Tesco Steel & Engineering manufactures ASTM A182 F53 socketweld flanges — super duplex 2507, UNS S32750, W.Nr. 1.4410 — to ASME B16.5 from ½″ to 3″ NB in Classes 150–1500. Super duplex is the 40-PREN grade: chromium to 25%, molybdenum toward 5%, and a nitrogen floor three times 2205's — the threshold offshore practice demands before an alloy touches seawater. It also carries the strongest stainless certificate on this site: 550 MPa yield, 800 MPa tensile — which is why offshore hydraulic, chemical injection and seawater utility small bore is exactly F53 socket weld territory, and why the TESCO-marked S32750 flanges pictured below are our production for such systems. Welding: super duplex heat-input discipline, no preheat, no PWHT ever — explained honestly, along with where the class says butt-weld instead. Sibling F55 (S32760) forged to order. Facings: SWRF, SWFF, SWRTJ. Every lot with EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM A182 F53 Socketweld Flanges — Specifications at a Glance
What is an ASTM A182 F53 Socketweld Flange?
The seawater grade in the small-bore pattern. A forged super duplex 2507 flange (ASTM A182 F53 / UNS S32750) with a machined socket: pipe seated square by geometry, one external fillet weld under super duplex discipline, through-bore matched to the pipe schedule. PREN ≥40 — the offshore ticket for seawater — from Cr 24–26%, Mo to 5% and an N floor of 0.24%. Tensile ≥800 MPa, yield ≥550 MPa — the strongest stainless certificate on this site — solution annealed. The classic alloy of offshore hydraulic, injection and seawater utility small bore. Sized by ASME B16.5 at ½″–3″ NB, Classes 150–1500; EN 10204 3.1 on every lot.
Also searched as: super duplex socket weld flange, 2507 SW flange, S32750 SWRF flange, 1.4410 socket weld flange, SAF 2507 flange — all the same product family. Related pages: the facings — SWRF / SWFF / SWRTJ — the socketweld hub, the other F53 types — blind, weld neck, slip-on, F53 grade hub — the family neighbours F51 socketweld / F55 and the duplex hub.
Offshore practice draws the seawater line at PREN 40 — many piping classes are written around exactly that number, and F53 clears it with all three levers at once.
What Clearing the Bar Buys
Seawater Without Apology
Pitting and crevice thresholds far above 2205's — hot seawater, splash zones and the harshest brines are the design duty, not the exception.
The Strongest Stainless Certificate Here
550 MPa yield / 800 MPa tensile — Class 900–1500 hydraulic and injection small bore in compact joints, which is exactly where platforms use it.
Nitrogen Tripled, On Purpose
N 0.24–0.32% — the austenite balancer and 16× PREN multiplier, floored three times higher than 2205. The little element that makes super duplex super.
Same Duplex Rulebook, Narrower Window
No preheat, PWHT prohibited, heat input controlled — and at 25% Cr the sigma clock runs faster, so the interpass discipline tightens. Details below.
ASTM A182 F53 Chemical Composition (UNS S32750)
Element
C
Mn
Si
Cr
Ni
Mo
N
Cu
P
S
Weight %
≤0.030
≤1.20
≤0.80
24.0–26.0
6.0–8.0
3.0–5.0
0.24–0.32
≤0.50
≤0.035
≤0.020
Against 2205: Cr up three points, Mo's ceiling at 5%, N floor tripled — and Mn/Si held tighter because intermetallics form more readily at this alloy level. Cu is a residual cap here, not an addition — the deliberately Cu-and-W-alloyed sibling is F55. PMI reads the Cr-Ni-Mo-N signature on every piece.
