Zeron Fastners
SS 347 Socket Weld Flanges (SWF) - High Pressure
SS 347 Socket Weld Flanges (SWF) are pipe forgings designed for small-bore, high-pressure piping where butt-welding is difficult or impractical. The flange features a recess (socket) into which the pipe is inserted, and a single fillet weld is applied on the outside circumference. This design makes them easier to align and install than Weld Neck Flanges but provides less integrity in fatigue and is not recommended for severely erosive service. The material, SS 347, is an austenitic stainless steel stabilized with Niobium (Columbium). This stabilization is essential as the necessary welding process would otherwise leave the Heat Affected Zone (HAZ) vulnerable to **intergranular corrosion** if the flange were subjected to the high operating temperatures (**up to 870°C**) found in chemical processing or power plants. Zeron Fasteners manufactures these flanges to strict ASME B16.5 standards, guaranteeing a robust and corrosion-resistant connection point.
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SS 347 Socket Weld Flanges Chemical Composition
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.08 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulfur (S) | 0.030 max |
| Silicon (Si) | 1.00 max |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | 9.00 – 13.00 |
| Niobium (Nb) + Tantalum (Ta) | 10 x C – 1.00 |
Note: The combined Niobium and Tantalum content must be ten times the Carbon content minimum, up to a maximum of 1.00%.
SS 347 Socket Weld Flanges Mechanical Properties
| Property | Value (Typical, ASTM A182 F347) |
|---|---|
| Tensile Strength | 515 MPa |
| Yield Strength (0.2% Offset) | 205 MPa |
| Elongation | 30% |
| Hardness (Brinell, HB) | 217 max |
| Design Standard | ASME B16.5 |