Stainless steel 316 fittings are corrosion-resistant pipe connectors in ASTM A403 WP316 / WP316L, alloyed with 2–3% molybdenum for superior resistance to chloride pitting and crevice corrosion. Available ½" to 48" NPS, SCH 10–XXS, they're the standard choice for marine, offshore, chemical, and food/pharma piping.
ASTM A403 WP316 Stainless Steel Pipe Fittings Manufacturer and Supplier in India
As an ISO-certified manufacturer of ASTM A403 WP316 stainless steel 316 fittings in India, we supply a complete range of buttweld fittings for welded piping networks and forged fittings for high-pressure service — elbows, tees, reducers, caps, and stub ends — to engineering, EPC and export customers across 60+ countries. Fittings are available from NPS ½" to 48" in seamless and welded construction, across all standard schedules from SCH 10 through XXS.
We manufacture in compliance with ASME B16.9 and B16.28, in both seamless and welded (ERW) forms. Our in-house ISO-certified quality control, 100% radiography testing, and support for custom sizes from NPS ½" to 24" make us a trusted source for complex engineering and export projects. Full EN 10204 3.1 and 3.2 material test certificates are available on request, along with third-party inspection by SGS, Bureau Veritas, or Lloyd's Register.
The 2 to 3 percent molybdenum content in grade 316 gives it a higher PREN than grade 304, making it the correct material selection for service environments involving chloride ions, seawater, acidic process fluids, and aggressive cleaning cycles. For applications requiring post-weld corrosion resistance without annealing, 316L (low-carbon variant, 0.03 percent C max) is the specified choice.
Standard stock items dispatched within 3–5 working days from our Mumbai warehouse. Custom sizes and certified material: 2–4 weeks. Export packaging and sea-freight documentation included.
For more information and pricing on 316 Stainless Steel Fittings, please contact us directly.
ISO 9001:2015 | EN 10204 3.1/3.2 MTC | NACE MR0175/ISO 15156 compliance available | Third-party inspection: SGS, BV, TUV on request
Testing
100% Radiography | Hydrostatic | PMI (Positive Material Identification) | Visual & dimensional per ASME B16.9
316 Stainless Pipe Fittings Chemical Composition
The critical differentiator is molybdenum (Mo) at 2.00–3.00% — absent in grade 304. This element raises the Pitting Resistance Equivalent Number (PREN) from approximately 18 (grade 304) to approximately 25 (grade 316), providing a measurable improvement in resistance to chloride-induced pitting corrosion.
C
Si
Mn
P
S
Cr
Ni
Mo
Fe
0.08 max
1.0 max
2.0 max
0.045 max
0.030 max
16.00–18.00
11.00–14.00
2.00–3.00
67.845 min
Mechanical Properties of 316 Pipe Fittings
Melting Point
Density
Yield Strength (0.2% offset)
Elongation
Tensile Strength
1400°C / 2552°F
8.0 g/cm³
30,000 PSI / 205 MPa
35%
75,000 PSI / 515 MPa
Equivalent Grades of Stainless Steel 316 Pipe Fittings
AISI/ASTM
UNS
Werkstoff Nr.
JIS
EN
BS
AFNOR
316 (A276, A403, A479)
S31600
1.4401 / 1.4436
SUS 316
X5CrNiMo17-12-2 / X3CrNiMo17-13-3
316S31 / 316S33
Z7CND17-11-02
When to Specify 316L Over 316
For all welded installations, specify 316L (WP316L per ASTM A403). The low-carbon formulation (max 0.03% C vs 0.08% for standard 316) eliminates the risk of sensitisation — chromium carbide precipitation at weld heat-affected zones that can create intergranular corrosion paths in aggressive environments.
Standard 316 is acceptable for non-welded, mechanical connections. For all piping that will be field-welded or shop-welded without post-weld annealing, WP316L is the correct specification. Both grades carry the same molybdenum content and corrosion resistance — the difference is only in carbon content and therefore weld performance.
