SS 321/321H Fittings & Flanges – Buttweld, Forged & Outlet Types – Engineered for Thermal Processing, Petrochemical & Refinery Use – NACE, PED, IBR Approved.
We are a recognized ISO-certified manufacturer and exporter of premium stainless steel products, offering a comprehensive range in Stainless Steel 321 – a titanium-stabilized austenitic stainless steel ideal for high-temperature service. Our product line includes SS 321H Buttweld Fittings, Flanges, Forged Fittings, and Olets, engineered for long-term durability in applications involving elevated temperatures and intergranular corrosion risks. With modern manufacturing capabilities and a strong global supply chain, we serve industries such as heat exchangers, refineries, power generation, and chemical processing.
Stainless Steel 321H provides excellent resistance to oxidation and scaling at high temperatures, and superior weldability due to its titanium stabilization which prevents carbide precipitation. Our fittings and flanges are manufactured as per global norms: ASTM A403 / ASME B16.9 for Buttweld Fittings, ASTM A182 / ASME B16.5 & B16.47 for Flanges, ASTM A182 / ASME B16.11 for Forged Fittings, and ASTM A182 / MSS SP-97 for Branch Outlet Fittings. We offer buttweld fittings from 1/2” to 48”, forged fittings from 1/8” to 4”, and flanges from 1/2” NB to 24” NB in pressure ratings from 150# to 2500#. All materials come with full traceability and certification as per EN 10204 3.1 or 3.2.
We manufacture a complete range of SS 321 Buttweld Fittings, including elbows (90°/45°), concentric and eccentric reducers, equal/reducing tees, caps, and stub ends. Our forged fittings are available in Socket Weld and Threaded ends, including elbows, tees, couplings, unions, caps, plugs, bushings, and swage nipples in accordance with ASME B16.11. Our flanges are produced in multiple types like Weld Neck, Slip-On, Blind, Socket Weld, Lap Joint, Threaded, and Orifice designs. We also supply branch connection fittings such as Weldolets, Threadolets, Sockolets, and Nipolets, conforming to MSS SP-97 for use in pressure and high-temperature piping systems.
Chemical Composition (%): C ≤ 0.08, Mn ≤ 2.00, Si ≤ 1.00, P ≤ 0.045, S ≤ 0.030, Cr 17.0–19.0, Ni 9.0–12.0, Ti ≥ 5 × C%, Fe balance. Mechanical Properties: Tensile Strength ≥ 515 MPa, Yield Strength ≥ 205 MPa, Elongation ≥ 40%, Hardness ≤ 95 HRB. SS 321/321H is ideal for high-temperature applications up to 900°C, offering resistance to scaling and phase instability. It eliminates the risk of intergranular corrosion during welding thanks to titanium stabilization, making it a preferred choice for welded structures. Common applications include exhaust manifolds, furnace parts, expansion joints, pressure vessels, and thermal oxidizers. The alloy delivers long-lasting performance in oxidizing environments and maintains mechanical strength under fluctuating thermal conditions, making it a reliable material for critical service environments.
Trusted Stockholder of SS 321 Flanges (WNRF, SORF, Blind), Buttweld Elbows, Tees, Reducer & Forged Couplings, Unions, Bushings, and Full Range of Olets (Weldolet, Sockolet, Threadolet) – Manufactured to ASME B16.5, B16.9, B16.11, and MSS SP-44 – Available in Class 150# to 2500#.
