Socket Weld Flange
Socket Weld Flange: Specifications | Materials | Types | Dimensions | Weight Chart | Tolerances | FAQ
Socket Weld Flanges Manufacturer & Exporter – ASME B16.5 & B16.47 | Carbon, Stainless, Alloy, Duplex & High Nickel Alloys | Sizes ½”–24”, Pressure Classes 150#–2500# | Supplied to USA, Canada, Mexico & Brazil
Best Export Prices: sales@midlandforgefittings.com
Midland Forge and Fittings Pvt. Ltd. is a trusted name in precision-engineered piping components, with a specialization in Socket Weld Flanges. Designed for high-pressure and leak-proof performance, these flanges are widely preferred in critical flow systems where space constraints and durability matter.
Manufactured in carbon steel, stainless steel, alloy steel, duplex, super duplex, and high-nickel alloys. Our socket weld flanges are supplied in sizes ranging from ½” to 60” and pressure classes 150# to 2500#, ensuring compatibility with a wide range of industrial piping standards.
What sets our swrf flange apart is the meticulous manufacturing process that combines forging, precision machining, and strict quality control. Each flange is tested for dimensional accuracy, surface finish, and metallurgical integrity, making them suitable for demanding applications in oil & gas, chemical processing, power generation, shipbuilding, and offshore drilling. With a deep socket design, they allow strong pipe alignment and provide a smooth bore, which enhances flow efficiency and minimizes turbulence.
At Midland Forge, We understand that every project requires reliability, performance, and global compliance. That’s why our socket weld flanges are manufactured in accordance with international standards such as ANSI, ASME, ASTM, API, and DIN. With a strong supply chain and ready stock, we serve industries across USA, Europe, Middle East, Africa, and Asia, delivering products that meet the highest engineering expectations. Whether for critical pipelines or specialized equipment installations, our socket weld flanges ensure long-term durability and cost-effective solutions.
Socket Weld Pipe Flange Specifications
Socket Weld Flange – Materials, Grades & Standards
| Material Category | Standards / Grades (ASTM / ASME) | Pressure Class / Size Range | Typical Use / Application |
|---|---|---|---|
| Stainless Steel | ASTM A182 F304 / F304L / F304H | Class 150 – 2500, Size ½”–48” | General purpose, corrosion-resistant piping |
| ASTM A182 F316 / F316L / F316H | Class 150 – 2500, Size ½”–48” | Chemical, marine, food & pharma industries | |
