Stainless Steel 316 Buttweld Fittings Manufacturer | ASTM A403 WP316 Butt Weld Fittings Supplier

Stainless Steel 316 Buttweld Fittings Manufacturer & Supplier

Amardeep Steel center is a manufacturer, supplier and exporter of SS 316 Buttweld Fittings in the world. Our A403 WP316 fittings are the standard of the piping systems in the industry in which chloride resistance, sulfuric acid and marine environment are non-negotiable. Grade 316 (UNS S31600) is competitive by virtue of molybdenum (2–3%), which increases its pitting-resistance equivalent (PRE) the most among the various grades by a factor of four over Grade 304, and is the most preferable in offshore, pharmaceutical and chemical-processing applications across the world. All our UNS S31600 fittings are fully equipped with EN 10204 3.1 MTCs and can be inspected by third parties.

What Are Stainless Steel 316 Butt Weld Fittings?

Stainless Steel 316 Buttweld Fittings are high-integrity components used to connect, divert, or terminate piping systems. By welding the beveled ends directly to the pipe, a continuous metal structure is created that is as leak-proof and pressure-rated as the pipe itself.

The intentional addition of molybdenum elevates these fittings significantly beyond the 304 grade, providing:

Excellent Corrosion Resistance: High levels of pitting and crevice corrosion resistance in environments with chloride (seawater, brines and de-icing salts).
Improved Acid Resistance: Strengths in sulfuric, acetic, formic, tartaric acids and alkaline chlorides.
High-Temperature Strength: A higher creep and stress-rupture strength at high temperatures than that of normal austenitic grades.

Amardeep Steel as a specialized manufacturer will make sure that every ASME SA403 WP316 Fitting is guaranteeing the long-term reliability of the processes of the most vital process industries of the world.

SS 316 Buttweld Fittings Specifications

Parameter	Details
Material Standard	ASTM A403 / ASME SA403
Grade / UNS	WP316 / UNS S31600 / WNR 1.4401
Dimensional Standard	ASME B16.9, ASME B16.28, MSS-SP-43
Size Range	1/2″ NB to 48″ NB (Seamless & Welded/Fabricated)
Wall Thickness / Schedule	Sch 5s, 10s, 40s, STD, 80s, XS, 160s, XXS
Bending Radius	R = 1D, 2D, 3D, 5D, 6D, 8D, 10D or Custom
End Finish	Beveled End (BE) per ASME B16.25 (standard); Plain End (PE); Threaded on request
Surface Finish	Pickled & Passivated, Polished (2B / BA / Mirror)
Delivery Condition	Solution Annealed (1040–1120°C + Rapid Quench)
Forms / Types	Elbow (45° / 90° / 180°), Tee, Reducer, Cap, Stub End, Bend, Cross, Lateral
Test Certificates	EN 10204 / 3.1 Mill TC, PMI, Hydrostatic, UT, Radiography

Chemical Composition (wt %) of SS 316 / UNS S31600 Fittings

Grade	C	Mn	Si	P	S	Cr	Ni	Mo
SS 316 (WP316)	0.08 max	2.0 max	0.75 max	0.045 max	0.030 max	16.0–18.0	10.0–14.0	2.0–3.0

Mechanical Properties — ASTM A403 WP316 Minimum Values

Property	SS 316 (WP316)
Tensile Strength (min)	515 MPa (75,000 psi)
Yield Strength 0.2% (min)	205 MPa (30,000 psi)
Elongation in 50 mm (min)	40%
Hardness, Rockwell B (max)	95 HRB
Hardness, Brinell (max)	217 HBW

SS 316 vs SS 316L Buttweld Fittings — Which to Choose?

SS 316 Buttweld Fittings	SS 316L Buttweld Fittings
Standard Carbon (C ≤ 0.08%)	Low Carbon (C ≤ 0.03%)
Better high-temperature strength above 425°C	Eliminates sensitisation risk at weld zones
ASTM A403 WP316 / ASME SA403	ASTM A403 WP316L / ASME SA403
Ideal for service above 425°C with PWHT	Best for fabricated assemblies without PWHT
Common in chemical processing, oil & gas reactors	Preferred in pharmaceutical, food & marine applications

For side-by-side specification data, see our SS 316L Buttweld Fittings page.

