ASTM A182 F316H Weld Neck Flanges — High-Carbon SS 316H (UNS S31609)
Tesco Steel & Engineering forges ASTM A182 F316H weld neck flanges in stainless steel 316H — UNS S31609, Werkstoff Nr. 1.4919, the molybdenum-bearing austenitic with carbon deliberately held at 0.04–0.10% — from 1/2″ NB to 56″ NB, in ASME B16.5 Class 150–2500 and European PN patterns. The carbon floor buys the creep and stress-rupture strength ASME codes credit above ~525 °C, while the 2–3% molybdenum keeps 316's corrosion advantage — the flange for hot service where heat and aggressive chemistry meet: refinery heaters, chemical plant hot sections and power circuits, mating A312 TP316H pipe. Solution annealed for creep service, welded with E316H, with IBR, PMI and EN 10204 3.1/3.2 on request. ISO 9001:2015, made in Mumbai, India — exported worldwide.
A182 F316H · UNS S31609 · 1.4919
C 0.04–0.10% · Creep Rated
2–3% Mo · Corrosion Margin
1/2″ – 56″ NB
Class 150 – 2500 · PN 2.5 – 400
Service Above 525 °C
ISO 9001:2015 · Exported Worldwide
ASTM A182 F316H Weld Neck Flange — Stainless Steel 316H (UNS S31609), Technical Specifications
What is an ASTM A182 F316H Weld Neck Flange?
ASTM A182 F316H is the forged-flange grade of stainless steel 316H (UNS S31609 / 1.4919) — 316's 16Cr-12Ni-2Mo chemistry with one decisive change: carbon is required at 0.04–0.10%, a minimum as well as a maximum. That carbon pins grain boundaries against creep, so ASME code tables carry 316H above ~525 °C with certified time-dependent allowable stresses — while the molybdenum keeps the grade's corrosion margin. An F316H weld neck flange pairs that pedigree with a long tapered hub butt-welded to the pipe, bore matched to schedule, joint fully radiographable.
The 316 family splits by carbon exactly as 304's does: 316L (0.030% max) owns welded corrosive service, standard 316 covers the middle, and 316H claims the creep range. Against 304H, the H-grade decision is chemistry: where the hot stream is corrosive — acids, chloride-bearing condensates, aggressive process gas — 316H's molybdenum earns its premium.
H-grade practice adds a high-temperature solution anneal and coarser grain, both extending stress-rupture life; carbide precipitation in service is accepted metallurgy, with the stabilized 321H/347 family covering shutdown-corrosion risks.
Also searched as: SS 316H weld neck flange, UNS S31609 flange, 1.4919 flange, 316H WNRF flange, SA182 F316H flange, high temperature 316 flange — all refer to the product on this page.
Chemical Composition of ASTM A182 F316H
| C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|
| 0.04-0.10 | 2.00 max | 0.75 max | 0.045 max | 0.030 max | 16.00-18.00 | 2.00-3.00 | 10.00-14.00 | 0.10 max |
Values in weight %. The 0.04% carbon minimum is the H grade's defining requirement — it underwrites the creep strength — while the 2.00–3.00% molybdenum carries 316's corrosion advantage into the hot range. Every certificate demonstrates both.
Mechanical Properties of ASTM A182 F316H
| Tensile Strength, MPa | Yield Strength, Min, MPa | Elongation % min. |
|---|
| 515 | 205 | 30 |
Minimums per ASTM A182 — identical to standard 316 at room temperature. The H grade's advantage lives in the ASME time-dependent allowable stresses above ~525 °C, where 316H's certified creep and stress-rupture values carry the design. The mandatory solution-annealed condition is documented on every certificate.
Equivalent Grades of ASTM A182 F316H
| Standard | Werkstoff Nr. | UNS |
|---|
| SS 316H | 1.4919 | S31609 |
Also written EN X6CrNiMo17-13. System partners: A312 TP316H seamless pipe, A403 WP316H butt-weld fittings and A240 316H plate. The creep-range stainless family continues with 304H, 321H and 310/310S.
ASTM A182 F316H Weld Neck Flange Specifications
| ASTM A182 316H 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 (high-temperature practice for creep service) |
| Other Services | Pickling & passivation on ASTM A182 316H Weld Neck Flanges
Sand Blasting on ASTM A182 316H Weld Neck Flanges
Shot Peening on ASTM A182 316H Weld Neck Flanges
PMI, grain size reporting & IBR Form III-C certification
Project-specific marking, wrapping & export packing |
Why 316H When Heat Meets Chemistry
Code-Listed Creep Strength
Above ~525 °C, ASME allowable stresses become time-dependent — and only the H grade carries certified values there. The 0.04% carbon floor is what the code is crediting.
