|Flange America standard||1/2"~100"||DN15-DN2500||Class150~Class2500|
|Flange Europe standard||1/2"~100"||DN15-DN2500||PN2.5~PN400|
|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|
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.
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.