Description
Table Of Content
- Specifications of Stainless Steel 321 / 321H Flanges
- Size Range of A182 321 / 321H Pipe Flange
- Chemical Composition of SS 321 / 321H Flange
- Mechanical Properties ASME 321 Pipe Flange
- Types of Stainless Steel 321/321H Pipe Flange
- 321 / 321H Stainless Steel Flange Equivalent Grades
- 321 / 321H SS Blind Flange Stock List
- Applications of Stainless Steel 321 / 321H Flanges
- FAQs – Stainless Steel 321 / 321H Flanges
321/321H Stainless Steel Flange
Stainless Steel 321 / 321H Flanges are titanium-stabilized austenitic stainless steel flanges engineered for excellent performance in high-temperature and corrosive environments. Grade 321 is designed to resist intergranular corrosion after exposure to temperatures in the range of 427–816°C, making it ideal for thermal cycling applications. Grade 321H, with a higher carbon content, offers improved high-temperature strength and creep resistance. These flanges are commonly used in heat exchangers, pressure vessels, refinery units, and exhaust systems. With good weldability, formability, and resistance to oxidation up to 900°C, SS 321/321H flanges are a reliable choice for industries requiring long-term performance in extreme conditions.
Specifications of Stainless Steel 321 / 321H Flanges
| Standards | GOST Flange, JISB2220, BS1560-3.1, API7S-15, API7S-43, API605, EN1092, BS, BS4504, BS 10, EN-1092, DIN, ANSI, ASME, DIN, MSS S44, ISO70051, ANSI/ASME B16.5, ASME/ANSI B16.5/16.36/16.47A/16.47B, B16.47 Series A & B, B16.48, EN |
|---|---|
| Pressure Rating ANSI | Class 1500, Class 150, Class 900, Class 2500, Class 300, Class 600, |
| Pressure Calculation in DIN | 10Bar, 16Bar, 25Bar, 40Bar, 6Bar, / PN16, PN64, PN40, PN25, PN10, PN6 |
| JIS | 16 K, 20 K, 5K, 10 K, 40 K, 63 K, 30 K, |
| UNI | 10Bar 16Bar 6Bar 25Bar 40Bar |
| EN | 6Bar 25Bar 40Bar 10Bar 16Bar |
| Most common Types | Threaded / Screwed / Forged / Plate |
| Production technique |
|
| Shapes and Types we produce | Large Male-Female (LMF), Ring Type Joint (RTJ), Flat Face (FF), Small Tongue, Small Male-Female (SMF),Raised Face (RF), Large Tongue & Groove, Groove, Lap-Joint Face (LJF) |
| Test | Direct-reading Spectrograph, Magnetic particle detector, Hydrostatic testing machine, X-ray detector, UI trasonic flaw detector |
| Equipment | Pushing Machine, Press machine, Bending machine, Sand-blasting machine, electric bevelling machine etc |
Size Range of A182 321 / 321H Pipe Flange
- UNS S32100 Flange : 1/2″ (15 NB) to 48″ (1200NB)
- ASME SA182 F321 Blind Flange : 1/2″ NB – 24″ NB
- SS A182 F321H Slip on Flange : 1/2″ NB – 12″ NB
Chemical Composition of SS 321 / 321H Flange
| Grade | C | Mn | Si | P | S | Cr | N | Ni | Ti |
| SS 321 | 0.08 max | 2.0 max | 1.0 max | 0.045 max | 0.030 max | 17.00 – 19.00 | 0.10 max | 9.00 – 12.00 | 5(C+N) – 0.70 max |
| SS 321H | 0.04 – 0.10 | 2.0 max | 1.0 max | 0.045 max | 0.030 max | 17.00 – 19.00 | 0.10 max | 9.00 – 12.00 | 4(C+N) – 0.70 max |
Mechanical Properties ASME 321 Pipe Flange
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 8.0 g/cm3 | 1457 °C (2650 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 35 % |
Types of SS 321 / 321H Flange
 |  |  |  |
| Blind Flanges | Lap Joint Flanges | Long Weld Neck Flanges | Plate Flanges |
 |  |  |  |
| Reducing Flanges | Ring Type Joint Flanges | Slip On Flanges | Socket Weld Flanges |
 |  |  |  |
| Weld Neck Flanges | Tongue & Groove Flanges | Threaded / Screwed Flanges | Spectacle Blind Flanges |
321 / 321H Stainless Steel Flange Equivalent grades
| STANDARD | WERKSTOFF NR. | UNS | JIS | EN |
| SS 321 | 1.4541 | S32100 | SUS 321 | X6CrNiTi18-10 |
| SS 321H | 1.4878 | S32109 | SUS 321H | X12CrNiTi18-9 |
321 / 321H SS Blind Flange Stock List
| Stainless Steel 321 Flange | 321 SS Blind Flange |
| 321H Stainless Steel Slip on Flange | SS A182 F321H Threaded Flange |
| UNS S32100 Reducing Flange | Stainless Steel 1.4541 Socket Weld Flange |
| ASTM A182 F321H Weld Neck Flanges | ASME SA182 F321 Lap Joint Flanges |
