ASTM A182 F1 – UNS K12822
Forged carbon-molybdenum (C-½Mo) steel for elevated temperature
C-0.5Mo steel forged to ASTM A182 for flanges, fittings and valves in moderately hot service. Molybdenum raises creep resistance over A105, but the grade is susceptible to graphitization on prolonged exposure above ≈ 425–440 °C and today is rarely specified in new designs (F11/F12 preferred).
Designations and equivalents
| System | Designation |
|---|---|
| UNS | K12822 |
| W.Nr./EN | ≈ 16Mo3 – 1.5415 (EN 10222-2, lower C) |
| DIN | ≈ 15Mo3 (old) |
| JIS | ≈ SFVA F1 (JIS G3203) |
| Trade names | C-½Mo, F1 |
| Others | Pipe A335 P1; plate A204 Gr B; fittings A234 WP1; casting A217 WC1 |
Standards by product form
| Form | Standard |
|---|---|
| Forging (flanges, fittings, valves) | ASTM A182/A182M F1; ASME SA-182 |
| Pipe | ASTM A335 P1 |
| Plate | ASTM A204 Gr A/B |
| Butt-welding fittings | ASTM A234 WP1 |
| Casting | ASTM A217 WC1 |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7228.40.00 | 7228.40 | 7228.40.0000 | 7228 40 90 |
| Plate (> 10 mm, width ≥ 600 mm) | 7225.40.90 | 7225.40 | 7225.40.3050 | 7225 40 40 |
| Seamless pipe | 7304.19.00 | 7304.19 | 7304.19.5050 | 7304 19 10 |
| Welded pipe | 7306.19.00 | 7306.19 | 7306.19.5150 | 7306 19 00 |
| Flange and fitting | 7307.91.00 | 7307.91 | 7307.91.5030 | 7307 91 00 |
Tariff class: alloy steel (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
Pipe: 7304.19 and 7306.19 are line pipe for oil and gas pipelines; boiler, heat exchanger or process tubes go under 7304.39/7304.59 (seamless) and 7306.30/7306.50 (welded).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM A182/A182M – F1
| Element | Range (%) |
|---|---|
| C | ≤ 0.28 |
| Mn | 0.60 – 0.90 |
| P | ≤ 0.045 |
| S | ≤ 0.045 |
| Si | 0.15 – 0.35 |
| Mo | 0.44 – 0.65 |
Mechanical properties
Annealed, normalized or normalized + tempered – ASTM A182 F1
| Property | Value |
|---|---|
| Yield strength (0.2%) | ≥ 275 MPa |
| Tensile strength | ≥ 485 MPa |
| Elongation | ≥ 20% |
| Reduction of area | ≥ 30% |
| Hardness | 143 – 192 HBW |
Typical physical properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Modulus of elasticity | ≈ 205 GPa |
| Thermal conductivity (20 °C) | ≈ 45 W/m·K (typical) |
| Thermal expansion (20–100 °C) | ≈ 12.0 µm/m·K (typical) |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Up to ≈ 425–455 °C in continuous service; above that there is a risk of graphitization (ASME warns of prolonged exposure > 468 °C). |
| Heat treatment | Annealing, normalizing (≈ 900–930 °C) or normalizing + tempering (subcritical tempering ≥ 620 °C). |
| Welding | Good with C-½Mo consumables: AWS E7018-A1 (A5.5), ER70S-A1 / ER80S-D2 (A5.28). Preheat ≈ 80–150 °C; PWHT 595–720 °C for thicknesses above the code limit. |
| Machining | Good, similar to A105. |
Filler metal for welding
The wire composition is usually not identical to the material: each page explains why.
Typical applications
- Flanges and fittings for medium-temperature steam lines
- Valves in boilers and refineries (older units)
- Replacement in plants designed with P1/WC1
- Vessel nozzles in A204
Alternatives: A182 F11 Cl.2 or F12 for new designs (no graphitization risk); A105 below ≈ 400 °C; F22 for higher temperature and pressure.
ASTM A182 F1: complete guide
What ASTM A182 F1 steel is
F1 is the simplest grade in the ASTM A182 series of high-temperature alloy steels. It contains only iron, carbon, manganese, silicon and 0.44 – 0.65% molybdenum; it has no chromium. It sits between A105 (carbon steel) and F11 (1¼Cr-½Mo) on the design temperature scale, and is the forged version of A335 P1 pipe.
Chemical composition and role of the elements
Molybdenum in solid solution slows creep deformation and allows higher allowable stresses than carbon steel above 400 °C. As there is no chromium, oxidation resistance is the same as carbon steel. Carbon is limited to 0.28% to ensure weldability and toughness.
Mechanical properties
In the annealed or normalized and tempered condition the standard requires a minimum yield strength of 275 MPa, minimum tensile strength of 485 MPa, minimum elongation of 20%, minimum reduction of area of 30% and hardness between 143 and 192 HBW.
Service temperature and graphitization
C-Mo steels suffer graphitization, the decomposition of carbides into graphite, when they operate for long periods above approximately 425 – 455 °C, with loss of toughness in the heat-affected zone of welds. That is why, although the codes allow stresses up to higher temperatures, refinery practice limits F1 to about 425 °C and uses Cr-Mo above that.
Applications
Forged flanges, fittings and valves for medium-temperature steam lines, heat exchangers, industrial boilers and process piping in refineries and petrochemical plants, always within the limit of ≈ 425 °C.
Supply forms and Dustre services
Round bars and blocks forged in open die, cut to size on a band saw, with rough or finish machining, heat treatment in our own furnaces and hardness, tensile and impact testing. All material is supplied with a 3.1 inspection certificate and heat traceability.
Frequently asked questions
What is the chemical composition of ASTM A182 F1?
Per ASTM A182/A182M – F1: C ≤ 0.28; Mn 0.60 – 0.90; P ≤ 0.045; S ≤ 0.045; Si 0.15 – 0.35; Mo 0.44 – 0.65.
Which standards cover ASTM A182 F1?
Forging (flanges, fittings, valves): ASTM A182/A182M F1; ASME SA-182. Pipe: ASTM A335 P1. Plate: ASTM A204 Gr A/B. Butt-welding fittings: ASTM A234 WP1. Casting: ASTM A217 WC1.
Up to what temperature can ASTM A182 F1 be used?
Up to ≈ 425–455 °C in continuous service; above that there is a risk of graphitization (ASME warns of prolonged exposure > 468 °C).
Which materials can replace ASTM A182 F1?
A182 F11 Cl.2 or F12 for new designs (no graphitization risk); A105 below ≈ 400 °C; F22 for higher temperature and pressure.
