ASTM A182 F304L Slip On Flanges — Low Carbon SS 304L Manufacturer
Tesco Steel & Engineering forges ASTM A182 F304L slip on flanges — the low-carbon (0.030% max) version of stainless steel 304 that welds without sensitization — to ASME B16.5 Class 150–2500 from ½″ to 24″ NB, larger patterns to order. A slip-on is a welded flange by definition, and the L grade is its natural stainless partner: the default of welded process piping, hygienic systems and cryogenic service down to LNG temperatures. Supplied solution annealed, commonly dual-certified 304/304L, with 304, 304H and 316L from the same forge. Ready stock in common sizes; every lot with EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM A182 F304L · SA182 · S30403C ≤ 0.030% · 1.4306/1.4307 · SUS 304LASME B16.5 Class 150–2500½″ – 24″ NB · SORFWelds Without SensitizationCryogenic / LNG Duty · Ready StockEN 10204 3.1 / 3.2 · ISO 9001:2015
ASTM A182 F304L Stainless Steel Slip On Flange — Raised Face (SORF)
What is an ASTM A182 F304L Slip On Flange?
F304L = 304 built for welding.ASTM A182 F304L (UNS S30403) caps carbon at 0.030%, starving the sensitization reaction that can strip chromium from weld heat-affected zones in standard-carbon stainless. Since a slip-on is secured by two fillet welds, the L grade is its natural specification: weld with E308L and walk away — no post-weld anneal, corrosion resistance intact. Cryogenic to ~425 °C; the reference grade of LNG and welded hygienic piping.
Also searched as: SS 304L slip on flange, 304L SORF flange, low carbon stainless slip on flange, SA182 F304L slip on flange, SUS 304L flange, 1.4306 / 1.4307 slip on flange, S30403 slip on flange — all refer to the product on this page.
Rule of thumb: within the 304 family the selector is carbon — L for welded corrosive duty, standard for general service, H for creep-range heat. Across families the selector is chloride exposure, stepping up through 316L and duplex.
ASTM A182 F304L (UNS S30403) Chemical Composition
C
Mn
Si
P
S
Cr
Ni
Fe
0.030 max
2.00 max
1.00 max
0.045 max
0.030 max
18.0-21.0
8.0-13.0
Bal
Values in weight % per ASTM A182 for UNS S30403. The 0.030% carbon cap is the grade — it starves the sensitization reaction. The slightly wider chromium and nickel ranges than standard F304 keep the structure fully austenitic with the carbon removed.
ASTM A182 F304L Mechanical Properties
Tensile Strength, MPa (ksi)
Yield Strength, Min, MPa (ksi)
Elongation % min (2")
Reduction of Area % min
485 (70) min
170 (25) min
30
50
Slightly below standard 304's 515/205 MPa — carbon is a strengthener, and removing it costs a little. In Class 150/300 general service the difference is rarely felt, and dual-certified 304/304L heats meet the higher 304 minimums anyway. Values demonstrated per heat on the EN 10204 certificate.
A182 F304L Slip On Flange Specifications
ASTM A182 F304L Slip On Flanges are available in the following specifications:
1/2"NB to 24"NB per ASME B16.5; larger patterns and EN 1092-1 stainless flanges 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
Temperature Range
Cryogenic (no impact transition — LNG duty) to ~425 °C working practice; hotter: F304 / F304H
Installation
Two fillet welds (hub + bore), pipe set back 1/8"; E308L/ER308L consumables, no preheat, no PWHT
Ready Stock
Class 150 & 300 common sizes (dual 304/304L) — typically quick dispatch
Certification
EN 10204 3.1 (standard) / 3.2 witnessed; intergranular corrosion testing on request
Equivalent Grades of ASTM A182 F304L
Standard
Werkstoff Nr.
UNS
JIS
BS
EN
SS 304L
1.4306 / 1.4307
S30403
SUS 304L
304S11
X2CrNi19-11 / X2CrNi18-9
ASME SA182 F304L is the boiler-code twin. System partners: ASTM A312 TP304L pipe and A403 WP304L fittings — the welded-stainless trio. Certificates always state the actual grade forged, including dual 304/304L where the heat qualifies.