| ASTM A182 F321 / F321H | Class 150 – 1500, Size ½”–24” | High temperature, stabilized service | |
| Carbon Steel | ASTM A105 (Forged CS) | Class 150 – 2500, Size ½”–48” | Pressure piping, oil & gas, general industries |
| ASTM A350 LF2 (Low Temp CS) | Class 150 – 1500, Size ½”–24” | Cryogenic & low temperature applications | |
| Alloy Steel | ASTM A182 F11 / F22 (Cr-Mo) | Class 150 – 2500, Size ½”–24” | Power plants, refineries, steam pipelines |
| ASTM A182 F91 | Class 150 – 2500, Size ½”–24” | High-temperature, power generation | |
| Duplex / Super Duplex | ASTM A182 F51 / F53 / F55 / F60 (UNS S31803 / S32205 / S32750 / S32760) | Class 150 – 2500, Size ½”–24” | Offshore, seawater, high corrosion service |
| Nickel Alloys | ASTM B564 Inconel 600 / 625 / 718 | Class 150 – 2500, Size ½”–24” | Heat exchangers, chemical, aerospace |
| ASTM B564 Monel 400 / K500 | Class 150 – 2500, Size ½”–24” | Marine, seawater handling, pumps | |
| Copper Nickel | ASTM B151 / B467 (Cu-Ni 90/10, 70/30) | Class 150 – 600, Size ½”–24” | Shipbuilding, desalination, seawater systems |
| Titanium | ASTM B381 Gr. 2 / Gr. 5 | Class 150 – 600, Size ½”–12” | Aerospace, seawater, lightweight piping |
| Aluminium | ASTM B247 6061 / 5083 | Class 150 – 300, Size ½”–12” | Lightweight, non-corrosive, low-pressure piping |
ANSI/ASME B16.5 Class 150 RF Socket Weld Flange – Dimensions & Sizes in mm
| Nominal size |
Outside Dia of Flange (D) |
Thick of Flange (B) |
Dia of Raised Face (G) |
Dia of Hub at Base (A) |
Length thru Hub (H) |
Dia of Bore (ID) |
Depth of Socket (F) | No of Holes |
Dia of Holes (L) |
Dia of Bolts |
Dia of Bolt Circle (K) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 88.9 | 11.2 | 35.1 | 30.2 | 15.7 | 22.4 | 9.7 | 4 | 15.7 | 1/2 | 60.5 |
| 3/4 | 98.6 | 12.7 | 42.9 | 38.1 | 15.7 | 27.7 | 11.2 | 4 | 15.7 | 1/2 | 69.9 |
| 1 | 108 | 14.2 | 50.8 | 49.3 | 17.5 | 34.5 | 12.7 | 4 | 15.7 | 1/2 | 79.2 |
| 1-1/4 | 117.3 | 15.7 | 63.5 | 58.7 | 20.6 | 43.2 | 14.2 | 4 | 15.7 | 1/2 | 88.9 |
| 1-1/2 | 127 | 17.5 | 73.2 | 65 | 22.4 | 49.5 | 15.7 | 4 | 15.7 | 1/2 | 98.6 |
| 2 | 152.4 | 19.1 | 91.9 | 77.7 | 25.4 | 62 | 17.5 | 4 | 19.1 | 5/8 | 120.7 |
| 2-1/2 | 177.8 | 22.4 | 104.6 | 90.4 | 28.4 | 74.7 | 19.1 | 4 | 19.1 | 5/8 | 139.7 |
| 3 | 190.5 | 23.9 | 127 | 108 | 30.2 | 90.7 | 20.6 | 4 | 19.1 | 5/8 | 152.4 |
| 3-1/2 | 215.9 | 23.9 | 139.7 | 122.2 | 31.8 | 103.4 | 8 | 19.1 | 5/8 | 177.8 | |
| 4 | 228.6 | 23.9 | 157.2 | 134.9 | 33.3 | 116.1 | 8 | 19.1 | 5/8 | 190.5 | |
