ASTM A182 F321 Slip On Flanges — SS 321 / 1.4541 Manufacturer
Tesco Steel & Engineering forges ASTM A182 F321 slip on flanges — titanium-stabilised stainless steel 321 (UNS S32100, Werkstoff 1.4541), the classic grade for cyclic hot service — to ASME B16.5 Class 150–2500 from ½″ to 24″ NB, larger patterns to order. The titanium ties up carbon against sensitization through the 425–815 °C band that welding and hot duty impose — the aerospace-heritage stainless of exhaust systems, expansion bellows, heater circuits and hot cyclic process lines. Supplied solution annealed, with 321H, the niobium-stabilised 347 and 316Ti from the same forge. Every lot with EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM A182 F321 Slip On Flange — Specifications at a Glance
What is an ASTM A182 F321 Slip On Flange?
F321 = the thermal-cycling stainless.ASTM A182 F321 (UNS S32100) adds titanium at 5×(C+N) minimum to the 18-10 austenitic base: carbon precipitates as harmless titanium carbides, so the steel passes through the 425–815 °C sensitization band — on every weld, every heat-up, every cool-down — with its chromium intact. Born in aircraft exhausts, at home in bellows, heaters and hot cyclic lines. As a slip-on: two fillet welds (E347 filler), no preheat, no PWHT.
Also searched as: SS 321 slip on flange, 321 SORF flange, 1.4541 slip on flange, X6CrNiTi18-10 flange, SA182 F321 slip on flange, S32100 slip on flange, SUS 321 flange — all refer to the product on this page.
Rule of thumb: hot duty that cycles wants a stabilised grade; hot duty that creeps wants an H grade; hot duty that does both wants 321H/347H. Hotter than all of them, 310 takes over.
ASTM A182 F321 (UNS S32100) Chemical Composition
C
Mn
Si
P
S
Cr
Ni
Ti
N
Fe
0.08 max
2.00 max
1.00 max
0.045 max
0.030 max
17.0-19.0
9.0-12.0
5×(C+N) min – 0.70 max
0.10 max
Bal
Values in weight % for UNS S32100. The titanium formula is the grade: at five times the carbon-plus-nitrogen content, every carbon atom finds a titanium partner before it can touch the chromium. No molybdenum — chloride duty belongs to 316Ti.
ASTM A182 F321 Mechanical Properties
Tensile Strength, MPa (ksi)
Yield Strength, Min, MPa (ksi)
Elongation % min (2")
Hardness, HB max
515 (75) min
205 (30) min
30
217
Supplied solution annealed. The titanium's contribution appears at temperature: stabilised carbides resist coarsening, so 321 holds strength and corrosion resistance through hot cyclic service where plain 304 progressively sensitizes. Values demonstrated per heat on the EN 10204 certificate.
A182 F321 Slip On Flange Specifications
ASTM A182 F321 Slip On Flanges are available in the following specifications:
1/2"NB to 24"NB per ASME B16.5; larger patterns to order
Class
150#, 300#, 400#, 600#, 900#, 1500#, 2500#
Facing
Raised Face (SORF) — default; Flat Face or RTJ where the piping class specifies
Heat Treatment
Solution annealed per ASTM A182, thermal record retained
Service
Cyclic hot duty — stabilised through 425-815 °C exposure; oxidation to ~870 °C; cryogenic capable
Installation
Two fillet welds (hub + bore), pipe set back 1/8"; E347/ER347 filler, no preheat, no PWHT
Testing
Intergranular corrosion testing (e.g. ASTM A262) on request
Certification
EN 10204 3.1 (standard) / 3.2 witnessed
Equivalent Grades of ASTM A182 F321
Standard
Werkstoff Nr.
UNS
JIS
BS
EN
SS 321
1.4541
S32100
SUS 321
321S31
X6CrNiTi18-10
ASME SA182 F321 is the boiler-code twin. System partners: ASTM A312 TP321 pipe and A403 WP321 fittings — the stabilised trio of hot piping. Certificates always state the actual grade forged with the qualifying titanium ratio.
Why A182 F321 Slip Ons Are Specified
Immune to the Sensitization Band
Every weld and every thermal cycle passes through 425–815 °C — titanium claims the carbon first, and the chromium never leaves solution.
Built for Thermal Cycling
Aircraft exhausts proved it: where the metal breathes between hot and cold on every run, the stabilised grade outlives plain 304 decisively.
Holds Strength Hot
Stabilised carbides resist coarsening through sustained heat — strength retention the L grades give away with their carbon.