Technical Index
Industrial Stainless Steel 321/321H Specifications
| Material Grade | Stainless Steel 321, 321H / 1.4541, 1.4878 / UNS S32100, S32109 |
|---|---|
| Available Product Types | Flanges, Buttweld Fittings, Forged Fittings, Olets |
| Flanges Size Range | ½” (15 NB) to 48” (1200 NB) |
| Class | 150, 300, 600, 900, 1500, 2500, PN6, PN10, PN16, PN25, PN40, PN64 |
| Standard Specifications | ASTM A182, A403 / ASME SA182, SA403 |
| Standards | ASME B16.5, B16.47 Series A & B, B16.48, EN 1092-1, DIN, BS4504, BS10, ISO 7005-1, GOST, JIS B2220, MSS SP-44, API 605 |
| Types | Weld Neck Flange (WNRF), Slip-On Flange (SORF), Socket Weld Flange (SWRF), Threaded Flange, Blind Flange (BLRF), Lap Joint Flange, Ring Type Joint Flange (RTJ), Long Weld Neck Flange, Reducing Flange, Expander Flange, Orifice Flange, Spectacle Blind Flange, Spacer Flange, Paddle Blank, Paddle Spacer, Raised Face (RF), Flat Face (FF), Large Male-Female (LMF), Small Male-Female (SMF), Tongue & Groove |
| Buttweld Fittings Size | ½” NB to 24” NB (seamless), ½” NB to 48” NB (welded) |
| Wall Thickness | SCH 10, SCH 20, SCH 40, SCH 80, SCH 160, XXS |
| Standards | ASME B16.9, MSS SP-75, EN 10253, DIN 2605/2615/2616, ISO 3419, JIS B2312 |
| Types | Elbow (90°, 45°, Long Radius, Short Radius), Tee (Equal & Reducing), Reducer (Concentric & Eccentric), Caps, Stub Ends |
| Forged Fittings Size | ½” NB to 4” NB (Socket Weld & Threaded) |
| Class | Class 2000, 3000, 6000, 9000 (psi) |
| Standards | ASME B16.11, MSS SP-83, MSS SP-95, JIS B2316 |
| Types | 90° Elbow, 45° Elbow, Tee, Cross, Full Coupling, Half Coupling, Pipe Cap, Union, Reducer Insert, Boss, Hex Head Bushing, Hex Head Plug, Square Head Plug, Round Head Plug, Bull Plug, Boss, Outlet, Hex Nipple, Swage Nipple. |
| Olets (Outlet Fittings) Size | Branch Sizes ½” to 24” | Run Pipe Sizes up to 36” (custom) |
| Class | 3000#, 6000#, 9000# |
| Standards | MSS SP-97, ASME B16.11, ANSI, DIN, EN, JIS (custom) |
| Types | Weldolet, Sockolet, Threadolet, Elbolet, Latrolet, Nipolet, Sweepolet, Brazolet |
| End Connection Types | Buttweld, Socket Weld, Threaded (NPT/BSP), Flanged (RF, FF, RTJ), Custom Branch Outlets |
| Testing & Certifications | EN 10204 3.1 & 3.2, NACE MR0175, NACE MR0103, IBR, PMI, Ultrasonic Test, Radiography, Magnetic Particle Inspection |
| Surface Finish Options | Pickled, Passivated, Mirror Finish, Satin Finish, Sandblasted, Coated (Black, Yellow Transparent, Zinc) |
| Manufacturing Capabilities | CNC Machining, Cold/Hot Forming, Beveling, Drilling, Induction Heating, Forging, Custom Fabrication |
| Raw Material Sources | India, Japan, South Korea, USA, Germany, Italy |
| Export Destinations | USA, UAE, Saudi Arabia, Qatar, Kuwait, Oman, Egypt, South Africa, Kenya, Nigeria, Singapore, Malaysia, Australia |
Industrial Stainless Steel 321/321H Standards
| ANSI/ASME B16.47 Flanges | ANSI/ASME B16.36 Flanges | ANSI/ASME B16.5 Flanges | Pr. EN1902-1 Flanges |
| DIN Flanges | JIS Flanges | BS 4504 Flanges | BS 10 Flanges |
