+91-9619103479
or
vishal@solitaire-overseas.com
Stainless Steel 321 Fittings Supplier and Exporter
Solitaire Overseas is a trusted supplier as well as an exporter of Stainless Steel Fittings, which are listed throughout the SS Products Hub. Stainless Steel 321 (UNS S32100 / DIN 1.4541) is not an austenitic grade that has a general application. It is specially designed to resist service at temperatures between 425 and 875°C which causes precipitation of chromium carbide at the grain boundaries of standard grades such as SS 304, resulting in intergranular corrosion. Titanium, which is at least 5 times more abundant than carbon, is able to bind carbon first, leaving grain boundaries without carbon, and thereby inhibiting corrosion of the grain boundaries. This is because the specification SS 321 is the appropriate one when welded assemblies and fabricated piping cannot be solution-annealed following the manufacture. Solitaire Overseas offers standard sizes readily available and can accommodate custom size requirements for worldwide export. For the same grade in tubular and pipe forms, see SS 321 / 321H Pipes and SS 321 / 321H Tubes also available from Solitaire Overseas.
Table of Contents
- Stainless Steel 321 Fittings Supplier and Exporter Overview
- SS 321 Fittings Full Specification
- SS 321 vs SS 347 vs SS 304L Grade Comparison
- Types of SS 321 Fittings Available
- SS 321 Chemical Composition
- Mechanical and Physical Properties of Stainless Steel 321 Fittings
- 321 Stainless Steel Pipe Fittings Dimensions
- 321 Stainless Steel Equivalent Grades
- Industry Applications of Stainless Steel 321 Fittings
- Frequently Asked Questions
- Related Products
SS 321 Fittings Full Specification
Solitaire Overseas supplies SS 321 Fittings conforming to the following specifications. All test certificates are EN 10204 3.1 MTC as standard; 3.2 is available on request.
| Parameter | Details |
|---|---|
| Grade | Stainless Steel 321 / UNS S32100 |
| DIN / Werkstoff Nr. | 1.4541 |
| EN Designation | X6CrNiTi18-10 |
| Buttweld Standard | ASTM A403 WP321 / ASME SA403 WP321 |
| Forged Standard | ASTM A182 F321 / ASME SA182 F321 |
| Dimension Standard (BW) | ASME B16.9 / MSS SP-43 |
| Dimension Standard (Forged) | ASME B16.11 / MSS SP-79 |
| Forms | Elbow, Tee, Reducer, Cap, Stub End, Lap Joint, Cross, Coupling, Half-Coupling, Union, Plug, Bushing, Insert |
| Size Range (BW) | 1/2" NB to 48" NB |
| Size Range (Forged) | 1/8" NPS to 4" NPS, Class 2000 / 3000 / 6000 / 9000 |
| Schedule Range | SCH 5S / 10S / 40S / 80S / 160 / XXS |
| End Types | Beveled End (BE), Plain End (PE), Threaded End (TE) |
| Test Certificates | EN 10204 3.1 MTC (standard); 3.2 on request |
| Third-Party Inspection | SGS / TUV / Bureau Veritas / Intertek (on request) |
| PMI Testing | Available on request |
| Surface Finish | Pickled, Annealed, Polished (2B, No.4, Mirror) on request |
| Origin | India / Japan / Europe (confirmed at order stage) |
| Delivery | Ready stock for common sizes; custom: 4 to 8 weeks |
SS 321 vs SS 347 vs SS 304L Grade Comparison
| Property | SS 321 (this grade) | SS 347 | SS 304L |
|---|---|---|---|
| Stabilising element | Titanium (Ti) | Niobium / Columbium (Nb/Cb) | None (low carbon) |
| Carbon max | 0.08% | 0.08% | 0.03% |
| Sensitisation resistance | Excellent (Ti stabilised) | Excellent (Nb stabilised) | Good (low carbon only) |
| Best for | 425 to 875C service, welded assemblies | 425 to 875C, nuclear / radiation service | Ambient-temperature welded assemblies |
| Weldability | Good | Good | Excellent |
For applications where titanium loss during welding is a concern,SS 347 Fittings (niobium-stabilised) offer an alternative in the same temperature service window. If your application requires molybdenum-enhanced corrosion resistance rather than sensitisation protection,SS 316 Flanges and related 316 components are available separately from Solitaire Overseas.
