Stainless Steel 1.4539-C850
Supply condition
EN 1.4539 · UNS N08904 · ASTM 904L · GB 00Cr20Ni25Mo4.5Cu
C850 = cold worked to Rm ≥ 850 MPa
Half-hard strip/wire for high-strength clamps, springs and reinforcement where corrosion life still matters.
Values for the C850 condition
Other 1.4539 tempers and conditions
1.4539 is listed in 6 conditions; see the grade overview at 1.4539.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Forged + solution annealed (bar, flange, valve body) | Heavy sections per ASTM B649/B564-type practice; forged then re-annealed and quenched to restore corrosion resistance. | 250 | 580 | 43 | 160 HB | 1.7 % IACS |
ATDefault Solution annealed | Standard supply condition for plate, bar, pipe and fittings; maximum corrosion resistance and ductility. | 260 | 600 | 45 | 165 HB | — |
As-welded deposit | Weld-metal condition — use overalloyed Ni-base filler (e.g. ERNiCrMo-3/-13) to avoid Mo depletion in dendrite cores. | 330 | 590 | 35 | 180 HB | 1.7 % IACS |
Cold drawn | Pick for fasteners, shafts and instrument tubing needing closer tolerance and higher yield than annealed. | 480 | 720 | 28 | 19 HRC | 1.7 % IACS |
Cold worked to Rm ≥ 700 MPa | Light strain-hardened temper (≈1/4 hard) for springy sheet parts and strength-critical thin sections. | 480 | 760 | 25 | 20 HRC | 1.7 % IACS |
C850This page Cold worked to Rm ≥ 850 MPa | Half-hard strip/wire for high-strength clamps, springs and reinforcement where corrosion life still matters. | 650 | 900 | 15 | 27 HRC | 1.7 % IACS |
What is 1.4539-C850?
1.4539-C850 is 1.4539 supplied in the C850 condition — half-hard strip/wire for high-strength clamps, springs and reinforcement where corrosion life still matters. 1.4539-C850 has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 90% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 195 GPa (28.3 Msi). 1.4539-C850 has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,320°C (2,408 °F). AT is the default condition FabDigit quotes; C850 is available on request or by drawing note.
Advantages
- High strength — 650 MPa (94.3 ksi), better than 90% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
- Good corrosion resistance — 74/100, better than 78% of stainless steel grades
Limitations
- Limited service temperature — 250°C (482 °F), 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
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- High embodied carbon — 6.5 kg CO₂/kg, worse than 93% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
1.4539-C850 properties
Typical room-temperature values for 1.4539-C850; 23 are specific to this condition. Other listed values are 1.4539 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.4539-C850 has a density of 7.95 g/cm³ (0.287 lb/in³), heavier than 81% of stainless steel grades. It melts at 1,320°C (2,408 °F).
Mechanical15
1.4539-C850 has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 90% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
1.4539-C850 is rated for continuous service to 250°C (482 °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 15.8 µm/m·K (8.78 µin/in·°F).
Electrical3
1.4539-C850 conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (74/100), better than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.4539-C850 takes about 88 MJ of energy and emits 6.5 kg of CO₂ — more than 93% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
1.4539-C850's machinability is poor (34/100, worse than 55% of stainless steel grades); weldability very good (70/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.4539-C850
Is 1.4539 easy to machine?
Machine like a high-Ni superaustenitic: rigid setup, sharp positive-rake carbide, heavy positive feed to cut under the work-hardened skin, ~30 % of 1212 speeds, flood emulsion or high-pressure coolant.
Can 1.4539 be welded?
Excellent weldability by GTAW/GMAW/SMAW with low heat input (<1.5 kJ/mm) and interpass <150 °C; use overalloyed filler (ERNiCrMo-3, ERNiCrMo-13 or 27-31-4-Cu) to offset Mo segregation; no preheat or PWHT required.
Can 1.4539 be formed, bent or molded?
Very ductile but strongly work hardening — allow 1.5–2× the press force used for carbon steel, generous bend radii, intermediate solution anneals for deep multi-stage draws; hot work 1150–900 °C then re-anneal.
What surface finishes work on 1.4539?
Pickle in HNO₃/HF or use paste after welding, then passivate (ASTM A967) or electropolish for maximum pitting resistance; takes a high mechanical or mirror polish; never anodise.
1.4539 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, resists sensitisation | ≤ 0.02 | 0.01 |
| Si | ≤ 0.7 | 0.4 |
| Mn | ≤ 2 | 1.5 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.01 | 0 |
| Cr | 19 – 21 | 20 |
| Nistabilises austenite, resists reducing acids | 24 – 26 | 25 |
| Mo | 4 – 5 | 4.5 |
| Cukey for sulphuric acid resistance | 1.2 – 2 | 1.5 |
| NEN 10088 optional | ≤ 0.15 | 0.06 |
| Fe | balance | — |
1.4539-C850 — frequently asked
What is 1.4539-C850 used for?
1.4539-C850 is typically used for sulfuric acid plants, flue gas desulfurization scrubbers, pulp bleaching equipment, seawater piping and food and pharma processing. In short: baseline superaustenitic grade; best-stocked acid stainless; strong sulfuric acid resistance.
What is the yield strength of 1.4539-C850?
1.4539-C850 has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 90% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 1.4539-C850 easy to machine?
Not especially — machinability is rated poor (34/100, worse than 55% of stainless steel grades). Machine like a high-Ni superaustenitic: rigid setup, sharp positive-rake carbide, heavy positive feed to cut under the work-hardened skin, ~30 % of 1212 speeds, flood emulsion or high-pressure coolant.
Can 1.4539-C850 be welded?
Yes — weldability is rated very good (70/100). Excellent weldability by GTAW/GMAW/SMAW with low heat input (<1.5 kJ/mm) and interpass <150 °C; use overalloyed filler (ERNiCrMo-3, ERNiCrMo-13 or 27-31-4-Cu) to offset Mo segregation; no preheat or PWHT required.
What surface finishes work on 1.4539-C850?
Pickle in HNO₃/HF or use paste after welding, then passivate (ASTM A967) or electropolish for maximum pitting resistance; takes a high mechanical or mirror polish; never anodise.
Can 1.4539-C850 be formed, bent or molded?
Very ductile but strongly work hardening — allow 1.5–2× the press force used for carbon steel, generous bend radii, intermediate solution anneals for deep multi-stage draws; hot work 1150–900 °C then re-anneal.
What is the maximum service temperature of 1.4539-C850?
1.4539-C850 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.4539-AT and 1.4539-C850?
AT is the default condition — standard supply condition for plate, bar, pipe and fittings; maximum corrosion resistance and ductility. C850: half-hard strip/wire for high-strength clamps, springs and reinforcement where corrosion life still matters. Yield strength is 260 MPa in AT versus 650 MPa in C850.
Sources
- EN 10088-1/-2/-3 Stainless steels — X1NiCrMoCu25-20-5 (1.4539) — CEN (2014)
- ASTM A240/A240M — plate, sheet, strip (UNS N08904) — ASTM (2023)
- ASTM B625 / B649 / B677 — N08904 plate, bar and tube — ASTM (2022)
- 904L / 1.4539 alloy datasheet — Outokumpu (2023)
- Sanicro 28 / 904L family corrosion data — Alleima (Sandvik) (2023)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels — ASM International (1990)
- GB/T 24511 / GB/T 4237 (00Cr20Ni25Mo4.5Cu) — SAC (2017)
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.