| MSS SP-44 Flanges | JIS B2220 Flanges | KS B1503 Flanges | UNI Flanges |
| SABS/SANS 1123 Flanges | AS 2129, AS 4087 Flanges | ISO 9624, ISO 7005-1 Flanges | AWWA Flanges Standard |
| GOST Standard Flanges | API Flanges | AS/ANZ 4331.1 Flanges | Series A Flange |
| Series B Flange | SAE J518 Flanges | GB Flange | Norwegian Standard Flanges |
| ASME B16.11 – Forged Steel Fittings, Socket-Welding and Threaded | BS 3799 – Screwed and Socket-Welding for the Petroleum Industry | MSS SP-79 – Socket-Welding Reducer Inserts | MSS SP-83 – Class 3000 Steel Pipe Unions, Socket-Welding and Threaded |
| MSS SP-95 – Swage(d) Nipples and Bull Plugs | MSS SP-97 – Integrally Reinforced Forged Branch Outlet Fittings | DIN 2986 – Threaded Fittings | DIN 2999 – Pipe Threads for Fittings (British Standard Pipe Threads) |
| ISO 49 – Malleable Iron Fittings, Threaded | ISO 7/1 – Pipe Threads Where Pressure-tight Joints Are Made on the Threads | EN 10241 – Steel Threaded Pipe Fittings | JIS B2316 – Japanese standard for forged pipe fittings. |
| ANSI/ASME B16.9 – Factory-Made Wrought Steel Buttwelding Fittings | ANSI/ASME B16.28 – Wrought Steel Short Radius Elbows and Returns | ANSI/ASME B16.25 – Buttwelding Ends(beval standards) | MSS SP-43 – Wrought and fabricated Butt welding Fittings for Light Wall Applications |
| MSS SP-75 – High Test Wrought Butt welding Fittings | DIN 2616 – Butt welding Pipe Fittings: Reducers | DIN 2617 – Butt welding Pipe Fittings: Caps | DIN28011 – Dished Ends(used in pressure vessels) |
| EN10253-1 Butt-welding Pipe Fittings(Non Alloy Steels) | EN10253-2 Butt-welding Pipe Fittings(Stainless/Alloy Steels) |
Stainless Steel 321/321H International Standards
| STANDARD | WERKSTOFF NR. | UNS | JIS | EN |
| SS 321 | 1.4541 | S32100 | SUS 321 | X6CrNiTi18-10 | SS 321H | 1.4878 | S32109 | SUS 321H | X10CrNiTi18-10 |
Stainless Steel 321 Chemical Composition
| 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 | ≥5(C+N) – 0.80 max |
Stainless Steel 321H Mechanical Properties
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| SS 321 | 8.0 g/cm3 | 1457 °C (2650 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 35 % |
| SS 321H | 7.9 g/cm³ | 1400 – 1425 °C (2550 – 2600 °F) | Psi – 85000 , MPa – 585 | Psi – 30000 , MPa – 205 | 40 % |
Stainless Steel Types
Stainless Steel 321/321H Industries & Applications
Stainless Steel 321/321H Flange Size Chart
| Flange Weights by Pressure Class and Size | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pipe Size | 150 # | 300 # | 600 # | 900 # | 1500 # | 2500 # | ||||||||||||
| WN | SO | BLD | WN | SO | BLD | WN | SO | BLD | WN | SO | BLD | WN | SO | BLD | WN | SO | BLD | |
| 1/2″ | 2 | 1 | 1 | 2 | 1 | 1 | 2 | 2 | 2 | SEE 1500 # WEIGHTS | 5 | 4 | 4 | 7 | 7 | 7 | ||
| 3/4″ | 2 | 2 | 2 | 3 | 3 | 3 | 4 | 3 | 3 | SEE 1500 # WEIGHTS | 6 | 5 | 6 | 8 | 8 | 8 | ||
| 1″ | 3 | 2 | 2 | 4 | 3 | 3 | 4 | 4 | 4 | SEE 1500 # WEIGHTS | 9 | 8 | 8 | 12 | 11 | 11 | ||
| 1 1/2″ | 4 | 3 | 3 | 7 | 6 | 6 | 8 | 7 | 8 | SEE 1500 # WEIGHTS | 13 | 12 | 13 | 25 | 22 | 23 | ||
