Stainless Steel 1.3940-CF3A
Grade
EN 1.3940
CF3A = high-ferrite (controlled ferrite/Cr-Ni balance) higher-strength cast…
Same chemistry family but composition balanced to a higher δ-ferrite level for ~10% higher strength; avoid above ~350 °C because of 475 °C embrittlement.
Values for the CF3A condition
Other 1.3940 tempers and conditions
1.3940 is listed in 5 conditions; see the grade overview at 1.3940.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for all pressure-retaining and corrosion service — carbides dissolved, maximum corrosion resistance and ductility. | 250 | 530 | 55 | 140 HB | — |
As fabricated | Only for non-critical, non-corrosive structural castings; residual casting stresses and coarse dendritic structure lower ductility and toughness. | 250 | 500 | 35 | 150 HB | 2.3 % IACS |
Solution annealed + low-temperature impact tested | Pick for cryogenic valves, pumps and LNG service where documented sub-zero Charpy energy is required; ferrite content is normally capped for toughness. | 250 | 530 | 55 | 140 HB | 2.3 % IACS |
As-welded deposit | Permitted for this grade because C ≤0.03% prevents sensitization; use when re-solution-annealing a large casting is impractical. | 250 | 520 | 45 | 150 HB | 2.3 % IACS |
CF3AThis page High-ferrite (controlled ferrite/Cr-Ni balance) higher-strength cast… | Same chemistry family but composition balanced to a higher δ-ferrite level for ~10% higher strength; avoid above ~350 °C because of 475 °C embrittlement. | 300 | 570 | 40 | 155 HB | 2.4 % IACS |
What is 1.3940-CF3A?
1.3940-CF3A is 1.3940 in the CF3A grade — same chemistry family but composition balanced to a higher δ-ferrite level for ~10% higher strength; avoid above ~350 °C because of 475 °C embrittlement. 1.3940-CF3A has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 195 GPa (28.3 Msi). 1.3940-CF3A has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). SA is the default condition FabDigit quotes; CF3A is available on request or by drawing note.
Advantages
- Readily welded — 85/100, better than 87% of stainless steel grades
Limitations
- Limited service temperature — 350°C (662 °F), worse than 84% of stainless steel grades
1.3940-CF3A properties
Typical room-temperature values for 1.3940-CF3A; 23 are specific to this condition. Other listed values are 1.3940 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
1.3940-CF3A has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
1.3940-CF3A has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
1.3940-CF3A is rated for continuous service to 350°C (662 °F). It conducts heat at 16.8 W/m·K (9.71 BTU/hr·ft·°F), better than 70% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
1.3940-CF3A conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (61/100), worse than 56% of stainless steel grades.
Sustainability4
Producing a kilogram of 1.3940-CF3A takes about 53 MJ of energy and emits 4.3 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
1.3940-CF3A's machinability is fair (37/100, better than 57% of stainless steel grades); weldability excellent (85/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.3940-CF3A
Is 1.3940 easy to machine?
Gummy and work-hardening: use rigid setups, sharp positive-rake carbide, 60–110 m/min, heavy feed and flood coolant, avoid dwelling; watch for hard casting skin and sand inclusions.
Can 1.3940 be welded?
Excellent — GTAW/SMAW/FCAW with 308L (or 309L for dissimilar) filler; no post-weld anneal needed thanks to ≤0.03% C, keep interpass low and ferrite 3–10 FN to avoid hot cracking.
Can 1.3940 be formed, bent or molded?
Supplied as sand/investment castings; design generous fillets and directional feeding for the wide freezing range, and allow ~2% shrinkage plus machining stock.
What surface finishes work on 1.3940?
Pickle/passivate (ASTM A967) or electropolish after grinding; shot blasting with iron-free media only. No anodizing; hard chrome or nitriding possible for wear faces.
1.3940 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 |
|---|---|---|
| Cextra-low carbon, prevents sensitization | ≤ 0.03 | 0.02 |
| SiEN cast practice; ASTM CF3 allows up to 2.00 | ≤ 1.5 | 1 |
| MnASTM CF3 max 1.50 | ≤ 2 | 1 |
| P | ≤ 0.04 | — |
| SASTM CF3 max 0.04 | ≤ 0.03 | — |
| CrASTM CF3 range 17.0–21.0 | 17 – 20 | 18.5 |
| NiEN 18-13 balance; ASTM CF3 range 8.0–12.0 | 11 – 14 | 12.5 |
| Moresidual only | ≤ 0.5 | — |
| Nnitrogen-alloyed EN designation GX2CrNiN18-13; ASTM CF3 has no N requirement | 0.1 – 0.2 | 0.15 |
| Fe | balance | — |
1.3940-CF3A — frequently asked
What is 1.3940-CF3A used for?
1.3940-CF3A is typically used for valve bodies, pump casings and food and chemical process fittings. In short: as-cast weldable 304L; no post-weld anneal; high 55 % elongation.
What is the yield strength of 1.3940-CF3A?
1.3940-CF3A has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 1.3940-CF3A easy to machine?
Not especially — machinability is rated fair (37/100, better than 57% of stainless steel grades). Gummy and work-hardening: use rigid setups, sharp positive-rake carbide, 60–110 m/min, heavy feed and flood coolant, avoid dwelling; watch for hard casting skin and sand inclusions.
Can 1.3940-CF3A be welded?
Yes — weldability is rated excellent (85/100). Excellent — GTAW/SMAW/FCAW with 308L (or 309L for dissimilar) filler; no post-weld anneal needed thanks to ≤0.03% C, keep interpass low and ferrite 3–10 FN to avoid hot cracking.
What surface finishes work on 1.3940-CF3A?
Pickle/passivate (ASTM A967) or electropolish after grinding; shot blasting with iron-free media only. No anodizing; hard chrome or nitriding possible for wear faces.
Can 1.3940-CF3A be formed, bent or molded?
Supplied as sand/investment castings; design generous fillets and directional feeding for the wide freezing range, and allow ~2% shrinkage plus machining stock.
What is the maximum service temperature of 1.3940-CF3A?
1.3940-CF3A is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.3940-SA and 1.3940-CF3A?
SA is the default condition — standard supply condition for all pressure-retaining and corrosion service — carbides dissolved, maximum corrosion resistance and ductility. CF3A: same chemistry family but composition balanced to a higher δ-ferrite level for ~10% higher strength; avoid above ~350 °C because of 475 °C embrittlement. Yield strength is 250 MPa in SA versus 300 MPa in CF3A.
Sources
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant (grade CF3, J92500) — ASTM International (2019)
- ASTM A351/A351M — Castings, Austenitic, for Pressure-Containing Parts — ASTM International (2018)
- EN 10213 — Steel castings for pressure purposes / EN 10283 corrosion-resistant steel castings — CEN (2016)
- ASM Specialty Handbook: Stainless Steels — Cast Stainless Steels — ASM International (1994)
- ASM Handbook Vol. 1: Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
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.