Stainless Steel CF8C-CF (Cold Finished)
Reinforced grade
ASTM CF8C · UNS J92710, S34700 · AISI/SAE 347 · EN 1.4550, GX5CrNiNb19-11 · JIS SCS21, SUS347
Pick for tight tolerance, bright surface small-diameter bar with higher yield strength for machined shafts and fasteners.
Values for the CF condition
Other CF8C tempers and conditions
CF8C is listed in 7 conditions; see the grade overview at CF8C.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot Finished | Economical large-diameter bar and shapes for machined fittings and high-temperature parts; scaled surface, wide tolerances. | 240 | 585 | 45 | 160 HB | — |
Annealed wrought 347 plate/sheet | Use when the same Nb-stabilized chemistry is needed in wrought plate/sheet for weldments mated to CF8C castings. | 245 | 620 | 45 | 160 HB | 2.4 % IACS |
Stabilization annealed | Choose when nitric-acid or long-term 425–815 °C service demands maximum immunity to intergranular and knife-line attack. | 250 | 515 | 36 | 150 HB | 2.4 % IACS |
Hardened | Specify when ASME creep allowables above 540 °C are required (steam headers, reformer and turbine casings). | 250 | 600 | 42 | 165 HB | 2.4 % IACS |
SADefault Solution annealed (≈1065 °C, water quenched), cast per ASTM A351/A743… | Standard supply condition for CF8C valve bodies, pump casings and pressure-containing castings. | 255 | 530 | 39 | 150 HB | — |
Spheroidize annealed | Lowest-cost condition for non-pressure, non-corrosive-service hardware; ductility and IGC resistance are lower than solution annealed. | 260 | 500 | 28 | 160 HB | 2.4 % IACS |
CFThis page Cold Finished | Pick for tight tolerance, bright surface small-diameter bar with higher yield strength for machined shafts and fasteners. | 415 | 655 | 32 | 190 HB | — |
What is CF8C-CF?
CF8C-CF is CF8C in the CF grade — pick for tight tolerance, bright surface small-diameter bar with higher yield strength for machined shafts and fasteners. CF8C-CF has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 32% and the elastic modulus is 193 GPa (28 Msi). CF8C-CF has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F). SA is the default condition FabDigit quotes; CF is available on request or by drawing note.
Advantages
- Readily welded — 85/100, better than 87% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
- High service temperature — 816°C (1,501 °F), better than 79% of stainless steel grades
Limitations
- Hard to polish — 60/100, worse than 80% of stainless steel grades
CF8C-CF properties
Typical room-temperature values for CF8C-CF; 13 are specific to this condition. Other listed values are CF8C reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CF8C-CF has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
CF8C-CF has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 32% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CF8C-CF is rated for continuous service to 816°C (1,501 °F). It conducts heat at 16.3 W/m·K (9.42 BTU/hr·ft·°F), better than 68% of stainless steel grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
CF8C-CF conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 56% of stainless steel grades.
Sustainability4
Producing a kilogram of CF8C-CF takes about 55 MJ of energy and emits 5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
CF8C-CF's machinability is fair (45/100, better than 84% of stainless steel grades); weldability excellent (85/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CF8C-CF
Is CF8C easy to machine?
Gummy and work-hardening — use rigid setups, positive-rake sharp carbide, heavy constant feed, generous coolant and avoid dwelling; expect ~45 % of AISI 1212 rates.
Can CF8C be welded?
Excellent — Nb stabilization means no post-weld solution anneal for IGC resistance; use ER347/E347 filler, low heat input, control delta ferrite 5–15 FN to avoid hot cracking, and stabilize-anneal if knife-line attack is a risk.
Can CF8C be formed, bent or molded?
Castings pour readily with 2.0–2.3 % shrinkage and need generous risering due to low thermal conductivity; wrought 347 cold-forms well but work-hardens fast and requires interstage annealing.
What surface finishes work on CF8C?
Passivate per ASTM A967 (nitric or citric) or pickle/electropolish after machining and welding; no anodizing — shot blast plus pickling removes casting scale before final polish.
CF8C 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 |
|---|---|---|
| CASTM A351/A743 CF8C | ≤ 0.08 | 0.06 |
| Mn | ≤ 1.5 | 1 |
| Si | ≤ 2 | 1.3 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Cr | 18 – 21 | 19.5 |
| Ni | 9 – 12 | 10.5 |
| Moresidual | ≤ 0.5 | 0.2 |
| NbNb (Cb) ≥ 8×C; Nb+Ta option in some specs | 0.48 – 1 | 0.7 |
| Fe | balance | — |
CF8C-CF — frequently asked
What is CF8C-CF used for?
CF8C-CF is typically used for high-temperature exhaust manifolds, turbine casings and heavy weldment valve bodies. In short: highest-temperature CF grade; cast 347 equivalent; stabilized against sensitization.
What is the yield strength of CF8C-CF?
CF8C-CF has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is CF8C-CF easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Gummy and work-hardening — use rigid setups, positive-rake sharp carbide, heavy constant feed, generous coolant and avoid dwelling; expect ~45 % of AISI 1212 rates.
Can CF8C-CF be welded?
Yes — weldability is rated excellent (85/100). Excellent — Nb stabilization means no post-weld solution anneal for IGC resistance; use ER347/E347 filler, low heat input, control delta ferrite 5–15 FN to avoid hot cracking, and stabilize-anneal if knife-line attack is a risk.
What surface finishes work on CF8C-CF?
Passivate per ASTM A967 (nitric or citric) or pickle/electropolish after machining and welding; no anodizing — shot blast plus pickling removes casting scale before final polish.
Can CF8C-CF be formed, bent or molded?
Castings pour readily with 2.0–2.3 % shrinkage and need generous risering due to low thermal conductivity; wrought 347 cold-forms well but work-hardens fast and requires interstage annealing.
What is the maximum service temperature of CF8C-CF?
CF8C-CF is rated for continuous use to about 816°C (1,501 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CF8C-SA and CF8C-CF?
SA is the default condition — standard supply condition for CF8C valve bodies, pump casings and pressure-containing castings. CF: pick for tight tolerance, bright surface small-diameter bar with higher yield strength for machined shafts and fasteners. Yield strength is 255 MPa in SA versus 415 MPa in CF.
Sources
- ASTM A351/A351M — Castings, Austenitic, for Pressure-Containing Parts — ASTM (2020)
- ASTM A743/A743M — Castings, Fe-Cr, Fe-Cr-Ni, Corrosion Resistant, General Application — ASTM (2021)
- ASTM A276/A479 & A240 (Type 347/347H) — ASTM (2023)
- EN 10213 / EN 10088 (GX5CrNiNb19-11 1.4552, X6CrNiNb18-10 1.4550) — CEN (2016)
- GB/T 12230 & GB/T 1220 (06Cr18Ni11Nb) — SAC (2016)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol.1 & Vol.13B — 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.