but with good sealing performance. However, the high processing precision increases the manufacturing cost, and the oval-shaped ring gasket can't be used again.

2. Application
The applicable metric pressure of metal ring gasket is 2.0MPA~42.0MPA, and it is often used high-pressure steam, gas, solvent and other tonsil-shaped devices, such as high-pressure containers, high-pressure valves. The highest operation pressure is 150MPA and temperature is 1000℃. For octagonal-shaped and R-shaped ring gasket, the highest operation pressure is 10000PSI and 15000 PSI for RX-shaped and BX-shaped.
Originated from the USA, metal ring gasket was used in boilers as early as 1920’s and then in the sealing of manhole cover, high-pressure kettle and later received a lot of special attention from petroleum producing and refining industry. With the temperature and pressure increase of steam-dynamic devices, the metal gaskets are used more and more widely.

3. Materials
The materials are generally malleable cast iron (soft iron), low carbon steel, F5，Cr5Mo,0Cr13,0Cr18Ni9,00Cr19Ni10, whose hardness is 30~40HBS lower than that of flange materials.

1. soft iron elements: C＜0.05，Si＜0.4,Mn＜0.60,P＜0.035,S＜0.04

2. F5 elements: stand for the chemical elements required in the ASTM technical regulationA182—72 ，4-6% Cr,0.5% Mo,

4. Type
G-307-1 OCTAGONAL GASKET
G-307-2 OVAL GASKET
G-307-3 RX GASKET
G-307-4 BX GASKET

5. Hardness, temperature and Labeling Method