Stainless Steel 1.4558 FORG-ANN
Heat-treated state
EN 1.4558 · UNS N08800 · also Incoloy 800
For heavy forged fittings and tube sheets requiring ASTM B564 / EN 10222-5 style properties.
Values for the FORG-ANN condition
Other 1.4558 tempers and conditions
1.4558 is listed in 5 conditions; see the grade overview at 1.4558.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
High-temperature solution annealed | Use for long-term creep service above 600 °C (furnace tubes, radiant tubes, reformers) where rupture strength governs. | 195 | 510 | 45 | 120 HB | 1.7 % IACS |
FORG-ANNThis page flanges, valve bodies, thick sections | For heavy forged fittings and tube sheets requiring ASTM B564 / EN 10222-5 style properties. | 230 | 530 | 40 | 138 HB | 1.7 % IACS |
ANNDefault Annealed | Standard stocked condition for plate, bar, tube and fittings up to ~600 °C service and for all corrosion service. | 240 | 550 | 42 | 140 HB | — |
As-welded deposit | Reference properties for fabricated weldments used without post-weld solution anneal. | 270 | 550 | 30 | 170 HB | 1.6 % IACS |
Cold drawn | Pick when higher room-temperature strength, closer tolerance and better chip control are needed; not for creep service. | 480 | 690 | 22 | 200 HB | — |
What is 1.4558 FORG-ANN?
1.4558 FORG-ANN is 1.4558 heat treated to FORG-ANN — for heavy forged fittings and tube sheets requiring ASTM B564 / EN 10222-5 style properties. 1.4558 FORG-ANN has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 99% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 196 GPa (28.4 Msi). 1.4558 FORG-ANN has a density of 7.94 g/cm³ (0.287 lb/in³), heavier than 78% of stainless steel grades. It melts at 1,357°C (2,475 °F). ANN is the default condition FabDigit quotes; FORG-ANN is available on request or by drawing note.
Advantages
- Forms and bends easily — 68/100, better than 75% of stainless steel grades
Limitations
- Low strength — 230 MPa (33.4 ksi), worse than 99% of stainless steel grades
- 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
1.4558 FORG-ANN properties
Typical room-temperature values for 1.4558 FORG-ANN; 21 are specific to this condition. Other listed values are 1.4558 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4558 FORG-ANN has a density of 7.94 g/cm³ (0.287 lb/in³), heavier than 78% of stainless steel grades. It melts at 1,357°C (2,475 °F).
Mechanical13
1.4558 FORG-ANN has a yield strength of 230 MPa (33.4 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 99% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal6
1.4558 FORG-ANN is rated for continuous service to 800°C (1,472 °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 14.4 µm/m·K (8 µin/in·°F).
Electrical3
1.4558 FORG-ANN conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4558 FORG-ANN takes about 90 MJ of energy and emits 7 kg of CO₂ — more than 94% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
1.4558 FORG-ANN's machinability is poor (29/100, worse than 76% of stainless steel grades); weldability very good (78/100); formability good (68/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4558 FORG-ANN
Is 1.4558 easy to machine?
Work-hardens fast and is gummy — use rigid setups, positive-rake carbide, heavy feeds with slow speed (20–30 m/min), continuous cut and flood coolant to avoid glazing.
Can 1.4558 be welded?
Readily welded by GTAW/GMAW/SMAW with ERNiCr-3 (Inconel 82) or ENiCrFe-3 fillers; keep interpass temperature low, no preheat and normally no PWHT, avoid heavy heat input to limit Ti-carbide sensitization.
Can 1.4558 be formed, bent or molded?
Good cold formability but ~1.5× the forming loads of 304; interstage annealing at 980–1050 °C after 40–50 % reduction; hot work 900–1200 °C with rapid cooling from the finishing temperature.
What surface finishes work on 1.4558?
Not anodizable — pickle in HNO3/HF then passivate, or electropolish; grinding/blasting media must be iron-free to preserve the oxidation-resistant surface.
1.4558 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 |
|---|---|---|
| Clow-carbon variant of Alloy 800; 1.4876/800H allow higher C | ≤ 0.03 | 0.02 |
| Si | ≤ 0.7 | 0.4 |
| Mn | ≤ 1 | 0.6 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Cr | 19 – 23 | 21 |
| NiN08800 range 30.0–35.0 | 30 – 34 | 32 |
| Alwith Ti gives oxidation/carburization resistance | 0.15 – 0.6 | 0.35 |
| Ticarbide stabilizer | 0.15 – 0.6 | 0.4 |
| CuASTM B409 limit | ≤ 0.75 | 0.2 |
| Fe≥ 39.5 % per UNS N08800 | balance | — |
1.4558 FORG-ANN — frequently asked
What is 1.4558 FORG-ANN used for?
1.4558 FORG-ANN is typically used for heat treatment furnace fixtures, petrochemical cracking tubes, steam generator components and high-temperature heat exchangers. In short: high-temperature superaustenitic; oxidation and carburization resistant; weldable to 800 °C service.
What is the yield strength of 1.4558 FORG-ANN?
1.4558 FORG-ANN has a typical yield strength of 230 MPa (33.4 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 99% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.4558 FORG-ANN easy to machine?
Not especially — machinability is rated poor (29/100, worse than 76% of stainless steel grades). Work-hardens fast and is gummy — use rigid setups, positive-rake carbide, heavy feeds with slow speed (20–30 m/min), continuous cut and flood coolant to avoid glazing.
Can 1.4558 FORG-ANN be welded?
Yes — weldability is rated very good (78/100). Readily welded by GTAW/GMAW/SMAW with ERNiCr-3 (Inconel 82) or ENiCrFe-3 fillers; keep interpass temperature low, no preheat and normally no PWHT, avoid heavy heat input to limit Ti-carbide sensitization.
What surface finishes work on 1.4558 FORG-ANN?
Not anodizable — pickle in HNO3/HF then passivate, or electropolish; grinding/blasting media must be iron-free to preserve the oxidation-resistant surface.
Can 1.4558 FORG-ANN be formed, bent or molded?
Good cold formability but ~1.5× the forming loads of 304; interstage annealing at 980–1050 °C after 40–50 % reduction; hot work 900–1200 °C with rapid cooling from the finishing temperature.
What is the maximum service temperature of 1.4558 FORG-ANN?
1.4558 FORG-ANN is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4558-ANN and 1.4558-CD?
ANN is the default condition — standard stocked condition for plate, bar, tube and fittings up to ~600 °C service and for all corrosion service. CD: pick when higher room-temperature strength, closer tolerance and better chip control are needed; not for creep service. Yield strength is 240 MPa in ANN versus 480 MPa in CD.
Sources
- EN 10095 Heat resisting steels and nickel alloys — CEN (1999)
- EN 10028-7 / EN 10216-5 (X2NiCrAlTi32-20, 1.4558) — CEN (2016)
- ASTM B409 / B408 / B407 / B564 (UNS N08800) — ASTM International (2020)
- INCOLOY alloy 800 technical bulletin — Special Metals Corporation (2004)
- VDM Alloy 800 / Nicrofer 3220 material data sheet — VDM Metals (2018)
- ASM Handbook Vol. 1 & Vol. 13B (heat-resistant Fe-Ni-Cr alloys) — ASM International (2005)
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.