| 5 | 254 | 23.9 | 185.7 | 163.6 | 36.6 | 143.8 | 8 | 22.4 | 3/4 | 215.9 | |
| 6 | 279.4 | 25.4 | 215.9 | 192 | 39.6 | 170.7 | 8 | 22.4 | 3/4 | 241.3 | |
| 8 | 342.9 | 28.4 | 269.7 | 246.1 | 44.5 | 221.5 | 8 | 22.4 | 3/4 | 298.5 | |
| 10 | 406.4 | 30.2 | 323.9 | 304.8 | 49.3 | 276.4 | 12 | 25.4 | 7/8 | 362 | |
| 12 | 482.6 | 31.8 | 381 | 365.3 | 55.6 | 327.2 | 12 | 25.4 | 7/8 | 431.8 | |
| 14 | 533.4 | 35.1 | 412.8 | 400.1 | 57.2 | 359.2 | 12 | 28.4 | 1 | 476.3 | |
| 16 | 596.9 | 36.6 | 469.9 | 457.2 | 63.5 | 410.5 | 16 | 28.4 | 1 | 539.8 | |
| 18 | 635 | 39.6 | 533.4 | 505 | 68.3 | 461.8 | 16 | 31.8 | 1-1/8 | 577.9 | |
| 20 | 698.5 | 42.9 | 584.2 | 558.8 | 73.2 | 513.1 | 20 | 31.8 | 1-1/8 | 635 | |
| 24 | 812.8 | 47.8 | 692.2 | 663.4 | 82.6 | 616 | 20 | 35.1 | 1-1/4 | 749.3 |
ANSI/ASME B16.5 Class 300 RF Socket Weld Flange – Dimensions & Sizes in mm
| Nominal size |
Outside Dia of Flange (D) |
Thick of Flange (B) |
Dia of Raised Face (G) |
Dia of Hub at Base (A) |
Length thru Hub (H) |
Dia of Bore (ID) |
Depth of Socket (F) |
No of Holes |
Dia of Holes (L) |
Dia of Bolts |
Dia of Bolt Circle (K) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 95.3 | 14.2 | 35.1 | 38.1 | 22.4 | 22.4 | 9.7 | 4 | 15.7 | 1/2 | 66.5 |
| 3/4 | 117.3 | 15.7 | 42.9 | 47.8 | 25.4 | 27.7 | 11.2 | 4 | 19.1 | 5/8 | 82.6 |
| 1 | 124 | 17.5 | 50.8 | 53.8 | 26.9 | 34.5 | 12.7 | 4 | 19.1 | 5/8 | 88.9 |
| 1-1/4 | 133.4 | 19.1 | 63.5 | 63.5 | 26.9 | 43.2 | 14.2 | 4 | 19.1 | 5/8 | 98.6 |
| 1-1/2 | 155.4 | 20.6 | 73.2 | 69.9 | 30.2 | 49.5 | 15.7 | 4 | 22.4 | 3/4 | 114.3 |
| 2 | 165.1 | 22.4 | 91.9 | 84.1 | 33.3 | 62 | 17.5 | 8 | 19.1 | 5/8 | 127 |
| 2-1/2 | 190.5 | 25.4 | 104.6 | 100.1 | 38.1 | 74.7 | 19.1 | 8 | 22.4 | 3/4 | 149.4 |
| 3 | 209.6 | 28.4 | 127 | 117.3 | 42.9 | 90.7 | 20.6 | 8 | 22.4 | 3/4 | 168.1 |
| 3-1/2 | 228.6 | 30.2 | 139.7 | 133.4 | 44.5 | 103.4 | 8 | 22.4 | 3/4 | 184.2 | |
| 4 | 254 | 31.8 | 157.2 | 146.1 | 47.8 | 116.1 | 8 | 22.4 | 3/4 | 200.2 | |
| 5 | 279.4 | 35.1 | 185.7 | 177.8 | 50.8 | 143.8 | 8 | 22.4 | 3/4 | 235 | |
| 6 | 317.5 | 36.6 | 215.9 | 206.2 | 52.3 | 170.7 | 12 | 22.4 | 3/4 | 269.7 | |
| 8 | 381 | 41.1 | 269.7 | 260.4 | 62 | 221.5 | 12 | 25.4 | 7/8 | 330.2 | |
| 10 | 444.5 | 47.8 | 323.9 | 320.5 | 66.5 | 276.4 | 16 | 28.4 | 1 | 387.4 | |
| 12 | 520.7 | 50.8 | 381 | 374.7 | 73.2 | 327.2 | 16 | 31.8 | 1-1/8 | 450.9 | |
| 14 | 584.2 | 53.8 | 412.8 | 425.5 | 76.2 | 359.2 | 16 | 31.8 | 1-1/8 | 514.4 | |