Need SS 321 Fittings for your project?
Solitaire Overseas stocks standard sizes for immediate dispatch. Send your size, schedule, grade, quantity, and inspection requirement for a fast quote with MTC availability and delivery timeline.
Request a QuoteTypes of SS 321 Fittings Available
Solitaire Overseas supplies the full SS Buttweld Fittings range and SS Forged Fittings range in Grade 321:
ASTM A182 SS 321 _ 321H Forged 45 Degree Elbow
ASTM A182 SS 321 _ 321H Forged 90 Degree Elbow
ASTM A182 SS 321 _ 321H Forged Socket Weld Cross
ASTM A182 SS 321 _ 321H Forged Socket Weld Tee
ASTM A182 SS 321 _ 321H Socket Weld Cap
ASTM A182 SS 321 _ 321H Threaded _ Screwed Bushing
ASTM A182 SS 321 _ 321H Threaded _ Screwed Hex Plug
ASTM A182 SS 321 _ 321H Threaded _ Screwed Union
ASTM A182 SS 321 Forged Socket Weld Full Coupling
ASTM A182 SS 321 Forged Socket Weld Half Coupling
ASTM A182 SS 321 Threaded _ Screwed Pipe Nipple
ASTM A182 SS 321 Threaded _ Screwed Street Elbow
ASTM A403 WP321 _ 321H SS 45° Elbow
ASTM A403 WP321 _ 321H SS 90° Elbow
ASTM A403 WP321 _ 321H SS 180° Elbow
ASTM A403 WP321 _ 321H SS Concentric Reducer
ASTM A403 WP321 _ 321H SS Eccentric Reducer
ASTM A403 WP321 _ 321H SS End Pipe Cap
ASTM A403 WP321 _ 321H SS Equal Cross
ASTM A403 WP321 _ 321H SS Equal Tee
ASTM A403 WP321 _ 321H SS LR Elbow
ASTM A403 WP321 _ 321H SS Reducing Tee
ASTM A403 WP321 _ 321H SS SR Elbow
ASTM A403 WP321 _ 321H SS Stub End
Solitaire Overseas also supplies complementary piping system components in Grade 321 and related grades, including SS Flanges, SS Pipes, and SS Tubes, all available with matching MTC documentation for complete system procurement.
SS 321 Chemical Composition
All values are percentage by weight per ASTM specification. Titanium is the defining stabilising element that differentiates this grade from standard 304.
| Element | Range / Limit | Note |
|---|---|---|
| Carbon (C) | 0.08% max | |
| Chromium (Cr) | 17.0 to 19.0% | |
| Nickel (Ni) | 9.0 to 12.0% | |
| Titanium (Ti) | 5xC min to 0.70% max | Stabilising element binds carbon, prevents sensitisation |
| Manganese (Mn) | 2.0% max | |
| Silicon (Si) | 1.0% max | |
| Phosphorus (P) | 0.045% max | |
| Sulphur (S) | 0.030% max |
Mechanical and Physical Properties of Stainlesss Steel 321 Fittings
Values are for annealed condition per ASTM A403 WP321 (buttweld) and ASTM A182 F321 (forged). Both MPa and ksi are provided.
| Property | Seamless | Welded | Forged |
|---|---|---|---|
| Tensile Strength (min) | 515 MPa / 75 ksi | 515 MPa / 75 ksi | 515 MPa / 75 ksi |
| Yield Strength 0.2% (min) | 205 MPa / 30 ksi | 205 MPa / 30 ksi | 205 MPa / 30 ksi |
| Elongation (min) | 35% | 35% | 35% |
| Hardness (max) | 217 HB / 96 HRB | 217 HB / 96 HRB | 217 HB / 96 HRB |
Note: SS 321 is NOT suitable for sustained service above 875 degrees Celsius due to titanium oxidation. For temperatures above 875 degrees Celsius, SS 310 or 310S is the correct specification. For creep-limited service above 550 degrees Celsius, specify SS 321H.
