Premium molybdenum-bearing grade of stainless steel buttweld fittings are the SS 316 Pipe Fittings, which are very commonly specified in marine, offshore, chemical processing, pharmaceutical, oil and gas and coastal industries throughout the world. These fittings, manufactured to ASTM A403 WP316 and WP316L, include molybdenum at 2 to 3 per cent, which gives much better pitting and crevice corrosion resistance in chloride-rich environments than do standard SS 304 fittings. This one addition is what renders SS 316 Pipe Fittings the choice of all alloys when sea water, brine, acids or chloride compounds are involved in the process medium.
At Metinox Overseas, we are distributing SS 316 and 316L Pipe Fittings ranging between 1/2 inch NB to 48 inch NB in a schedule ranging between SCH 5S all the way up to XXS and all types of fittings such as elbows, tees, reducers, stub ends, end caps, and long radius bends. Both grades are dual-certified and discussed on this page and complete data on the chemical composition, mechanical properties, cross-references of equivalent grades and dimensional standards are provided to make your decision on procurement and engineering operations. Browse our complete range of Stainless Steel Pipes and Tubes or contact us directly to request a quote.
Request a quote now!All SS 316 Pipe Fittings and SS 316L Pipe Fittings supplied by Metinox Overseas conform to ASTM A403 / ASME SA403, the governing standard for wrought austenitic stainless steel buttwelding fittings. Dimensional compliance is per ASME B16.9 for buttweld fittings and MSS SP-43 for lightweight fittings. Full EN 10204 3.1 Mill Test Certificates are provided with every shipment.
| Specification Parameter | Details |
|---|---|
| Standard | ASTM A403 / ASME SA403 |
| Grade | WP316 (SS 316) / WP316L (SS 316L) |
| UNS Number | S31600 (316) / S31603 (316L) |
| DIN / Werkstoff | 1.4401 (316) / 1.4404 (316L) |
| Japanese Equivalent | SUS 316 / SUS 316L |
| Dimensional Standard | ASME B16.9 (Buttweld) / MSS SP-43 |
| Wall Thickness / Schedule | SCH 5S, 10S, 40S, 80S, 160, XXS |
| Size Range | 1/2 inch NB to 48 inch NB (DN 15 to DN 1200) |
| End Finish | Beveled End (BE), Plain End (PE), Threaded End (TE) |
| Fittings Category | WP-S (Seamless) / WP-W (Welded) / WP-WX (Welded and X-Ray Tested) |
| Test Certificates | EN 10204 3.1 / 3.2 Mill Test Certificate |
| Heat Treatment | Solution Annealed |
The single most important difference between SS 316 and SS 316L Pipe Fittings is the carbon content. SS 316L (UNS S31603 / DIN 1.4404) has a maximum carbon of 0.03%, compared to 0.08% max for standard SS 316 (UNS S31600 / DIN 1.4401). This low carbon content makes SS 316L immune from sensitization at grain boundaries during welding, eliminating the risk of intergranular corrosion without requiring post-weld heat treatment (PWHT). This is why SS 316L Pipe Fittings are the preferred specification for welded piping assemblies in pharmaceutical, food processing, and marine applications.
Both grades carry identical molybdenum content (2 to 3%), chromium (16 to 18%), and nickel (10 to 14%), giving them equivalent pitting and crevice corrosion resistance in chloride environments. Metinox Overseas suppliesSS 316 / 316L Pipes alongside these fittings for complete system supply.
| Property | SS 316 | SS 316L |
|---|---|---|
| Carbon Content (C) | 0.08% max | 0.03% max |
| UNS Number | UNS S31600 | UNS S31603 |
| DIN / Werkstoff | 1.4401 | 1.4404 |
| Japanese Grade | SUS 316 | SUS 316L |
| Sensitization Risk | Possible at 425 to 815°C | Immune from sensitization |
| Post Weld Heat Treatment | May be required | Not required |
| Preferred For | General corrosion service | Welded assemblies, heavy fabrication |
| ASTM Standard | ASTM A403 WP316 | ASTM A403 WP316L |
The comparison between SS 304, SS 316, and SS 316L Pipe Fittings is the most common pre-purchase decision engineers face in the stainless steel fittings category. The key differentiator is molybdenum: SS 316 and 316L contain 2 to 3% Mo, SS 304 contains none. This makes SS 316 and 316L Pipe Fittings the correct choice for any service involving chlorides, acids, sea water, or coastal atmospheric exposure. The table below covers all critical decision parameters.
