... Steel:such as 201 301 304,304L,316,316L,321 and so on.3. Standard:GB,JIS,BS,DIN.ANSI/ASTM , NF ... and Non standard,4. Size:1/2"-40"5. Type:Slip-on flanges,Blind flanges, Spectacle flanges ... .7. Sealing surface : FF ,RF, LJ, FM ,R.T.J and so on .8. Production process : raw material--cutting--heating--forging--heat treatment ...