Tubewell Steel & Engg. Co. is a leading manufacturer and stockist specializing in Alloy Steel Pipes, Tubes, Fittings and Flanges for critical industrial applications.
ASTM A182 chrome-moly weld neck flanges with tapered hubs for high-pressure, high-temperature and cyclic-load piping systems.
Tubewell Steel & Engg. Co. manufactures, stocks and supplies alloy steel weld neck flanges from Mumbai, India in ASTM A182 F5, F9, F11, F22 and F91. The long tapered hub is butt-welded to the pipe, transferring stress smoothly into the line – making weld neck flanges the first choice for high-pressure, high-temperature and thermally cycling chrome-moly piping.
Why weld neck flanges are preferred for critical chrome-moly lines
A weld neck flange has a long tapered hub that transitions gradually from the flange ring to the pipe wall. The hub end is bevelled and butt-welded to the pipe, so the joint can be fully radiographed and the bore is continuous with the pipe – there is no step to cause turbulence, erosion or crevice corrosion. The reinforcement provided by the hub makes the weld neck the strongest standard flange type and the most resistant to bending, thermal cycling and fatigue.
We forge alloy steel weld neck flanges in ASTM A182 F5, F9, F11, F22 and F91, heat treat them as the specification requires, and CNC machine the bore and bevel to match the exact schedule of the mating A335 pipe. Long weld neck, reducing weld neck and RTJ versions are available, together with B16.47 Series A / B large-diameter flanges. Every piece is PMI-checked, hardness tested and supplied with EN 10204 3.1 / 3.2 certificates.
Standard supply range for alloy steel weld neck flanges
| Parameter | Details |
|---|---|
| Material Standard | ASTM A182, ASME SA182 |
| Grades | F5, F5a, F9, F11 Class 1 / 2 / 3, F12, F22 Class 1 / 3, F91 |
| Dimension Standard | ASME B16.5 (1/2" – 24"), ASME B16.47 Series A & B (26" – 48"), MSS SP-44, EN 1092-1 Type 11 |
| Size | 1/2" NB to 48" NB (DN 15 – DN 1200) |
| Pressure Class | ASME Class 150, 300, 600, 900, 1500, 2500 |
| PN Rating | PN6, PN10, PN16, PN25, PN40, PN64 |
| Types | Weld Neck (WN), Long Weld Neck (LWN), Reducing Weld Neck, Weld Neck Orifice |
| Facing | Raised Face (WNRF), Flat Face (WNFF), Ring Type Joint (WN-RTJ), Tongue & Groove |
| Face Finish | Serrated 125 – 250 µin Ra (3.2 – 6.3 µm); RTJ groove 63 µin Ra max |
| Bore / Schedule | SCH 10, 20, 40, STD, 60, 80, XS, 100, 120, 140, 160, XXS |
| Weld End Bevel | As per ASME B16.25 (37.5° ± 2.5°) |
| Heat Treatment | Annealed or Normalized & Tempered per ASTM A182 (F91: N&T) |
| Testing | PMI, Hardness, Tensile, Impact, UT, MPI / DPT, Visual & Dimensional |
| Certificates | EN 10204 3.1 / 3.2, IBR Certification, NACE MR0175, TPI Reports |
Grades available for weld neck flanges and their international equivalents
| Grade | ASTM / ASME | UNS | EN 10222-2 | W.Nr. | Matching Pipe | Nominal |
|---|---|---|---|---|---|---|
| F5 | A182 F5 | K41545 | X16CrMo5-1 | 1.7366 | A335 P5 | 5Cr-0.5Mo |
| F9 | A182 F9 | K90941 | X11CrMo9-1 | 1.7386 | A335 P9 | 9Cr-1Mo |
| F11 | A182 F11 Cl.2 | K11572 | 13CrMo4-5 | 1.7335 | A335 P11 | 1.25Cr-0.5Mo |
| F22 | A182 F22 Cl.3 | K21590 | 11CrMo9-10 | 1.7383 | A335 P22 | 2.25Cr-1Mo |
| F91 | A182 F91 | K90901 | X10CrMoVNb9-1 | 1.4903 | A335 P91 | 9Cr-1Mo-V |
Equivalents are the nearest comparable grades for reference; confirm suitability against the governing design code before substitution.
