Stainless Steel 321/321H Buttweld Fittings Manufacturer & Supplier
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Midland Alloys is a trusted Stainless Steel 321/321H Buttweld Fittings supplier, providing high-quality fittings that meet global standards. Stainless Steel 321/321H Buttweld Fittings are designed to provide greater strength and high-temperature resistance, making them a reliable choice for demanding applications. These fittings are manufactured of Grade WP321 and WP321H stainless steel, which contains components like carbon, manganese, silicon, phosphorus, sulfur, chromium, nitrogen, nickel, and titanium. The fittings have a density of 8.0 g/cm³, a melting point of 1457 °C, and a tensile strength of 75,000 psi, making them durable and efficient. Our seamless and welded fittings meet ASTM A403 / ASME SA403 requirements and come in sizes ranging from 1/2″ to 24″ and 1/8″ NB to 48″ NB SS 321. The collection contains elbows, tees, reducers, caps, bends, stub ends and numerous other designs. Our fittings are carefully manufactured using modern techniques like hot forming, solution annealing, heat treatment and precision machining to assure dimensional accuracy and long-lasting performance.
Benefits of Stainless Steel 321/321H Buttweld Fittings
- Excellent resistance to high-temperature oxidation keep stainless steel 321H butt weld fittings reliable in heat service.
- The titanium-stabilized structure in 321 buttweld fittings reduce carbide precipitation during welding.
- High strength under stress make these butt weld fittings dependable for pressure applications.
- 321 buttweld fittings provide good creep resistance, making them suitable for prolonged exposure to heat.
- Corrosion resistance in both oxidizing and reducing environments keeps fittings durable.
- Stainless steel 321H butt weld fittings maintain stability during fabrication and welding.
- 321 buttweld fittings are available in multiple dimensions support versatile project requirements.
Specification of SS 321/321H Buttweld Fittings
Seamless Butt Weld Fittings: 1/2" - 10" Welded Butt Weld Fittings: 1/2" - 48"
ASTM A403 / ASME SA403
Forge, Cast, Push, Press, etc.
90 Deg. Elbow, 45 Degree Elbow, LR/SR Elbow, Reducers, Tee, Cross, Bends, U bend, 180 Deg Bend, End Cap, Lap-joint Stub End
ASME/ANSI B16.9, ASME B16.28, MSS-SP-43, BS4504, BS4504, BS1560, BS10
Plain End, Beveled End, Treaded
SCH10, SCH20, SCH30, STD SCH40, SCH60, XS, SCH 80, SCH 100, SCH 120, SCH 140, SCH 160, XXS available with NACE MR 01-75
Seamless / Welded / Fabricated
Types of SS 321/321H Buttweld Fittings
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Elbow (90°, 45°, Long/Short Radius)Used to change the direction of flow in a pipeline at specified angles; available in short or long radius.
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Tee (Equal & Reducing)Divides flow into two branches; an equal tee has all ends the same size, a reducing tee has one smaller outlet.
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Reducer (Concentric & Eccentric)Connects pipes of different diameters; concentric type is symmetrical, eccentric has an offset centerline.
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Stub End (Short & Long Pattern)Used with lap joint flanges to allow easy dismantling; available in short and long lengths.
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End CapCloses the end of a pipe to stop flow and protect the system.
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Cross (Equal & Reducing)Connects four pipes; equal type has all ports the same size, reducing type has different sized outlets.
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Lateral TeeBranches pipe at a 45° angle for smoother flow direction changes.
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Pipe BendMakes gradual directional changes in piping with large-radius curves.
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Return Bends (180°)Turns the flow 180 degrees, commonly used in U-shaped configurations.
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CollarProvides a flat surface for bolted connections, often used with flanges.
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NippleShort length of pipe with male threads or beveled ends for close connection between fittings.
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Barred TeeFeatures a bar across the branch opening to prevent flow into unwanted areas, used in piggable systems.
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Expansion JointAbsorbs thermal expansion and vibration in piping systems.
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Swage NippleConnects pipes of different diameters, typically from a larger pipe to a smaller one.