| 2″ | 6 | 5 | 5 | 9 | 7 | 8 | 12 | 9 | 10 | SEE 1500 # WEIGHTS | 25 | 25 | 25 | 42 | 37 | 39 | ||
| 2 1/2″ | 8 | 7 | 7 | 12 | 10 | 12 | 18 | 13 | 15 | SEE 1500 # WEIGHTS | 36 | 36 | 35 | 52 | 55 | 56 | ||
| 3″ | 10 | 8 | 9 | 15 | 13 | 16 | 23 | 16 | 20 | 31 | 26 | 29 | 48 | 48 | 48 | 94 | 83 | 86 |
| 4″ | 15 | 13 | 17 | 25 | 22 | 27 | 42 | 37 | 41 | 53 | 53 | 54 | 73 | 73 | 73 | 145 | 125 | 130 |
| 5″ | 19 | 15 | 20 | 32 | 28 | 35 | 68 | 63 | 68 | 86 | 83 | 87 | 130 | 130 | 140 | 245 | 210 | 225 |
| 6″ | 24 | 19 | 26 | 42 | 39 | 50 | 81 | 80 | 86 | 110 | 110 | 115 | 165 | 165 | 160 | 380 | 325 | 345 |
| 8″ | 39 | 30 | 45 | 67 | 58 | 81 | 120 | 115 | 140 | 175 | 170 | 200 | 275 | 260 | 300 | 580 | 485 | 530 |
| 10″ | 52 | 43 | 70 | 91 | 81 | 124 | 190 | 170 | 230 | 260 | 245 | 290 | 455 | 435 | 510 | 1075 | 930 | 1025 |
| 12″ | 80 | 64 | 110 | 140 | 115 | 185 | 225 | 200 | 295 | 325 | 325 | 415 | 690 | 580 | 690 | 1525 | 1100 | 1300 |
| 14″ | 110 | 90 | 140 | 180 | 165 | 250 | 280 | 230 | 355 | 400 | 400 | 520 | 940 | NA | 975 | NA | NA | NA |
| 16″ | 140 | 98 | 180 | 250 | 190 | 295 | 390 | 330 | 495 | 495 | 425 | 600 | 1250 | NA | 1300 | NA | NA | NA |
| 18″ | 150 | 130 | 220 | 320 | 250 | 395 | 475 | 400 | 630 | 680 | 600 | 850 | 1625 | NA | 1750 | NA | NA | NA |
| 20″ | 180 | 165 | 285 | 400 | 315 | 505 | 590 | 510 | 810 | 830 | 730 | 1075 | 2050 | NA | 2225 | NA | NA | NA |
| 22″ | 225 | 185 | 355 | 465 | 370 | 640 | 720 | 590 | 1000 | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| 24″ | 260 | 220 | 430 | 580 | 475 | 790 | 830 | 730 | 1250 | 1500 | 1400 | 2025 | 3325 | NA | 3625 | NA | NA | NA |
SS 321 Buttweld Fittings Dimensions
| NOMINAL PIPE SIZE | ALL FITTINGS | ALL FITTINGS | ALL FITTINGS | ELBOWS AND TEES | 180 DEG RETURN BENDS | 180 DEG RETURN BENDS | 180 DEG RETURN BENDS | REDUCERS | CAPS |
|---|---|---|---|---|---|---|---|---|---|
| NPS | O.D. at Bevel (1), (2) | I.D. at End (1), (3), (4) |
Wall Thickness (3) | Centre-to-End Dimension A,B,C,M | Centre-to-Centre O | Back-to-Face K | Alignment of Ends U | Overall Length H | Overall Length E |
| ½ to 2½ | 0.06 -0.03 |
0.03 | Not less than 87.5% of nominal thickness | 0.06 | 0.25 | 0.25 | 0.03 | 0.06 | 0.12 |
| 3 to 3 ½ | 0.06 | 0.06 | Not less than 87.5% of nominal thickness | 0.06 | 0.25 | 0.25 | 0.03 | 0.06 | 0.12 |
| 4 | 0.06 | 0.06 | Not less than 87.5% of nominal thickness | 0.06 | 0.25 | 0.25 | 0.03 | 0.06 | 0.12 |
| 5 to 8 | 0.09 -0.06 |
0.06 | Not less than 87.5% of nominal thickness | 0.06 | 0.25 | 0.25 | 0.03 | 0.06 | 0.25 |
| 10 to 18 | 0.16 -0.12 |
0.12 | Not less than 87.5% of nominal thickness | 0.09 | 0.38 | 0.25 | 0.06 | 0.09 | 0.25 |
| 20 to 24 | 0.25 -0.19 |
0.19 | Not less than 87.5% of nominal thickness | 0.09 | 0.38 | 0.25 | 0.06 | 0.09 | 0.25 |
| 26 to 30 | 0.25 -0.19 |
0.19 | Not less than 87.5% of nominal thickness | 0.12 | … | … | … | 0.19 | 0.38 |
| 32 to 48 | 0.25 -0.19 |
0.19 | Not less than 87.5% of nominal thickness | 0.19 | … | … | … | 0.19 | 0.38 |