Why A182 F304L Slip Ons Are Specified
Weld It and Walk Away
No sensitization means no post-weld solution anneal and no intergranular corrosion risk along the fillet welds — the whole reason the L grade exists.
The Natural Grade for a Welded Flange
A slip-on carries two fillet welds by definition — pairing it with sensitization-proof stainless is simply correct specification practice.
The Cryogenic Reference
LNG, liquid nitrogen, liquid oxygen — 304L is the grade cryogenic engineering is written around, tough at −196 °C with no impact-test complications.
Hygienic Systems Standard
Orbital-welded food, dairy and pharma networks run on L-grade stainless — smooth, clean welds that CIP chemistry cannot undermine.
Know the Handoffs
Chlorides in the service: 316L, then duplex. Sustained heat above ~425 °C: 304 / 304H. Critical RT-mandated lines: F304L weld necks.
How Our A182 F304L Slip On Flanges Are Manufactured
1
Forging — cut billet of certified A182 F304L 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 dissolve carbides and restore the fully austenitic, corrosion-ready condition; 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 ≤0.030% carbon on every certificate (intergranular corrosion 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 F304L Slip On Flanges Are Used
Wherever stainless gets welded: process piping across chemical, fertiliser and refining utility services, orbital-welded food, dairy, brewery and pharmaceutical systems, cryogenic plants (LNG, air separation, liquid nitrogen and oxygen), water treatment and demineralised water, and effluent lines. Our 304L production and packing below:
A182 304L Flange O-let — 3″ Class 150304L Flangeolet — Laser-Marked, 3″ Class 150A182 F304L Flanges — Export Crated at Our Works
A182 F304L Slip On Flange Dimensions
F304L 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 150, RF, ASTM A182 F304L (dual 304/304L), EN 10204 3.1 — 50 pcs.” Ready-stock sizes quote with immediate delivery; the rest normally within 24 hours.
ASTM A182 F304L Slip On Flanges — Frequently Asked Questions
What is an ASTM A182 F304L slip on flange?
It is a slip-on flange forged from ASTM A182 F304L — the low-carbon version of stainless steel 304 (UNS S30403), capped at 0.030% carbon so it welds without sensitization — dimensioned to ASME B16.5. The flange slides over the pipe end and is secured with two fillet welds, and because a slip-on is by definition a welded flange, the L grade is its natural stainless partner: the default of welded stainless process piping and cryogenic systems.
What does the L in 304L mean — and what is sensitization?
L is low carbon: 0.030% max against standard 304's 0.08%. The reason is sensitization — when standard-carbon stainless is held at roughly 425-815 °C, as every weld heat-affected zone briefly is, carbon reacts with chromium to precipitate chromium carbides at the grain boundaries. The zones beside those carbides are locally stripped of chromium and lose their passive film, inviting intergranular corrosion along the weld. Starve the reaction of carbon and it cannot happen — that is the entire, elegant point of 304L.
What is the chemical composition of ASTM A182 F304L?
Per ASTM A182 for UNS S30403: carbon 0.030% max, manganese 2.00% max, silicon 1.00% max, phosphorus 0.045% max, sulphur 0.030% max, chromium 18.0-21.0% and nickel 8.0-13.0%. Note the slightly wider chromium and nickel ranges than standard F304 — the extra nickel allowance keeps the structure fully austenitic with the carbon removed. Otherwise it is the same 18-8 recipe.
What are the mechanical properties of A182 F304L slip on flanges?
Per ASTM A182: tensile strength 485 MPa (70 ksi) minimum, yield strength 170 MPa (25 ksi) minimum, elongation 30% minimum in 2" and reduction of area 50% minimum. The slightly lower strength than standard 304 (515/205 MPa) is the price of removing carbon — a solid-solution strengthener. For flanges in Class 150/300 general service the difference is rarely felt; ASME B16.5 rates the L grade accordingly. Values are demonstrated per heat on the EN 10204 certificate.
What is the difference between 304L and 304?
Only the carbon: 0.030% max against 0.08% max. That makes 304L immune to weld sensitization at the cost of slightly lower strength minimums. In modern practice the distinction has largely dissolved — most heats are melted low-carbon yet still meet 304's strength floor, and are dual-certified 304/304L, satisfying both specifications on one certificate. Where a specification names 304L explicitly, the certificate shows the qualifying carbon; either way the material welds clean.