Mechanical Properties (Solution Annealed)
Property
ASTM A182 F53 Requirement
Tensile Strength
≥ 800 MPa (116 ksi)
Yield Strength (0.2%)
≥ 550 MPa (80 ksi) — the strongest stainless certificate on this site
Elongation
≥ 15% — the usual price of strength; stated plainly
Condition
Solution annealed — the phase balance is set at the mill and must never be re-heat-treated on site
Service Band
~−50 °C to ~250–300 °C — the duplex walls arrive slightly earlier at 25% Cr
ASTM A182 F53 Socketweld Flanges are available in the following specifications:
Material Grade
ASTM A182 F53 (UNS S32750), W.Nr. 1.4410 — super duplex 2507; sibling F55 (S32760) forged to order where the specification names it
Heat Treatment
Solution annealed — furnace records certified; no site heat treatment is ever permitted on super duplex
Size
1/2"NB to 3"NB per ASME B16.5; 4″ and larger to order; EN 1092-1 patterns supplied — the marked units pictured are DN25 PN16
Class
150#, 300#, 600#, 900#, 1500# (900# shares 1500# dimensions in most sizes); 2500# on request — duty concentrates in 600–1500
Facings
Raised Face (SWRF), Flat Face (SWFF), Ring Type Joint (SWRTJ) with groove per B16.20
Bore
Socket bore to pipe OD; through-bore matched to pipe schedule (Sch 80/160 dominate offshore small bore)
Welding
Single external fillet with 1/16″ expansion gap; super duplex discipline — controlled heat input, interpass ~100–150 °C, 2594-type filler, no preheat, no PWHT
Service Span
Seawater systems, hydraulic and injection small bore, mildly sour wellhead-adjacent duty per ISO 15156-3 limits; ~−50 to 250–300 °C
Testing
Tension & chemistry per heat; PMI (Cr-Ni-Mo-N) on every piece; socket depth and bore gauged
Certification
EN 10204 3.1 with solution-anneal records (standard) / 3.2 witnessed; NACE MR0175 declaration where specified
Specification Notes — Getting Super Duplex Sockets Right
Four honest notes.The sigma clock runs faster at 25% Cr: heat input and interpass discipline are tighter than 2205's — a super duplex weld that lingered hot has quietly spent the corrosion resistance the grade was bought for. Never heat treat on site: PWHT is prohibited — only a full mill solution anneal resets the structure. Hot seawater under gaskets still deserves respect: super duplex's crevice threshold is high, not infinite — critical hot-seawater lines are commonly butt-welded by class rule, and the F53 weld neck is the matching flange. And name the sibling precisely: S32750 (this page) and S32760 (F55) are close kin, but an auditor reads UNS numbers literally — a specification naming either gets exactly that grade on our certificate.
How Our A182 F53 Socketweld Flanges Are Manufactured
1
Forging — cut billet of the spectro-verified F53 heat — Cr, Ni, Mo windows and the 0.24% nitrogen floor confirmed — is hot-forged in the grade's narrow working window with full heat traceability.
2
Solution annealing — the anneal-and-quench that sets the 50/50 phase balance and dissolves any intermetallics; furnace charts retained against the heat number.
3
Machining — faces, OD and drilling to ASME B16.5 (or EN 1092-1 to order); socket counterbore and depth gauged piece by piece, through-bore matched to the ordered schedule; RF serrations, flat face or RTJ groove per B16.20.
4
Testing — tension and full chemistry per heat; PMI reads the Cr-Ni-Mo-N signature on every piece — 2507, 2205 and austenitic can never mix on our shelves.
5
Finishing & marking — pickled or natural machined finish; laser-marked with grade, size, class, schedule and heat number — exactly as the S32750 units photographed on this page.
6
Certification & packing — EN 10204 3.1 MTC with solution-anneal records (3.2 witnessed on request); NACE declaration where specified; packed sea-worthy with no carbon-steel contact.
Where ASTM A182 F53 Socketweld Flanges Are Used
The classic super duplex small bore: offshore hydraulic systems on platforms, FPSOs and subsea control skids; chemical injection into seawater-wetted and produced-fluid systems; seawater lift, cooling and firewater auxiliaries; desalination high-pressure sections; wellhead-adjacent instrument connections in mildly sour duty. Production below — including our marked S32750 units:
TESCO-Marked S32750 Flanges — Our ProductionSocket Weld Flanges — Machined BatchThe Socket Weld Joint — Note the Expansion Gap (X)
A182 F53 Socketweld Flange Dimensions
Socket weld flange dimensions are class-governed per ASME B16.5 — identical across material grades (pressure-temperature ratings follow the super duplex material group). Full charts:
An ASTM A182 F53 socketweld flange is a forged super duplex 2507 stainless steel flange — UNS S32750, W.Nr. 1.4410 — whose back carries a machined socket: the pipe end seats inside, self-aligned square to the face, and is secured with a single external fillet weld made under super duplex welding discipline. 2507 is the 40-PREN grade of seawater engineering: 25% chromium, up to 5% molybdenum and a nitrogen floor three times 2205's deliver 550 MPa yield — the strongest stainless certificate on this site — with pitting and crevice thresholds that carry hot seawater and the harshest brines. Dimensioned to ASME B16.5 for ½" to 3" NB in Classes 150 to 1500, in raised face, flat face and ring joint facings.
What does 'super duplex' mean — and why does PREN 40 matter?