Equivalent Grades — SS 316 Buttweld Fittings

UNS	WNR (EN)	EN Designation	JIS	BS
S31600	1.4401	X5CrNiMo17-12-2	SUS 316	316S31

OD & Wall Thickness Chart — ASME B16.9

NPS (Inch)	OD (mm)	Sch 10S WT (mm)	Sch 40S / STD WT (mm)	Sch 80S / XS WT (mm)
1/2″	21.3	2.77	3.73	5.54
1″	33.4	2.77	4.55	7.14
2″	60.3	3.91	5.54	8.74
4″	114.3	5.74	8.56	13.49
6″	168.3	7.11	10.97	14.27
8″	219.1	8.18	12.70	18.26
10″	273.0	9.27	12.70	18.26
12″	323.8	9.53	12.70	17.48

Full dimensional tables per ASME B16.9 available on request. Larger diameter / custom schedules quoted individually.

ASME B16.9 Dimensional Tolerances — SS 316 Buttweld Fittings

Adherence to dimensional tolerances is essential for efficient on-site installation. All fittings are manufactured to the exact tolerances defined in ASME B16.9, guaranteeing consistency in center-to-face dimensions, angular accuracy, wall thickness uniformity, and precision-machined end bevels.

Parameter	Tolerance — NPS ≤ 10″	Tolerance — NPS > 10″
Center-to-Face / End-to-End	±1.6 mm (±1/16″)	±3.2 mm (±1/8″)
Wall Thickness (min.)	87.5% of nominal	87.5% of nominal
Outside Diameter at End	+1.6 / −0.8 mm	+3.2 / −1.6 mm
Bevel Angle	37.5° ± 2.5°	37.5° ± 2.5°

Tolerances per ASME B16.9 — Factory-Made Wrought Buttwelding Fittings. Verify with supplied MTC for actual measured dimensions.

Heat Treatment of ASTM A403 WP316 Buttweld Fittings

All ASTM A403 WP316 Fittings are supplied in the solution-annealed condition. The material is heated to 1040–1120°C (1900–2050°F) and then rapidly quenched. This critical step dissolves any harmful carbide precipitates, relieves internal stresses from the forming process, and restores the material’s maximum corrosion resistance and ductility.

Types of Stainless Steel 316 Buttweld Fittings We Supply

SS 316 Elbows (45°, 90°, 180°): Long Radius (LR) and Short Radius (SR) — change pipe direction with minimal pressure drop.
SS 316 Equal & Reducing Tees: Create 90° branch connections from the main pipe run.
SS 316 Concentric & Eccentric Reducers: Join pipes of different diameters; eccentric type prevents air/sediment trapping in horizontal lines.
SS 316 Pipe Caps: Leak-proof termination of pipeline ends.
SS 316 Stub Ends: Used with lap joint flanges for bolt-hole alignment in flanged assemblies.
SS 316 Pipe Bends (3D, 5D, 10D): Larger bending radius than elbows; ideal for high-velocity, low-turbulence systems.
SS 316 Crosses & Laterals (Equal & Reducing): Four-way intersection fittings for distribution headers, manifolds, and complex piping layouts.
SS 316 Welded / Fabricated Fittings: For larger diameters (>24"); 100% radiographed welds to ensure integrity and performance.

Applications of Stainless Steel 316 Buttweld Fittings

The superior corrosion resistance of UNS S31600 Fittings makes them the material of choice for demanding industries worldwide:

Marine & Offshore: Subsea pipelines, vessel fittings & offshore platforms. Exceptional chloride and seawater corrosion resistance.
Pharmaceutical & Biotech: CIP/SIP process piping; withstands aggressive sterilisation agents. Hygienic surface finishes available.
Chemical Processing: Handles sulfuric, acetic, formic acids and acid sulfates in reactors, columns & transfer lines.
Food & Beverage: Brine lines, acidic food products, dairy CIP loops & beverage process piping.
Pulp & Paper: Resists corrosive bleaching liquors & sulfite compounds in paper mill piping.
Oil & Gas Refining: Heat exchangers, condensers & process piping exposed to corrosive streams and elevated temperatures.
Desalination & Water Treatment: Chlorinated and brackish water pipelines, RO membrane housings.
Textile & Dye Industry: Acid-dyeing lines, bleaching equipment & chemical transfer headers.
Architectural & Structural: Coastal railings, cladding supports and marine architectural structures where chloride-driven corrosion disqualifies Grade 304.

