Spectacle Blind Flange
Spectacle blind (also known as figure 8 blind), is a safety device used for pipeline or equipment isolation. It is designed with 2 discs: one of them is a solid plate and the other one is a metal ring. Spectacle blind flange is mainly made from carbon steel, stainless steel, or alloy. Different materials are employed according to the pipe pressure ratings and the medium.
Production Range| Type | Nominal diameter | Pressure | |
| Flange America standard | 1/2"~100" | DN15-DN2500 | Class150~Class2500 |
| Flange Europe standard | 1/2"~100" | DN15-DN2500 | PN2.5~PN400 |
Manufacturing Technique
Spectacle blinds, blind flanges and gaskets are made from die stamping, welding and machining techniques. Casting treatment is unacceptable. Because compared with forgings with the same shape and dimension, castings show inferior size uniformity, lower dimensional accuracy and poorer bearing capacity.
| Austenitic stainless steel | Super duplex stainless steel | Nickel-based alloy steel | Carbon steel/alloy steel | Other materials |
| 304 304L 304H 304LN | S31803 S32205 | N10276 N04400 N06600 | Q235 20# 20G | TA1 TA2 TA3 TC1~TC9 |
| 316 316L 316H 316Ti | S32304 S32760 | N06600 N06625 N06690 | WPB A105 16Mn | LF2 LF3 LF5 LF6 LF10 |
| 310S 321 321H 347 | S32550 S32750 | N08800 N08825 N08904 | 45# 15CrMo | Al, Ti, martensite |
| S31254 | S33400 | N08020 N08810 N08811 | A350LF2 A420Gr.WPL6 |
| Steel pipe flange for petrochemical use: | SH3406 |
| Blind flange for steel pipes in petrochemical field: | SH3425 |
| Steel pipe flange, washer, fasteners (PN series): | HG/T20592 |
| Steel pipe flange (CLASS series): | HG/T20615 |
| Large-diameter steel pipe flange (CLASS series): | HG/T20623 |
| Steel pipe flanges: | GB/T9124 |
| Pipe flanges and flange fittings: | ASME B16.5 |
| Large-diameter steel flange: | ASME B16.47 |
| Forged or rolled pipe flange, forged pipe fittings, valves and accessories: | ASTM A182/A182M |
| Cast steel flange fittings: | EN 1092 |
| Steel pipe flange: | JIS B2220 |
Our company can provide spectacle blind flanges according to custom need materials like austenitic stainless steel, duplex stainless steel, carbon steel and alloy steel listed as follows:
304 stainless steel flange
304L stainless steel flange
304H stainless steel flange
304LN austenitic stainless steel flange
316 stainless steel flange
316L stainless steel flange
316H stainless steel flange
316Ti stainless steel flange
310S stainless steel flange
321 stainless steel flange
321H stainless steel flange
347 stainless steel flange
S31254 austenitic stainless steel flange
S31803 duplex stainless steel flange
S32205 duplex stainless steel flange
S32304 duplex stainless steel flange
S32760 duplex stainless steel flange
S32550 duplex stainless steel flange
S32750 duplex stainless steel flange
S33400 stainless steel flange
N10276 Nickel alloy flange
N04400 Nickel alloy flange
N06600 Nickel alloy flange
N06625 Nickel alloy flange
N06690 Nickel alloy flange
N08800 Nickel alloy flange
N08825 Nickel alloy flange
N08904 Nickel alloy flange
N08020 Nickel alloy flange
N08810 Nickel alloy flange
N08811 Nickel alloy flange
Q235 carbon steel flange
20# carbon steel flange
20G carbon steel flange
WPB carbon steel flange
A105 carbon steel flange
16Mn steel flange
45# carbon steel flange
15CrMo alloy steel flange
A350 LF2 carbon steel flange
A420 grade WPL6 carbon steel flange
TA1 titanium flange
TA2 titanium flange
TA3 titanium flange
TC1—TC9 titanium alloy flange
LF2 alloy steel flange
LF3 alloy steel flange
LF5 alloy steel flange
LF6 alloy steel flange
LF10 alloy steel flange
Martensite stainless steel flange