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Reducer InsertInserted into a fitting to reduce the outlet size without using a separate reducer.
Technical Details & Delivery Condition
| 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 |
| 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 % |
| STANDARD | WERKSTOFF NR. | UNS | JIS | EN |
| SS 321 | 1.4541 | S32100 | SUS 321 | X6CrNiTi18-10 |
| SS 321H | 1.4878 | S32109 | SUS 321H | X12CrNiTi18-9 |
| Temperature (°C) | Pressure Rating (MPa) | Pressure Rating (psi) |
|---|---|---|
| -29 to 38 | 20.0 | 2900 |
| 100 | 17.6 | 2550 |
| 200 | 15.5 | 2250 |
| 300 | 13.5 | 1960 |
| 400 | 12.0 | 1740 |
| 500 | 10.5 | 1520 |
| 600 | 9.0 | 1310 |
Stainless Steel Buttweld Fittings We Offer
Stainless Steel 321/321H Buttweld Fittings Dimension
| Nominal Pipe Size | Outside Diameter | 90° Elbows | 45° Elbows | 180° Returns | ||||
| (inches) | Long Radius | Short Radius | Long Radius | Long Radius | ||||
| (mm) | (inches) | Center to Face (inches) | Center to Face (inches) | Center to Face (inches) | Radius (inches) | Center to Center (inches) | Back to face (inches) | |
| 1/2 | 21.3 | 0.840 | 1 1/2 | – | 5/8 | 2 | 1 7/8 | |
| 3/4 | 26.7 | 1.050 | 1 1/8 | – | 7/16 | 2 1/4 | 1 11/16 | |
| 1 | 33.4 | 1.315 | 1 1/2 | 1 | 7/8 | 3 | 2 3/16 | |
| 1 1/4 | 42.2 | 1.660 | 1 7/8 | 1 1/4 | 1 | 3 3/4 | 2 3/4 | |
| 1 1/2 | 48.3 | 1.900 | 2 1/4 | 1 1/2 | 1 1/8 | 3 | 4 1/2 | 3 1/4 |
| 2 | 60.3 | 2.375 | 3 | 2 | 1 3/8 | 4 | 6 | 4 3/16 |
| 2 1/2 | 73.0 | 2.875 | 3 3/4 | 2 1/2 | 1 3/4 | 5 | 7 1/2 | 5 3/16 |
| 3 | 88.9 | 3.500 | 4 1/2 | 3 | 2 | 6 | 9 | 6 1/4 |
| 3 1/2 | 101.6 | 4.000 | 5 1/4 | 3 1/2 | 2 1/4 | 7 | 10 1/2 | 7 1/4 |
| 4 | 114.3 | 4.500 | 6 | 4 | 2 1/2 | 8 | 12 | 8 1/4 |
| 5 | 141.3 | 5.563 | 7 1/2 | 5 | 3 1/8 | 10 | 15 | 10 5/16 |
| 6 | 168.3 | 6.625 | 9 | 6 | 3 3/4 | 12 | 18 | 12 5/16 |
| 8 | 219.1 | 8.625 | 12 | 8 | 5 | 12 | 24 | 16 5/16 |
| 10 | 273.1 | 10.750 | 15 | 10 | 6 1/4 | 15 | 30 | 20 3/8 |
| 12 | 323.9 | 12.750 | 18 | 12 | 7 1/2 | 18 | 36 | 24 3/8 |
Stainless Steel 321/321H Buttweld Fittings Weight Chart
| Pipe Elbow Nominal Size | Pipe Elbow Outside Diameter Y | Wall Thickness T (Pipe Elbow Schedule) | 45 Deg. Elbow LR Centre to Face B | 45 Deg. Elbow LR Weight | 90 Deg. Elbow LR Centre to Face A | 90 Deg. Elbow LR Weight | 90 Deg. Elbow SR Centre to Face A | 90 Deg. Elbow SR Weight | ||
| mm | in | mm | mm | Schedule | mm | kg | mm | kg | mm | kg |
| 15 | 1/2” | 21.3 | 2.78 | STD | 15.9 | 0.04 | 38.1 | 0.08 | – | – |
| 3.73 | X.S | 15.9 | 0.05 | 38.1 | 0.10 | – | – | |||
| 20 | 3/4” | 26.7 | 2.87 | STD | 11.1 | 0.04 | 28.6 | 0.08 | – | – |
| 3.91 | X.S | 11.1 | 0.05 | 28.6 | 0.11 | – | – | |||
| 25 | 1” | 33.4 | 3.38 | STD | 22.2 | 0.09 | 38.1 | 0.15 | 25.4 | 0.11 |
