Tesco Steel & Engineering forges ASTM A182 F9 slip on flanges — the 9% chromium, 1% molybdenumalloy steel one rung above F5 on the refinery corrosion ladder — to ASME B16.5 Class 150–2500 from ½″ to 24″ NB, larger patterns to order. Chosen when the stream is too hot or too sulfurous for 5Cr steel: fired-heater outlets, hydrodesulfurizer hot sections, the hottest transfer lines. Supplied heat treated per ASTM A182 with full heat traceability, faced SORF (flat face or RTJ where specified), alongside the complete chrome-moly family F5, F11, F22 and F91. Every lot with EN 10204 3.1/3.2 MTC. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
ASTM A182 F9 · SA182 · K909419Cr-1Mo · Werkstoff 1.7386ASME B16.5 Class 150–2500½″ – 24″ NB · SORFRated to 649 °C per B16.5EN 10204 3.1 / 3.2 MTCISO 9001:2015 · Exported Worldwide
ASTM A182 Alloy Steel Slip On Flanges — Mixed Sizes, Export Crated at Our Mumbai Works
What is an ASTM A182 F9 Slip On Flange?
F9 = the hotter sulfidation rung.ASTM A182 F9 is a 9Cr-1Mo alloy steel forging grade: roughly double the chromium of F5, for streams too hot or too sulfurous for 5Cr steel, with raised silicon reinforcing the protective scale. As a slip-on, it installs with two fillet welds under strict alloy discipline — preheat, B8 consumables, PWHT. Rated to 649 °C in the B16.5 tables, it is the last alloy-steel rung before stainless takes over.
Also searched as: F9 slip on flange, 9Cr slip on flange, 9Cr-1Mo slip on flange, SA182 F9 slip on flange, 1.7386 slip on flange, K90941 slip on flange — all refer to the product on this page.
Creep-strength-enhanced — modern high-energy steam
Rule of thumb: refineries climb the ladder for corrosion (sulfur), power plants climb it for creep strength (temperature). F9 is the top corrosion rung of the alloy steels — beyond it, duty passes to stainless steel.
ASTM A182 F9 Chemical Composition
C
Mn
Si
P
S
Cr
Mo
0.15 max
0.30-0.60
0.50-1.00
0.030 max
0.030 max
8.00-10.00
0.90-1.10
Values in weight % per ASTM A182 for the F9 forging grade. Note the deliberately raised silicon (0.50-1.00%) — it reinforces the protective oxide-sulfide scale — and the low carbon, which keeps this strongly air-hardening steel weldable under proper procedure.
ASTM A182 F9 Mechanical Properties
Tensile Strength, MPa (ksi)
Yield Strength, Min, MPa (ksi)
Elongation % min (2")
Reduction of Area % min
Hardness, HB
585 (85) min
380 (55) min
20
40
179-217
Notably stronger than F5 (585 vs 485 MPa minimum tensile) — the 9Cr matrix tempers back to a tougher, stronger condition. F9 is supplied heat treated per ASTM A182 with the bounded 179-217 HB hardness window, and values are demonstrated per heat on the EN 10204 certificate.
A182 F9 Slip On Flange Specifications
ASTM A182 F9 Slip On Flanges are available in the following specifications:
Material
ASTM A182 F9 / ASME SA182 F9 (UNS K90941)
Size
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
Annealed or normalized & tempered per ASTM A182, thermal record retained
Service
Hot refinery duty — rated to 649 °C in the ASME B16.5 tables, creep governing in the upper range
Installation
Two fillet welds (hub + bore), pipe set back 1/8"; preheat + E8018-B8 consumables + PWHT ~730-760 °C per B31.3
Finish
Bare (anti-rust oiled); other surface preparation on request
Certification
EN 10204 3.1 (standard) / 3.2 witnessed
Equivalent Grades of ASTM A182 F9
Standard
ASME
UNS
Werkstoff Nr.
