Steel C4C +A (Annealed)
Heat-treated state
EN 1.0303
Pick when maximum softness/ductility is wanted before very heavy upsetting or deep cold extrusion of low-carbon parts.
Values for the +A condition
Other C4C tempers and conditions
C4C is listed in 5 conditions; see the grade overview at C4C.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Spheroidized rod for the most severe cold-heading/extrusion ratios and for parts to be redrawn afterwards. | 175 | 300 | 43 | 85 HB | — |
+AThis page Annealed | Pick when maximum softness/ductility is wanted before very heavy upsetting or deep cold extrusion of low-carbon parts. | 180 | 300 | 42 | 88 HB | — |
+UDefault Hot rolled | Standard mill supply condition for wire rod; already soft enough for light-to-moderate heading, or for further drawing. | 210 | 330 | 38 | 95 HB | — |
Spheroidize annealed then cold drawn | The classic fastener-wire condition: annealed for maximum heading ductility, then lightly drawn to size and surface finish. | 355 | 420 | 16 | 120 HB | — |
Cold drawn | Drawn wire/bar with tight size tolerance and higher strength from work hardening; use when the part needs only modest further deformation. | 400 | 460 | 12 | 132 HB | — |
What is C4C +A?
C4C +A is C4C heat treated to +A — pick when maximum softness/ductility is wanted before very heavy upsetting or deep cold extrusion of low-carbon parts. C4C +A has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 99% of steel grades. Elongation at break is 42% and the elastic modulus is 207 GPa (30 Msi). C4C +A has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,500°C (2,732 °F). +U is the default condition FabDigit quotes; +A is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 42%, better than 100% of steel grades
- Forms and bends easily — 99/100, better than 100% of steel grades
- Conducts heat well — 58 W/m·K (33.5 BTU/hr·ft·°F), better than 99% of steel grades
- High electrical conductivity — 11.5 % IACS, better than 99% of steel grades
- Readily welded — 95/100, better than 97% of steel grades
Limitations
- Low strength — 180 MPa (26.1 ksi), worse than 99% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
C4C +A properties
Typical room-temperature values for C4C +A; 10 are specific to this condition. Other listed values are C4C reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C4C +A has a density of 7.87 g/cm³ (0.284 lb/in³), heavier than 92% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical16
C4C +A has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 99% of steel grades. Elongation at break is 42% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
C4C +A is rated for continuous service to 400°C (752 °F). It conducts heat at 58 W/m·K (33.5 BTU/hr·ft·°F), better than 99% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
C4C +A conducts electricity at 11.5 % IACS, better than 99% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C4C +A takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
C4C +A's machinability is fair (40/100, worse than 77% of steel grades); weldability excellent (95/100); formability excellent (99/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C4C +A
Is C4C easy to machine?
Soft and gummy — use sharp positive-rake tools, high speed, generous coolant and chip-breaking geometry; expect stringy chips and poor surface unless cold-drawn.
Can C4C be welded?
Excellent weldability by any process (RSW, MIG, TIG, projection); carbon equivalent well under 0.20 so no preheat or PWHT needed.
Can C4C be formed, bent or molded?
Outstanding cold heading/extrusion ductility — tolerates multi-station upsetting and severe reductions; phosphate + soap or polymer lubricant recommended for drawing.
What surface finishes work on C4C?
No anodizing; protect by zinc or zinc-nickel electroplating, hot-dip galvanizing, mechanical zinc or Dacromet/zinc-flake; can be carburized or nitrocarburized for surface hardness.
C4C 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, EN 10263-2 | ≤ 0.06 | 0.04 |
| Sialuminium-killed practice; Si often kept low | ≤ 0.3 | 0.1 |
| Mn | 0.2 – 0.45 | 0.3 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Curesidual | ≤ 0.25 | 0.1 |
| Altotal Al, killed/grain-refined | ≥ 0.02 | 0.04 |
| Fe | balance | — |
C4C +A — frequently asked
What is C4C +A used for?
C4C +A is typically used for cold-headed bolts and screws, rivets, wire fasteners and cold-formed pins. In short: cold-heading quality rod; very high forming ductility; low strength as-formed.
What is the yield strength of C4C +A?
C4C +A has a typical yield strength of 180 MPa (26.1 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 99% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is C4C +A easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Soft and gummy — use sharp positive-rake tools, high speed, generous coolant and chip-breaking geometry; expect stringy chips and poor surface unless cold-drawn.
Can C4C +A be welded?
Yes — weldability is rated excellent (95/100). Excellent weldability by any process (RSW, MIG, TIG, projection); carbon equivalent well under 0.20 so no preheat or PWHT needed.
What surface finishes work on C4C +A?
No anodizing; protect by zinc or zinc-nickel electroplating, hot-dip galvanizing, mechanical zinc or Dacromet/zinc-flake; can be carburized or nitrocarburized for surface hardness.
Can C4C +A be formed, bent or molded?
Outstanding cold heading/extrusion ductility — tolerates multi-station upsetting and severe reductions; phosphate + soap or polymer lubricant recommended for drawing.
What is the maximum service temperature of C4C +A?
C4C +A is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10263-2 — Steel rod, bars and wire for cold heading and cold extrusion, Part 2: non-heat-treatable steels — CEN (2017)
- EN 10027-2 — Numerical designation system for steels (1.0303) — CEN (2015)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook (machinability ratings, carbon steels) — Industrial Press (2020)
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.