Property
316 (WP316)
316L (WP316L)
Max Carbon (C)
0.08%
0.03%
Molybdenum (Mo)
2.00–3.00%
2.00–3.00%
Chloride resistance
Excellent
Excellent
Weld sensitisation risk
Moderate — anneal recommended
Very low — no post-weld anneal required
Food/pharma use
Suitable
Preferred (low C prevents CIP attack)
ASTM fitting spec
A403 WP316
A403 WP316L
Need the low-carbon grade specifically? See our dedicated Stainless Steel 316L Fittings page for WP316L-specific stock and pricing.
Pressure Ratings for SS 316 Pipe Fittings
Pressure ratings are determined by fitting type, connection class, and wall schedule. The following are indicative cold working pressure ratings at ambient temperature:
Connection Type
Standard
Class/Schedule
Approx. Max Pressure
Threaded / Socket Weld
ASME B16.11
Class 3000
~3,000 PSI (207 bar)
Threaded / Socket Weld
ASME B16.11
Class 6000
~6,000 PSI (414 bar)
Threaded / Socket Weld
ASME B16.11
Class 9000
~9,000 PSI (621 bar)
Butt Weld
ASME B16.9
Schedule 40 @ 1" NPS
~740 PSI (51 bar)
Butt Weld
ASME B16.9
Schedule 80 @ 1" NPS
~1,130 PSI (78 bar)
Butt Weld
ASME B16.9
Schedule 160 @ 1" NPS
~2,050 PSI (141 bar)
Flanged
ASME B16.5
Class 150
~275 PSI (19 bar) ambient
Flanged
ASME B16.5
Class 600
~1,480 PSI (102 bar) ambient
Note: All pressure ratings decrease with increasing temperature. Derate per ASME B31.3 for your service temperature. Class ratings are for cold working pressure (CWP) / water, oil, gas (WOG) service.
Pressure Rating vs. Temperature — Class 150 & 300 Flanged (316 SS)
Ambient-temperature ratings above only tell part of the story. Use the guide below for a quick check on how far a Class 150 or Class 300 316 SS flanged connection de-rates as service temperature rises — and always confirm against the current ASME B16.5 table for final design.
Temperature
Class 150 (PSI)
Class 300 (PSI)
Ambient – 100°F (38°C)
275
720
200°F (93°C)
235
620
300°F (149°C)
215
560
400°F (204°C)
195
515
500°F (260°C)
170
470
600°F (316°C)
140
410
Size Chart of 316 Stainless Steel Fittings
Cap dimensions per ASME B16.9 (mm). All rows sorted by NPS ascending.
NPS (inches)
OD (mm)
Cap Length (mm)
1/2
21.3
25
3/4
26.7
25
1
33.4
38
1.1/4
42.2
38
1.1/2
48.3
38
2
60.3
38
2.1/2
73.0
38
3
88.9
51
3.1/2
101.6
64
4
114.3
64
5
141.3
76
6
168.3
89
8
219.1
102
10
273.0
127
12
323.8
152
14
355.6
165
16
406.4
178
18
457.0
203
20
508.0
229
22
559.0
254
24
610.0
267
26
660.0
267
28
711.0
267
30
762.0
267
32
813.0
267
34
864.0
237
36
914.0
267
38
965.0
305
40
1016.0
305
All dimensions per ASME B16.9 / MSS SP-43. Other schedules and fitting types on request.
Source: ASME B16.9. All weights are approximate and for planning purposes only — confirm with mill certifications.
ASTM A403 WP316 Fittings HS Code
For streamlined international logistics and customs clearance, reference the following Harmonized System codes for ASTM A403 WP316 stainless steel fittings:
Fitting Type
HS Code
Description
Butt-weld fittings (elbows, tees, reducers)
7307.23.00
Tube or pipe fittings of stainless steel — butt welding fittings
Threaded, socket-weld, other fittings
7307.99.00
Tube or pipe fittings of stainless steel — other
Verify against current Indian Customs Tariff and destination country tariff schedule at time of shipping. Chapter 73.07 covers all iron/steel pipe fittings.
Dimensions per ASME B16.9. OD in both metric (mm) and imperial (inches).
NPS (in)
OD (mm)
OD (in)
Cap Length (in)
Tee C-E (in)
Cross C-E (in)
Stub End Lap Ø (in)
Stub Long (in)
Stub Short (in)
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
4
114.3
4.500
2 1/2
4 1/8
4 1/8
6 3/16
6
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
5
12
323.9
12.750
6
10
10
15
10
6
SS 316 Pipe Fittings Dimensions — Elbows (Centre-to-End) per ASME B16.9
Dimensions per ASME B16.9. OD in both metric (mm) and imperial (inches).