DIN / EN (working equivalent)
ASTM A182 F9
SA182 F9
K90941
1.7386
X12CrMo9-1
European grades are duty equivalents rather than chemistry-identical matches — certificates always state the actual grade forged. System partners: ASTM A335 P9 pipe and A234 WP9 fittings — the 9Cr trio specified together on the hottest refinery lines.
Why A182 F9 Slip Ons Are Specified
Survives What Retires 5Cr
When heater outlet temperatures or sulfur levels eat through F5 corrosion allowances, the step to 9% chromium cuts the wastage rate again — the classic next rung.
Oxidation Resistance Included
9Cr with raised silicon holds its scale in hot air and flue-gas environments better than any lower rung — useful around fired heaters, not just inside the pipe.
Stronger Than the Rungs Below
585 MPa minimum tensile and 380 MPa yield — F9 out-muscles F5 and the carbon grades while carrying the same B16.5 ratings table to 649 °C.
Slip-On Fit-Up Economy
Where the piping class permits, the slip-on saves the weld-neck's bevel-matching and cut-length precision — welcome on alloy lines where every rework costs PWHT.
Forging — cut billet of certified A182 F9 heat is hot-forged into the flange blank, keeping full heat traceability from raw material to despatch.
2
Heat treatment — annealed or normalized & tempered per ASTM A182; 9Cr steel is strongly air-hardening, so the controlled cycle is what delivers the 179-217 HB working condition.
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 — SORF raised face with serrated stock finish; flat face or RTJ groove where the order specifies.
5
Testing & marking — mechanical, chemical and hardness verification against the heat, 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 F9 Slip On Flanges Are Used
The hottest sulfur-bearing hydrocarbon services: fired-heater outlet and transfer piping, hydrodesulfurizer and hydrocracker hot sections, vacuum unit bottoms circuits, delayed coker heaters, and elevated-temperature lines where even 5Cr corrosion allowances stop adding up. Our alloy steel production and packing below:
Example: “Slip On Flange, 6″ NB, ASME B16.5 Class 300, RF, ASTM A182 F9, EN 10204 3.1 — 20 pcs.” Quotations normally within 24 hours with price, unit weight and delivery.
ASTM A182 F9 Slip On Flanges — Frequently Asked Questions
What is an ASTM A182 F9 slip on flange?
It is a slip-on flange forged from ASTM A182 F9 — a 9% chromium, 1% molybdenum alloy steel — dimensioned to ASME B16.5. The flange slides over the pipe end and is secured with two fillet welds, and the 9Cr-1Mo chemistry sits one rung above F5 on the refinery corrosion ladder: chosen when the stream is too hot or too sulfurous for 5Cr steel. It serves fired-heater outlet piping, hydrodesulfurizer hot sections and other severe hot hydrocarbon services.
What is the chemical composition of ASTM A182 F9?
Per ASTM A182: carbon 0.15% max, manganese 0.30-0.60%, silicon 0.50-1.00%, phosphorus 0.030% max, sulphur 0.030% max, chromium 8.0-10.0% and molybdenum 0.90-1.10%. The high chromium is the working element against hot sulfidation and oxidation, the deliberately raised silicon reinforces the protective scale, and the low carbon keeps the air-hardening steel weldable under proper procedure.
What are the mechanical properties of A182 F9 slip on flanges?
Per ASTM A182: tensile strength 585 MPa (85 ksi) minimum, yield strength 380 MPa (55 ksi) minimum, elongation 20% minimum in 2", reduction of area 40% minimum, and hardness 179-217 HB — notably stronger than F5's 485/275 MPa, because the 9Cr matrix tempers back to a tougher, stronger condition. F9 is supplied heat treated per ASTM A182 and the values are demonstrated per heat on the EN 10204 certificate.
What is the difference between A182 F9 and F5?