The Economical Stabilised Grade
No molybdenum premium — where the hot duty is clean air, gas or steam rather than corrosive media, 321 delivers stabilisation for less.
How Our A182 F321 Slip On Flanges Are Manufactured
1
Forging — cut billet of certified A182 F321 / 1.4541 heat is hot-forged into the flange blank, keeping full heat traceability from raw material to despatch.
2
Solution annealing — heated and quenched per ASTM A182 to restore the fully austenitic, corrosion-ready condition; the titanium stabilisation then does its work in service; furnace record retained.
3
Machining — hub, faces and bolt holes to ASME B16.5; the bore machined slightly over pipe OD per the slip-on tolerance.
4
Facing & finish — SORF raised face with serrated stock finish, flat face or RTJ groove; pickled and passivated on request.
5
Testing & marking — mechanical and chemical verification against the heat, the qualifying titanium ratio on every certificate (ASTM A262 intergranular testing where the order specifies), then permanent marking of grade, size, class and heat number.
6
Certification & packing — EN 10204 3.1 MTC (3.2 witnessed on request), export-packed as pictured on this page.
Where A182 F321 Slip On Flanges Are Used
Wherever hot service cycles: aircraft and gas-turbine exhaust systems, expansion joints and bellows assemblies, fired-heater and furnace circuits, hot air and combustion-gas ducting, steam and process lines with frequent start-stop duty, and radiant sections where plain 304 would progressively sensitize. Our stainless production and packing below:
Stainless Slip On Flanges — Wrapped & Bagged for ExportStainless Flanges — Face-Protected Stacks at Our Works
A182 F321 Slip On Flange Dimensions
F321 slip-on dimensions follow the ASME B16.5 slip-on tables — identical for every material. Full charts by class:
Example: “Slip On Flange, 4″ NB, ASME B16.5 Class 300, RF, ASTM A182 F321 (1.4541), EN 10204 3.1 — 25 pcs.” Quotations normally within 24 hours with price, unit weight and delivery.
ASTM A182 F321 Slip On Flanges — Frequently Asked Questions
What is an ASTM A182 F321 slip on flange?
It is a slip-on flange forged from ASTM A182 F321 — titanium-stabilised stainless steel 321 (UNS S32100, Werkstoff 1.4541) — dimensioned to ASME B16.5. The flange slides over the pipe end and is secured with two fillet welds, and the titanium ties up carbon so the steel shrugs off the 425-815 °C sensitization band that welding and hot service impose. It is the classic stainless of cyclic hot duty: exhaust systems, expansion bellows, heater circuits and hot process lines.
What does the titanium in 321 do?
It stabilises the steel. Titanium bonds with carbon far more eagerly than chromium does, so the carbon precipitates as harmless titanium carbides instead of the chromium carbides that cause sensitization in weld zones and hot service. The chromium stays in solution, the passive film stays intact — through welding, through sustained 425-815 °C exposure, and through the repeated thermal cycling that would progressively sensitize an unstabilised grade.
What is the chemical composition of ASTM A182 F321?
For UNS S32100: carbon 0.08% max, manganese 2.00% max, silicon 1.00% max, phosphorus 0.045% max, sulphur 0.030% max, chromium 17.0-19.0%, nickel 9.0-12.0%, nitrogen 0.10% max, and the defining addition: titanium at a minimum of five times the carbon-plus-nitrogen content, up to 0.70% max. It is the 18-10 austenitic base with the carbon chemically neutralised — no molybdenum; that is 316Ti's territory.
What are the mechanical properties of A182 F321 slip on flanges?
Tensile strength 515 MPa (75 ksi) minimum, yield strength 205 MPa (30 ksi) minimum, elongation 30% minimum in 2" and hardness 217 HB maximum — supplied solution annealed. The titanium's contribution appears at temperature: stabilised carbides resist coarsening, so 321 holds strength and corrosion resistance through hot cyclic service where plain 304 progressively sensitizes. Values are demonstrated per heat on the EN 10204 certificate.
What is the difference between 321 and 304/304L?
The titanium. 304 sensitizes when held at 425-815 °C; 304L avoids that by removing carbon but gives up creep strength, making it unsuitable for sustained hot duty. 321 solves both at once — the titanium neutralises the carbon without removing it, so the grade is sensitization-proof and keeps its hot strength. That is why the classic escalation for hot service reads: 304 for ambient, 304L for welded ambient, 321 the moment the service lives between 425 and 815 °C.
What is the difference between 321 and 347?
