Stainless Steel Alloy 803-HF (Hot finished)
Grade
UNS S35045 · also Incoloy alloy 803
Pick for heavy bar, thick plate and extruded tube where mill hot-finishing plus anneal is the economical route.
Values for the HF condition
Other Alloy 803 tempers and conditions
Alloy 803 is listed in 5 conditions; see the grade overview at Alloy 803.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed (mill annealed plate, sheet, bar, tube) | Default stocked condition: maximum ductility and creep performance for furnace tubes, coils and fabricated hardware. | 265 | 585 | 45 | 165 HB | — |
Cold drawn and re-annealed tube/bar | Best combination of tight dimensions, fine grain and full high-temperature ductility for pyrolysis and reformer tubing. | 270 | 590 | 45 | 160 HB | 1.7 % IACS |
HFThis page Hot finished | Pick for heavy bar, thick plate and extruded tube where mill hot-finishing plus anneal is the economical route. | 285 | 600 | 40 | 175 HB | 1.7 % IACS |
Stress relieved | Use when residual stresses from forming or welding must be lowered while retaining part of the cold-work strength. | 380 | 660 | 32 | 14 HRC | 1.7 % IACS |
Cold drawn | Choose for close-tolerance bar/tube needing higher room-temperature strength; not for long-term high-temperature creep service without re-annealing. | 460 | 720 | 25 | 20 HRC | 1.7 % IACS |
What is Alloy 803-HF?
Alloy 803-HF is Alloy 803 in the HF grade — pick for heavy bar, thick plate and extruded tube where mill hot-finishing plus anneal is the economical route. Alloy 803-HF has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 74% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi). Alloy 803-HF has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,345°C (2,453 °F). Annealed is the default condition FabDigit quotes; HF is available on request or by drawing note.
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
Limitations
- Poor heat conductor — 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades
- High embodied carbon — 7 kg CO₂/kg, worse than 96% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
Alloy 803-HF properties
Typical room-temperature values for Alloy 803-HF; 21 are specific to this condition. Other listed values are Alloy 803 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
Alloy 803-HF has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,345°C (2,453 °F).
Mechanical13
Alloy 803-HF has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 74% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
Alloy 803-HF is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades. Thermal expansion is 14.8 µm/m·K (8.22 µin/in·°F).
Electrical3
Alloy 803-HF conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 73% of stainless steel grades.
Sustainability4
Producing a kilogram of Alloy 803-HF takes about 100 MJ of energy and emits 7 kg of CO₂ — more than 98% of stainless steel grades. Typical recycled content is 40%.
Manufacturability8
Alloy 803-HF's machinability is poor (26/100, worse than 84% of stainless steel grades); weldability good (65/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Alloy 803-HF
Is Alloy 803 easy to machine?
Machine like alloy 800H but tougher: rigid setups, positive-rake carbide, low speed / heavy positive feed, flood coolant and no dwelling to avoid work-hardened glaze.
Can Alloy 803 be welded?
Readily GTAW/GMAW/SMAW welded with matching 803 or Ni-Cr-Nb (ERNiCr-3 / 617-type) filler; keep heat input low, no preheat needed, avoid long dwell in the 650–900 °C sigma/carbide range.
Can Alloy 803 be formed, bent or molded?
Good hot workability at 1050–1200 °C; cold forms well but work-hardens fast — allow extra power, generous bend radii and intermediate anneals at 1100–1150 °C followed by rapid cooling.
What surface finishes work on Alloy 803?
Descale by pickling or grit blasting after hot work; passivate for cleanliness. Not anodizable; paint/plating rarely used since the Cr₂O₃ scale is the working surface.
Alloy 803 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 |
|---|---|---|
| Ni | 32 – 37 | 34 |
| Cr | 25 – 29 | 27 |
| Ccarbon kept high for creep strength | 0.06 – 0.1 | 0.08 |
| Al | 0.15 – 0.6 | 0.3 |
| TiAl+Ti 0.30–1.20 total | 0.15 – 0.6 | 0.4 |
| Si | ≤ 1.5 | 0.7 |
| Mn | ≤ 1.5 | 0.8 |
| Cu | ≤ 0.75 | 0.1 |
| S | ≤ 0.02 | 0 |
| Febalance, 34.5 % min per ASTM | balance | — |
Alloy 803-HF — frequently asked
What is Alloy 803-HF used for?
Alloy 803-HF is typically used for petrochemical furnace components, ethylene cracking equipment, radiant tubes and high-temperature fixtures. In short: carburization-resistant furnace alloy; service to 1100 °C; ti/Al precipitation strengthened.
What is the yield strength of Alloy 803-HF?
Alloy 803-HF has a typical yield strength of 285 MPa (41.3 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 74% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is Alloy 803-HF easy to machine?
Not especially — machinability is rated poor (26/100, worse than 84% of stainless steel grades). Machine like alloy 800H but tougher: rigid setups, positive-rake carbide, low speed / heavy positive feed, flood coolant and no dwelling to avoid work-hardened glaze.
Can Alloy 803-HF be welded?
Yes — weldability is rated good (65/100). Readily GTAW/GMAW/SMAW welded with matching 803 or Ni-Cr-Nb (ERNiCr-3 / 617-type) filler; keep heat input low, no preheat needed, avoid long dwell in the 650–900 °C sigma/carbide range.
What surface finishes work on Alloy 803-HF?
Descale by pickling or grit blasting after hot work; passivate for cleanliness. Not anodizable; paint/plating rarely used since the Cr₂O₃ scale is the working surface.
Can Alloy 803-HF be formed, bent or molded?
Good hot workability at 1050–1200 °C; cold forms well but work-hardens fast — allow extra power, generous bend radii and intermediate anneals at 1100–1150 °C followed by rapid cooling.
What is the maximum service temperature of Alloy 803-HF?
Alloy 803-HF is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Alloy 803 Annealed and Alloy 803-CD?
Annealed is the default condition — default stocked condition: maximum ductility and creep performance for furnace tubes, coils and fabricated hardware. CD: choose for close-tolerance bar/tube needing higher room-temperature strength; not for long-term high-temperature creep service without re-annealing. Yield strength is 265 MPa in Annealed versus 460 MPa in CD.
Sources
- INCOLOY alloy 803 technical bulletin — Special Metals Corporation (2004)
- ASTM B409 — Ni-Fe-Cr Alloy Plate, Sheet and Strip — ASTM International (2021)
- ASTM B407 — Ni-Fe-Cr Alloy Seamless Pipe and Tube — ASTM International (2019)
- ASTM B408 — Ni-Fe-Cr Alloy Rod and Bar — ASTM International (2019)
- ASM Specialty Handbook: Heat-Resistant Materials — ASM International (1997)
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.