| Property | SS 304 | SS 316 | SS 316L |
|---|---|---|---|
| UNS Number | UNS S30400 | UNS S31600 | UNS S31603 |
| Molybdenum (Mo) | None | 2.00 to 3.00% | 2.00 to 3.00% |
| Chromium (Cr) | 18.00 to 20.00% | 16.00 to 18.00% | 16.00 to 18.00% |
| Nickel (Ni) | 8.00 to 10.50% | 10.00 to 14.00% | 10.00 to 14.00% |
| Carbon (C) max | 0.08% | 0.08% | 0.03% |
| Pitting Resistance | Moderate | High | High |
| Chloride Resistance | Moderate | Excellent | Excellent |
| Marine / Coastal Use | Not recommended | Recommended | Highly recommended |
| Sensitization Risk | Moderate | Moderate | Immune |
| PWHT After Welding | May be required | May be required | Not required |
| Cost vs SS 304 | Base reference | Higher (Mo content) | Higher (Mo content) |
| Typical Application | General fabrication, food equipment | Marine, chemical, pharma | Welded marine, pharma, food |
For complete piping solutions, also see our SS 316 / 316L Seamless Pipes and SS 316 / 316L Welded Pipes available for supply alongside these fittings.
Metinox Overseas stocks and supplies the complete range of SS 316 Pipe Fittings and SS 316L Pipe Fittings per ASTM A403 and ASME B16.9. Each fitting type is available in seamless (WP-S) and welded (WP-W / WP-WX) construction across the full size and schedule range.
| SS 316 Fitting Type | Description | Common Application |
|---|---|---|
| 90 Degree Long Radius Elbow | Changes pipe direction by 90 degrees; radius = 1.5 x nominal pipe diameter | General piping, process plants, marine systems |
| 45 Degree Elbow | Changes pipe direction by 45 degrees; lower pressure drop than 90 deg LR | Chemical and pharmaceutical lines |
| 180 Degree Return Bend | Full U-turn flow reversal; short radius and long radius types available | Heat exchangers, jacketed piping |
| Equal Tee | Splits or combines flow in three directions; all three outlets same diameter | Widely used in distribution headers |
| Reducing Tee | Branch outlet smaller than run pipe diameter | Process piping with differing branch flow |
| Concentric Reducer | Gradual pipe size reduction; centered axis | Pumps, compressors, general pipelines |
| Eccentric Reducer | Pipe size reduction with flat bottom; prevents air pockets | Pump suction lines, horizontal pipelines |
| End Cap / Pipe Cap | Closes the open end of a pipe | Blanking off pipe ends, pressure testing |
| Stub End (Long and Short) | Used with lap joint flanges to allow rotation without welding flanges | Lined piping systems, corrosion-resistant assemblies |
| Cross (4-Way Tee) | Connects four pipes at 90 degrees to each other | Complex manifold systems |
| 3D Bend / 5D Bend | Long radius piping bend; 3D = 3x pipe diameter, 5D = 5x pipe diameter | Offshore, subsea and long-distance pipeline systems |
All SS 316 Pipe Fittings are available with accompanyingSS 316 / 316L Tubes andSS 316L Bright Annealed Tubes for instrumentation and process tubing requirements.
The chemical composition of SS 316 Pipe Fittings is defined by ASTM A403 WP316 and WP316L. The most critical element is Molybdenum (Mo) at 2.00 to 3.00%, which is absent in SS 304 and responsible for the superior pitting and crevice corrosion resistance of the 316 family. The side-by-side table below covers SS 316 (DIN 1.4401) and SS 316L (DIN 1.4404) for direct comparison.