Roughly double the chromium — 8-10% against 4-6% — plus double the molybdenum and a raised silicon. That buys markedly better resistance to high-temperature sulfidation and oxidation, so specifications step from F5 to F9 when stream temperature or sulfur content retires the 5Cr grade too early. F9 is also stronger (585 vs 485 MPa minimum tensile) but costs more and demands the same preheat-and-PWHT welding discipline. Where F5 survives economically, F5 stays.
What is the difference between A182 F9 and F91?
They share the 9Cr-1Mo base but are different materials for different jobs. F91 is the modified grade — micro-alloyed with vanadium, niobium and nitrogen — a creep-strength-enhanced ferritic steel with far higher allowable stresses for high-energy steam piping, bought together with strict welding, hardness and heat-treatment controls. F9 is the plain grade, selected for hot-corrosion resistance in refinery service. They are not interchangeable; substituting one for the other requires engineering approval, never a warehouse decision.
What temperature can A182 F9 slip on flanges handle?
F9 works the same roughly 400-650 °C window as the other chrome-molys — ASME B16.5 rates the 9Cr material class to 649 °C, with creep governing the allowable stresses in the upper range — but within that window it tolerates hotter, more sulfurous streams than F5 and resists oxidation better. As with every flange, the pressure rating falls as temperature rises; check the B16.5 table for the class at design temperature.
Why does F9 contain 9% chromium?
Because sulfidation resistance scales with chromium. Hot crude fractions and hydrogen-hydrocarbon streams attack steel through their sulfur compounds, accelerating sharply above about 260 °C, and industry corrosion curves show the wastage rate falling step by step as chromium rises — carbon steel to 5Cr to 9Cr. F9 is the rung refineries reach for when even 5Cr corrosion allowances stop adding up, classically at heater outlets and the hottest transfer lines.
How is an A182 F9 slip on flange welded to pipe?
With two fillet welds — hub outside, bore inside, pipe set back 1/8" (3 mm) from the face — under strict alloy discipline: 9Cr steel is strongly air-hardening, so practice per ASME B31.3 requires preheat (typically 200 °C or higher), matching E8018-B8 / ER80S-B8 consumables, and post-weld heat treatment at about 730-760 °C. Plan the PWHT into fabrication; skipping it leaves a hard, crack-prone weld zone.
What is the equivalent of ASTM A182 F9 in other standards?
ASME SA182 F9 is the boiler-code twin and UNS K90941 the designation number. The European working equivalent is the 9% chromium steel X12CrMo9-1 (Werkstoff 1.7386). System partners specified alongside it: ASTM A335 P9 pipe and A234 WP9 fittings — the 9Cr trio of hot refinery lines. Certificates always state the actual grade forged.
Are slip on flanges allowed in high-temperature service?
Within limits. Slip-on flanges are permitted by ASME B31.3 and serve on lower-criticality hot lines, but many refinery piping classes restrict creep-range and cyclic services to weld neck flanges, whose full-penetration butt weld can be radiographed and resists thermal fatigue better than fillet welds. Follow the piping class: where it allows a slip-on, an F9 slip-on delivers the metallurgy at lower flange and fit-up cost.
Is A182 F9 a stainless steel?
No — close, but not stainless. At 8-10% chromium, F9 still sits below the roughly 10.5% threshold where steel passivates, so it rusts in ambient wet service and is not the answer to aqueous corrosion. Its chromium earns its keep at high temperature against sulfidation and oxidation. For wet corrosion move to 300-series stainless; F9 is the last rung of the alloy-steel ladder before stainless takes over.
What sizes and classes are A182 F9 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. 9Cr material is project-specific rather than shelf stock, so flanges are typically forged against the order — standard sizes normally dispatch 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 F9 slip on flange quotation?
Five elements plus commercial terms: (1) size and standard — e.g. 6" 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 F9, with any supplementary requirements such as hardness limits; (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 F9 slip on flanges in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified flange manufacturer based in Mumbai, India, forging ASTM A182 F9 slip on flanges from ½" to 24" NB per ASME B16.5 — alongside the full chrome-moly family F5, F11, F22 and F91 — with heat-treated supply, 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.