| 4.55 | X.S | 22.2 | 0.11 | 38.1 | 0.19 | 25.4 | 0.14 | |||
| 32 | 11/4” | 42.2 | 3.56 | STD | 25.4 | 0.14 | 47.6 | 0.28 | 31.75 | 0.18 |
| 4.85 | X.S | 25.4 | 0.2 | 47.6 | 0.39 | 31.75 | 0.24 | |||
| 40 | 11/2” | 48.3 | 3.68 | STD | 28.6 | 0.2 | 57.1 | 0.4 | 38.1 | 0.26 |
| 5.08 | X.S | 28.6 | 0.25 | 57.1 | 0.5 | 38.1 | 0.35 | |||
| 50 | 2” | 60.3 | 3.91 | STD | 34.9 | 0.36 | 76.2 | 0.72 | 50.8 | 0.5 |
| 5.54 | X.S | 34.9 | 0.5 | 76.2 | 1.0 | 50.8 | 0.68 | |||
| 65 | 21/2” | 73.0 | 5.16 | STD | 44.4 | 0.73 | 95.2 | 1.46 | 63.5 | 0.95 |
| 7.01 | X.S | 44.4 | 0.91 | 95.2 | 1.82 | 63.5 | 1.27 | |||
| 80 | 3” | 88.9 | 5.49 | STD | 50.8 | 1.1 | 114.3 | 2.18 | 76.2 | 1.45 |
| 7.62 | X.S | 50.8 | 1.45 | 114.3 | 2.86 | 76.2 | 1.95 | |||
| 100 | 4” | 114.3 | 6.02 | STD | 63.5 | 2.1 | 152.4 | 4.2 | 101.6 | 2.8 |
| 8.56 | X.S | 63.5 | 2.9 | 152.4 | 5.7 | 101.6 | 3.9 | |||
| 125 | 5” | 141.3 | 6.65 | STD | 79.4 | 3.4 | 190.0 | 6.8 | 127.0 | 4.8 |
| 9.5 | X.S | 79.4 | 5.0 | 190.0 | 10.0 | 127.0 | 6.5 | |||
| 150 | 6” | 168.3 | 7.11 | STD | 95.2 | 5.1 | 229.0 | 10.1 | 152.4 | 6.8 |
| 10.97 | X.S | 95.2 | 7.7 | 229.0 | 15.3 | 152.4 | 10.2 | |||
| 200 | 8” | 219.1 | 8.18 | STD | 127.0 | 10.2 | 305.0 | 20.4 | 203.0 | 13.6 |
| 12.7 | X.S | 127.0 | 15.5 | 305.0 | 30.9 | 203.0 | 20.9 | |||
| 250 | 10” | 273.9 | 9.27 | STD | 159.0 | 18.1 | 381.0 | 36.1 | 254.0 | 24.1 |
| 12.7 | X.S | 159.0 | 24.4 | 381.0 | 48.8 | 254.0 | 32.5 | |||
| 300 | 12” | 323.9 | 9.52 | STD | 190.0 | 26.6 | 457.0 | 53.1 | 305.0 | 35.4 |
| 12.7 | X.S | 190.0 | 35.0 | 457.0 | 70.0 | 305.0 | 46.7 | |||
| 350 | 14” | 355.6 | 9.52 | STD | 222.0 | 34.1 | 533.0 | 68.1 | 356.0 | 45.4 |
| 12.7 | X.S | 222.0 | 45.0 | 533.0 | 90.0 | 356.0 | 60.0 | |||
| 400 | 16” | 406.4 | 9.52 | STD | 254.0 | 45.0 | 610.0 | 89.3 | 406.0 | 59.5 |
| 12.7 | X.S | 254.0 | 59.0 | 610.0 | 118.0 | 406.0 | 78.7 | |||
| 450 | 18” | 457.0 | 9.52 | STD | 286.0 | 56.5 | 686.0 | 113.0 | 457.0 | 75.6 |
| 12.7 | X.S | 286.0 | 75.0 | 686.0 | 150.0 | 457.0 | 100.0 | |||
| 500 | 20” | 508.0 | 9.52 | STD | 318.0 | 85.0 | 762.0 | 140.0 | 508.0 | 93.5 |
| 12.7 | X.S | 318.0 | 112.5 | 762.0 | 186.0 | 508.0 | 124.0 | |||
| 600 | 24” | 610.00 | 9.52 | STD | 381.0 | 101.5 | 914.0 | 203.0 | 610.0 | 135.0 |
| 12.7 | X.S | 381.0 | 134.5 | 914.0 | 269.0 | 610.0 | 179.0 | |||
Difference Between 321 vs 321H Butt Weld Fittings
The primary difference between UNS S32100 buttweld fittings (321) and UNS S32109 butt weld fittings (321H) is their carbon content. UNS S32100 fittings having a lower carbon content, improving weldability and lowering the possibility of carbide precipitation. UNS S32109 fittings include more carbon which increases strength at high temperatures and improves creep resistance. Both classes contain similar elements such as chromium, nickel, and titanium, however their uses vary depending on the thermal service requirements. In layman’s terms, 321 is better for welded structures, whereas 321H is best for high-temperature pressure systems.
