Stainless Steel CF16Fa-AC (Spheroidize annealed)
Heat-treated state
ASTM CF16Fa
Lowest-cost condition for non-critical, low-corrosion-duty parts where sensitized grain boundaries and lower ductility are acceptable.
Values for the AC condition
Other CF16Fa tempers and conditions
CF16Fa is listed in 3 conditions; see the grade overview at CF16Fa.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for corrosion-resistant castings — carbides dissolved and quenched for maximum ductility and corrosion resistance. | 240 | 500 | 42 | 150 HB | — |
Hot isostatically pressed then solution annealed | Choose when internal shrinkage porosity must be closed for pressure-tight or fatigue-loaded valve/pump bodies. | 245 | 520 | 48 | 150 HB | 2.3 % IACS |
ACThis page Spheroidize annealed | Lowest-cost condition for non-critical, low-corrosion-duty parts where sensitized grain boundaries and lower ductility are acceptable. | 260 | 510 | 25 | 165 HB | 2.4 % IACS |
What is CF16Fa-AC?
CF16Fa-AC is CF16Fa heat treated to AC — lowest-cost condition for non-critical, low-corrosion-duty parts where sensitized grain boundaries and lower ductility are acceptable. CF16Fa-AC has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 193 GPa (28 Msi). CF16Fa-AC 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; AC is available on request or by drawing note.
Advantages
- Easy to machine — 68/100, better than 98% of stainless steel grades
Limitations
- Hard to polish — 40/100, worse than 99% of stainless steel grades
- Difficult to weld — 15/100, worse than 98% of stainless steel grades
- Limited formability — 8/100, worse than 97% of stainless steel grades
- Low strength — 260 MPa (37.7 ksi), worse than 84% of stainless steel grades
- Low fracture toughness — 70 MPa·√m (63.7 ksi·√in), worse than 83% of stainless steel grades
CF16Fa-AC properties
Typical room-temperature values for CF16Fa-AC; 22 are specific to this condition. Other listed values are CF16Fa reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CF16Fa-AC 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).
Mechanical16
CF16Fa-AC has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 84% of stainless steel grades. Elongation at break is 25% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CF16Fa-AC is rated for continuous service to 500°C (932 °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
CF16Fa-AC conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of CF16Fa-AC takes about 52 MJ of energy and emits 5.2 kg of CO₂ — less than 76% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
CF16Fa-AC's machinability is good (68/100, better than 98% of stainless steel grades); weldability poor (15/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CF16Fa-AC
Is CF16Fa easy to machine?
Excellent for a stainless casting — run sharp carbide at 25–45 % higher speed than CF8M with positive rake and good chip-breaking; sulfides give short chips and clean threads.
Can CF16Fa be welded?
Not recommended for structural welds; sulfur/selenium promotes hot cracking — if repair is unavoidable use low-heat-input GTAW with 309/312 filler and re-solution-anneal.
Can CF16Fa be formed, bent or molded?
Sand or investment cast with generous risering; austenitic solidification shrinkage ~2.1 % and low thermal conductivity require directional feeding of heavy sections.
What surface finishes work on CF16Fa?
Passivate (nitric or citric, ASTM A967) after machining; mirror polishing and electropolishing are limited by inclusion pull-out, so specify a satin/bead-blast finish where cosmetics matter.
CF16Fa 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 |
|---|---|---|
| C | ≤ 0.16 | 0.12 |
| Mn | ≤ 1.5 | 1 |
| Si | ≤ 2 | 1.3 |
| P | ≤ 0.04 | 0.03 |
| Sfree-machining addition; some heats substitute Se 0.20–0.35 (CF16F) | 0.2 – 0.4 | 0.28 |
| Cr | 18 – 21 | 19.5 |
| Ni | 9 – 12 | 10.5 |
| Mooptional/residual Mo permitted, aids machinability and corrosion | ≤ 1.5 | 0.5 |
| Fe | balance | — |
CF16Fa-AC — frequently asked
What is CF16Fa-AC used for?
CF16Fa-AC is typically used for machined fittings, precision valve components, valve trim and stems, instrument housings with tapped ports, threaded adapters and couplings and small pump and meter bodies. In short: free-machining moly cast stainless; better machinability than CF8M; machined fittings grade.
What is the yield strength of CF16Fa-AC?
CF16Fa-AC has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 84% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CF16Fa-AC easy to machine?
Reasonably — machinability is rated good (68/100, better than 98% of stainless steel grades). Excellent for a stainless casting — run sharp carbide at 25–45 % higher speed than CF8M with positive rake and good chip-breaking; sulfides give short chips and clean threads.
Can CF16Fa-AC be welded?
Not readily — weldability is rated poor (15/100). Not recommended for structural welds; sulfur/selenium promotes hot cracking — if repair is unavoidable use low-heat-input GTAW with 309/312 filler and re-solution-anneal.
What surface finishes work on CF16Fa-AC?
Passivate (nitric or citric, ASTM A967) after machining; mirror polishing and electropolishing are limited by inclusion pull-out, so specify a satin/bead-blast finish where cosmetics matter.
Can CF16Fa-AC be formed, bent or molded?
Sand or investment cast with generous risering; austenitic solidification shrinkage ~2.1 % and low thermal conductivity require directional feeding of heavy sections.
What is the maximum service temperature of CF16Fa-AC?
CF16Fa-AC is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CF16Fa-SA and CF16Fa-AC?
SA is the default condition — standard supply condition for corrosion-resistant castings — carbides dissolved and quenched for maximum ductility and corrosion resistance. AC: lowest-cost condition for non-critical, low-corrosion-duty parts where sensitized grain boundaries and lower ductility are acceptable. Yield strength is 240 MPa in SA versus 260 MPa in AC.
Sources
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application — ASTM International (2019)
- ASTM A744/A744M — Castings, Corrosion Resistant, for Severe Service — ASTM International (2019)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASTM A967/A967M — Chemical Passivation Treatments for Stainless Steel Parts — ASTM International (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.