ASTM A182 F316 Weld Neck Flanges — Marine-Grade SS 316 (UNS S31600)
Tesco Steel & Engineering forges ASTM A182 F316 weld neck flanges in stainless steel 316 — UNS S31600, Werkstoff Nr. 1.4401, the austenitic grade with 2–3% molybdenum — from 1/2″ NB to 56″ NB, in ASME B16.5 Class 150–2500 and European PN patterns. The molybdenum is the marine industry's insurance: it lifts chloride pitting resistance well above 304, carrying flanged joints through coastal atmospheres, brackish water and chloride-bearing process chemistry, with austenitic toughness down to cryogenic temperatures — mating A312 TP316 pipe. Dual-certifiable 316/316L, supplied pickled & passivated with IGC ASTM A262, PMI and EN 10204 3.1/3.2 on request. ISO 9001:2015, made in Mumbai, India — exported worldwide.
A182 F316 · UNS S31600 · 1.4401
2–3% Mo · Marine Grade
1/2″ – 56″ NB
Class 150 – 2500 · PN 2.5 – 400
Cryogenic to −196 °C
Dual-Certified 316/316L
ISO 9001:2015 · Exported Worldwide
ASTM A182 F316 Weld Neck Flange — Stainless Steel 316 (UNS S31600), Technical Specifications
What is an ASTM A182 F316 Weld Neck Flange?
ASTM A182 F316 is the forged-flange grade of stainless steel 316 (UNS S31600 / 1.4401) — austenitic 16Cr-12Ni chemistry carrying 2–3% molybdenum, the element that hardens the passive film against chloride pitting and crevice attack. An F316 weld neck flange pairs that chemistry with the strongest flange design: a long tapered hub butt-welded to the pipe, bore matched to schedule, joint fully radiographable — the marine and chemical industries' standard stainless flange.
The molybdenum lifts the pitting resistance number from 304's ~19 to the mid-20s — in practice, the difference between corroding and surviving once salt enters the service. Carbon splits the family the same way as 304's: 316L (0.030% max) owns welded corrosive duty, standard 316 covers the middle, and 316H takes the creep range. Modern melts usually satisfy both 316 and 316L — our stock is typically dual-certified.
Honest limits: fully immersed raw seawater eventually finds crevices, and hot chlorides above ~60 °C can crack any austenitic — that service belongs to duplex 2205 and beyond. For coastal, brackish and chemical duty, 316 remains the working answer.
Also searched as: SS 316 weld neck flange, UNS S31600 flange, 1.4401 flange, 316 WNRF flange, SA182 F316 flange, marine grade stainless steel flange — all refer to the product on this page.
Chemical Composition of ASTM A182 F316
| C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|
| 0.080 max | 2.00 max | 1.00 max | 0.045 max | 0.030 max | 16.00-18.00 | 2.00-3.00 | 11.00-14.00 | 0.10 max |
Values in weight %. The 2.00–3.00% molybdenum is the grade's working element; the extra nickel over 304 keeps the Mo-bearing melt fully austenitic. Where the heat's carbon also sits at or below 0.030%, flanges are dual-certified 316/316L.
Mechanical Properties of ASTM A182 F316
| Tensile Strength, MPa | Yield Strength, Min, MPa | Elongation % min. | Hardness Rockwell HRB | Hardness Brinell HB |
|---|
| 515 | 205 | 30 | 95 max | 217 max |
Minimums per ASTM A182. The solution-annealed condition is documented on every certificate; austenitic work-hardening gives generous margin beyond the modest yield, which the flange pressure-temperature ratings already account for.
Equivalent Grades of ASTM A182 F316
| Standard | Werkstoff Nr. | UNS | JIS | BS | AFNOR | EN |
|---|
| SS 316 | 1.4401 / 1.4436 | S31600 | SUS 316 | 316S31 / 316S33 | Z7CND17‐11‐02 | X5CrNiMo17-12-2 / X3CrNiMo17-13-3 |
System partners: A312 TP316 seamless pipe, A403 WP316 butt-weld fittings and A240 316 plate. The family continues with 316L for welded corrosive duty and 316H for the creep range.
ASTM A182 F316 Weld Neck Flange Specifications
| ASTM A182 316 Weld Neck Flanges are available in the following specifications: |
|---|
| Size | 1/2"NB to 56"NB |
| Class | 150#, 300#, 400#, 600#, 900#, 1500#, 2500# |
| Sch (Schedule) | XS, XXS, STD & Schedule 20, 40, 80, 160 |
| Pressure Ratings | PN 2.5 - PN 400 |
| Standards | ASME B16.5, ASME B16.47, EN 1092-1 Type 11, DIN 2631–2635, BS 4504 |
| Condition | Solution Annealed; dual-certifiable 316/316L |
| Other Services | Pickling & passivation on ASTM A182 316 Weld Neck Flanges
Sand Blasting on ASTM A182 316 Weld Neck Flanges
Shot Peening on ASTM A182 316 Weld Neck Flanges
IGC (ASTM A262) & PMI testing
Project-specific marking, wrapping & export packing |
Why 316 is the Marine & Chemical Standard
Molybdenum Against Chlorides
2–3% Mo lifts pitting resistance well above 304 — the practical difference between corroding and surviving in coastal air, spray and brackish water.