Super duplex is the duplex concept pushed past the seawater threshold. The pitting resistance number — PREN = %Cr + 3.3×%Mo + 16×%N — predicts chloride pitting resistance, and offshore practice long ago settled on 40 as the ticket for seawater systems: below it, crevice attack under deposits and gaskets is a matter of time; at or above it, super duplex serves hot seawater for decades. F53 clears the bar through all three levers at once — chromium to 25%, molybdenum toward 5%, nitrogen floored at 0.24% — while keeping the half-ferrite, half-austenite balance that gives duplex its strength and SCC immunity. Many offshore piping classes are written around exactly this threshold: 2205 for process chloride duty, 40-PREN super duplex for anything touching the sea.
What is the chemical composition of ASTM A182 F53 (UNS S32750)?
Carbon ≤0.030%, manganese ≤1.20%, silicon ≤0.80%, chromium 24.0-26.0%, nickel 6.0-8.0%, molybdenum 3.0-5.0%, nitrogen 0.24-0.32%, copper ≤0.50%, phosphorus ≤0.035%, sulphur ≤0.020%. Against 2205 the escalation reads clearly: chromium up three points, molybdenum's ceiling up to 5%, and the nitrogen floor tripled — nitrogen being both the austenite balancer and the PREN multiplier at 16×. Manganese and silicon are held tighter than 2205's because intermetallic phases form more readily at this alloy level. Note copper is a residual cap here, not an addition — the deliberately copper-and-tungsten-alloyed sibling is F55 (S32760). Chemistry is verified per heat and travels on the EN 10204 3.1 MTC.
What are the mechanical properties of A182 F53 socketweld flanges?
In the solution-annealed condition A182 requires tensile strength 800 MPa (116 ksi) minimum, yield strength 550 MPa (80 ksi) minimum and elongation 15% minimum — the strongest stainless certificate on this site, above duplex 2205's 450 MPa and far above any austenitic grade. On small bore that strength means Class 900-1500 hydraulic and injection duty in compact joints, which is precisely where offshore platforms use it. The honest counterpart is the 15% elongation floor — lower than 2205's 25%, the usual price of strength. Where a design needs more still, the strength ladder on this site continues into the nickel and titanium worlds; for chloride duty, F53 is already at the practical summit of stainless.
F53 or F51 — where is the dividing line?
The sea. F51 (2205, PREN ≥34) carries brackish water, produced water, firewater and most process chloride duty economically — but its crevice threshold falls short of hot open seawater, and offshore classes respect that line. F53 clears the 40-PREN bar and takes the seawater systems proper: lift and injection lines, seawater cooling and utility circuits, hydraulic systems exposed to splash and spray. The strength gap (550 versus 450 MPa yield) adds a second reason on high-pressure small bore. The practical rule written into many piping classes: if the fluid is or ever becomes seawater, super duplex; otherwise 2205 earns its keep. Both ship as socket welds from our works, and our F51 page carries the other half of this story.
F53 or F55 — what is the difference between the super duplex twins?
Two routes to the same 40-PREN destination. F53 (S32750, 2507) is the 'lean-alloyed' route: chromium, molybdenum and nitrogen alone. F55 (S32760, the Zeron 100 type) adds deliberate copper and tungsten — 0.5-1.0% of each — claiming extra margin in acidic and erosive seawater conditions, and it carries its own dedicated following in UK-influenced offshore specifications. In practice their performance envelopes overlap almost completely, both are solution-annealed, both weld under the same discipline, and the choice is nearly always made by the project specification rather than by metallurgy: North Sea heritage documents tend to name S32760, others 2507. We forge both — a specification naming either gets exactly that grade and UNS number on the certificate.
How is an F53 socketweld flange welded — the super duplex rules?
Like duplex, but with a narrower window. The joint geometry is standard — pipe bottomed, withdrawn 1/16" (1.6 mm), single external fillet — and the discipline is phase balance: controlled heat input, interpass temperature typically capped around 100-150°C (tighter than 2205's), and over-alloyed 2594-type filler. At 25% chromium and 4% molybdenum, intermetallic sigma phase forms faster than in 2205 if the metal lingers hot, and the penalty is paid in corrosion resistance exactly where the grade was bought for it. The two absolute rules carry over: no preheat beyond dryness, and no PWHT ever — only a full mill solution anneal resets super duplex. Our flanges arrive solution annealed with records; the joint's phase balance is the fabricator's craft.
Does the socket crevice matter in super duplex seawater service?
Less than in 2205 — and still worth honest words. Super duplex's crevice temperature threshold sits far above 2205's, which is why 40-PREN grades are trusted with seawater at all; ambient-temperature seawater utility and hydraulic sockets are routine offshore practice. The care point is the hot end: heated seawater, stagnant deposits and gasket crevices push toward the grade's crevice threshold, and critical hot-seawater lines are commonly butt-welded as a class rule regardless of alloy. The practical division: sockets for hydraulic, injection, instrument and ambient utility duty — the overwhelming volume of super duplex small bore — and butt welds where the class demands them; our F53 weld neck page carries the matching flange.
