Flat Face Flanges
The Flat Face flange has a gasket surface in the same plane as the bolting circle face. Applications using flat face flanges are frequently those in which the mating flange or flanged fitting is made from a casting.
Flat face flanges are never to be bolted to a raised face flange. ASME B31.1 says that when connecting flat face cast iron flanges to carbon steel flanges, the raised face on the carbon steel flange must be removed, and that a full face gasket is required. This is to keep the thin, bittle cast iron flange from being sprung into the gap caused by the raised face of the carbon steel flange.

We are Manufacturer, Supplier and Exporter of ASME 16.5 Flat Flanges. Our flat flanges sit flat on the ground and have a neck. The flat face (full face) flange has a gasket surface in the same plane as the bolting circle face.
Raised Face Flanges | |
• | RTJ Face Flanges |
• | Flat Face Flanges |
American Standard Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
ANSI B 16.5(88) | 1/2″-24″ | Class 150、300、600、900、1500、2500 |
ANSI B 16.47(90) | 26″-60″ | Class 150、300、600、900 |
ASME B 16.5(96) | 1/2″-24″ | Class 150、300、600、900、1500、2500 |
ISO7005-1(92) | 1/2″-24″ | PN2.0 5.0 11.0 15.0 26.0 42.0 |
BS4504-3.1(89) | 1/2″-24″ | Class 150、300、600、900、1500、2500 |
JPI 7S-15-93 | 1/2″-24″ | Class 150、300、600、900、1500、2500 |
NF E29-203 | 1/2″-24″ | PN2.0 5.0 11.0 15.0 26.0 42.0 |
API605-81 | 26″-60″ | Class 150、300、600 |
ASME B 16.36(96) | 1″-24″ | Class 300、400、600、900、1500、2500 |
German Standard Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
DIN 2630 WN | DN1200-DN2400 | 1 Bar |
DIN 2631 WN | DN10-DN3600 | 6 Bar |
DIN 2632 WN | DN200-DN3000 | 10 Bar |
DIN 2633 WN | DN10-DN2000 | 16 Bar |
DIN 2634 WN | DN200-DN1000 | 25 Bar |
DIN 2635 WN | DN10-DN500 | 40 Bar |
DIN 2636 WN | DN10-DN400 | 64 Bar |
DIN 2637 WN | DN10-DN350 | 100 Bar |
DIN 2638 WN | DN10-DN300 | 160 Bar |
DIN 2573 PL | DN10-DN500 | 6 Bar |
DIN 2576 PL | DN10-DN500 | 10 Bar |
DIN 2527 PL | DN10-DN500 | 6 10 16 25 40 Bar |
DIN 2501 WN | DN15-DN500 | 10 16 25 40 63 100 160 250 320 400 Bar |
DIN 2566 TH | DN15-DN500 | 10 16 Bar |
DIN 2655 PL | DN15-DN500 | 0.25 0.6 1.0 1.6 2.5 4.0 Bar |
DIN 2656 PL | DN15-DN500 | 0.25 0.6 1.0 1.6 2.5 4.0 Bar |
Japanese Standard Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
JIS B 2220 PL | DN10-DN400 | 5K |
JIS B 2220 SO | DN450-DN1000 | 5K |
JIS B 2220 PL | DN10-DN225 | 10K |
JIS 2220 SO | DN250-DN1000 | 10K |
JIS 2220 SO | DN10-DN1200 | 16K 20K 30K |
JIS 2220 WN | DN15-DN400 | 30K |
National Standard Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
GB/T 9112-9113.4-2000 | DN10-DN2000 | PN 0.25 0.6 1.0 2.5 4.0 6.3 10.0 16.0 Mpa |
JB/T 74-86.2-94 | DN10-DN1600 | PN 0.25 0.6 1.0 2.5 4.0 6.3 10.0 16.0 20.0 Mpa |
HG 20592-20626-97 | DN10-DN2000 | PN 0.25 0.6 1.0 2.0 2.5 4.0 5.0 6.3 10.0 11.0 15.0 16.0 25.0 26.0 42.0 Mpa |
SH 3406-96 | DN10-DN1500 | PN 1.0 2.0 5.0 6.8 10.0 15.0 25.0 42.0 Mpa |
GB/T 17241.1-17241.7 | DN10-DN4000 | PN 0.25 0.6 1.0 1.6 2.0 2.5 4.0 5.0 Mpa |
GB/T 15530.1-15530.8 | DN10-DN1800 | PN 0.6 1.0 1.6 2.0 2.5 4.0 5.0 Mpa |
Power Ministry Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
D-GD86-0510-0537 | DN15-DN2000 | PN 0.25 0.6 1.0 1.6 2.5 4.0 6.4 10.0 Mpa |
DG0511-0541 | DN15-DN1000 | PN 0.25 0.6 1.0 1.6 2.5 4.0 6.4 10.0 20.0 32.0 Mpa |
Pressure Vessel Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
JB/T 4701-2000 | DN300-DN2000 | PN 0.25 0.6 1.0 1.6 10.0 Mpa |
JB/T 4702-2000 | DN300-DN3000 | PN 0.25 0.6 1.0 1.6 2.5 4.0 Mpa |
JB/T 4703-2000 | DN300-DN2000 | PN 0.6 1.0 1.6 2.5 4.0 6.4 Mpa |
Shipping Series | ||
STANDARD CODES | NOMINAL SIZE | PRESSURE GRADE |
GB573-581-76 | DN20-DN500 | PN 0.6 1.0 1.6 2.5 4.0 6.4 Mpa |
GB2506-2507-89 | DN10-DN2000 | PN 0.25 0.6 1.0 1.6 2.5 Mpa |
GB4450-84 | DN20-DN500 | PN 0.6 1.0 1.6 Mpa |
GB10746-10749-89 | DN10-DN600 | PN 0.6 1.0 1.6 2.5 4.0 6.4 Mpa |