According to the different classification standards, flanges can be divided into many parts, the common ones are as follows:
Flange: Pg25Dg20, HG5010-58
Flange with convex surface: Pg25Dg20, HG5012-58;.
Salient welded flange: Pg40Dg20, Pg64Dg20, HG5016-58;
Flange size also conforms to GB2555-81;
Seal face shape conforms to GB2556-81.