| Stainless Steel 1.4541 Long Weld Neck Flanges | 321H Stainless Steel Spectacle Blind Flanges |
| UNS S32100 Spades & Ring Spacers | 321 SS Nipoflange |
| SS A182 F321H 5D Weldoflange | ASTM A182 F321H Flange Outlet |
| Stainless Steel 321 Forged Flanges | Stainless Steel 1.4541 Plate Flange |
| SS A182 F321H Ring Type Joint Flanges | UNS S32100 Raised Face Flanges |
| ASME SA182 F321 Tongue and Groove Flanges | 321H Stainless Steel Male and Female Flange |
| ASTM A182 F321H Reducing Flanges | 321 SS ASME B16.5 Flanges |
| Stainless Steel 321 Flanges | Stainless Steel 1.4541 BS 10 Flanges |
| UNS S32100 BS 4504 Flanges | SS A182 F321H EN 1092-1 Flanges |
| ASTM A182 F321H SORF Flange | 321H Stainless Steel BLRF Flange |
| 321 SS WNRF Flange | Stainless Steel 321 Series a Lap Joint Ring Flange |
| Stainless Steel 1.4541 PN16 blind flange | UNS S32100 Forged Socket Weld Pipe Flange |
| 321H Stainless Steel Class 300 slip on flange | ASTM A182 F321H Slip On Weld Flange |
| SS A182 F321H Forged steel slip on flanges | 321 SS Race face slip on flange |
| Stainless Steel 321 SWRF Flange | ASME SA182 F321 Forged blind flange |
| 321H Stainless Steel groove weld neck flange | Stainless Steel 1.4541 Socket Weld Hub Flange |
| UNS S32100 threaded lap joint flange | 321 SS Slip On Integral flange |
| ASME SA182 F321 Forged integral puddle flange | SS A182 F321H table e long weld neck |
| 321H Stainless Steel Class 150 LBS Flange | ASME SA182 F321 PN10 Forged Flanges |
Applications of Stainless Steel 321 / 321H Flanges
Stainless Steel 321 and 321H flanges are widely used in industries that demand high-temperature strength, corrosion resistance, and structural stability. These flanges are ideal for:
Heat Exchangers – Withstand thermal cycling and intergranular corrosion in petrochemical systems.
Furnace and Boiler Components – Provide long-term stability under continuous high-heat service.
Exhaust Manifolds and Ducting – Common in aircraft, automotive, and power plant exhaust systems.
Refinery and Chemical Processing Units – Handle aggressive media and fluctuating pressures.
Pressure Vessels and Reactors – Especially in environments involving organic and inorganic acids.
Thermal Oxidizers and Flue Gas Systems – Withstand oxidative conditions in waste treatment and incineration plants.
Power Generation Plants – Used in steam piping and turbine exhaust sections.
These flanges are especially valued in applications where resistance to sensitization and high-temperature oxidation is critical, making SS 321/321H flanges a preferred choice in high-performance industrial systems.
FAQs – Stainless Steel 321 / 321H Flanges
Q1: What is the difference between 321 and 321H stainless steel flanges?
A: The main difference lies in the carbon content. 321H has a higher carbon content (0.04–0.10%) compared to 321 (max 0.08%), which improves high-temperature strength and creep resistance. 321H is preferred for applications above 537°C (1000°F).
Q2: Are 321/321H flanges resistant to intergranular corrosion?
A: Yes. Grade 321 is specifically stabilized with titanium to prevent chromium carbide precipitation, which makes it highly resistant to intergranular corrosion after exposure to high temperatures.
Q3: What temperature range can Stainless Steel 321 / 321H flanges withstand?
A: These flanges offer excellent performance in continuous service up to 900°C (1650°F), making them ideal for high-temperature industrial environments.
Q4: Can 321/321H flanges be welded?
A: Yes. Both grades offer good weldability using standard welding methods. However, post-weld heat treatment is typically not required for 321, while it may be considered for 321H in certain critical applications.
Q5: In which industries are SS 321 / 321H flanges most commonly used?
A: They are widely used in oil & gas, petrochemical, power generation, aerospace, and thermal processing industries—especially where exposure to elevated temperatures and corrosive gases is frequent.
