Steel FDC-ANN (Annealed)
Heat-treated state
For heavy cold forming, heading or parts that will be hardened and tempered after shaping.
Values for the ANN condition
Other FDC tempers and conditions
FDC is listed in 5 conditions; see the grade overview at FDC.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page Annealed | For heavy cold forming, heading or parts that will be hardened and tempered after shaping. | 390 | 640 | 22 | 190 HB | — |
Class I | Use when formability and cost matter more than stress level (larger diameters, gentle bends). | 1,250 | 1,480 | 5 | 44 HRC | 9 % IACS |
CDDefault Cold drawn | Standard stocked condition: patented and hard-drawn wire coiled directly into springs. | 1,360 | 1,600 | 4 | 46 HRC | — |
Cold drawn + stress relieved | Post-coiling low-temperature bake: raises elastic limit, relieves coiling stresses and hydrogen, standard for finished springs. | 1,450 | 1,620 | 3.5 | 47 HRC | 9 % IACS |
Class II | Choose for higher design stress and better set resistance in the same wire size. | 1,490 | 1,750 | 3 | 49 HRC | 9 % IACS |
What is FDC-ANN?
FDC-ANN is FDC heat treated to ANN — for heavy cold forming, heading or parts that will be hardened and tempered after shaping. FDC-ANN has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 64% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi). FDC-ANN has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). CD is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- Forms and bends easily — 75/100, better than 90% of steel grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 100% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
FDC-ANN properties
Typical room-temperature values for FDC-ANN; 10 are specific to this condition. Other listed values are FDC reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
FDC-ANN has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical12
FDC-ANN has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 64% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
FDC-ANN is rated for continuous service to 120°C (248 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
FDC-ANN conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of FDC-ANN takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability6
FDC-ANN's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (20/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with FDC-ANN
Is FDC easy to machine?
Rarely machined in the hard-drawn state; grind or use carbide for wire-end operations, or machine after annealing.
Can FDC be welded?
Poor weldability — 0.45–0.85 % C gives brittle martensite in the HAZ and destroys the drawn strength; use mechanical joining or resistance-weld with preheat/post-bake only for non-stressed tabs.
Can FDC be formed, bent or molded?
Coils and bends readily on CNC spring formers; allow for large springback, avoid bend radii below about 2× wire diameter, then bake 230–260 °C for 20–30 min to relieve stresses.
What surface finishes work on FDC?
Supplied oiled or phosphated; zinc/zinc-nickel plating, mechanical galvanizing or powder coating are common — bake within 4 h after electroplating to avoid hydrogen embrittlement; shot peening markedly improves fatigue life.
FDC 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 |
|---|---|---|
| Ccarbon level selected by wire size / tensile class | 0.45 – 0.85 | 0.65 |
| Mn | 0.3 – 1.3 | 0.7 |
| Si | 0.1 – 0.3 | 0.2 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.02 |
| Fe | balance | — |
FDC-ANN — frequently asked
What is FDC-ANN used for?
FDC-ANN is typically used for light mechanical springs, clips and retaining rings and small compression/extension springs. In short: lowest-cost spring wire; hard-drawn, not oil-tempered; 120 °C service ceiling.
What is the yield strength of FDC-ANN?
FDC-ANN has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is FDC-ANN easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Rarely machined in the hard-drawn state; grind or use carbide for wire-end operations, or machine after annealing.
Can FDC-ANN be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — 0.45–0.85 % C gives brittle martensite in the HAZ and destroys the drawn strength; use mechanical joining or resistance-weld with preheat/post-bake only for non-stressed tabs.
What surface finishes work on FDC-ANN?
Supplied oiled or phosphated; zinc/zinc-nickel plating, mechanical galvanizing or powder coating are common — bake within 4 h after electroplating to avoid hydrogen embrittlement; shot peening markedly improves fatigue life.
Can FDC-ANN be formed, bent or molded?
Coils and bends readily on CNC spring formers; allow for large springback, avoid bend radii below about 2× wire diameter, then bake 230–260 °C for 20–30 min to relieve stresses.
What is the maximum service temperature of FDC-ANN?
FDC-ANN is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between FDC-CD and FDC-ANN?
CD is the default condition — standard stocked condition: patented and hard-drawn wire coiled directly into springs. ANN: for heavy cold forming, heading or parts that will be hardened and tempered after shaping. Yield strength is 1,360 MPa in CD versus 390 MPa in ANN.
Sources
- ASTM A227/A227M — Steel Wire, Cold-Drawn for Mechanical Springs — ASTM International (2023)
- JIS G 3521 — Hard drawn steel wire — JSA (2020)
- EN 10270-1 — Steel wire for mechanical springs, patented cold drawn unalloyed — CEN (2017)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- SAE HS-795 Spring Design Manual — SAE International (1996)
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.