Zeron Fastners
SS 347 Blind Flanges (BLF) - Line Closure
SS 347 Blind Flanges (BLF) are solid pipe forgings used to seal off a pipeline or to temporarily close a vessel opening. Unlike other flange types, the Blind Flange has no bore and its purpose is to withstand the maximum system pressure and temperature when terminating a line. Manufactured from SS 347, an austenitic stainless steel stabilized with Niobium, these flanges are inherently resistant to **intergranular corrosion**, which is a crucial advantage in the demanding environments of chemical and power plants. Supplied by Zeron Fasteners, these flanges offer the superior mechanical strength and thermal stability required for permanent or temporary high-pressure containment **up to 870°C**. They are bolted onto the corresponding pipe flange with a gasket to ensure a leak-proof seal.
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SS 347 Blind 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 Blind 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 |
| Pressure Rating | Class 150 to Class 2500 |