ASTM A182 F51 Duplex Stainless Steel Flange
Apr 28, 2026
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What is ASTM A182 F51 Flange?
An ASTM A182 F51 flange refers to a pipe flange manufactured from forged duplex stainless steel grade UNS S31803, designed for use in pressure piping systems. Flanges produced in accordance with ASME B16.5 or ASME B16.47 standards shall not be used at service temperatures below -60°F (-51°C) or above 600°F (315°C).
ASTM A182 F51 Flange Supplier
GNEE is a reliable duplex stainless steel manufacturer with over 20 years of production and export experience, having provided dependable piping solutions to more than 50 countries worldwide. We offer a full range of ASTM A182 F51 (UNS S31803) duplex stainless steel flanges, fully compliant with ASME B16.5, ASME B16.47, and other global industrial standards.
Our ASTM A182 F51 flanges include a wide variety of types such as Slip On, Weld Neck, Blind, Socket Weld, Threaded, and Lap Joint flanges, as well as SORF, WNRF, and RTJ configurations. Pressure ratings range from Class 150 to Class 1500, with sizes from 1/2 inch to 48 inches. Custom non-standard machining services are also available.
Each F51 flange produced by GNEE undergoes professional forging and heat treatment processes. All products are certified by ISO 9001, PED, SGS, and BV, and are supplied with EN 10204 3.1 Material Test Certificates (MTC), ensuring full traceability of quality. We support both stable large-scale supply and small-batch sample orders.
ASTM A182 UNS S31803 RTJ Flanges Material Specification
| Specification | ASTM A182 / ASME SA182 F51 |
|---|---|
| UNS Grade | UNS S31803, S32205, S2205, S32550, S32750, S32760. |
| Standard | ANSI Flanges, ASME Flanges, BS Flanges, DIN Flanges, EN Flanges, etc. |
| Size | ½" to 24″ |
| Dimensions | ANSI/ASME B16.5, B 16.47 Series A & B, B16.48, BS4504, BS 10, EN-1092, DIN, etc. |
| Class / Pressure | 150#, 300#, 600#, 900#, 1500#, 2500#, PN6, PN10, PN16, PN25, PN40, PN64 etc. |
Chemical composition
|
CHEMICAL |
C |
Mn |
p |
S |
Si |
Cr |
Ni |
Mo |
N |
|
ASTM A182 F51 |
0.030max |
2.00max |
0.030max |
0.020max |
1.00max |
21.0-23.0 |
4.5-6.5 |
2.5-3.5 |
0.08-0.20 |
Mechanical properties
|
GRADE |
ASTM A182 F51 |
|
Tensile strength |
620 min |
|
Yield strength |
450 min |
|
Elongation% |
25 min |
|
Reduction of area% |
45 min |
A182 F51 Flange Pressure Rating Table
|
Table Il-2-2.8 Pressure-Temperature Ratings for Group 2.8 Materials |
|||||||
|
Nominal Designation |
Forgings |
Castings |
Plates |
||||
|
22Cr-5Ni-3Mo-N |
A182 Gr.F51(1) |
A240 Gr.S31803(1) |
|||||
|
Working Pressures by Classes,psig |
|||||||
|
Class |
|||||||
|
Temp.,F |
150 |
300 |
400 |
600 |
900 |
1500 |
2500 |
|
-20 to 100 |
290 |
750 |
1000 |
1500 |
2250 |
3750 |
6250 |
|
200 |
260 |
745 |
990 |
1490 |
2230 |
3720 |
6200 |
|
300 |
230 |
665 |
890 |
1335 |
2000 |
3335 |
5560 |
|
400 |
200 |
615 |
820 |
1230 |
1845 |
3070 |
5120 |
|
500 |
170 |
580 |
775 |
1160 |
1740 |
2905 |
4840 |
|
600 |
140 |
555 |
740 |
1115 |
1670 |
2785 |
4640 |
|
650 |
125 |
545 |
730 |
1095 |
1640 |
2735 |
4560 |
|
700 |
110 |
540 |
725 |
1085 |
1625 |
2710 |
4520 |
|
750 |
95 |
530 |
710 |
1065 |
1595 |
2660 |
4430 |
What is the difference between ASTM A182 F51, S31803, and S32205?
F51 is the grade designation for forged Duplex Stainless Steel 2205 within the ASTM A182 standard.
S31803 represents the original standard for the chemical composition of Duplex Stainless Steel.
S32205 is an enhanced version of S31803 (featuring higher nitrogen, chromium, and molybdenum content), offering superior corrosion resistance.
Currently, F51 flanges are typically "Dual Certified," meeting the requirements of both S31803 and S32205 to deliver enhanced performance.
ASTM A182 F51 Duplex Stainless Steel Flange Price
| Product Description | Size / Type | Price (USD / pc) | Price (CNY / pc) | |
|---|---|---|---|---|
| ASTM A182 F51 Slip On Flange (SO Flange) | 3 mm | 130 | 887 | |
| ASTM A182 F51 Slip On Flange (SO Flange) | 1.5 mm | 81 | 557 | |
| ASTM A182 F51 SORF with Hub | 1-1/2" #600 | 21 | 143 | |
| ASTM A182 F51 SORF with Hub | 4" #600 | 145 | 993 |
We maintain a comprehensive inventory of WN (Weld Neck), SO (Slip-On), and Blind flanges. If you have any project requirements, please contact us promptly to obtain the latest pricing.
When purchasing F51 flanges, certification must be provided.
It is mandatory to require the supplier to provide an EN 10204 3.1 Material Test Certificate (MTC), which includes:
Chemical composition analysis
Mechanical properties (tensile strength, yield strength, elongation)
Hardness testing
Solution heat treatment parameters
PMI (Positive Material Identification) spectroscopic test results
High-Quality Packaging:
Sealing Face Protection: The sealing face of each flange is coated with anti-rust oil.
End Protection: The ends are sealed using heavy-duty plastic protective caps.
Outer Packaging: Fumigation-free wooden crates are utilized; flanges are separated by cardboard or foam pads to prevent impact damage.
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