WELD NECK FLANGE BS 4504 1. Standard: BS45042. Type: Welding NeckFlange, WN Flange (Raised Face)3. Pressure: PN6, PN10, PN16, PN25, PN404. Size: DN15 – DN1000, larger Sizes available on request5. Raw Material: P245GH, P250GH, RSt37.2, C22.8, S235JR6. Process: Forged, Stamped7. Basic requirements for Material and Flange