Acid Resistance in the Bargain
The same molybdenum improves resistance to sulphuric, acetic and other process acids — why chemical plants default to 316 wherever 304 hesitates.
Cryogenic Without Drama
No ductile-brittle transition: full toughness at −196 °C for LNG and liquid-gas systems — impact-tested at design temperature on request.
Dual-Certified 316/316L
One heat, two grades on the certificate — a dual flange satisfies purchase orders written around either specification and consolidates inventory.
Deep Stock, Fast Quotes
The second-highest-volume stainless flange we forge — common sizes on the shelf, quotations usually within 24 hours.
Welding 316 — Standard Practice, Low-Carbon Filler
316 welds with standard austenitic ease: E316L / ER316L filler, moderate heat input, no preheat, no PWHT. Industry practice uses the low-carbon filler on both 316 and 316L joints — it keeps the weld metal sensitization-safe regardless of base-metal carbon. Back-purge TIG roots on hygienic and high-purity lines, and pickle or brush weld discoloration where the service warrants.
Chloride ceiling: 316 resists chlorides — it is not immune. Fully immersed raw seawater eventually finds crevices under gaskets and deposits, and hot chloride media above ~60 °C can stress-corrosion crack any austenitic grade. For those services, step up to
duplex 2205 or
super duplex.
Where ASTM A182 F316 Weld Neck Flanges Are Used
Marine and coastal installations lead: dockside piping, shipboard systems, coastal plants living in salt air. Chemical and petrochemical plants flange chloride- and acid-bearing streams in it; pharmaceutical and food processors specify it where cleaning chemistry is aggressive; desalination pretreatment, pulp and paper and cryogenic systems complete the range. The boxed weld necks below are our own production:
F316 Weld Neck Flanges — Machined & Packed Production
ASTM A182 F316 Weld Neck Flange Dimensions
F316 weld neck flanges share their dimensions with every other material in the same class — OD, thickness, hub, bore, bolt circle and bolting per the standard tables. Full ASME B16.5 charts:
European PN dimensions are published on the EN 1092-1 Type 11, DIN 2631–2635 and BS 4504 pages.
Price List & How to Order
Stainless pricing tracks nickel and molybdenum plus the certification scope, so we quote live with a stated validity rather than publish a static list. To get a firm quotation, usually within 24 hours:
1
List your requirement — size (NB), class or PN, standard (ASME B16.5 / B16.47 / EN / DIN / BS), grade (F316, or dual-certified 316/316L), pipe schedule or bore, and quantity.
2
Add the testing scope — IGC ASTM A262, 3.2 witness, PMI, impact testing for cryogenic duty, or project specifications.
ASTM A182 F316 Weld Neck Flanges — Frequently Asked Questions
What is an ASTM A182 F316 weld neck flange?
It is a weld neck flange forged from ASTM A182 grade F316 — the molybdenum-bearing austenitic stainless steel, UNS S31600, with 16-18% chromium, 11-14% nickel and the 2-3% molybdenum that defines the grade. The long tapered hub is butt-welded to the pipe with the bore matched to the pipe schedule, giving a radiographable, fatigue-resistant joint in the stainless the marine and chemical industries treat as their standard.
What is the difference between 316 and 304 stainless steel?
Molybdenum. 316 adds 2 to 3% of it, lifting the pitting resistance number from about 19 to the mid-20s — the practical difference between corroding and surviving in coastal atmospheres, brackish cooling water and chloride-bearing process chemistry. It also buys better resistance to many acids. 304 remains the economical choice where chlorides stay low; 316 is the default once salt enters the conversation.
What is the difference between 316 and 316L flanges?
Carbon: 316 allows up to 0.08%, 316L caps it at 0.030% so welded joints cannot sensitize. The L grade gives up a little room-temperature strength (485 versus 515 MPa tensile minimum) in exchange for weld-safe metallurgy. Modern melt practice usually satisfies both — low carbon, full strength — which is why our stock is typically dual-certified 316/316L, covering purchase orders written around either grade with one flange.
Is 316 stainless steel suitable for marine service?
Yes — 316 is the classic marine-grade stainless, resisting coastal atmospheres, spray and brackish water where 304 pits. Two honest limits: fully immersed raw seawater eventually finds crevices under gaskets and deposits, and hot chloride media above roughly 60 °C can crack any austenitic grade. For those services the ladder continues to duplex 2205 and super duplex, which we also forge. For decks, coastal plants and marine hardware, 316 remains the standard answer.
What temperature range can F316 flanges be used in?
Austenitic stainless has no ductile-brittle transition, so 316 stays tough to cryogenic temperatures — LNG and colder — while at the hot end it serves to around 500-550 °C for pressure duty in the standard grade. Sustained creep-range service belongs to 316H, whose minimum-carbon chemistry the ASME code credits with time-dependent allowable stresses. One family covers the whole span; the carbon level picks the member.
What are the equivalent designations for A182 F316?
