Metinox Overseas SS 310 Pipe Fittings are designed to ASTM A403 WP310 and WP310S standards, designed with service applications where standard austenitic alloys like SS 304 and SS 316 have limitations. The distinguishing feature of this alloy is its chemistry; 25% Chromium and 20% Nickel, which provides excellent high-temperature oxidation strength to 1050 deg C in continuous service, as well as excellent resistance to carburizing atmospheres, reducing atmospheres, and sulfidation. These features have established SS 310 / 310S Pipe Fittings as the choice in furnace internals, heat treatment chambers, radiant tubes, combustion chambers, kiln components, high temperature chemical processing piping systems all over the world.
Metinox Overseas also provides the entire variety of SS 310 / 310S Buttweld Fittings in all standard types and schedules 1/2 to 48 NB and 90 degree Long Radius Elbows, 45 degree Elbows, Equal Tees, Reducing Tees, Eccentric Reducers, End Caps, Stub Ends, Return Bends The entire fittings can be supplied with EN 10204 3.1 material test certificates, third-party inspection, and export certificates to supply globally.
Our SS 310 Pipe Fittings inventory provides support on-site dispatching on stock sizes, and a small lead time on non stock sizes. Our exports are to the United Arab Emirates, Saudi Arabia, Qatar, Kuwait, Oman, Bahrain, the United States, the United Kingdom, Germany, Singapore, Indonesia, Malaysia, Australia, South Africa, and throughout Southeast Asia.
Browse our complete range of stainless steel piping products: View all Stainless Steel Pipes and Tubes
SS 310 and SS 310S Pipe Fittings both have the same high-chromium, high-nickel base chemistry and provide the same oxidation resistance at high-temperature conditions. The key difference is the carbon content and its implications on the weldability and long-term performance at grain boundaries.
SS 310 (UNS S31000 / DIN 1.4841 / WERKSTOFF 1.4841) has a carbon content of up to 0.25%. This increased carbon gives it better strength at high temperatures and results in a higher chance of carbide being formed at the heat affected part of the weld thus causing sensitization and intergranular corrosion in some service applications.
SS 310S (UNS S31008 / DIN 1.4845 / WERKSTOFF 1.4845) is the low-carbon variant, with carbon capped at 0.08% maximum. The decreased carbon content inhibits carbide formation at heat-affected areas of the weld with enhanced weldability, intergranular corrosion resistance and applicability to the field of fabricated assemblies which require multiple welding passes. In the majority of modern piping systems, where the service is at high temperature, SS 310S is the engineered choice since it offers the 25Cr-20Ni oxidation resistance in addition to high weld integrity. Metinox Overseas inventories and provides both grades and can recommend the grade that you should use depending on your operating temperature, welding operation and post-weld heat treatment.
| Feature | SS 310 (UNS S31000) | SS 310S (UNS S31008) |
|---|---|---|
| Carbon Content (max) | 0.25% | 0.08% |
| DIN / Werkstoff No. | 1.4841 | 1.4845 |
| Chromium | 24 to 26% | 24 to 26% |
| Nickel | 19 to 22% | 19 to 22% |
| Weldability | Moderate | Superior (low carbide precipitation) |
| Carbide Precipitation Risk | Higher at weld HAZ | Significantly reduced |
| Max Service Temperature | 1050 deg C (oxidizing) | 1050 deg C (oxidizing) |
| Primary Use Case | High-temperature structural fittings | Welded assemblies, heat treatment |
| Preferred For | Furnace parts, radiant tubes, kiln internals | Piping systems with site welding |
All SS 310 Pipe Fittings supplied by Metinox Overseas conform to ASTM A403 / ASME SA403 standard, which governs wrought austenitic stainless steel buttweld fittings. The standard covers two product grades, WP310 and WP310S, covering the full range of UNS S31000 and UNS S31008 chemistries. Dimensional standards conform to ASME B16.9 for buttweld fittings and MSS SP-43 for lightweight schedule fittings.