| 16 | 647.7 | 57.2 | 469.9 | 482.6 | 82.6 | 410.5 | 20 | 35.1 | 1-1/4 | 571.5 | |
| 18 | 711.2 | 60.5 | 533.4 | 533.4 | 88.9 | 461.8 | 24 | 35.1 | 1-1/4 | 628.7 | |
| 20 | 774.7 | 63.5 | 584.2 | 587.2 | 95.3 | 513.1 | 24 | 35.1 | 1-1/4 | 685.8 | |
| 24 | 914.4 | 69.9 | 692.2 | 701.5 | 106.4 | 616 | 24 | 41.1 | 1-1/2 | 812.8 |
ANSI/ASME B16.5 Class 600 RF Socket Weld Flange – Dimensions & Sizes in mm
| Nominal size |
Outside Dia of Flange (D) |
Thick of Flange (B) |
Dia of Raised Face (G) |
Dia of Hub at Base (A) |
Length thru Hub (H) |
Dia of Bore (ID) |
Depth of Socket (F) |
No of Holes |
Dia of Holes (L) |
Dia of Bolts |
Dia of Bolt Circle (K) |
Approx Weight (kg) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 95.3 | 14.2 | 35.1 | 38.1 | 22.4 | 22.4 | 9.7 | 4 | 15.7 | 1/2 | 66.5 | 1 |
| 3/4 | 117.3 | 15.7 | 42.9 | 47.8 | 25.4 | 27.7 | 11.2 | 4 | 19.1 | 5/8 | 82.6 | 1 |
| 1 | 124 | 17.5 | 50.8 | 53.8 | 26.9 | 34.5 | 12.7 | 4 | 19.1 | 5/8 | 88.9 | 2 |
| 1-1/4 | 133.4 | 20.6 | 63.5 | 63.5 | 28.4 | 43.2 | 14.2 | 4 | 19.1 | 5/8 | 98.6 | 2 |
| 1-1/2 | 155.4 | 22.4 | 73.2 | 69.9 | 31.8 | 49.5 | 15.7 | 4 | 22.4 | 3/4 | 114.3 | 3 |
| 2 | 165.1 | 25.4 | 91.9 | 84.1 | 36.6 | 62 | 17.5 | 8 | 19.1 | 5/8 | 127 | 4 |
| 2-1/2 | 190.5 | 28.4 | 104.6 | 100.1 | 41.1 | 74.7 | 19.1 | 8 | 22.4 | 3/4 | 149.4 | 6 |
| 3 | 209.6 | 31.8 | 127 | 117.3 | 46 | 90.7 | 20.6 | 8 | 22.4 | 3/4 | 168.1 | 7 |
| 3-1/2 | 228.6 | 35.1 | 139.7 | 133.4 | 49.3 | 103.4 | 8 | 25.4 | 7/8 | 184.2 | 10 | |
| 4 | 273.1 | 38.1 | 157.2 | 152.4 | 53.8 | 116.1 | 8 | 25.4 | 7/8 | 215.9 | 17 | |
| 5 | 330.2 | 44.5 | 185.7 | 189 | 60.5 | 143.8 | 8 | 28.4 | 1 | 266.7 | 29 | |
| 6 | 355.6 | 47.8 | 215.9 | 222.3 | 66.5 | 170.7 | 12 | 28.4 | 1 | 292.1 | 36 | |
| 8 | 419.1 | 55.6 | 269.7 | 273.1 | 76.2 | 221.5 | 12 | 31.8 | 1-1/8 | 349.3 | 52 | |
| 10 | 508 | 63.5 | 323.9 | 342.9 | 85.9 | 276.4 | 16 | 35.1 | 1-1/4 | 431.8 | 77 | |
| 12 | 558.8 | 66.5 | 381 | 400.1 | 91.9 | 327.2 | 20 | 35.1 | 1-1/4 | 489 | 91 | |
| 14 | 603.3 | 69.9 | 412.8 | 431.8 | 93.7 | 359.2 | 20 | 38.1 | 1-3/8 | 527.1 | 104 | |
| 16 | 685.8 | 76.2 | 469.9 | 495.3 | 106.4 | 410.5 | 20 | 41.1 | 1-1/2 | 603.3 | 150 | |
| 18 | 743 | 82.6 | 533.4 | 546.1 | 117.3 | 461.8 | 20 | 44.5 | 1-5/8 | 654.1 | 181 | |
| 20 | 812.8 | 88.9 | 584.2 | 609.6 | 127 | 513.1 | 24 | 44.5 | 1-5/8 | 723.9 | 231 | |
| 24 | 939.8 | 101.6 | 692.2 | 717.6 | 139.7 | 616 | 24 | 50.8 | 1-7/8 | 838.2 | 331 |
ANSI/ASME B16.5 Class 1500 RF Socket Weld Flange – Dimensions & Sizes in mm
