Steel C45EC +AC (Spheroidize annealed)
Heat-treated state
AISI/SAE 1045 · EN 1.1192 · GB 45
Softest, most formable rod/wire condition — pick for severe cold heading, cold extrusion or upsetting before quench & temper.
Values for the +AC condition
Other C45EC tempers and conditions
C45EC is listed in 8 conditions; see the grade overview at C45EC.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ACThis page Spheroidize annealed | Softest, most formable rod/wire condition — pick for severe cold heading, cold extrusion or upsetting before quench & temper. | 340 | 570 | 22 | 170 HB | — |
Annealed | General soft-annealed condition for easier machining and light cold forming when full spheroidization is not required. | 350 | 600 | 20 | 180 HB | — |
Treated for improved shearability | Structure conditioned for clean billet shearing on the header when heading strains are moderate. | 380 | 620 | 18 | 185 HB | 10 % IACS |
Hot rolled | Cheapest wire rod/bar condition; for hot forging, machining or as feedstock for in-house spheroidizing. | 400 | 700 | 16 | 200 HB | — |
Lightly cold drawn | Minimal reduction after annealing to clean the surface and hold diameter while keeping near-annealed formability. | 430 | 600 | 16 | 178 HB | 10 % IACS |
+AC+CDefault Spheroidize annealed and cold drawn | Standard cold-heading wire delivery: spheroidized then drawn to size/tolerance and surface finish for automatic header feed. | 520 | 630 | 12 | 185 HB | — |
Cold drawn | Drawn without prior spheroidizing — highest as-drawn strength and best straightness/tolerance for machined parts, limited heading ability. | 620 | 760 | 10 | 220 HB | — |
Guaranteed hardenability (Jominy band), hardened and tempered condition | Order +H when the headed part must be quench-hardened to a defined core hardness (e.g. property class 8.8 bolts); values below are typical after 830–860 °C quench + 550–600 °C temper. | 620 | 850 | 15 | 25 HRC | — |
What is C45EC +AC?
C45EC +AC is C45EC heat treated to +AC — softest, most formable rod/wire condition — pick for severe cold heading, cold extrusion or upsetting before quench & temper. C45EC +AC has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 76% of steel grades. Elongation at break is 22% and the elastic modulus is 208 GPa (30.2 Msi). C45EC +AC 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). +AC+C is the default condition FabDigit quotes; +AC is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Forms and bends easily — 75/100, better than 90% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
C45EC +AC properties
Typical room-temperature values for C45EC +AC; 14 are specific to this condition. Other listed values are C45EC reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C45EC +AC 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).
Mechanical16
C45EC +AC has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 76% of steel grades. Elongation at break is 22% and the elastic modulus is 208 GPa (30.2 Msi).
Thermal6
C45EC +AC is rated for continuous service to 300°C (572 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
C45EC +AC conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C45EC +AC takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
C45EC +AC's machinability is good (55/100, better than 62% of steel grades); weldability fair (40/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C45EC +AC
Is C45EC easy to machine?
Machines predictably at ~60 % of 1212; spheroidized structure smears slightly, cold drawn or normalized gives the best chip break — carbide tooling, 120–180 m/min dry or emulsion.
Can C45EC be welded?
CEV ≈ 0.6 — weldable only with 150–250 °C preheat, low-hydrogen consumables and post-weld stress relief; avoid welding hardened parts.
Can C45EC be formed, bent or molded?
Designed for cold heading/extrusion in the +AC or +AC+C condition with phosphate + soap or polymer lubricant; annealed rod tolerates upset ratios typical of class 8.8 bolt geometry.
What surface finishes work on C45EC?
No corrosion resistance of its own — zinc electroplate (with baking against hydrogen embrittlement), zinc-flake, phosphate + oil, or QPQ/nitride; polishes and hard-chromes well.
C45EC 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 | 0.42 – 0.5 | 0.45 |
| Sirestricted for cold heading / tool life | ≤ 0.3 | 0.2 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Crresidual | ≤ 0.3 | 0.15 |
| Niresidual | ≤ 0.3 | 0.1 |
| Moresidual | ≤ 0.1 | 0.03 |
| Curesidual, limits hot/cold workability | ≤ 0.25 | 0.15 |
| Cr+Mo+Nisum of residual alloying elements | ≤ 0.63 | — |
| Fe | balance | — |
C45EC +AC — frequently asked
What is C45EC +AC used for?
C45EC +AC is typically used for cold-headed fasteners, shafts, forged machine parts and bolts and studs. In short: cold-heading grade 1045; stronger than C35EC; class 8.8 bolt stock.
What is the yield strength of C45EC +AC?
C45EC +AC has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is C45EC +AC easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines predictably at ~60 % of 1212; spheroidized structure smears slightly, cold drawn or normalized gives the best chip break — carbide tooling, 120–180 m/min dry or emulsion.
Can C45EC +AC be welded?
With care — weldability is rated fair (40/100). CEV ≈ 0.6 — weldable only with 150–250 °C preheat, low-hydrogen consumables and post-weld stress relief; avoid welding hardened parts.
What surface finishes work on C45EC +AC?
No corrosion resistance of its own — zinc electroplate (with baking against hydrogen embrittlement), zinc-flake, phosphate + oil, or QPQ/nitride; polishes and hard-chromes well.
Can C45EC +AC be formed, bent or molded?
Designed for cold heading/extrusion in the +AC or +AC+C condition with phosphate + soap or polymer lubricant; annealed rod tolerates upset ratios typical of class 8.8 bolt geometry.
What is the maximum service temperature of C45EC +AC?
C45EC +AC is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10263-4 Steel rod, bars and wire for cold heading and cold extrusion — Part 4: Steels for quenching and tempering — CEN (2019)
- EN 10083-2 Steels for quenching and tempering — Non-alloy steels — CEN (2006)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, machinability ratings — Industrial Press (2020)
- Cold heading wire rod grade datasheets (C45EC/ML45) — Ovako / Saarstahl / wire rod (2023)
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.