ASTM A182 F347 / F347H Weld Neck Flange RF
High-Temperature Stainless Steel Weld Neck Flanges for Critical Piping Systems
ASTM A182 F347 and F347H weld neck flanges (RF) are forged austenitic stainless steel flanges designed for high-temperature and pressure service. Manufactured in accordance with ASTM A182 and dimensional standard ASME / ANSI B16.5, these flanges provide excellent resistance to intergranular corrosion, oxidation, and thermal fatigue, especially in elevated temperature environments.
F347 / F347H weld neck flanges are widely used in refineries, petrochemical plants, power generation, and high-temperature process piping systems.
What Is ASTM A182 F347 / F347H?
ASTM A182 covers forged or rolled stainless steel materials for flanges, fittings, valves, and pressure-retaining parts.
- F347 is a niobium-stabilized austenitic stainless steel designed to prevent carbide precipitation during welding.
- F347H is the high-carbon version of F347, offering higher creep strength and improved performance at elevated temperatures.
Both grades are preferred for continuous service above 425°C.
Material Grade Overview
ASTM A182 F347
- Nb-stabilized stainless steel
- Excellent resistance to intergranular corrosion
- Good weldability without post-weld heat treatment
ASTM A182 F347H
- Higher carbon content (0.04–0.10%)
- Improved high-temperature strength
- Suitable for severe thermal and pressure conditions
Flange Type – Weld Neck Flange (WN), Raised Face (RF)
ASTM A182 F347 / F347H weld neck flanges with RF facing feature a long tapered hub that ensures smooth stress transition between the flange and pipe.
Advantages of Weld Neck Flanges
- Excellent fatigue resistance
- Reduced stress concentration
- Strong, leak-resistant butt weld joint
- Ideal for high-pressure and high-temperature service
F347 is stabilized austenitic stainless steel with columbium (niobium) added to improve resistance to intergranular corrosion after welding.
F347H is the high-carbon version of F347, offering better creep strength and high-temperature resistance.
F347 Flanges made according to ASTM A182 standard had excellent resistance to intergranular corrosion and high-temperature strength. These flanges are ideal for chemical processing, petroleum refining, food processing, and high-heat applications.
Specifications:
- Size range: ½” to 48”
- Standards: ASME B16.5, ASME B16.47, MSS SP-44, API 605, DIN, EN 1092-1
- Pressure ratings: 150#, 300#, 600#, 900#, 1500#, 2500#
- Flange type:ASTM A182 F347 Weld neck flanges,ASTM A182 F347 Slip on Flange,ASTM A182 F347 Blind Flange
- Face:Raise face,RF,Flat Face,Ring Joint,RTJ
Chemical Composition of ASTM A182 F347/347H Flanges
| Element | F347 | F347H |
|---|---|---|
| Carbon (C) | ≤ 0.08 | 0.04 – 0.10 |
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 |
| Chromium (Cr) | 17.0 – 20.0 | 17.0 – 20.0 |
| Nickel (Ni) | 9.0 – 13.0 | 9.0 – 13.0 |
| Titanium (Ti) | ≥ 5x(C+N) | ≥ 5x(C+N) |
ASTM A182 F347/347H Flanges Heat Treatment requirement
| Grade | Heat Treat Type | Austenitizing/Solutioning Temperature, Minimum or Range, °F [°C]^A | Cooling Media | Quenching Cool Below °F [°C] | Tempering Temperature, Minimum or Range, °F [°C] |
|---|---|---|---|---|---|
| F 347 | solution treat and quench | 1900 [1040] | liquid^E | 500 [260] | ^B |
| F 347H | solution treat and quench | 2000 [1095] | liquid^E | 500 [260] | ^B |
Test Requirements for A182 F347 Flanges
| Test Type | Requirement / Method |
|---|---|
| Chemical Analysis | ASTM A182 F347/H |
| Tensile Test | Per ASTM A370 – One per heat / lot |
| Hardness Test | Brinell or Rockwell, per ASTM A370 |
| Intergranular Corrosion (IGC) | ASTM A262 Practice E (as applicable) |
| Visual Inspection | Surface free from cracks, laps, etc. |
| Dimensional Check | As per ASME B16.5 / B16.47/EN 1092-1 |
| Nondestructive Testing (Optional) | UT, PT, as per PO or client spec |
Marking Requirements of F347H flanges
- Material Grade (e.g., A182 F347H)
- Heat No.
- Manufacturer’s logo
- Size and pressure rating
- Standard (e.g., ASTM A182 / ASME B16.5)
ASTM A182 F347 and F347H weld neck flanges RF manufactured to ASME / ANSI B16.5 provide excellent corrosion resistance, thermal stability, and mechanical reliability in high-temperature pressure systems. With stabilized stainless steel chemistry and proven performance in refineries and power plants, F347 / F347H flanges are a trusted solution for critical piping applications.