| Property | SS 310 / WP310 | SS 310S / WP310S |
|---|---|---|
| ASTM Standard | ASTM A403 Grade WP310 | ASTM A403 Grade WP310S |
| ASME Standard | ASME SA403 WP310 | ASME SA403 WP310S |
| UNS Number | UNS S31000 | UNS S31008 |
| DIN / EN Number | 1.4841 | 1.4845 |
| Japanese Equivalent | SUS 310 | SUS 310S |
| Dimensional Standard | ASME B16.9 / MSS SP-43 | ASME B16.9 / MSS SP-43 |
| Product Form | Buttweld Fittings | Buttweld Fittings |
| Wall Thickness | SCH 5S to SCH XXS | SCH 5S to SCH XXS |
| Size Range | 1/2" to 48" NB | 1/2" to 48" NB |
| Finish | Pickled / Bright Annealed | Pickled / Bright Annealed |
| Supply Condition | WP-S (Seamless) / WP-W (Welded) / WP-WX (Welded Examined) | WP-S / WP-W / WP-WX |
| Test Certificate | EN 10204 3.1 / 3.2 | EN 10204 3.1 / 3.2 |
When ordering ASTM A403 WP310 or WP310S SS 310 Pipe Fittings, the suffix after the grade designation identifies the manufacturing method and weld examination level. This distinction matters for projects requiring specific inspection documentation:
Metinox Overseas can supply SS 310 / 310S Pipe Fittings in all three conditions. Please specify WP-S, WP-W, or WP-WX in your enquiry for accurate quotation.
Metinox Overseas maintains a comprehensive inventory of SS 310 Pipe Fittings and SS 310S Buttweld Fittings across all standard types. Each fitting type is produced to ASME B16.9 / MSS SP-43 dimensional requirements and is available with mill test certificates in accordance with EN 10204 3.1.
Elbows redirect flow within a piping system and are available in both Long Radius (LR) and Short Radius (SR) configurations:
All SS 310 / 310S Pipe Fittings are available with beveled ends, plain ends, or threaded ends as specified. Pickle-passivated and bright-annealed surface finishes are available.
The exceptional high-temperature performance of SS 310 / 310S Pipe Fittings is rooted in their chemistry. The 25% Chromium and 20% Nickel combination forms a stable, tenacious oxide scale that resists breakdown even at continuous service temperatures up to 1050 deg C. The chromium content also provides resistance to hydrogen sulfide attack and sulfidation in refinery and chemical environments.
| Grade | C (max) | Cr | Ni | Mn (max) | Si (max) | P (max) |
|---|---|---|---|---|---|---|
| SS 310 / UNS S31000 | 0.25% | 24 to 26% | 19 to 22% | 2.00% | 1.50% | 0.045% |
| SS 310S / UNS S31008 | 0.08% | 24 to 26% | 19 to 22% | 2.00% | 1.50% | 0.045% |
| Grade | Tensile (min) | Yield 0.2% (min) | Elongation (min) | Hardness (Brinell max) |
|---|---|---|---|---|
| SS 310 / WP310 | 515 MPa | 205 MPa | 30% | 217 HB |
| SS 310S / WP310S | 515 MPa | 205 MPa | 30% | 217 HB |
Note: Mechanical properties are at room temperature per ASTM A403 requirements. High-temperature tensile and creep properties are available on request for design purposes. All SS 310 / 310S Buttweld Fittings from Metinox Overseas are supplied with hardness test results included in the Mill Test Certificate.
When specifying SS 310 / 310S Pipe Fittings for global projects, engineers frequently encounter the same alloy referenced under different designation systems. The table below provides a complete cross-reference of all internationally recognized equivalents:
| Grade | UNS | DIN / EN | JIS | WERKSTOFF | BS |
|---|---|---|---|---|---|
| SS 310 | S31000 | X15CrNi25-20 | SUS 310 | 1.4841 | 310S24 |
| SS 310S | S31008 | X6CrNi25-20 | SUS 310S | 1.4845 | 310S16 |
Metinox Overseas can supply ASTM A403 WP310 Fittings, DIN 1.4841 Fittings, DIN 1.4845 310S Fittings, and WERKSTOFF 1.4841 Fittings all from the same stock, with traceability to the same heat and EN 10204 3.1 certification. This simplifies procurement for projects that specify under European, American, or Japanese standards.
