| Standard ID | HG 20629-1997 (HG20629-1997) |
| Description (Translated English) | (Steel pipe flanges with flexible graphite gaskets (American System)) |
| Sector / Industry | Chemical Industry Industry Standard |
| Classification of Chinese Standard | J15 |
| Classification of International Standard | 23.040.60 |
| Word Count Estimation | 32,344 |
| Date of Issue | 1997/11/27 |
| Date of Implementation | 1998/2/1 |
| Older Standard (superseded by this standard) | HGJ 44��76-1991 |
| Adopted Standard | ISO 7483-1991, NEQ |
| Regulation (derived from) | Chemical Industry National Standard, Industry Standard and the International Standard Catalog 2006; Industry-Science [2009] No. 27 |