SS 316 in general usage; UNS S31600; Werkstoff Nr. 1.4401 / 1.4436 (EN X5CrNiMo17-12-2 / X3CrNiMo17-13-3); JIS SUS 316; BS 316S31 / 316S33; and AFNOR Z7CND17-11-02. Its system partners share the chemistry: A312 TP316 seamless pipe, A403 WP316 butt-weld fittings and A240 316 plate. An enquiry in any of these designations is quoted as the same material.
What is the chemical composition of ASTM A182 F316?
Per our supply practice: carbon 0.080% max, manganese 2.00% max, silicon 1.00% max, phosphorus 0.045% max, sulphur 0.030% max, chromium 16.00 to 18.00%, molybdenum 2.00 to 3.00%, nickel 11.00 to 14.00% and nitrogen 0.10% max. The molybdenum is the working element — it hardens the passive film against chloride pitting and crevice attack.
What are the mechanical properties of A182 F316 flanges?
Minimum tensile strength 515 MPa (75 ksi), minimum yield strength 205 MPa (30 ksi) and minimum elongation 30%, with hardness typically limited to 95 HRB / 217 HB. The solution-annealed condition is documented on every certificate. Like all austenitics the yield is modest — flange pressure ratings already account for it, and work-hardening gives the material generous margin beyond yield.
Which pipe grades do F316 weld neck flanges mate with?
ASTM A312 TP316 seamless and welded pipe is the standard partner, with A403 WP316 butt-weld fittings completing the system. The weld neck bore is machined to the pipe schedule you state, so the bore runs flush through the joint and the bevel arrives ready for a matched-chemistry butt weld.
How are 316 flanges welded to pipe?
With E316L / ER316L filler and standard austenitic practice: moderate heat input, no preheat, no post-weld heat treatment. The low-carbon filler keeps the weld metal sensitization-safe regardless of base-metal carbon — standard industry practice for both 316 and 316L joints. Back-purge TIG roots on hygienic and high-purity lines, and pickle weld discoloration where the service warrants.
What does dual-certified 316/316L mean?
A heat melted with carbon at or below 0.030% while still meeting standard 316's strength minimums certifies to both specifications on one mill certificate. That is normal modern practice — our stainless stock is typically dual-certified — so one flange satisfies a purchase order written around either grade, and inventories consolidate instead of splitting.
What testing and certification do you supply with F316 flanges?
Every lot ships with EN 10204 3.1 mill test certificates covering chemical analysis including molybdenum, mechanical properties and the solution-anneal record, with 3.2 certification witnessed by Lloyd's, DNV, BV or TÜV on request. We also offer intergranular corrosion testing to ASTM A262, PMI verification and hydrostatic or hardness testing to project specifications, with full heat-number traceability.
Can 316 flanges be used at cryogenic temperatures?
Yes — austenitic stainless keeps its toughness to liquid nitrogen temperatures and below, with no ductile-brittle transition. LNG terminals, cold boxes and liquid-gas systems flange in the 316 family where the process chemistry also demands molybdenum's corrosion resistance, with impact testing at design temperature available on request.
Where are ASTM A182 F316 weld neck flanges used?
Marine and coastal installations; chemical and petrochemical plants handling chlorides and acids; pharmaceutical and food processing where cleaning chemistry is aggressive; pulp and paper; water and desalination pretreatment; and cryogenic systems. Wherever 304 pits and duplex is more than the service needs, 316 is the working answer — the second-highest-volume stainless flange grade we forge.
What sizes and standards do you manufacture F316 weld neck flanges in?
From 1/2 inch NB to 56 inch NB: ASME B16.5 Class 150 to 2500 up to 24 inch, ASME B16.47 above, and European PN 2.5 to PN 400 patterns to EN 1092-1 Type 11, DIN and BS 4504. Raised face is standard, flat face and ring joint on request — the boxed weld necks photographed on this page are our own production — and every bore is machined to the mating pipe schedule from Sch 10 through XXS.
Do you keep A182 F316 weld neck flanges in stock? What is the lead time?
Yes — 316/316L dual-certified stock covers the common sizes in Class 150, 300 and 600, usually available immediately. Larger diameters, higher classes and witness-tested lots are forged to order, typically in 2 to 4 weeks. Prices track nickel and molybdenum, so quotations carry a validity period — send the size list and we confirm the stock position the same day.
What information should I include in an F316 flange enquiry?
Six things: size (NB), pressure class or PN rating, dimensional standard (ASME B16.5, B16.47 or EN/DIN/BS), grade (F316, or dual-certified 316/316L), pipe schedule or bore, and quantity. Add any testing scope — IGC ASTM A262, 3.2 witness, PMI, impact testing for cryogenic duty — and the facing if other than raised face. With these details we return a firm quotation, usually within 24 hours.
Do you export ASTM A182 F316 flanges outside India?
Yes. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer based in Mumbai, and F316 flanges ship to marine, chemical, pharmaceutical and water projects across the Middle East, Europe, Africa, Southeast Asia and the Americas. Flanges travel pickled, face-protected and seaworthy-packed, with full heat-number and test traceability.