| Parameter | Range | Standard | Remarks |
|---|---|---|---|
| Nominal Bore (NB) | 1/2" to 48" | ASME B16.9 | Also per MSS SP-43 for lightweight |
| Wall Thickness | SCH 5S to SCH XXS | ASME B36.19M / B36.10M | Full schedule range available |
| Elbow Radius | 1D (Short Radius), 1.5D (Long Radius), 3D, 5D | ASME B16.9 | Custom radii on request |
| Tee Types | Equal and Reducing | ASME B16.9 | All sizes in stock |
| Reducer Types | Concentric and Eccentric | ASME B16.9 | All size combinations |
| End Prep | Beveled / Plain End / Threaded | ASME B16.25 | Per customer specification |
The following table provides indicative dimensional and weight data for SS 310 / 310S 90 Degree Long Radius Elbows per ASME B16.9. Please contact Metinox Overseas for certified dimensional drawings and weights for other fitting types, schedules, and non-standard sizes:
| NB Size | OD (mm) | SCH 40 WT (mm) | SCH 80 WT (mm) | Center to Face (mm) | Approx Wt SCH 40 (kg) |
|---|---|---|---|---|---|
| 1/2" | 21.3 | 2.77 | 3.73 | 38.1 | 0.07 |
| 1" | 33.4 | 3.38 | 4.55 | 50.8 | 0.17 |
| 2" | 60.3 | 3.91 | 5.54 | 76.2 | 0.52 |
| 3" | 88.9 | 5.49 | 7.62 | 114.3 | 1.65 |
| 4" | 114.3 | 6.02 | 8.56 | 152.4 | 2.88 |
| 6" | 168.3 | 7.11 | 10.97 | 228.6 | 7.14 |
| 8" | 219.1 | 8.18 | 12.70 | 304.8 | 14.48 |
| 10" | 273.0 | 9.27 | 12.70 | 381.0 | 24.83 |
| 12" | 323.9 | 9.53 | 12.70 | 457.2 | 35.71 |
Note: Weights are approximate and may vary by manufacturer. Certified dimensional drawings are available on request for all ASME B16.9 SS 310 Fittings supplied by Metinox Overseas.
The main motivation in engineers to use SS 310 / 310S Pipe Fittings instead of the standard 304 or 316 grades is performance at the limits of austenitic stainless steel service temperature capability. The 25% Cr 20% Ni alloy offers three important characteristics to challenging thermal conditions:
The protective scale of chromium rich oxide that develops on the surfaces of SS 310 / 310S can withstand temperatures at which 304 and 316 suffer severe scaling and metal loss. This causes SS 310 Pipe Fittings to be the standard of furnace piping systems, high-temperature unit headers of heat exchangers, and manifolds of combustion air distribution.
In carbonaceous environments (endothermic gas atmospheres, hydrocarbon cracking, methane-containing gases), the high nickel content of SS 310 offers better resistance to carbon uptake and metal dusting than lower-alloy grades. SS 310 Pipe Fittings are applied in piping of heat treatment furnace, petrochemical cracking, and carburizing furnace retort.
A large number of industrial furnaces are run in conditions of reducing circumstances or under reducing circumstances entirely. The Cr-Ni balance of SS 310 / 310S provides structural integrity in these conditions where oxidizing grade alloys can fail quickly.
The high chromium content offers significant resistance to the attack of sulfur in the refinery, gas processing and chemical plant environments that contain H2S.
Metinox Overseas supplies SS 310 Pipe Fittings to engineers and procurement teams across multiple high-temperature industries:
The price of SS 310 Pipe Fittings depends on the fitting type, nominal bore, wall schedule, manufacturing method (WP-S / WP-W / WP-WX), and quantity. SS 310 / 310S is a specialty high-alloy grade, and raw material (25Cr-20Ni) pricing is subject to nickel and chromium commodity fluctuations. Metinox Overseas provides firm quotations valid for a specified period to protect project budgets.
Payment modes accepted include wire transfer (T/T), letter of credit (LC at sight or usance), and document against payment (DP / DA) for established trade relationships. Export packing conforms to ISPM 15 (heat-treated wooden crates or pallets) with full export documentation including commercial invoice, packing list, bill of lading, certificate of origin, material test certificate, third-party inspection reports, and fumigation certificate as required.