The stabilising element: titanium in 321, niobium (columbium) in 347. Both neutralise carbon the same way; the practical differences are at the margins. Niobium survives arc transfer, so 347 weld metal stays stabilised while 321 must borrow 347 filler; 347 also resists stabilisation break-down slightly better in the harshest cyclic service, which is why refinery heater circuits often name it. 321 is the more available, more economical of the pair and dominates aerospace and general hot duty. We forge both.
What is the difference between 321 and 316Ti?
Molybdenum. Both are titanium-stabilised austenitics, but 321 is built on the 304 base (18Cr-10Ni, no Mo) while 316Ti is built on the 316 base with 2-3% molybdenum — adding chloride pitting resistance that 321 lacks. 321 is the hot-air and clean-heat grade of aerospace and combustion systems; 316Ti is the chemical-plant grade where heat meets corrosive media. If the hot service also sees chlorides or acids, step across to 316Ti.
What temperature range can F321 slip on flanges handle?
Its home ground is the 425-815 °C band — hot enough to sensitize unstabilised grades, exactly where 321's titanium earns its keep — with oxidation resistance to about 870 °C in continuous service and unrestricted cryogenic capability below. For creep-governed design above 538 °C the code conditions its higher stresses on carbon, which is where the controlled-carbon 321H comes in. Across that whole span, 321 handles the thermal cycling that retires plain 304.
What is 321H — and when is it needed?
The controlled-carbon version (UNS S32109, carbon 0.04-0.10%) that combines stabilisation with the H-grade carbon minimum the code demands for full creep stresses above 538 °C. Order plain 321 for hot cyclic duty where sensitization is the enemy; order 321H where the design also leans on the code's elevated-temperature allowable stresses — refinery heater outlets are the classic case. We forge both; the certificate shows the qualifying carbon either way.
How is an A182 F321 slip on flange welded to pipe?
With two fillet welds — hub outside, bore inside, pipe set back 1/8" (3 mm) — no preheat, no PWHT. Filler practice is the classic quirk: titanium transfers poorly across an arc, so 321 is conventionally welded with niobium-stabilised E347/ER347 filler, keeping the weld metal stabilised by the element that survives the journey. The parent metal's own stabilisation is unaffected — fabricators have run this combination for as long as jet engines have existed.
Why is 321 associated with aerospace and exhaust systems?
Because it was the answer to thermal cycling. Aircraft exhaust manifolds, jet-pipe components and combustion hardware heat and cool through the sensitization band on every flight — plain 304 would progressively sensitize and crack, while 321 stays immune. The same logic carried it into expansion bellows, furnace and heater components, and hot cyclic process piping. Where the metal breathes between hot and cold, the stabilised grade is the specification.
Can 321 slip on flanges be used in chloride or seawater service?
Treat it like 304 in this respect: with no molybdenum, 321's pitting resistance is that of the 18-8 family — fine for fresh water and mild atmospheres, unsuited to serious chlorides and out of the question for seawater immersion. Stabilisation protects against sensitization, not pitting. For chloride-bearing hot duty specify 316Ti; for brines and immersion, duplex 2205 and beyond. 321's territory is heat, not salt.
What sizes and classes are A182 F321 slip on flanges available in?
From ½" to 24" NB per ASME B16.5 in Classes 150 through 2500, with larger patterns forged to order. 321 is project material rather than shelf stock, forged against the order from certified heats with the qualifying titanium ratio, with standard sizes normally dispatching within a few weeks with EN 10204 3.1 certification. State the required delivery on the enquiry and we confirm the schedule with the quotation.
What details are needed to get an accurate A182 F321 slip on flange quotation?
Five elements plus commercial terms: (1) size and standard — e.g. 4" NB ASME B16.5; (2) pressure class — 150 through 2500; (3) facing — SORF (raised face) default, flat face or RTJ where specified; (4) grade — ASTM A182 F321, or 321H where the design requires the code's creep stresses, with intergranular corrosion testing where the project specifies; (5) certification — EN 10204 3.1 or 3.2. No pipe schedule is needed for the slip-on bore. Add the quantity and destination and we return price, weight and delivery.
Who manufactures ASTM A182 F321 slip on flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, forging ASTM A182 F321 / 1.4541 slip on flanges from ½" to 24" NB per ASME B16.5 — alongside 321H, the niobium-stabilised 347, 316Ti and the full 300-series family — in solution-annealed condition with full heat traceability and EN 10204 3.1/3.2 certification on every lot. Flanges are marked with grade, size, class and heat number and export to more than 50 countries.