SS 321H Forged Fittings Dimensions
| Size | OD | WT | SR 90 Deg Elbows Centre – Face A | Weight | LR 90 Deg Elbows Centre – Face A | Weight | SR 45 Deg Elbows Centre – Face B | Weight | ||
|---|---|---|---|---|---|---|---|---|---|---|
| mm | inch. | mm | mm | SCH | mm | kg | mm | kg | mm | kg |
| 500 | 20″ | 508 | 9.52 | STD | 508 | 93.5 | 762 | 140 | 318 | 85 |
| 12.7 | X.S | 508 | 124 | 762 | 186 | 318 | 112.5 | |||
| 450 | 18″ | 457 | 9.52 | STD | 457 | 75.6 | 686 | 113 | 286 | 56.5 |
| 12.7 | X.S | 457 | 100 | 686 | 150 | 286 | 75 | |||
| 400 | 16″ | 406.4 | 9.52 | STD | 406 | 59.5 | 610 | 89.3 | 254 | 45 |
| 12.7 | X.S | 406 | 78.7 | 610 | 118 | 254 | 59 | |||
| 350 | 14″ | 355.6 | 9.52 | STD | 356 | 45.4 | 533 | 68.1 | 222 | 34.1 |
| 12.7 | X.S | 356 | 60 | 533 | 90 | 222 | 45 | |||
| 300 | 12″ | 323.9 | 9.52 | STD | 305 | 35.4 | 457 | 53.1 | 190 | 26.6 |
| 12.7 | X.S | 305 | 46.7 | 457 | 70 | 190 | 35 | |||
| 250 | 10″ | 273.9 | 9.27 | STD | 254 | 24.1 | 381 | 36.1 | 159 | 18.1 |
| 12.7 | X.S | 254 | 32.5 | 381 | 48.8 | 159 | 24.4 | |||
| 200 | 8″ | 219.1 | 8.18 | STD | 203 | 13.6 | 305 | 20.4 | 127 | 10.2 |
| 12.7 | X.S | 203 | 20.9 | 305 | 30.9 | 127 | 15.5 | |||
| 150 | 6″ | 168.3 | 7.11 | STD | 152.4 | 6.8 | 229 | 10.1 | 95.2 | 5.1 |
| 10.97 | X.S | 152.4 | 10.2 | 229 | 15.3 | 95.2 | 7.7 | |||
| 125 | 5″ | 141.3 | 6.65 | STD | 127 | 4.8 | 190 | 6.8 | 79.4 | 3.4 |
| 9.5 | X.S | 127 | 6.5 | 190 | 10 | 79.4 | 5 | |||
| 100 | 4″ | 114.3 | 62 | STD | 101.6 | 2.8 | 152.4 | 4.2 | 63.5 | 2.1 |
| 8.56 | X.S | 101.6 | 3.9 | 152.4 | 5.7 | 63.5 | 2.9 | |||
| 80 | 3″ | 88.9 | 5.49 | STD | 76.2 | 1.45 | 114.3 | 2.18 | 50.8 | 1.1 |
| 7.62 | X.S | 76.2 | 1.95 | 114.3 | 2.86 | 50.8 | 1.45 | |||
| 65 | 21/2″ | 73 | 5.16 | STD | 63.5 | 0.95 | 95.2 | 1.46 | 44.4 | 0.73 |
| 71 | X.S | 63.5 | 1.27 | 95.2 | 1.82 | 44.4 | 0.91 | |||
| 50 | 2″ | 60.3 | 3.91 | STD | 50.8 | 0.5 | 76.2 | 0.72 | 34.9 | 0.36 |
| 5.54 | X.S | 50.8 | 0.68 | 76.2 | 1 | 34.9 | 0.5 | |||
| 40 | 11/2″ | 48.3 | 3.68 | STD | 38.1 | 0.26 | 57.1 | 0.4 | 28.6 | 0.2 |
| 58 | X.S | 38.1 | 0.35 | 57.1 | 0.5 | 28.6 | 0.25 | |||
| 32 | 11/4″ | 42.2 | 3.56 | STD | 31.75 | 0.18 | 47.6 | 0.28 | 25.4 | 0.14 |
| 4.85 | X.S | 31.75 | 0.24 | 47.6 | 0.39 | 25.4 | 0.2 | |||
| 25 | 1″ | 33.4 | 3.38 | STD | 25.4 | 0.11 | 38.1 | 0.15 | 22.2 | 09 |
| 4.55 | X.S | 25.4 | 0.14 | 38.1 | 0.19 | 22.2 | 0.11 | |||
| 20 | 3/4″ | 26.7 | 2.87 | STD | – | – | 28.6 | 08 | 11.1 | 04 |
| 3.91 | X.S | – | – | 28.6 | 0.11 | 11.1 | 05 | |||
| 15 | 1/2″ | 21.3 | 2.78 | STD | – | – | 38.1 | 08 | 15.9 | 04 |
| 3.73 | X.S | – | – | 38.1 | 0.10 | 15.9 | 05 | |||
Major Industrial Stainless Steel 321 Fittings & Flanges Export Countries
United Arab Emirates (UAE), Jordan, Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, United States of America (USA), Singapore, Malaysia, Azerbaijan, Armenia, Georgia, Egypt, Algeria, Nigeria, South Africa, Kenya, Morocco, Ethiopia, Ghana, Tanzania, Sudan, Uganda, Angola.