NPS (in)
OD (mm)
90° LR Elbow C-E (in)
90° SR Elbow C-E (in)
45° LR Elbow C-E (in)
180° LR Return C-C (in)
1/2
21.3
1 1/2
1
15/16
3
3/4
26.7
1 1/2
1
1 1/8
3
1
33.4
1 1/2
1
1 1/2
3
1 1/2
48.3
2 1/4
1 1/2
1 7/8
4 1/2
2
60.3
3
2
2 1/2
6
3
88.9
4 1/2
3
3 3/4
9
4
114.3
6
4
5
12
6
168.3
9
6
7 1/2
18
8
219.1
12
8
10
24
10
273.1
15
10
12 1/2
30
12
323.9
18
12
15
36
Types of Stainless Steel 316 Pipe Fittings
Our inventory covers a full spectrum of 316 stainless steel pipe fittings and 316 stainless steel tube fittings to accommodate any piping configuration.
SUS 316 Cross
INOX 316 Nipple
SS 316 Short Radius Pipe Elbows
WNR 1.4401 Long Radius Return Bends
UNS S31600 Reducing Elbow
AISI 316 Stub Ends
316 Stainless Steel Coupling
316 Stainless Steel Unequal Tee
ASTM A403 WP316 Pipe Caps
Stainless Steel 316 Short Radius Return Bends
ASTM A403 Gr Wp316 Concentric Reducer
ASTM A403 Grade WP316 Collar Pipe Fittings
Fabrication Notes for SS 316 Fittings
Grade 316 is weldable by all standard fusion methods, with or without filler metals. For welded service, specify WP316L (low-carbon) to eliminate sensitisation risk at the weld heat-affected zone — post-weld annealing is not required for 316L.
If standard 316 fittings have been welded, restore full corrosion resistance by solution annealing at 1,050–1,150°C (1,922–2,102°F) followed by rapid water quench. Avoid service in the sensitisation temperature range of 425–860°C (797–1,580°F) without subsequent annealing.
Machining note: 316 work-hardens rapidly. Use heavy positive feeds at low speeds with chip breakers, generous cutting fluid, and sharp tooling to avoid galling.
Heat Treatment Quick-Reference
The same anneal parameters from the Fabrication Notes above, pulled into a scannable line for quick spec-checking:
Parameter
Value
Solution anneal temperature
1,050–1,150°C (1,922–2,102°F)
Quench method
Rapid water quench
Sensitisation range to avoid post-weld
425–860°C (797–1,580°F)
Post-weld anneal required for 316L?
No
Applications of Stainless Steel 316 Fittings
The molybdenum content in grade 316 makes these fittings the standard specification wherever chlorides, acids, or aggressive chemicals are present. Below are the primary industries and the specific reason 316 is required over grade 304:
Specialty Chemicals: Process streams containing hydrochloric, phosphoric, and sulphuric acids at concentrations and temperatures that cause rapid pitting in grade 304. Grade 316 provides the additional corrosion barrier required for reliable service life.
Oil & Gas / Offshore: Seawater injection lines, chemical dosing systems, and topside piping on offshore platforms are exposed to chloride-rich environments. Grade 316 stainless pipe fittings are mandated by NORSOK M-630 and similar offshore standards.
Marine & Seawater Equipment: 316 stainless fittings resist seawater and brine solutions at ambient temperature where 304 would suffer pitting corrosion within months. Standard specification for desalination, shipbuilding, and coastal infrastructure.
Pharmaceuticals: 316L (low-carbon variant) is required for direct-product-contact piping in pharmaceutical manufacturing per FDA and GMP guidelines. The electro-polished surface finish (Ra ≤ 0.8 µm) prevents microbial retention.
Food & Beverage: 316L sanitary fittings (tri-clamp, SMS, DIN 11851) are specified for dairy, beverage, and food processing lines. Resistance to CIP (clean-in-place) chemicals such as caustic soda and nitric acid makes 316L the hygienic grade of choice.