| Nominal size |
Outside Dia of Flange (D) |
Thick of Flange (B) |
Dia of Raised Face (G) |
Dia of Hub at Base (A) |
Length thru Hub (H) |
Dia of Bore (ID) |
Depth of Socket (F) |
No of Holes |
Dia of Holes (L) |
Dia of Bolts |
Dia of Bolt Circle (K) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 120.7 | 22.4 | 35.1 | 38.1 | 31.8 | 22.4 | 9.7 | 4 | 22.4 | 3/4 | 82.6 |
| 3/4 | 130 | 25.4 | 42.9 | 44.5 | 35.1 | 27.7 | 11.2 | 4 | 22.4 | 3/4 | 88.9 |
| 1 | 149.4 | 28.4 | 50.8 | 52.3 | 41.1 | 34.5 | 12.7 | 4 | 25.4 | 7/8 | 101.6 |
| 1-1/4 | 158.8 | 28.4 | 63.5 | 63.5 | 41.1 | 43.2 | 14.2 | 4 | 25.4 | 7/8 | 111.3 |
| 1-1/2 | 177.8 | 31.8 | 73.2 | 69.9 | 44.5 | 49.5 | 15.7 | 4 | 28.4 | 1 | 124 |
| 2 | 215.9 | 38.1 | 91.9 | 104.6 | 57.2 | 62 | 17.5 | 8 | 25.4 | 7/8 | 165.1 |
| 2-1/2 | 244.3 | 41.1 | 104.6 | 124 | 63.5 | 74.7 | 8 | 19.1 | 28.4 | 1 | 190.5 |
| 3 | 266.7 | 47.8 | 127 | 133.4 | 73.2 | 8 | 31.8 | 1-1/8 | 203.2 | ||
| 4 | 311.2 | 53.8 | 157.2 | 162.1 | 90.4 | 8 | 35.1 | 1-1/4 | 241.3 | ||
| 5 | 374.7 | 73.2 | 185.7 | 196.9 | 104.6 | 8 | 41.1 | 1-1/2 | 292.1 | ||
| 6 | 393.7 | 82.6 | 215.9 | 228.6 | 119.1 | 12 | 38.1 | 1-3/8 | 317.5 | ||
| 8 | 482.6 | 91.9 | 269.7 | 292.1 | 142.7 | 12 | 44.5 | 1-5/8 | 393.7 | ||
| 10 | 584.2 | 108 | 323.9 | 368.3 | 158.8 | 12 | 50.8 | 1-7/8 | 482.6 | ||
| 12 | 673.1 | 124 | 381 | 450.9 | 180.8 | 16 | 53.8 | 2 | 571.5 | ||
| 14 | 749.3 | 133.4 | 412.8 | 495.3 | 16 | 60.5 | 2-1/4 | 635 | |||
| 16 | 825.5 | 146.1 | 469.9 | 552.5 | 16 | 66.5 | 2-1/2 | 704.9 | |||
| 18 | 914.4 | 162.1 | 533.4 | 596.9 | 16 | 73.2 | 2-3/4 | 774.7 | |||
| 20 | 984.3 | 177.8 | 584.2 | 641.4 | 16 | 79.2 | 3 | 831.9 | |||
| 24 | 1168.4 | 203.2 | 692.2 | 762 | 16 | 91.9 | 3-1/2 | 990.6 |
Socket Weld Piping Flange Weight Chart (lbs) – Pressure Class 150 to 2500
| Nominal Pipe Size (NPS) | 150# | 300# | 400# | 600# | 900# | 1500# | 2500# |
|---|---|---|---|---|---|---|---|
| ½” | 1.0 | 1.5 | 1.8 | 2.1 | 3.0 | 4.2 | 6.5 |
| ¾” | 1.2 | 1.9 | 2.3 | 2.8 | 4.0 | 5.8 | 8.7 |
| 1” | 1.5 | 2.5 | 3.0 | 3.6 | 5.2 | 7.6 | 11.4 |
| 1 ½” | 2.3 | 3.8 | 4.6 | 5.5 | 8.1 | 12.0 | 18.2 |
| 2” | 3.1 | 5.0 | 6.1 | 7.2 | 10.6 | 15.8 | 24.5 |
| 3” | 5.2 | 8.7 | 10.5 | 12.7 | 18.7 | 27.8 | 43.0 |
| 4” | 7.8 | 13.0 | 15.8 | 19.0 | 28.0 | 41.8 | 65.0 |
| 6” | 13.8 | 23.0 | 27.5 | 33.0 | 49.0 | 74.0 | 115.0 |
| 8” | 21.0 | 35.0 | 42.0 | 50.0 | 75.0 | 113.0 | 176.0 |
| 10” | 30.0 | 50.0 | 60.0 | 72.0 | 108.0 | 162.0 | 252.0 |
| 12” | 42.0 | 70.0 | 84.0 | 101.0 | 151.0 | 227.0 | 353.0 |