| Element | SS 316 (UNS S31600) | SS 316L (UNS S31603) | Significance |
|---|---|---|---|
| Carbon (C) | 0.08% max | 0.03% max | Key differentiator 316L |
| Chromium (Cr) | 16.00 to 18.00% | 16.00 to 18.00% | Corrosion resistance base |
| Nickel (Ni) | 10.00 to 14.00% | 10.00 to 14.00% | Austenitic stability |
| Molybdenum (Mo) | 2.00 to 3.00% | 2.00 to 3.00% | Pitting and crevice resistance |
| Manganese (Mn) | 2.00% max | 2.00% max | — |
| Silicon (Si) | 0.75% max | 0.75% max | — |
| Phosphorus (P) | 0.045% max | 0.045% max | — |
| Sulfur (S) | 0.030% max | 0.030% max | — |
| Nitrogen (N) | 0.10% max | 0.10% max | — |
| Iron (Fe) | Balance | Balance | — |
| Mechanical Property | SS 316 (WP316) | SS 316L (WP316L) |
|---|---|---|
| Tensile Strength | 515 MPa (75 ksi) min | 485 MPa (70 ksi) min |
| Yield Strength (0.2% offset) | 205 MPa (30 ksi) min | 170 MPa (25 ksi) min |
| Elongation | 35% min | 35% min |
| Hardness (Brinell) | 217 HB max | 217 HB max |
| Hardness (Rockwell) | 95 HRB max | 95 HRB max |
All mechanical property values are as-manufactured in the solution-annealed condition per ASTM A403 / ASME SA403. Third-party inspection certificates per EN 10204 3.2 are available on request.
The table below lists all internationally recognized equivalent designations for SS 316 and SS 316L Pipe Fittings across American (UNS), German (DIN / Werkstoff), Japanese (JIS / SUS), and European (EN) standards.
| Grade | UNS | DIN / Werkstoff | JIS (Japan) | EN Designation |
|---|---|---|---|---|
| SS 316 | UNS S31600 | DIN 1.4401 | SUS 316 | EN X5CrNiMo17-12-2 |
| SS 316L | UNS S31603 | DIN 1.4404 | SUS 316L | EN X2CrNiMo17-12-2 |
ASTM A403 classifies SS 316 Pipe Fittings into three construction categories based on manufacturing method and inspection level. Specifying the correct suffix is critical for pressure rating and service suitability.
| ASTM A403 Suffix | Meaning and Manufacturing Method | Preferred Application |
|---|---|---|
| WP-S | Seamless: No longitudinal weld seam; manufactured by extrusion or piercing | High-pressure, high-temperature and critical service applications |
| WP-W | Welded: Formed from plate and seam-welded; weld seam not radiographically tested as standard | General process piping, structural and non-critical applications |
| WP-WX | Welded and 100% X-Ray Tested: All weld seams radiographically inspected; equivalent reliability to seamless | Critical service, offshore, nuclear and high-integrity piping systems |
| NPS (Nominal Pipe Size) | DN (Nominal Diameter) | Schedule Range | Manufacturing Method |
|---|---|---|---|
| 1/2" to 1-1/2" | DN 15 to DN 40 | SCH 5S to XXS | Seamless (WP-S) |
| 2" to 6" | DN 50 to DN 150 | SCH 5S to XXS | Seamless (WP-S) / Welded (WP-W / WP-WX) |
| 8" to 24" | DN 200 to DN 600 | SCH 10S to SCH 160 | Welded (WP-W / WP-WX) |
| 26" to 48" | DN 650 to DN 1200 | SCH 10S to SCH 80 | Welded (WP-W / WP-WX) |
Custom sizes, special schedules, and non-standard dimensions are available on inquiry. Contact Metinox Overseas for drawings, dimensional data sheets, or ASME B16.9 weight charts for any specific SS 316 Pipe Fittings requirement.
The molybdenum-bearing composition of SS 316 Pipe Fittings makes them the standard specification across six critical industry sectors where SS 304 is not suitable:
SS 316 and SS 316L Pipe Fittings are the standard material for all sea water piping, ballast systems, deck pipework, offshore platform process lines, and subsea equipment. The 2 to 3% molybdenum content provides resistance to pitting corrosion initiated by chloride ions in sea water that SS 304 cannot withstand. Bolted flange assemblies are completed with ourSS 316 Flanges for fully specification-matched systems.
In chemical plants handling sulfuric acid at moderate concentrations, acetic acid, bleaching agents, phosphoric acid, and halide-containing process streams, SS 316 Pipe Fittings offer the combination of corrosion resistance and fabricability required for welded piping systems operating at elevated temperatures.
SS 316L Pipe Fittings (C 0.03% max / UNS S31603 / DIN 1.4404) are specified by pharmaceutical and food industry standards worldwide for product-contact piping. The low carbon grade eliminates sensitization risk during orbital welding operations, producing clean, crevice-free weld joints that meet hygienic design requirements. Paired withSS 316L Flanges for complete sanitary connections.