What are the temperature limits of super duplex 2507?
The duplex family band, slightly sharpened: roughly -50°C to +250-300°C. Cold: the ferrite half's ductile-brittle transition draws the same ~-46 to -50°C line as 2205, below which austenitics or nickel steels take over. Hot: at 25% chromium the embrittlement chemistry is more eager than 2205's — 475°C embrittlement and sigma phase both arrive faster — so design codes cap sustained super duplex service around 250-300°C and prohibit any stress-relieving heat treatment absolutely. Inside the band the grade is at its formidable best; a specification pushing either wall gets an honest alloy change on our quotation rather than a silent supply.
Is A182 F53 suitable for NACE MR0175 sour service?
Yes, within the environmental limits ISO 15156-3 defines for super duplex stainless steels — ceilings on H2S partial pressure, chloride content and temperature that sit meaningfully above 2205's, which is why super duplex appears in mildly sour subsea and wellhead-adjacent service. As with all duplex grades, compliance is supply discipline: solution-annealed condition, hardness within the listed limits, and the declaration stated on the certificate. State NACE MR0175 on the enquiry and our quotation and EN 10204 certificate carry it explicitly; where the sour envelope exceeds the super duplex limits, the escalation is the nickel-alloy world — 825, 625 and the C-family — each with its own pages on this site.
What facings are A182 F53 socketweld flanges made with?
All three, each with its own page on this site: raised face (SWRF) — the default, and the pattern of the TESCO-marked S32750 flanges photographed on this page — flat face (SWFF) for GRP and lined mates in offshore utility systems, and ring type joint (SWRTJ) for high-pressure wellhead-adjacent duty. Gasket practice in seawater service is corrosion design: avoid adding avoidable crevices, use inner-ring spiral wounds or kammprofile types, and where the mating flange is a lesser alloy, remember the joint corrodes as a system. NPT-tapped variants are machined and certified at the works.
What sizes and pressure classes do F53 socketweld flanges come in?
ASME B16.5 standardises socket weld flanges from ½" to 3" NB in Classes 150, 300, 600, 900 and 1500 — Class 900 sharing Class 1500 dimensions in most small-bore sizes — with 4" and Class 2500 made to order. Super duplex small bore concentrates at the working end: Class 600-1500 hydraulic, chemical injection and wellhead-adjacent connections, where the 550 MPa yield earns its place. As with every socket flange, put the pipe schedule on the enquiry — Sch 80 and 160 dominate offshore small bore — so the through-bore matches the pipe ID. B16.5 pressure-temperature ratings for the super duplex material group govern the limits; our quotations state them per class.
Where are F53 socketweld flanges used?
The classic super duplex small-bore duties: offshore hydraulic systems on platforms, FPSOs and subsea control skids; chemical injection points into seawater-wetted and produced-fluid systems; seawater lift, cooling and firewater auxiliaries; desalination high-pressure sections; and wellhead-adjacent instrument connections in mildly sour service. The marked S32750 units photographed on this page are our production for exactly such systems — EN 1092-1 patterns included, because offshore projects specify both flange worlds. Wherever the line itself is 2507, the closures should match the alloy: same certificate, same PREN, no odd member in the joint.
What details are needed to get an accurate F53 socketweld flange quotation?
Six elements plus commercial terms: (1) size — ½" to 3" NB; (2) pressure class — 150 to 1500; (3) facing — SWRF, SWFF or SWRTJ with ring number; (4) the pipe schedule — Sch 40, 80 or 160, so the through-bore matches the pipe ID; (5) grade detail — F53/S32750, or F55/S32760 if your specification names the Zeron type, with NACE MR0175 declaration if sour; (6) certification — EN 10204 3.1 with solution-anneal records (our standard) or 3.2 witnessed, PMI as applicable. Add quantity and destination and we return price, weight and delivery — normally within 24 hours.
Who manufactures ASTM A182 F53 socketweld flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, producing ASTM A182 F53 super duplex socket weld flanges from ½" to 3" NB (larger to order) in Classes 150-1500 — each forged from certified heats, solution annealed with furnace records, machined with gauged socket depth and schedule-matched bore, PMI-checked with the Cr-Ni-Mo-N signature read on every piece, and laser-marked with grade, size, class, schedule and heat number — exactly as the S32750 units photographed on this page. Supplied with EN 10204 3.1/3.2 certification and NACE MR0175 declaration where specified, alongside the F51 and F55 duplex families and the complete socket weld range. Exported to more than 50 countries.