Power Generation: Condenser tubing systems, cooling water circuits, and flue gas desulphurisation (FGD) units operate in high-chloride environments where 304 would suffer crevice corrosion. 316 extends maintenance cycles significantly.
Pulp & Paper: Chlorine-based bleaching agents and high-temperature wash liquors attack standard stainless. Grade 316 fittings in pulp digesters and bleach plant piping outlast 304 by a factor of 3–5x in service life.
Heat Exchangers: 316 stainless fittings are used on the waterside of heat exchangers handling cooling tower water, seawater, or brackish water — environments where chloride concentration is high enough to initiate pitting on grade 304 surfaces.
Gas Processing: Natural gas dehydration units and amine treating systems use 316 stainless fittings to handle wet gas, condensate, and glycol/amine solutions that contain dissolved chlorides and H₂S.
Maintenance & Handling Tips for SS 316 Fittings
A short checklist that extends service life on already-installed 316 stainless fittings and 316 grade stainless fittings alike:
Clean with neutral or mild alkaline solutions — avoid chloride-based cleaning agents, which can defeat the corrosion resistance the grade is chosen for.
Inspect periodically for early signs of pitting or crevice corrosion, especially at gasket faces and low-flow dead legs.
Maintain correct alignment and bolt torque during installation to prevent stress concentration and fatigue cracking.
Use dedicated stainless steel tools during fabrication and installation to avoid carbon-steel cross-contamination and surface rust staining.
Flush and passivate after welding or machining to restore the passive chromium-oxide layer before the fitting goes into service.
Frequently Asked Questions About Stainless Steel 316 Fittings
The primary difference is molybdenum present at 2–3% in grade 316 and absent in 304. Molybdenum dramatically improves resistance to pitting and crevice corrosion from chloride ions, making 316 stainless steel pipe fittings the correct specification for marine, chemical processing, offshore, and coastal environments where grade 304 would corrode prematurely.
Pressure ratings depend on fitting type and class. Socket-weld and threaded fittings per ASME B16.11 are rated Class 3000 (~3,000 PSI), Class 6000 (~6,000 PSI), or Class 9000. Butt-weld fittings per ASME B16.9 are rated by wall schedule (Schedule 40, 80, 160) — see the Pressure Ratings table above for specifics. All ratings decrease with increasing temperature; derate per ASME B31.3 for your service conditions.
With minimal maintenance, grade 316 stainless steel fittings are engineered for 20–50 years or more of service life, depending on environment and media. The molybdenum content provides extended service in chloride-bearing applications such as marine, chemical, and offshore environments where grade 304 would require replacement in a fraction of that time.
Stainless steel 316 pipe fittings are used to connect, control, change the direction of, and terminate piping systems in industries including oil & gas, chemical processing, pharmaceuticals, food & beverage, marine, power generation, and water treatment — wherever corrosion resistance, hygiene, and pressure-bearing reliability are required.
SS 316 fittings are available in five end connection types: Butt Weld (ASME B16.9), Socket Weld, Threaded/Screwed (ASME B16.11), Flanged (ASME B16.5), and Compression/Instrumentation. Selection depends on pressure class, pipe schedule, and whether the joint needs to be dismantleable for maintenance.
Grade 316 stainless steel fittings maintain structural integrity at continuous operating temperatures up to 870°C (1,598°F) in oxidising atmospheres, and up to 925°C (1,697°F) in intermittent service. For aqueous service with chlorides, the critical pitting temperature (CPT) is the more relevant limit — typically above 15°C for seawater with grade 316.
316 stainless steel weld fittings are typically manufactured using processes such as seamless pipe forming, hot or cold forging, fabrication from stainless steel plates, and precision welding techniques. After forming, the fittings undergo CNC machining, heat treatment (solution annealing), and surface finishing processes like pickling and passivation to ensure high strength, dimensional accuracy, and superior corrosion resistance for industrial applications.
Both share the same 2–3% molybdenum content and corrosion resistance; the difference is carbon content — 316L caps carbon at 0.03% against 0.08% for standard 316, which prevents sensitisation at weld heat-affected zones and removes the need for post-weld annealing.
Get the latest pricing for Stainless Steel 316 Fittings! Email
vishal@solitaire-overseas.com
now for an immediate quote and our updated 2025 price guide.
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