Molybdenum in the Hot Range
2–3% Mo resists the acids and chloride-bearing condensates that attack 304H in chemical plant hot sections — corrosion margin where clean-service grades corrode.
One Chemistry, Pipe to Flange
A312 TP316H pipe, A403 WP316H fittings, A182 F316H flanges — a matched creep-rated system with E316H weld metal holding the pedigree through the joints.
Boiler Paperwork Ready
IBR Form III-C for Indian boiler scope, 3.2 witness inspection, PMI and grain size reporting — the documentation high-temperature projects specify, delivered with the flange.
The Full Stainless Creep Family
304H, 316H, 321H, 347 and 310 from one forge — whichever member the process chemistry picks, the paperwork and bevels arrive matched.
Welding 316H — Keep the Carbon in the Joint
316H welds with standard austenitic ease — no preheat, no PWHT in normal practice, moderate heat input. The discipline is in the consumable: use E316H / ER316H, whose controlled carbon keeps the weld metal as creep-resistant as the base material. Substituting ordinary 316L filler quietly deletes the creep strength the H grade was specified for — a paperwork-invisible downgrade that surfaces years later, at temperature.
Sensitization note: carbide precipitation during creep-range service is accepted H-grade metallurgy — but where shutdown chemistry (classically polythionic acid in refinery units) threatens intergranular attack, specify the stabilized grades
321H or
347 instead.
Where ASTM A182 F316H Weld Neck Flanges Are Used
Refining and chemicals lead: fired heaters and transfer lines, hot sections where the process stream is corrosive, ethylene and ammonia units. Power plants follow with boiler circuits and steam auxiliaries; waste heat recovery and high-temperature exchangers complete the range — any flanged joint above 525 °C where clean-service 304H would be attacked by the chemistry. The heavy weld neck below is our own production:
Heavy F316H Weld Neck Flange — Machined in Our Workshop
ASTM A182 F316H Weld Neck Flange Dimensions
F316H 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 (F316H), pipe schedule or bore, and quantity.
2
Add the certification scope — IBR Form III-C, 3.2 witness, PMI, grain size reporting or project specifications.
ASTM A182 F316H Weld Neck Flanges — Frequently Asked Questions
What is an ASTM A182 F316H weld neck flange?
It is a weld neck flange forged from ASTM A182 grade F316H — the high-carbon variant of molybdenum-bearing stainless steel 316, UNS S31609, with carbon deliberately held at 0.04 to 0.10%. 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 austenitic grade that combines code-listed creep strength above about 525 °C with molybdenum's resistance to corrosive chemistry.
What is the difference between 316, 316L and 316H?
Carbon — and the jobs it enables. 316L caps carbon at 0.030% to keep welds sensitization-safe in corrosive aqueous service; standard 316 allows up to 0.08%; 316H requires a minimum of 0.04% because at high temperature carbon is a strength element, pinning grain boundaries against creep. The H grade is the only member the ASME code tables carry into the creep range with full time-dependent allowable stresses — the L grade's insurance and the H grade's strength solve opposite problems.
When should I choose 316H over 304H?
When the hot service also carries corrosive chemistry. Both are creep-rated austenitics, but 316H brings 2-3% molybdenum — better resistance to acids and chloride-bearing condensates that appear in chemical plant hot sections, and slightly higher creep strength in most of the range. For clean steam, hot air and combustion gas, 304H does the job at lower cost; when the process stream would attack 304 at any temperature, 316H is the H grade to specify.
Why does 316H require a minimum carbon content?
Because above roughly 525 °C the design question changes from short-term strength to creep — slow, continuous deformation under sustained load. Carbon in solution and as fine carbides resists that mechanism, so the H specification writes a floor of 0.04% into the chemistry, paired with a high-temperature solution anneal and coarser grain practice that further improve stress-rupture life. A lean-carbon 316L simply cannot certify allowable stresses at 600 °C.
What temperature range are F316H flanges used in?
The grade earns its keep from about 525 °C — where ASME allowable stresses become time-dependent and standard or L-grade 316 drops out — up to roughly 815 °C for pressure duty. Below the creep range, 316 or 316L is the economical choice; above it, 316H holds code-listed allowable stresses with molybdenum's corrosion margin that plain 304H cannot offer.
What are the equivalent designations for A182 F316H?