Current export destinations for SS 310 / 310S Pipe Fittings from Metinox Overseas include the UAE, Saudi Arabia, Qatar, Kuwait, Oman, Bahrain, the UK, Germany, France, the Netherlands, the USA, Canada, Singapore, Indonesia, Malaysia, Thailand, Vietnam, Australia, South Africa, Nigeria, and Brazil. Contact our export desk for country-specific documentation requirements.
Complete your SS 310 / 310S system with our full range of related products:
Metinox Overseas is a reputable supplier and a producer of SS 310 Pipe Fittings and ASTM A403 WP310 Fittings to be used in industrial applications with high temperatures across the globe. All significant sizes and schedules of WP310 and WP310S are stocked, and EN 10204 3.1 test certification is a matter of course. We also provide competitive prices, short lead time, third party examination (SGS, Bureau Veritas, TUV, Lloyds) and complete export papers to ship to any place across the globe.
In order to obtain a quotation on SS 310 / 310S Buttweld Fittings, we would like to know your size, schedule, grade, fitting type, quantity, deliver port and any special inspection or documentation. Technical team will reply within 24 hours with pricing and availability.
You can also browse our complete range of stainless steel products by visiting View all Pipes and Tubes.
Carbon is the main difference between SS 310 and SS 310S Pipe Fittings. SS 310 (UNS S31000 / DIN 1.4841) has a maximum carbon content of 0.25%, while SS 310S (UNS S31008 / DIN 1.4845) is the low-carbon variant with a maximum carbon of 0.08%. The 25% Chromium and 20% Nickel make-up of both grades and offer the same oxidation resistance to temperatures up to 1050 deg C. The reduced carbon content in SS 310S inhibits the formation of carbide at the heat-affected areas of the weld and thus it is the material of choice in welded piping assemblies. SS 310 is used in cases where no heat-treatment after the welding is needed but the strength of the high-temperature is essential.
SS 310 Pipe Fittings are produced to ASTM A403 / ASME SA403, Grade WP310 of SS 310 and Grade WP310S of SS 310S. Dimensions are ASME B16.9 in the case of buttweld fittings and MSS SP-43 in the case of lightweight schedule fittings. Certification of material tests is done according to EN 10204 3.1 and radiographic inspection is provided according to ASTM A403 supplementary requirements to have the designation of WP-WX.
SS 310 / 310S Pipe Fittings can offer a continuous service life of up to 1050 deg C and intermittent service life of up to about 1150 deg C. These are the maximum temperatures that can be attained in normal austenitic stainless steel buttweld fittings. Nickel alloy alloys like Alloy 601 or 310MoLN would be considered in applications above this range. The service of carburizing atmosphere must be considered individually because the activity of carbon and the composition of gases can greatly influence the maximum possible safe service temperature.
Yes. SS 310 and SS 310S Pipe Fittings are a standard engineering specification of piping in carburizing furnace atmosphere. The large nickel content (20%) offers significant resistance to carbon absorption (metal dusting) in endothermic gas environments with CO, CO2, CH4 and H2. Nevertheless, in highly carburizing conditions where carbon activity is very high nickel-based alloys like Alloy 601 could be ordered to last as long as possible. Metinox Overseas will be happy to help you select a grade depending on your furnace atmosphere composition and temperature of operation.
Metinox Overseas is the supplier of SS 310 / 310S Pipe Fittings, ranging in size between 1/2" NB to 48" NB wall thickness between SCH 5S and Schedule XXS, all standard schedules as defined in ASME B36.19M and ASME B36.10M. It has all types of standard fittings such as 90 degree LR Elbow, 45 degree LR Elbow, 90 degree SR Elbow, 180 degree Return Bend, Equal Tee, Reducing Tee, Concentric Reducer, Eccentric Reducer, End Cap, Long Stub End, Short Stub End and Pipe Cross. Unusual sizes and tailor-made designs can be ordered upon request and engineering drawings will be provided so that the customer can approve the design before it can be made.
Get pricing within 24 hours!