What is the difference between 304L and 316L?
Molybdenum — the same split as their standard-carbon parents. 316L adds 2-3% molybdenum for markedly better resistance to chloride pitting and crevice corrosion, so it takes the coastal, marine-adjacent and chloride-bearing duties while 304L covers everything milder. Both share the low-carbon weldability. The choice is service chemistry, not weldability: fresh water, food and general chemical lines run 304L; anything with salt steps up to 316L.
What temperature range can F304L slip on flanges handle?
Downward, effectively unlimited — 304L is the reference grade of cryogenic engineering, serving LNG, liquid nitrogen and liquid oxygen at -196 °C and below with no brittle transition and no impact-test complications. Upward, working practice caps the L grade around 425 °C, because its lower carbon also means lower creep strength — sustained hot duty belongs to standard 304 or, above 538 °C, to 304H. Between those bounds, 304L simply works.
Why is 304L the standard grade for welded stainless piping?
Because it removes the one metallurgical risk welding poses to austenitic stainless. Standard-carbon 304 can sensitize in the weld heat-affected zone and later suffer intergranular corrosion; the historical fixes — post-weld solution annealing or stabilised grades — cost money and time. 304L needs neither: weld it with E308L and walk away, corrosion resistance intact. A slip-on flange carries two fillet welds by definition, which is why the L grade is its natural specification.
Is dual-certified 304/304L the same as 304L?
For every 304L purpose, yes. Dual-certified material has carbon at or below 0.030% — meeting 304L's chemistry — while also meeting standard 304's higher strength minimums, so one heat satisfies both specifications and the certificate lists both designations. It is today's default mill supply. A specification that calls for 304L is fully answered by dual-certified stock; one that demands 304's strength values is answered by the same material.
What is the equivalent of ASTM A182 F304L in other standards?
ASME SA182 F304L is the boiler-code twin; UNS S30403 the designation; the European equivalents are X2CrNi19-11 (Werkstoff 1.4306) and the closely related X2CrNi18-9 (1.4307); JIS SUS 304L the Japanese. System partners specified alongside it: ASTM A312 TP304L pipe and A403 WP304L fittings — the welded-stainless trio. Certificates always state the actual grade forged, including dual 304/304L where the heat qualifies.
When is 304L not enough — and what replaces it?
The same chloride limits as all 18-8 stainless: warm chloride water pits it, and above roughly 60 °C chlorides can drive stress-corrosion cracking. The escalation runs 316L for modest chlorides, duplex 2205 for serious brine and coastal duty, super duplex or 6-moly for hot seawater, and nickel alloys for reducing acids. And for sustained service above about 425 °C, the low carbon works against you — standard 304 or 304H takes over. Within its envelope, 304L is the economical welded-service default.
Is 304L used in food and pharmaceutical piping?
Extensively — welded hygienic systems are practically built on it. Food, dairy, brewery and pharmaceutical lines are orbital-welded networks of stainless tube, and 304L welds stay smooth, corrosion-resistant and free of the sensitized zones that could harbour attack — with 316L taking over where products or CIP chemistry run chloride-heavy. Solution-annealed, pickled 304L flanges fit straight into that world.
What sizes and classes are A182 F304L slip on flanges available in?
From ½" to 24" NB per ASME B16.5 in Classes 150 through 2500, with larger patterns and DIN/EN 1092-1 stainless flanges forged to order. Because dual-certified 304/304L is the default stainless supply, common Class 150/300 sizes rotate through ready stock, typically available for quick dispatch — larger sizes and higher classes are forged against the order. Every quotation states the stock position alongside price and weight.
What details are needed to get an accurate A182 F304L 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 — F304L or dual-certified 304/304L, with pickling/passivation or 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 — often from ready stock.
Who manufactures ASTM A182 F304L slip on flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, forging ASTM A182 F304L stainless steel slip on flanges from ½" to 24" NB per ASME B16.5 — alongside standard 304, 304H and the full 300-series family — in solution-annealed condition with ready stock in common sizes, 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.
