F5 八角型金属环垫 

F5 Octagonal ring type joints

Ring joint gaskets come in two basic types,an oval cross section and an octagonal cross
section. These basic shapes are used in pressures up to 10,000 psi. The dimensions are
standardized and require specially grooved flanges. The octagonal cross section has a
higher sealing efficiency than the oval and would be the preferred gasket. However, only
the oval cross section can be used in the old type round bottom groove. The newer flat bottom
groove design will accept either the oval or the octagonal cross section. The sealing surfaces
on the ring joint grooves must be smoothly finished to 63 microinches and be free of obJectionable
ridges, tool or chatter marks. They seal by an initial line contact or a wedging
action as the compressive forces are applied.
The hardness of the ring should always be less than the hardness of the flanges. Dimensions for
API ring joint gaskets and grooves are covered in ANSI B16.20 and API6A
Lamons stocks a wide range of sizes and materials ready for immediate shipment from
R11 to R105. Stock materials include soft iron, low carbon steel, 4-6 chrome (F5), 304 & 304L,
316 & 316L, 347, 410, Monel, Inconel and Incoloy.

F5 Octagonal ring type joints

Gasket Material	Identification	Max. Hardness
		Brinell	Rockwell B Scale
Soft Iron	D	90	56
Low Carbon Steel	S	120	68
4-5 Chrome Half Moly	F5	130	72
Type 410	S410	170	86
Type 304	S304	160	83
Type 316	S316	160	83
Type 347	S347	160	83