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Stainless Steel 321H Fittings Supplier and Exporter
Solitaire Overseas is a leading supplier and exporter of Stainless Stee; 321H Fittings. The key difference between the standard SS 321 and Stainless Steel 321H Fittings (UNS S32109 / DIN 1.4878) is that the latter has a controlled minimum carbon content of 0.04 - 0.10% (maximum carbon content in the standard version is only 0.08%). This lower limit on carbon content is why 321H is the preferred grade of Section I and Section VIII elevated-temperature pressure applications in accordance with the ASME B&PV Code. Both grades are titanium stabilised for sensitisation resistance but 321H is the only grade that provides the creep performance that engineers can count on for long service.
Solitaire Overseas supplies a complete range of Stainless Steel Fittings in this grade, available in both SS Buttweld Fittings and SS Forged Fittings configurations for every pressure class and end connection.
Table of Contents
- Stainless Steel 321H Fittings Supplier and Exporter
- SS 321H Fittings Specifications
- Types of SS 321H Fittings
- Chemical Composition of SS 321H Fittings
- Mechanical Properties of SS 321H Fittings
- SS 321H vs SS 321 vs SS 304H Grade Comparison
- SS 321H Fitting Equivalent Grade
- 321H Stainless Steel Fitting Dimensions
- Applications of SS 321H Fittings by Industry
- Frequently Asked Questions
- Related Products
SS 321H Fittings Specifications
| Parameter | Details |
|---|---|
| Grade | Stainless Steel 321H / S32109 |
| UNS Number | S32109 |
| DIN / Werkstoff Nr. | 1.4878 |
| EN Designation | X8CrNiTi18-10 |
| JIS Equivalent | SUS 321H |
| Buttweld Standard | ASTM A403 WP321H / ASME SA403 WP321H |
| Forged Standard | ASTM A182 F321H / ASME SA182 F321H |
| Dimension Standard (Buttweld) | ASME B16.9 / MSS SP-43 |
| Dimension Standard (Forged) | ASME B16.11 / MSS SP-79 |
| Forms Available | Elbow, Tee, Reducer, Cap, Stub End, Lap Joint, Cross, Coupling, Half-Coupling, Union, Plug, Bushing, Insert |
| Size Range (Buttweld) | 1/2 inch NB to 48 inch NB |
| Size Range (Forged) | 1/8 inch NPS to 4 inch 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 |
For pressure-boundary components that pair with these fittings in the same installation, Solitaire Overseas supplies SS Flanges and SS Pipes in Grade 321H and all allied stainless grades.
Types of SS 321H Fittings
Solitaire Overseas supplies SS 321H Buttweld Fittings and SS 321H forged fittings, manufactured to the applicable ASME and ASTM standards. The table below covers all available forms.
321H Forged 45 Degree Elbow
321H Forged 90 Degree Elbow
321H Forged Socket Weld Cross
321H Forged Socket Weld Tee
321H Socket Weld Cap
321H Threaded Screwed Bushing
321H Threaded Screwed Hex Plug
321H Threaded Screwed Union
321H Forged Socket Weld Full Coupling
321H Forged Socket Weld Half Coupling
321H Threaded Screwed Pipe Nipple
321H Threaded Screwed Street Elbow
321H 45 Degree Elbow
321H 90 Degree Elbow
321H 180 Degree Elbow
321H Concentric Reducer
321H Eccentric Reducer
321H End Pipe Cap
321H Equal Cross
321H Equal Tee
321H LR Elbow
321H Reducing Tee
321H SR Elbow
321H Stub End
For complete piping system builds in this grade, Solitaire Overseas also supplies SS 321/321H Pipes and SS 321/321H Tubes in seamless and welded form, ensuring a single-source supply for all 321H grade requirements.
Need SS 321H 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 QuoteChemical Composition of SS 321H Fittings
All values are percentage by weight as per ASTM A403 WP321H / ASTM A182 F321H specification.
| Element | Range / Limit | Note |
|---|---|---|
| Carbon (C) | 0.04 to 0.10% | Controlled minimum, mandatory for high-temperature creep strength |
| Chromium (Cr) | 17.0 to 19.0% | Primary corrosion resistance element |
| Nickel (Ni) | 9.0 to 12.0% | Austenite stabiliser |
| Titanium (Ti) | 4 x C min to 0.70% max | Stabilising element, prevents sensitisation while carbon provides creep strength |
| Manganese (Mn) | 2.0% max | |
| Silicon (Si) | 1.0% max | |
| Phosphorus (P) | 0.045% max | |
| Sulphur (S) | 0.030% max |
Mechanical Properties of SS 321H Fittings
Values are for annealed condition per ASTM A403 WP321H (buttweld) and ASTM A182 F321H (forged).
| 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 |
SS 321H vs SS 321 vs SS 304H Grade Comparison
Use this table to confirm the right grade for your application. Specifying 321H instead of standard 321 ensures ASME code compliance at elevated temperatures.
| Property | SS 321H (this grade) | SS 321 | SS 304H |
|---|---|---|---|
| Carbon range | 0.04 to 0.10% | 0.08% max | 0.04 to 0.10% |
| Stabilising element | Titanium (Ti) | Titanium (Ti) | None |
| High-temp creep strength | Superior (controlled C) | Standard | Superior (controlled C) |
| Sensitisation resistance | Excellent (Ti) | Excellent (Ti) | Poor (no stabiliser) |
| ASME BPV Code high-temp use | Preferred | Limited high-temp allowable | Preferred, no Ti loss at weld |
| Weld sensitisation risk | Very low (Ti stabilised) | Very low (Ti stabilised) | High (no stabiliser) |
Buyers specifying the standard-carbon variant should refer to SS 321 Fittings for the complete grade-specific data, where the differences in allowable stresses and application suitability are covered in detail.
SS 321H Fitting Equivalent Grade
| Standard | Werkstoff Nr. | UNS | JIS | EN |
|---|---|---|---|---|
| SS 321 | 1.4541 | S32100 | SUS 321 | X6CrNiTi18-10 |
| SS 321H | 1.4878 | S32109 | SUS 321H | X8CrNiTi18-10 |
321H Stainless Steel Fitting 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 | - |
Applications of SS 321H Fittings by Industry
- Oil & Gas Industry
- Chemical Industry
- Petrochemical
- Power Industry
- Construction
- Fertilizers Industry
- Automotive Industry
- Food Industry
For tube-side applications in the same high-temperature installations, SS Tubes in Grade 321/321H are stocked by Solitaire Overseas in seamless and welded form for heat exchanger, superheater, and process service.
Frequently Asked Questions
SS 321H has controlled min carbon of 0.04% vs 0.08% max for 321, giving superior creep strength above 550C. Both are Ti-stabilised. Specify 321H when ASME B&PV Code elevated-temperature allowable stresses are required.
ASTM A403 WP321H covers buttweld fittings; ASTM A182 F321H covers forged fittings. ASME equivalents are SA403 WP321H and SA182 F321H for pressure code applications.
SS 321H retains titanium stabilisation, resisting sensitisation in the 425 to 875C range. SS 304H has no stabiliser and can sensitise. For high-temperature service with sensitisation risk, 321H is the preferred choice.
ASTM requires minimum carbon of 0.04% for SS 321H. This is mandatory. A heat with carbon below 0.04% does not qualify as 321H regardless of other compositional compliance. Always verify minimum carbon on the MTC.
Yes. Solitaire Overseas supplies SS 321H fittings with ASME SA403 WP321H and SA182 F321H certification, EN 10204 3.1 MTCs, PMI testing, and third-party inspection on request.
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