Steel C20C +A (Annealed)
Heat-treated state
EN 1.0411
Fully softened ferrite-pearlite condition for maximum ductility before deep drawing or heavy machining of blanks.
Values for the +A condition
Other C20C tempers and conditions
C20C is listed in 8 conditions; see the grade overview at C20C.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+AThis page Annealed | Fully softened ferrite-pearlite condition for maximum ductility before deep drawing or heavy machining of blanks. | 240 | 395 | 32 | 111 HB | — |
Hot rolled | Cheapest as-rolled bar/coil for welded structures, machined parts and blanks that will be carburized later. | 250 | 420 | 28 | 116 HB | — |
Spheroidize annealed | Spheroidized wire rod/bar with the lowest work-hardening rate — the standard EN 10263-3 delivery state for severe cold heading and cold extrusion. | 250 | 400 | 33 | 112 HB | — |
Normalized | Uniform fine-grained structure with the best toughness/strength balance; typical for machined shafts and welded parts before carburizing. | 300 | 440 | 28 | 126 HB | — |
Light drawn | Only a few percent reduction to clean the surface and set size while keeping nearly annealed formability for subsequent heading. | 320 | 430 | 22 | 122 HB | — |
+U+CDefault Untreated and cold drawn | Standard bright cold-drawn bar/wire: tight tolerances, good straightness and higher yield strength for turned and cold-headed parts. | 390 | 470 | 15 | 131 HB | — |
Spheroidized and cold drawn | Best combination for multi-station cold formers: spheroidized structure plus drawn size/surface, giving low heading loads and few head cracks. | 400 | 470 | 16 | 135 HB | — |
Carburized and hardened | Final service condition for pins, bushings and small gears: 0.3–1.0 mm hard case on a tough, still-ductile low-carbon core. | 400 | 600 | 13 | 60 HRC | — |
What is C20C +A?
C20C +A is C20C heat treated to +A — fully softened ferrite-pearlite condition for maximum ductility before deep drawing or heavy machining of blanks. C20C +A has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 96% of steel grades. Elongation at break is 32% and the elastic modulus is 205 GPa (29.7 Msi). C20C +A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). +U+C is the default condition FabDigit quotes; +A is available on request or by drawing note.
Advantages
- Forms and bends easily — 88/100, better than 98% of steel grades
- Readily welded — 95/100, better than 97% of steel grades
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- Ductile — tolerates forming and impact — 32%, better than 95% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 96% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
C20C +A properties
Typical room-temperature values for C20C +A; 12 are specific to this condition. Other listed values are C20C reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C20C +A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
C20C +A has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 96% of steel grades. Elongation at break is 32% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
C20C +A is rated for continuous service to 350°C (662 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
C20C +A conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C20C +A takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
C20C +A's machinability is good (55/100, better than 62% of steel grades); weldability excellent (95/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C20C +A
Is C20C easy to machine?
Cold-drawn condition cuts best; annealed/spheroidized stock is gummy and smears — use sharp positive-rake tools, high speed and generous coolant, or switch to 1215/11SMn30 if free-machining is critical.
Can C20C be welded?
Excellent weldability by MIG/TIG/stick/resistance with CE ≈ 0.30; no preheat needed below ~25 mm, use ER70S-6 / E7018 fillers.
Can C20C be formed, bent or molded?
Very good cold formability — +AC or +AC+C rod is designed for multi-blow cold heading and cold extrusion; hot forge 1100–1250 °C.
What surface finishes work on C20C?
No natural corrosion protection: specify zinc or zinc-nickel plating, phosphate + oil, black oxide, hot-dip galvanizing or paint; polishes only to a modest luster.
C20C 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 |
|---|---|---|
| CEN 10263-3 C20C | 0.17 – 0.24 | 0.2 |
| Si | ≤ 0.3 | 0.2 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Curesidual, max | ≤ 0.25 | 0.1 |
| Crresidual, max | ≤ 0.3 | 0.1 |
| Niresidual, max | ≤ 0.3 | 0.08 |
| Fe | balance | — |
C20C +A — frequently asked
What is C20C +A used for?
C20C +A is typically used for gears, camshafts, small pins and sprockets. In short: cold-heading carburizing grade; excellent weldability; tough core after carburizing.
What is the yield strength of C20C +A?
C20C +A has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 395 MPa (57.3 ksi) — weaker than 96% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is C20C +A easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Cold-drawn condition cuts best; annealed/spheroidized stock is gummy and smears — use sharp positive-rake tools, high speed and generous coolant, or switch to 1215/11SMn30 if free-machining is critical.
Can C20C +A be welded?
Yes — weldability is rated excellent (95/100). Excellent weldability by MIG/TIG/stick/resistance with CE ≈ 0.30; no preheat needed below ~25 mm, use ER70S-6 / E7018 fillers.
What surface finishes work on C20C +A?
No natural corrosion protection: specify zinc or zinc-nickel plating, phosphate + oil, black oxide, hot-dip galvanizing or paint; polishes only to a modest luster.
Can C20C +A be formed, bent or molded?
Very good cold formability — +AC or +AC+C rod is designed for multi-blow cold heading and cold extrusion; hot forge 1100–1250 °C.
What is the maximum service temperature of C20C +A?
C20C +A is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C20C +U+C and C20C-CH?
+U+C is the default condition — standard bright cold-drawn bar/wire: tight tolerances, good straightness and higher yield strength for turned and cold-headed parts. CH: final service condition for pins, bushings and small gears: 0.3–1.0 mm hard case on a tough, still-ductile low-carbon core. Yield strength is 390 MPa in +U+C versus 400 MPa in CH.
Sources
- EN 10263-3 Steel rod, bars and wire for cold heading and cold extrusion — Case hardening steels — CEN (2017)
- EN 10084 Case hardening steels — Technical delivery conditions — CEN (2008)
- ASTM A108 / SAE J403 (AISI 1020) — ASTM / SAE (2018)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 Heat Treating (carburizing of low-carbon steels) — ASM International (1991)
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.