Manufacturing Process of Stainless Steel 321/321H Buttweld Fittings
Pipe
Cutting
Forming
Sizing
Heat Treatment
Pickling
Beveling
Polishing
Sand Blasting
Elbow
Inspection
Analytic
Marking
Packing & Shipping
ASME SA403 WP321/321H Fittings Uses
ASME SA403 WP321/321H fittings are used in industries that require high heat tolerance and resistance to corrosion. A 321 long-radius elbow buttweld is used in pipelines for smooth direction changes in refineries and chemical plants. A 321 short radius elbow buttweld is applied in tight spaces where flow redirection is needed without losing efficiency. 321H reducing tees buttweld are used to connect pipes of various sizes in power plants and petrochemical facilities. SS 321 butt weld fittings for oil refineries are installed in crude distillation units and catalytic reforming systems. SS 321H butt weld fittings for heat exchangers improve thermal processing equipment stability and dependability. These fittings provide reliable performance in the aerospace, pharmaceutical and marine engineering industries.
Why Choose Midland Alloys Inc. for Stainless Steel 321/321H Buttweld Fittings
Midland Alloys Inc. is a leading ASME SA403 WP321/321H fittings supplier with a proven commitment to quality. Every fitting is manufactured under tight quality control and backed up by certifications like as ISO 9001:2015, PED 2014/68/EU and EN 10204 3.1/3.2 mill test certificates. We also provide third-party inspections (TPI) by reputable agencies like as TÜV, BV, SGS and DNV. We supply engineering firms, EPC contractors, marine operators, and chemical plants with a strong reputation for delivering reliable products on time. Testing is a vital part of the process, where ANSI B16.28 321H butt weld elbows go through hydrostatic testing for pressure resistance, ultrasonic testing for internal flaws, radiographic testing for weld quality, and PMI for grade validation. Mechanical test such as tensile, hardness, flattening, and bend tests are performed according to the client specifications. We assure complete export compliance and proper documentation which make us a reliable partner of ASTM A403 WP321 butt weld fittings to global clients in the Middle East, Europe, and Southeast Asia. Our focus on professionalism and consistent quality has led to strong repeat business worldwide.
FAQs – Stainless Steel 321/321H Buttweld Fitting
Yes. These fittings need controlled heat input and proper cooling to avoid carbide precipitation.
321/321H fittings handle higher temperature better while 304/304L and 316/316L focus more on corrosion resistance.