| 14” | 51.0 | 85.0 | 102.0 | 122.0 | 183.0 | 275.0 | 428.0 |
| 16” | 64.0 | 107.0 | 128.0 | 153.0 | 229.0 | 343.0 | 535.0 |
| 18” | 77.0 | 128.0 | 153.0 | 183.0 | 275.0 | 411.0 | 642.0 |
| 20” | 92.0 | 153.0 | 183.0 | 220.0 | 330.0 | 493.0 | 771.0 |
| 24” | 120.0 | 200.0 | 240.0 | 288.0 | 432.0 | 648.0 | 1015.0 |
SWRF Flange Tolerances as per ANSI / ASME B16.5, 16.47
| Parameter | Tolerance (as per ASME B16.5 / B16.47) |
|---|---|
| Outside Diameter of Flange (OD) | ±1.5 mm (for sizes ≤ 24″) / ±3.0 mm (for sizes > 24″) |
| Bolt Circle Diameter | ±1.5 mm |
| Bolt Hole Diameter | ±1.0 mm |
| Bolt Hole Center-to-Center | ±1.0 mm |
| Thickness of Flange (T) | +1.5 mm / –0.0 mm |
| Raised Face Height (RF) | ±0.5 mm |
| Raised Face Diameter | ±1.5 mm |
| Hub Bore (Socket Bore ID) | +1.0 mm / –0.5 mm |
| Socket Depth | ±1.0 mm |
| Concentricity of Bore to OD | ≤ 1.5 mm |
| Runout of Facing (Flatness) | ≤ 0.3 mm for ≤ 10″ / ≤ 0.5 mm for > 10″ |
| Bevel Angle (if applicable) | ±1° |
| Straightness of Hub | ≤ 0.5 mm per 100 mm length |
What makes Socket Weld Flanges different from Slip On and Weld Neck Flanges?
-
Connection Method: Socket weld flanges have a recessed socket to insert the pipe, followed by fillet welding. Slip On flanges fit over the pipe and are fillet welded inside & outside, while Weld Neck flanges require butt welding.
-
Strength: Socket weld flanges are stronger than Slip On flanges but less robust than Weld Neck flanges in high-pressure/cyclic loading.
-
Applications: Preferred for small-bore, high-pressure piping (up to 24”), whereas Weld Neck is used for large-bore or severe cyclic conditions.
What welding considerations should be followed for Socket Weld Flanges?
-
Gap Allowance: A gap (~1.6 mm) should be left between pipe end and flange socket bottom to avoid stress during thermal expansion.
-
Welding Sequence: Single fillet weld around the pipe OD. No internal weld is required, unlike Slip On flanges.
-
Inspection: Radiography is not effective (since it’s a fillet weld), so dye penetrant or ultrasonic testing is often used.
Why are Socket Weld Flanges limited to small bore piping (generally ≤ 24”)?
-
Design Restriction: The socket design is not practical for large diameter pipes due to alignment and stress issues.
-
Fabrication Ease: Easier to align and weld in smaller pipe sizes (½”–2” is most common).
-
Standards: ASME B16.5 covers socket weld flanges up to 24” only. Beyond that, Weld Neck or Blind flanges are recommended.