The blind flange is basically a flange that does not have a hub or a bored center. Blind flanges is a solid disk used to seal the end of piping systems or pressure vessel openings. They are commonly used for testing the flow of gas or liquid through a pipe or vessel, in addition to allowing for easy access to the pipe in case work must be done inside the line. Similar to a regular flange, a blind flange has mounting holes around the perimeter and the gasket sealing rings are machined into the mating surface.
The most common two types are the flat face (FF) and the raised face (RF) blind flange. A flat face flange is completely smooth and level across the surface. The raised face flange has a slightly elevated middle area that creates two levels on the surface of the flange. Some blind flanges will be required a 1/2" or 3/4" FNPT threaded hole or SW hole in the center。
We GUTE is the manufacture that provide all kinds of steel flanges like Blind Flanges, Plate flat Flanges, Weld Neck Flanges, Slip On Flanges, Socket Weld Flanges, and so on, and also other special flanges according to the client's requirement.
Blind Flange Specification:
| Standard | Type | Class | Size |
| ASME B16.5 | WN/LWN/SO/Blind/Lap Joint | 150#-2500# | 1/2"-24"(Except Blind Flange 2500lb 1/2"-12") |
| ASME B16.47 Series A | WN/blind flange | 150# -900# | 22"-48"(Except 900# Size:26"-48") |
| ASME B16.47 Series B | WN/blind flange | 75#-300# | 26"-48" |
| 400# 600# 900# | 26"-36" | ||
| DIN2527 | Blind flange | PN6-PN100 | DN10-DN1000 |
| EN1092-1:2002 | Plate flange for welding/loose plate flange with weld-on plate collar or for lapped pipe end/Blind Flange/WN flange | PN2.5-PN100 | DN10-DN4000 |
| Sealing Surface | RF FF RTJ TF GF LF LM | ||
| Flange Face Finish | Stock Finish/Spiral Serrated/Concentric Serrated/Smooth Finish(Ra 3.2 and 6.3 micrometers) | ||
| 125-250 AARH(it is called smooth finish) | |||
| 250-500 AARH(it is called stock finish) | |||
| Coating | Vanish, yellow paint, anti-rust oil, galvanizing etc | ||
Blind Flange Material Grades:
| Carbon Steel | ASTM /ASME A/SA105(N), A350 LF2/LF3, A694 F52, F56, F60, F65, F70 |
| Alloy Steel | ASTM/ASME A/SA 182 F5, F9, F11, F22, F91 |
| Stainless Steel | ASTM/ASME A/SA 182 F304, 304L, 304H, 310H, 316, 316H, 316L, 316Ti, 317, 317L, 321, 321H, 347, 347H, 904L |
| Duplex and Super Duplex | ASTM/ASME A/SA 182 F44, F45, F51, F53, F55, F60, F61, S31803, S32205, S32550, S31254, SMO254, S32750, S32760, S32950 |
| Nickel Alloy Steel | ASTM/ASME B/SB 564 UNS N02200(NICKEL 200), UNS N04400, (MONEL 400), UNS N08825( INCOLOY 825), UNS N06600(INCONEL 600), UNS N06601(INCONEL 601), UNS N06625(INCONEL 625), UNS N10276(HASTELLOY C276) |
| ASTM/ASME B/SB160 UNS N02201(NICKEL 201), ASTM B/SB472 UNS N08020(Alloy 20) | |
| Copper Alloy | ASTM/ASME B/SB151 UNS N07060, 71500, C70600(CuNi 90/10), C71500(CuNi 70/30) |
| Titanium | ASTM/ASME B/SB381 Grade 2, Grade 5, Grade 7 |