321 Stainless Steel Pipe Fittings Dimensions
| NPS (Inch) | O.D. (MM) | O.D. (Inch) | 90° LR Elbow Center-Face (Inch) | 90° SR Elbow Center-Face (Inch) | 45° LR Elbow Center-Face (Inch) | 45° SR Elbow Radius (Inch) | 180° LR Return Center-Center (Inch) | 180° LR Return Back-Face (Inch) |
|---|---|---|---|---|---|---|---|---|
| 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 |
| NPS (Inch) | O.D. (MM) | O.D. (Inch) | BW Pipe End Cap Length (Inch) | BW Straight Tee Center-End (Inch) | BW Straight Cross Center-End (Inch) | Stub End Lap Diameter (Inch) | Stub End Length Long Pattern (Inch) | Stub End Length Short Pattern (Inch) |
|---|---|---|---|---|---|---|---|---|
| 1/2 | 21.3 | 0.840 | 1 | 1 | - | 1 3/8 | 3 | 2 |
| 3/4 | 26.7 | 1.050 | 1 | 1 1/8 | - | 1 11/16 | 3 | 2 |
| 1 | 33.4 | 1.315 | 1 1/2 | 1 1/2 | 1 1/2 | 2 | 4 | 2 |
| 1 1/4 | 42.2 | 1.660 | 1 1/2 | 1 7/8 | 1 7/8 | 2 1/2 | 4 | 2 |
| 1 1/2 | 48.3 | 1.900 | 1 1/2 | 2 1/4 | 2 1/4 | 2 7/8 | 4 | 2 |
| 2 | 60.3 | 2.375 | 1 1/2 | 2 1/2 | 2 1/2 | 3 5/8 | 6 | 2 1/2 |
| 2 1/2 | 73.0 | 2.875 | 1 1/2 | 3 | 3 | 4 1/8 | 6 | 2 1/2 |
| 3 | 88.9 | 3.500 | 2 | 3 3/8 | 3 3/8 | 5 | 6 | 2 1/2 |
| 3 1/2 | 101.6 | 4.000 | 2 1/2 | 3 3/4 | 3 3/4 | 5 1/2 | 6 | 3 |
| 4 | 114.3 | 4.500 | 2 1/2 | 4 1/8 | 4 1/8 | 6 3/16 | 6 | 3 |
| 5 | 141.3 | 5.563 | 3 | 4 7/8 | 4 7/8 | 7 5/16 | 8 | 3 |
| 6 | 168.3 | 6.625 | 3 1/2 | 5 5/8 | 5 5/8 | 8 1/2 | 8 | 3 1/2 |
| 8 | 219.1 | 8.625 | 4 | 7 | 7 | 10 5/8 | 8 | 4 |
| 10 | 273.1 | 10.750 | 5 | 8 1/2 | 8 1/2 | 12 3/4 | 10 | - |
321 Stainless Steel Equivalent Grades
| STANDARD | UNS | WERKSTOFF NR. | JIS | EN |
|---|---|---|---|---|
| SS 321 | S32100 | 1.4541 | SUS 321 | X6CrNiTi18-10 |
Industry Applications of Stainless Steel 321 Fittings
- Oil & Gas Industry
- Chemical Industry
- Petrochemical
- Power Industry
- Construction
- Fertilizers Industry
- Automotive Industry
- Food Industry
Frequently Asked Questions
SS 321 is titanium-stabilised, preventing chromium carbide precipitation at grain boundaries during 425 to 875 degrees Celsius service. SS 304 is not stabilised and will sensitise in this range, causing intergranular corrosion. For sustained service in this temperature band without post-weld heat treatment, 321 is the correct specification.
ASTM A403 WP321 covers buttweld fittings. ASTM A182 F321 covers forged fittings. ASME equivalents are SA403 WP321 and SA182 F321.
Both are stabilised austenitic grades. SS 321 uses titanium as the stabilising element; SS 347 uses niobium. SS 347 is preferred for nuclear and weld-clad applications where titanium can cause issues. For most industrial service, both are equivalent. Confirm the applicable standard with Solitaire Overseas.
Yes. SS 321 is readily weldable by all standard methods. However, titanium is partially lost to the weld arc, so ER347 filler wire (niobium-stabilised) is typically recommended for welding SS 321 to ensure the weld deposit is also sensitisation-resistant.
SS 321 can be used continuously up to approximately 870 to 900 degrees Celsius in oxidising conditions. For temperatures above this, SS 310 or 310S grades are typically specified. For creep-limited service above 550 degrees Celsius, specify SS 321H.
Request a Quote for Stainless Steel 321 Fittings
Share your specification and quantity. Our team will respond with pricing, availability, testing options, and export documentation within 24 hours.
Get a Quote