Weight %, as per ASTM A182
| Grade | C | Mn | P max | S max | Si | Cr | Mo | Others |
|---|---|---|---|---|---|---|---|---|
| F5 | 0.15 max | 0.30 – 0.60 | 0.030 | 0.030 | 0.50 max | 4.0 – 6.0 | 0.44 – 0.65 | Ni 0.50 max |
| F9 | 0.15 max | 0.30 – 0.60 | 0.030 | 0.030 | 0.50 – 1.00 | 8.0 – 10.0 | 0.90 – 1.10 | – |
| F11 Cl.2 | 0.10 – 0.20 | 0.30 – 0.80 | 0.040 | 0.040 | 0.50 – 1.00 | 1.00 – 1.50 | 0.44 – 0.65 | – |
| F22 Cl.3 | 0.05 – 0.15 | 0.30 – 0.60 | 0.040 | 0.040 | 0.50 max | 2.00 – 2.50 | 0.87 – 1.13 | – |
| F91 | 0.08 – 0.12 | 0.30 – 0.60 | 0.020 | 0.010 | 0.20 – 0.50 | 8.0 – 9.5 | 0.85 – 1.05 | V 0.18–0.25, Nb 0.06–0.10, N 0.03–0.07, Ni 0.40 max |
Minimum values at room temperature, as per ASTM A182
| Grade | Tensile Strength | Yield Strength (0.2%) | Elongation (in 2") | Reduction of Area | Hardness (HBW) |
|---|---|---|---|---|---|
| F5 | 485 MPa (70 ksi) min | 275 MPa (40 ksi) min | 20% min | 35% min | 143 – 217 |
| F9 | 585 MPa (85 ksi) min | 380 MPa (55 ksi) min | 20% min | 40% min | 179 – 217 |
| F11 Cl.2 | 485 MPa (70 ksi) min | 275 MPa (40 ksi) min | 20% min | 30% min | 143 – 207 |
| F22 Cl.3 | 515 MPa (75 ksi) min | 310 MPa (45 ksi) min | 20% min | 30% min | 156 – 207 |
| F91 | 620 MPa (90 ksi) min | 415 MPa (60 ksi) min | 20% min | 40% min | 248 max |
Typical values (for reference)
| Property | F5 | F9 | F11 | F22 | F91 |
|---|---|---|---|---|---|
| Density (g/cm³) | 7.75 | 7.70 | 7.75 | 7.80 | 7.76 |
| Modulus of Elasticity (GPa) | 210 | 213 | 205 | 210 | 218 |
| Thermal Conductivity at 100°C (W/m·K) | 33 | 26 | 37 | 36 | 26 |
| Mean Thermal Expansion 20–300°C (µm/m·°C) | 11.9 | 11.6 | 12.4 | 12.6 | 11.3 |
| Specific Heat (J/g·°C) | 0.46 | 0.46 | 0.46 | 0.46 | 0.45 |
| Approx. Max. Service Temp. (°C) | ≈ 650 | ≈ 650 | ≈ 595 | ≈ 600 | ≈ 650 |
ASME B16.5 Class 150 & Class 300 weld neck flanges – dimensions in mm
| NPS | Weld Point Dia A | Cl.150 OD | Cl.150 Thk | Cl.150 Hub X | Cl.150 Length Y | Cl.300 OD | Cl.300 Thk | Cl.300 Hub X | Cl.300 Length Y |
|---|---|---|---|---|---|---|---|---|---|
| 1/2" | 21.3 | 90 | 9.6 | 30 | 46 | 95 | 12.7 | 38 | 51 |
| 3/4" | 26.7 | 100 | 11.2 | 38 | 51 | 115 | 14.3 | 48 | 56 |
| 1" | 33.4 | 110 | 12.7 | 49 | 54 | 125 | 15.9 | 54 | 60 |
| 1 1/4" | 42.2 | 115 | 14.3 | 59 | 56 | 135 | 17.5 | 64 | 64 |
| 1 1/2" | 48.3 | 125 | 15.9 | 65 | 60 | 155 | 19.1 | 70 | 67 |
| 2" | 60.3 | 150 | 17.5 | 78 | 62 | 165 | 20.7 | 84 | 68 |
| 2 1/2" | 73.0 | 180 | 20.7 | 90 | 68 | 190 | 23.9 | 100 | 75 |
| 3" | 88.9 | 190 | 22.3 | 108 | 68 | 210 | 27.0 | 117 | 78 |
| 4" | 114.3 | 230 | 22.3 | 135 | 75 | 255 | 30.2 | 146 | 84 |
| 5" | 141.3 | 255 | 22.3 | 164 | 87 | 280 | 33.4 | 178 | 97 |
| 6" | 168.3 | 280 | 23.9 | 192 | 87 | 320 | 35.0 | 206 | 97 |
| 8" | 219.1 | 345 | 27.0 | 246 | 100 | 380 | 39.7 | 260 | 110 |
| 10" | 273.1 | 405 | 28.6 | 305 | 100 | 445 | 46.1 | 321 | 116 |
| 12" | 323.9 | 485 | 30.2 | 365 | 113 | 520 | 49.3 | 375 | 129 |
| 14" | 355.6 | 535 | 33.4 | 400 | 125 | 585 | 52.4 | 425 | 141 |
| 16" | 406.4 | 595 | 35.0 | 457 | 125 | 650 | 55.6 | 483 | 144 |
| 18" | 457.0 | 635 | 38.1 | 505 | 138 | 710 | 58.8 | 533 | 157 |
| 20" | 508.0 | 700 | 41.3 | 559 | 143 | 775 | 62.0 | 587 | 160 |
| 24" | 610.0 | 815 | 46.1 | 663 | 151 | 915 | 68.3 | 702 | 167 |
A = hub diameter at weld point (equal to pipe OD), Thk = minimum flange thickness excluding 2 mm (0.06") raised face, X = hub diameter at base, Y = length through hub. Bore is machined to the specified pipe schedule. Bolt circle and bolting are identical to other B16.5 flange types of the same class.
Where alloy steel weld neck flanges are used
Main steam, reheat and feed-water lines with high pressure and temperature.
Heater outlets, hydroprocessing and reactor effluent piping.
Header and drum connections subject to thermal cycling.
Cracker and reformer lines carrying hot hydrogen and hydrocarbons.
Nozzle flanges on reactors, columns and heat exchangers.
High-pressure process manifolds and compressor piping.
Quality you can verify on every heat
Large inventory for fast dispatch
MTC EN 10204 3.1 / 3.2
Positive material identification
Pan-India & export shipping
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