SS 316 Pipe Fittings are used extensively in oil and gas production facilities for injection water lines, chemical injection skids, produced water treatment, and LNG plant utility piping. High-temperature service lines may specify SS 316H, for which see our range ofSS 316H Flanges andSS 316H Pipes.
In coastal industrial plants, desalination facilities, and offshore platform topsides where fittings are exposed to marine atmosphere, SS 316 Pipe Fittings provide the pitting corrosion resistance needed to prevent the rust staining and localized attack that rapidly degrades SS 304 fittings in salt-laden air.
Nuclear and conventional power plants use SS 316 and 316L Pipe Fittings (ASME B16.9 / ASME SA403) for secondary cooling circuits, demineralized water systems, and chemical dosing lines where trace chloride contamination is possible.
SS 316 / 316L Pipe Fittings Price Per Kg India varies based on fitting type, nominal pipe size, wall schedule, manufacturing method (seamless vs welded), and prevailing London Metal Exchange (LME) nickel and molybdenum surcharges. Contact Metinox Overseas for a current price list with delivery terms.
Payment Modes Accepted: Letter of Credit (LC), Telegraphic Transfer (TT), and Account Payee Cheque.
Export Destinations: UAE, Saudi Arabia, USA, UK, Singapore, South Africa, Australia, and all major global markets.
Request a quote now!Complete your SS 316 / 316L piping system with the following products available from Metinox Overseas:
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The first distinction is the carbon content. SS 316 (UNS S31600 / DIN 1.4401) has a maximum carbon of 0.08%, while SS 316L (UNS S31603 / DIN 1.4404) has a maximum of 0.03%. The 316L has this low carbon content that renders it immune to sensitization at grain boundaries during welding eliminating any risk of intergranular corrosion and does not require subsequent heat treatment of the weld. Both grades have the same 2 to 3 percent molybdenum content and therefore, pitting and crevice corrosion resistance is the same.
SS 316 pipe Fittings have a molybdenum (Mo) percentage ranging between 2 and 3 not found at all in SS 304. Molybdenum contributes a lot to the pitting and crevice corrosion resistance of the stainless steel in the chloride-containing environments like sea water, brine and salt-infested coastal environments. In the marine service, molybdenum-free SS 304 fittings quickly form rust pits and a crevice attack, resulting in its early failure. The given grade of all marine, offshore, and coastal piping systems therefore is SS 316 and SS 316L.
The ASTM A403 is a standard specification of the American Society of testing and Materials of wrought austenitic stainless steel buttwelding fittings. The designation of the grade (stainless steel 316, UNS S31600) is WP316. The suffix following WP316 is used to denote construction: WP316-S is seamless, WP316-W is welded and WP316-WX is welded and 100% radiographically inspected. The high standard 316L, which is referred to as low-carbon 316L (UNS S31603), fittings are called WP316L.
Metinox Overseas distributes SS 316 Pipe Fittings and SS 316L Pipe Fittings 1/2 inch NB (DN 15) to 48 inch NB (DN 1200) and wall schedules SCH 5S-XXS ( Schedule 160). Seamless fittings (WP-S) come in sizes of 1/2 to about 6 and welded construction (WP-W and WP-WX) extends the larger diameter sizes to 48.
No. SS 316L Pipe Fittings (UNS S31603 / DIN 1.4404) do not have post-weld heat treatment (PWHT). The 0.03% maximum carbon in 316L does not allow chromium carbides to form at grain boundaries during the welding (sensitization), which is the process that renders standard 316 to be susceptible to intergranular corrosion following welding. This is among the main reasons that 316L is required in all welded assemblies of pharmaceutical, food processing and marine piping as opposed to standard 316.
Metinox Overseas is a trusted supplier and manufacturer of SS 316 Pipe Fittings and SS 316L Pipe Fittings in India, exporting to UAE, Saudi Arabia, USA, UK, Singapore, South Africa, Australia, and all major global destinations. We provide EN 10204 3.1 and 3.2 Mill Test Certificates, ASME B16.9 dimensional compliance, and full ASTM A403 WP316 / WP316L material traceability for every order.
Send us your inquiry with the required fitting type, size, schedule, grade (316 or 316L), and construction (WP-S / WP-W / WP-WX) and we will respond with a competitive price and lead time within 24 hours. Payment modes accepted: LC, TT, and Cheque.
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