ASTM A182 F5 / F9 / F91 Alloy Steel Flanges
Teshi Group manufactures ASTM A182 F5 / F9 / F91 Alloy Steel flanges (P5, P9, P91 chrome-moly flanges, 9Cr-1Mo-V) as an OEM in India — forged, machined, marked and certified in-house to ASME B16.5, ASME B16.47, EN 1092-1 and customer drawings.
Chromium–molybdenum steels keep their strength and resist creep and hydrogen attack at high temperature, which makes them standard for steam, boiler, refinery heater and hot-blast service.
ASTM A182 F5 / F9 / F91 Alloy Steel flanges at a glance
| Material | ASTM A182 F5 / F9 / F91 Alloy Steel |
|---|---|
| Specification | ASTM A182 F5 / ASTM A182 F9 / ASTM A182 F91 |
| UNS / W.Nr. | K41545 / 1.7362 · K90941 / 1.7386 · K90901 / 1.4903 |
| Sizes | NPS ½"–24" (ASME B16.5), 26"–60" (ASME B16.47 A / B), DN 10–600 (EN 1092-1) |
| Pressure class | Class 150, 300, 600, 900, 1500, 2500 · PN 6–40 |
| Facing / ends | RF, FF, RTJ, tongue & groove, male-female; serrated or smooth finish |
| Certification | EN 10204 3.1 standard · 3.2 with third-party inspection · IBR on request |
| Testing | PMI, hardness, dimensional; UT, IGC, impact and ferrite as specified |
ASTM A182 F5 / F9 / F91 Alloy Steel chemistry and mechanical properties
Chemical composition of ASTM A182 F5 / F9 / F91 Alloy Steel (weight %, maximum unless a range)
| Grade | C | Mn | Si | Cr | Mo | N | Nb | V |
|---|---|---|---|---|---|---|---|---|
| F5 (5Cr-½Mo) | 0.15 | 0.30–0.60 | 0.50 | 4.0–6.0 | 0.44–0.65 | — | — | — |
| F9 (9Cr-1Mo) | 0.15 | 0.30–0.60 | 0.50–1.00 | 8.0–10.0 | 0.90–1.10 | — | — | — |
| F91 (9Cr-1Mo-V) | 0.08–0.12 | — | — | 8.0–9.5 | 0.85–1.05 | 0.03–0.07 | 0.06–0.10 | 0.18–0.25 |
Mechanical properties of ASTM A182 F5 / F9 / F91 Alloy Steel (minimum, room temperature)
| Grade | Tensile strength | Yield strength (0.2 %) | Elongation | Note |
|---|---|---|---|---|
| F5 (5Cr-½Mo) | 485 MPa (70 ksi) | 275 MPa (40 ksi) | 20 % | Refinery heaters |
| F9 (9Cr-1Mo) | 585 MPa (85 ksi) | 380 MPa (55 ksi) | 20 % | Hydrogen service |
| F91 (9Cr-1Mo-V) | 585 MPa (85 ksi) | 415 MPa (60 ksi) | 20 % | Supercritical boilers |
Matching specifications by product form
| Grade | Forged flanges & fittings | Butt weld fittings | Plate | Pipe |
|---|---|---|---|---|
| F5 (5Cr-½Mo)UNS K41545 · W.Nr. 1.7362 | ASTM A182 F5 | ASTM A234 WP5 | ASTM A387 Gr 5 | ASTM A335 P5 |
| F9 (9Cr-1Mo)UNS K90941 · W.Nr. 1.7386 | ASTM A182 F9 | ASTM A234 WP9 | ASTM A387 Gr 9 | ASTM A335 P9 |
| F91 (9Cr-1Mo-V)UNS K90901 · W.Nr. 1.4903 | ASTM A182 F91 | ASTM A234 WP91 | ASTM A387 Gr 91 | ASTM A335 P91 |
Limits and minimums from the governing ASTM / ASME specifications, summarised for convenience; the current edition takes precedence.
Pressure rating
Ratings follow the ASME B16.5 material group for each chrome-moly grade and are issued with the quotation. The applicable rating table is issued with every quotation, and flanges are marked with class, material and heat number.
Types we manufacture
Dimension charts
Where ASTM A182 F5 / F9 / F91 Alloy Steel is used
- Boiler, superheater and steam headers (IBR)
- Supercritical and ultra-supercritical power plants (F91)
- Blast-furnace hot-blast stoves and mains
- Refinery heaters and hydrogen service
- Petrochemical high-temperature lines
Testing & certification
- Normalised and tempered with recorded furnace charts
- Hardness testing of every heat treatment lot
- UT and MPI as specified; PMI on every piece
- IBR Form III-C certification when specified
Related materials
FAQ
ASTM A182 F5 / F9 / F91 Alloy Steel flanges: common questions
What specification covers ASTM A182 F5 / F9 / F91 Alloy Steel flanges?
ASTM A182 F5 / F9 / F91 Alloy Steel flanges are forged to ASTM A182 F5 / ASTM A182 F9 / ASTM A182 F91 and dimensioned to ASME B16.5, ASME B16.47 or EN 1092-1.
What is the chemical composition of F5 (5Cr-½Mo)?
F5 (5Cr-½Mo) (UNS K41545): C 0.15, Mn 0.30–0.60, Si 0.50, Cr 4.0–6.0, Mo 0.44–0.65 (weight %; single values are maximums).
What are the minimum mechanical properties of F5 (5Cr-½Mo)?
Tensile strength 485 MPa (70 ksi), yield strength 275 MPa (40 ksi), elongation 20 %.
Is Teshi Group a manufacturer of ASTM A182 F5 / F9 / F91 Alloy Steel flanges in India?
Yes. Teshi Group has manufactured flanges and fittings in India since 1971 and is ISO 9001:2015 certified and IBR approved. Every ASTM A182 F5 / F9 / F91 Alloy Steel piece is hard-stamped with its heat number and supplied with an EN 10204 3.1 certificate; 3.2 with third-party inspection on request.
Which chrome-moly grade is used for steam lines?
F11 (1¼Cr-½Mo) and F22 (2¼Cr-1Mo) are the common grades for steam and boiler lines; F91 (9Cr-1Mo-V) is used in supercritical and ultra-supercritical power plants for its creep strength.
How are F91 flanges heat treated?
F91 is normalised and tempered, typically normalised around 1040–1080 °C and tempered at 730–800 °C, with recorded furnace charts and hardness checks on every lot.
Chrome-moly alloy steel grade data sheets
Chrome-moly alloy steel overview →Chemical composition, mechanical properties and PDF data sheet for each grade.
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