Steel A182 F5-F5a
Grade
ASTM A182 F5 · UNS K41545 · EN X15CrMo5-1
F5a = high-strength 5Cr-0.5Mo grade
Same chemistry family but heat treated to the higher A182 F5a strength/hardness band (187–248 HB) for compact high-pressure fittings.
Values for the F5a condition
Other A182 F5 tempers and conditions
A182 F5 is listed in 4 conditions; see the grade overview at A182 F5.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal / isothermal anneal for maximum machinability | Choose for rough machining of large forgings or when the lowest hardness (≤187 HB) is specified. | 310 | 520 | 28 | 160 HB | — |
N+TDefault Normalized and tempered | Standard supply condition for F5 flanges, fittings and valve bodies in refinery hot piping. | 380 | 550 | 25 | 170 HB | — |
Quenched and tempered | Used for heavy-wall valve bodies and pressure parts needing higher yield strength with tempered-martensite toughness. | 470 | 640 | 22 | 18 HRC | — |
F5aThis page High-strength 5Cr-0.5Mo grade | Same chemistry family but heat treated to the higher A182 F5a strength/hardness band (187–248 HB) for compact high-pressure fittings. | 520 | 690 | 24 | 21 HRC | — |
What is A182 F5-F5a?
A182 F5-F5a is A182 F5 in the F5a grade — same chemistry family but heat treated to the higher A182 F5a strength/hardness band (187–248 HB) for compact high-pressure fittings. A182 F5-F5a has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 67% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi). A182 F5-F5a has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 91% of steel grades. It melts at 1,425°C (2,597 °F). N+T is the default condition FabDigit quotes; F5a is available on request or by drawing note.
Advantages
- High service temperature — 600°C (1,112 °F), better than 98% of steel grades
- Good corrosion resistance — 28/100, better than 94% of steel grades
Limitations
- Low electrical conductivity — 3.8 % IACS, worse than 84% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
A182 F5-F5a properties
Typical room-temperature values for A182 F5-F5a; 11 are specific to this condition. Other listed values are A182 F5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A182 F5-F5a has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 91% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
A182 F5-F5a has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 67% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A182 F5-F5a is rated for continuous service to 600°C (1,112 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
A182 F5-F5a conducts electricity at 3.8 % IACS, worse than 84% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of A182 F5-F5a takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
A182 F5-F5a's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (45/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A182 F5-F5a
Is A182 F5 easy to machine?
Machine in the annealed or N+T state with rigid setups, carbide tooling and moderate speeds (~60–90 m/min); the 5 % Cr gives stringy chips and work-hardened surfaces, so avoid dwelling and use ample coolant.
Can A182 F5 be welded?
Weld with matching 5Cr-0.5Mo (E8018-B6 / ER80S-B6) filler, preheat 200–260 °C, keep interpass ≥200 °C, and PWHT at 700–760 °C; slow-cool to prevent untempered martensite and hydrogen cracking.
Can A182 F5 be formed, bent or molded?
Hot forge at 1050–1180 °C with finishing above 900 °C, then normalize/temper; cold forming is limited because the alloy air-hardens.
What surface finishes work on A182 F5?
Not anodizable — protect with high-temperature aluminium/silicone paint, aluminizing or chromizing; phosphate or oil for storage since the alloy rusts in humid air.
A182 F5 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C0.15 max | ≤ 0.15 | 0.12 |
| Mn | 0.3 – 0.6 | 0.45 |
| Si | ≤ 0.5 | 0.3 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cr | 4 – 6 | 5 |
| Mo | 0.44 – 0.65 | 0.55 |
| Ni0.50 max | ≤ 0.5 | 0.2 |
| Fe | balance | — |
A182 F5-F5a — frequently asked
What is A182 F5-F5a used for?
A182 F5-F5a is typically used for refinery hot-service flanges, valve bodies and catalytic reformer piping fittings. In short: refinery 5Cr hot-service standard; oxidation resistance to 620 °C; weldable with strict PWHT.
What is the yield strength of A182 F5-F5a?
A182 F5-F5a has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A182 F5-F5a easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the annealed or N+T state with rigid setups, carbide tooling and moderate speeds (~60–90 m/min); the 5 % Cr gives stringy chips and work-hardened surfaces, so avoid dwelling and use ample coolant.
Can A182 F5-F5a be welded?
With care — weldability is rated fair (45/100). Weld with matching 5Cr-0.5Mo (E8018-B6 / ER80S-B6) filler, preheat 200–260 °C, keep interpass ≥200 °C, and PWHT at 700–760 °C; slow-cool to prevent untempered martensite and hydrogen cracking.
What surface finishes work on A182 F5-F5a?
Not anodizable — protect with high-temperature aluminium/silicone paint, aluminizing or chromizing; phosphate or oil for storage since the alloy rusts in humid air.
Can A182 F5-F5a be formed, bent or molded?
Hot forge at 1050–1180 °C with finishing above 900 °C, then normalize/temper; cold forming is limited because the alloy air-hardens.
What is the maximum service temperature of A182 F5-F5a?
A182 F5-F5a is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A182 F5 N+T and A182 F5-F5a?
N+T is the default condition — standard supply condition for F5 flanges, fittings and valve bodies in refinery hot piping. F5a: same chemistry family but heat treated to the higher A182 F5a strength/hardness band (187–248 HB) for compact high-pressure fittings. Yield strength is 380 MPa in N+T versus 520 MPa in F5a.
Sources
- ASTM A182/A182M — Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Fittings, Valves and Parts for High-Temperature Service — ASTM International (2023)
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (Grade P5) — ASTM International (2022)
- ASME BPVC Section II Part D — Material Properties (Metric) — ASME (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — API (2016)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.