... ANSI,BS,DIN,GB,ISO. 4.15--600mm. Product Description:Flange cover (HG20601, HG20622, GB/T9123, JB/T86) is also ... and ring connections surface. Cover flange sealing surface:FF, RF, MFM,TG, RJProduct materials for cover flange sealing surface:Carbon Steel ASTM ... ,A182F11,16MnR,Cr5Mo,12Cr1MoV,15CrMo,12Cr2Mo1,A335P22, St45.8/Flange Applicable standards:Ministry of Chemical Industry HG20601-1997, American ...