SS 310 / 310S Socket Weld FlangeASTM A182 · ASME B16.5 · Manufacturer, stockist & exporter, India
AISI 310S · UNS S31008 · SWRF
An SS 310 / 310S socket weld flange is a flange with a counterbore socket into which the pipe is inserted and fillet-welded, made from SS 310 / 310S to ASTM A182 F310. Socket weld flanges suit small-bore, high-pressure lines, usually 2" and under. A 1.6 mm (1/16") expansion gap is left at the bottom of the socket before welding.
- ASTM A182
- ASME B16.5
- EN 10204 3.1 / 3.2
- Export packing
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is an SS 310 / 310S Socket Weld Flange?
- What it is
- A flange with a counterbore socket into which the pipe is inserted and fillet-welded
- Material
- ASTM A182 F310
- Dimensions
- ASME B16.5
- Grade
- SS 310 / 310S · UNS S31008
- Best at
- Furnaces, burners and heat treatment at high temperature
SS 310 / 310S Socket Weld Flange Specification
| Product | SS 310 / 310S Socket Weld Flange |
|---|---|
| Material standard | ASTM A182 F310 |
| Dimensional standard | ASME B16.5 |
| Sizes | ½" – 24" (ASME B16.5) · 26" – 60" (ASME B16.47) |
| Pressure class | Class 150, 300, 400, 600, 900, 1500, 2500 · PN 6 – PN 100 |
| Facing | RF · FF · RTJ · tongue & groove |
| Bore | To match pipe schedule (state on order) |
| Testing | PMI · dimensional · NDT and IGC on request |
| Documents | EN 10204 3.1 · 3.2 with third-party inspection |
When to Choose a Socket Weld Flange
Socket weld flanges suit small-bore, high-pressure lines, usually 2" and under. A 1.6 mm (1/16") expansion gap is left at the bottom of the socket before welding.
- Leave a 1.6 mm gap before welding
- Not recommended where crevice corrosion is a concern
- Bore to match pipe schedule
SS 310 / 310S Socket Weld Flange Chemical Composition
| Element | Weight % |
|---|---|
| Chromium | 24.0 – 26.0 |
| Nickel | 19.0 – 22.0 |
| Carbon | 0.08 max |
| Manganese | 2.00 max |
| Silicon | 1.50 max |
| Phosphorus | 0.045 max |
| Sulphur | 0.030 max |
| Iron | Balance |
SS 310 / 310S Socket Weld Flange Mechanical Properties
| Annealed plate & sheet | Value |
|---|---|
| Tensile strength | 515 MPa · 75 ksi |
| Yield strength 0.2% | 205 MPa · 30 ksi |
| Elongation | 40% |
| Hardness | 217 HB max |
Full chemistry, properties and equivalents are on the SS 310 / 310S grade page.
Other SS 310 / 310S flanges
SS 310 / 310S Socket Weld Flanges for export
FOB / CIF · Nhava Sheva (JNPT), MumbaiSS 310 / 310S Socket Weld Flange dimensions — ASME B16.5 Class 150 & 300
Outside diameter, thickness and bolting are set by size and class. Values in mm; thickness excludes the 1.6 mm raised face.
| NPS | Cl 150 OD | Cl 150 thickness | Cl 150 bolt circle | Cl 150 bolts | Cl 300 OD | Cl 300 thickness | Cl 300 bolt circle | Cl 300 bolts |
|---|---|---|---|---|---|---|---|---|
| ½" | 90 | 9.6 | 60.3 | 4 × ½" | 95 | 12.7 | 66.7 | 4 × ½" |
| 1" | 110 | 12.7 | 79.4 | 4 × ½" | 125 | 15.9 | 88.9 | 4 × ⅝" |
| 1½" | 125 | 15.9 | 98.4 | 4 × ½" | 155 | 19.1 | 114.3 | 4 × ¾" |
| 2" | 150 | 17.5 | 120.7 | 4 × ⅝" | 165 | 20.7 | 127.0 | 8 × ⅝" |
| 3" | 190 | 22.3 | 152.4 | 4 × ⅝" | 210 | 27.0 | 168.3 | 8 × ¾" |
| 4" | 230 | 22.3 | 190.5 | 8 × ⅝" | 255 | 30.2 | 200.0 | 8 × ¾" |
| 6" | 280 | 23.9 | 241.3 | 8 × ¾" | 320 | 35.0 | 269.9 | 12 × ¾" |
| 8" | 345 | 27.0 | 298.5 | 8 × ¾" | 380 | 39.7 | 330.2 | 12 × ⅞" |
| 10" | 405 | 28.6 | 362.0 | 12 × ⅞" | 445 | 46.1 | 387.4 | 16 × 1" |
| 12" | 485 | 30.2 | 431.8 | 12 × ⅞" | 520 | 49.3 | 450.8 | 16 × 1⅛" |
Full chart: ASME B16.5 flange dimensions.
SS 310 / 310S Socket Weld Flange — questions buyers ask
Why leave a gap in a socket weld?
The gap lets the pipe expand during welding without cracking the fillet weld. ASME B31.3 requires it.
Which standard covers SS 310 / 310S socket weld flanges?
The material is ASTM A182 F310; dimensions follow ASME B16.5. Always state both on your purchase order, with the edition if your project specifies one.
What decides the price of a SS 310 / 310S socket weld flange?
The alloy price, the size and pressure class, quantity, and the testing and documents required. Send your list and we quote the same working day.
What documents do you supply?
EN 10204 3.1 mill certificates as standard, 3.2 with third-party inspection on request, plus dimensional and PMI reports.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026