SS 316H in general usage; UNS S31609; and Werkstoff Nr. 1.4919 (X6CrNiMo17-13) in the European system. Its system partners share the chemistry: A312 TP316H seamless pipe, A403 WP316H butt-weld fittings and A240 316H plate. An enquiry in any of these designations is quoted as the same material.
What is the chemical composition of ASTM A182 F316H?
Per our supply practice: carbon 0.04 to 0.10% — the defining requirement, with a minimum as well as a maximum — manganese 2.00% max, silicon 0.75% max, phosphorus 0.045% max, sulphur 0.030% max, chromium 16.00 to 18.00%, molybdenum 2.00 to 3.00%, nickel 10.00 to 14.00% and nitrogen 0.10% max. The carbon floor underwrites the creep strength; the molybdenum keeps the corrosion advantage.
What are the mechanical properties of A182 F316H flanges?
Minimum tensile strength 515 MPa (75 ksi), minimum yield strength 205 MPa (30 ksi) and minimum elongation 30% — the same room-temperature minimums as standard 316. The difference appears where it matters: in the ASME time-dependent allowable stresses above 525 °C, where 316H's certified creep and stress-rupture values carry the design and plain 316 has none listed.
Which pipe grades do F316H weld neck flanges mate with?
ASTM A312 TP316H seamless and welded pipe is the standard partner, with A403 WP316H 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 — one creep-rated chemistry from pipe to flange.
How are 316H flanges welded to pipe?
With E316H / ER316H filler — the H-grade consumable whose controlled carbon keeps the weld metal as creep-resistant as the base material. Standard austenitic practice applies: moderate heat input, no preheat, no PWHT in normal service. Substituting ordinary 316L filler on a 316H joint quietly deletes the creep strength the H grade was specified for, so consumable control matters on these systems.
Does 316H suffer from sensitization? Should I worry about corrosion?
In the creep range, chromium carbides do precipitate at grain boundaries — accepted metallurgy for H-grade service, where the environment is hot process gas or steam. The caveat applies at shutdowns: sensitized material can suffer intergranular attack or polythionic acid stress corrosion in refinery service. Where that risk drives the design, the stabilized grades 321H and 347 are the engineered answer — we forge those too.
Are F316H flanges suitable for IBR (boiler) applications?
Yes — high-temperature boiler and steam-line duty is H-grade territory, and we supply flanges with IBR Form III-C certification for Indian boiler regulation scope on request. State the IBR requirement in the enquiry so the heat, testing and documentation are aligned from the start.
What testing and certification do you supply with F316H flanges?
Every lot ships with EN 10204 3.1 mill test certificates covering chemical analysis — demonstrating the 0.04% carbon minimum and the molybdenum content — mechanical properties and the solution-anneal record, with 3.2 certification witnessed by Lloyd's, DNV, BV or TÜV on request. We also offer PMI verification, grain size reporting, IBR Form III-C and hydrostatic or hardness testing to project specifications, with full heat-number traceability.
Where are ASTM A182 F316H weld neck flanges used?
Refinery fired heaters and transfer lines, chemical and petrochemical plant hot sections where the process stream is corrosive, power plant boiler circuits and steam auxiliaries, ethylene and ammonia units, waste heat recovery and high-temperature heat exchangers — any flanged joint above 525 °C where clean-service 304H would be attacked by the chemistry.
What sizes and standards do you manufacture F316H 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, ring joint for high-class service on request — the heavy weld neck photographed on this page is our own production — and every bore is machined to the mating pipe schedule from Sch 10 through XXS.
Do you keep A182 F316H weld neck flanges in stock? What is the lead time?
Common refinery and power sizes in Class 150, 300 and 600 rotate through regular production, with popular items often available from stock. Larger diameters, higher classes and IBR or witness-tested lots are forged to order, typically in 3 to 5 weeks. Prices track nickel and molybdenum plus the testing scope, 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 F316H flange enquiry?
Six things: size (NB), pressure class or PN rating, dimensional standard (ASME B16.5, B16.47 or EN/DIN/BS), grade (F316H — or dual-certified 316/316H where the carbon window allows), pipe schedule or bore, and quantity. Add the certification scope — IBR Form III-C, 3.2 witness, PMI, grain size — since high-temperature paperwork is usually specification-driven. With these details we return a firm quotation, usually within 24 hours.
Do you export ASTM A182 F316H flanges outside India?
Yes. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer based in Mumbai, and F316H flanges ship to refinery, chemical and power 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.