Why Choose Amardeep Steel for SS 316 Buttweld Fittings?

With over 25 years of manufacturing experience and an active export portfolio spanning 40+ countries, Amardeep Steel Center is a reference-check-approved supplier for projects in the USA, UAE, Saudi Arabia, Europe, and Southeast Asia. Choosing Amardeep Steel means selecting a supplier that is fully invested in your success.

Precision Manufacturing: Our cold-forming and hot-pushing manufacturing lines produce dimensionally consistent fittings with PMI-verified chemistry, reducing fit-up rejections on site.
Global Exports: Robust global logistics network ensuring timely, secure delivery to 40+ countries. Active supply to ONGC-approved fabricators and European EPC contractors for offshore platform piping.
Rapid Turnaround & Stock Availability: Extensive inventory of standard SS 316 Buttweld Fittings enables prompt order fulfilment. Standard lead time for stock items: 3–5 business days.
Uncompromising Quality Certification: ISO 9001:2015 certified. Every fitting supplied with EN 10204 3.1 Mill Test Certificate, PMI reports, and third-party inspection from SGS, BV, TÜV, Lloyd’s & others on request.
IBR & PED Compliance: IBR-approved fittings available for Indian boiler and pressure vessel projects. PED 2014/68/EU compliant fittings available for European end-use clients.
Expert Technical Support: Dedicated engineers and material specialists provide guidance on grade selection, corrosion challenges, and certification requirements.
Export Packaging: All SS 316 Buttweld Fittings packed in wooden crates with end-cap protection, desiccant bags, and plyboard inner boxing. Each piece tagged with heat number, grade, size, and schedule per MSS SP-25.

In-stock inventory. Fast shipping. Mill TC & third-party inspection available. Our sales team is ready to assist with your project requirements. Please have your size, schedule, quantity, and certification requirements ready when you reach out. Standard lead time for stock items is 3–5 business days.

Frequently Asked Questions About SS 316 Buttweld Fittings

What is the ASTM standard for SS 316 Buttweld Fittings?

SS 316 Buttweld Fittings are manufactured to ASTM A403 / ASME SA403, Grade WP316. Dimensions follow ASME B16.9, ASME B16.28, and MSS-SP-43.

What is the difference between SS 316 and SS 316L Buttweld Fittings?

The key difference is carbon content. SS 316 (C ≤ 0.08%) offers better high-temperature tensile strength. SS 316L (C ≤ 0.03%) prevents sensitisation at weld zones — preferred for fabricated assemblies that cannot undergo post-weld heat treatment (PWHT).

What heat treatment is applied to ASTM A403 WP316 Fittings?

All fittings are supplied in the solution-annealed condition — heated to 1040–1120°C and rapidly quenched. This dissolves carbides, relieves residual stress, and restores maximum corrosion resistance and ductility.

What is the pressure rating of SS 316 Buttweld Fittings?

Pressure ratings for ASTM A403 WP316 fittings depend on nominal pipe size, wall schedule, and operating temperature. At ambient temperature, Sch 40S fittings in 1/2″ NPS are rated to approximately 1,480 psi. For exact pressure–temperature ratings, refer to ASME B16.9 and the applicable piping code (ASME B31.3 for process piping). Contact us with your operating parameters for a specific recommendation.

Can SS 316 Buttweld Fittings be used with 316L or dual-certified 316/316L pipe?

Yes. ASTM A403 WP316 fittings are routinely welded to 316L and dual-certified 316/316L pipe using matching filler metal (ER316L). For sections thicker than 6 mm, ER316L filler prevents sensitisation in the heat-affected zone. Always confirm heat input and post-weld requirements with your Welding Procedure Specification (WPS).