ANSI B16.5 Gwneuthurwr fflansau dur deublyg a super deublyg, ASTM A182 F44, F45, F51, F53, F55, F60, F61, fflansau WN, fflansau LWN, fflansau SW, fflansau wedi'u edafu, fflansau dall, fflansau, fflansau cyd-lin, fflansau plât, rfj-ff t, wyneb Zhengzhou Offer Co., Ltd.