SS 321/347 flange manufacturer, Mumbai. Ti/Nb-stabilized for high-temp welded service, refinery furnace outlet piping. Class 150-2500. Quote in 30 min.
ASTM A182 F321 (Titanium stabilized) and F347 (Niobium stabilized) forged flanges are specifically alloyed to eliminate intergranular corrosion in high-temperature service between 425°C and 815°C.
Governing specification limits per ASTM / ASME standards. Actual values provided on EN 10204 3.1 MTC.
| Element | Specification Limit / Composition |
|---|---|
| Titanium (Ti) | 5x C min, 0.70% max (F321) |
| Niobium + Tantalum (Nb+Ta) | N/A |
| Chromium (Cr) | 17.0 - 19.0% |
| Nickel (Ni) | 9.0 - 12.0% |
| Property | Specification Limit |
|---|---|
| Yield Strength | 205 MPa min |
| Tensile Strength | 515 MPa min |
| Service Temp | Class 150 | Class 300 | Class 600 | Class 900 |
|---|---|---|---|---|
| Ambient (-29 to 38°C) | 275 psi | 720 psi | 1440 psi | 2160 psi |
Flanges in Stainless Steel 321/347 Flanges are manufactured via precision closed-die or open-die forging to establish continuous metallurgical grain flow along the flange hub and neck contour. Raw billets are heated in calibrated gas-fired furnaces under strictly controlled soak temperatures to eliminate microstructural defects.
Depending on the alloy grade, components undergo certified thermal conditioning: normalizing for carbon steels (A105N, A350 LF2), rapid water quench solution annealing at 1040°C–1120°C for stainless and duplex grades, or controlled aging for nickel superalloys. This ensures exceptional notch toughness, yield strength, and resistance to stress corrosion cracking.
Final machining is executed on heavy-duty CNC turning centers to guarantee precise raised face, flat face, or ring type joint (RTJ) dimensions compliant with ASME B16.5, ASME B16.47, DIN, or EN 1092-1 standards. Gasket contact surfaces receive spiral or concentric serrations strictly controlled between 125 and 250 µin Ra.
Every production heat is issued with an EN 10204 Type 3.1 inspection certificate containing full heat chemistry, mechanical tensile test data, and Charpy impact values. Independent Third-Party Inspection (TPI) by Lloyd's, BV, DNV-GL, TÜV, and SGS is readily accommodated for global EPC and refinery contracts.
A: Titanium (in 321) and Niobium (in 347) have a higher affinity for carbon than chromium. They form stable carbides (TiC / NbC) during thermal exposure, preventing chromium depletion at grain boundaries.
Written commercial offer with Mill Test Certificate guarantee.