C10 steel (1.0301): properties, composition, equivalents
C10 (1.0301) / C10E (1.1121, ex Ck10) is the 0.10 % carbon case-hardening and cold-heading steel of EN 10084: carburized surface 55–60 HRC, very soft core. Composition, heat treatment, 1010/S10C/10# equivalents and the C8/C12 question.
What is C10?
C10 is the lowest-carbon case-hardening steel in EN 10084: 0.07–0.13 % carbon, 0.3–0.6 % manganese, Werkstoff number 1.0301 (base) or 1.1121 for C10E, the old Ck10. Its very soft core (≈ 110–140 HB normalized) and outstanding cold formability make it above all a cold-heading and deep-drawing steel — screws, rivets, clevis pins, small bushes and drawn cups — that can afterwards be carburized to a 55–60 HRC skin where wear resistance is needed.
Because hardenability is minimal, the case is thin and only small parts are treated; for anything larger or more highly loaded, C15E or 16MnCr5 take over. Un-carburized C10 is also a general low-carbon bar and tube steel comparable to AISI 1010.
A note on names: searches for 'C8 steel' and 'C12 steel' almost always mean the cold-heading wire grades C8C and C12C of EN 10263-2, or simply a 0.08–0.12 % C steel — there is no separate C8 or C12 grade in EN 10084. C10/C10E is the grade to order.
C10 chemical composition
| Element | Mass % | Note |
|---|---|---|
| C | 0.07 – 0.13 | |
| Si | ≤ 0.4 | |
| Mn | 0.3 – 0.6 | |
| P | ≤ 0.045 | C10E (1.1121): P ≤ 0.035, S ≤ 0.035; C10R (1.1207): S 0.020–0.040 |
| S | ≤ 0.045 | |
| Cr | ≤ 0.4 | Cr + Mo + Ni ≤ 0.63 (C10E/C10R) |
| Mo | ≤ 0.1 | |
| Ni | ≤ 0.4 |
EN 10084:2008 Table 3. There is no EN grade 'C8' or 'C12': those names belong to older DIN/ISO usage (C8C, C12C cold-heading grades of EN 10263-2 with C 0.06–0.10 / 0.10–0.15) — C10 covers the same territory.
C10 mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| Core after carburize, harden & temper, 11 mm ref. bar (C10E) | ≥ 295 (≥ 42.8) | 490–690 (71.1–100.1) | 15 | — |
| Core, 30 mm ref. bar | ≥ 255 (≥ 37.0) | 440–590 (63.8–85.6) | 16 | — |
| Surface after carburizing | — | — | — | 55–60 HRC |
| +N normalized (typical) | ≈ 240–300 (≈ 34.8–43.5) | ≈ 400–480 (≈ 58.0–69.6) | 30 | ≈ 110–140 HB |
| +A annealed (delivery) | — | — | — | ≤ 131 HB |
| Cold-drawn +C (typical, ≤ 16 mm) | ≥ 390 (≥ 56.6) | 500–650 (72.5–94.3) | 10 | ≈ 160–200 HB |
Core values per EN 10084 Annex F (informative). Normalized and cold-drawn values are typical, not standardized.
C10 equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| 1010 | AISI / SAE | Identical | AISI/SAE 1010 (G10100): C 0.08–0.13, Mn 0.30–0.60 — same window. |
| 045M10 | BS (superseded British) | Identical | BS 970 045M10: C 0.07–0.13, Mn 0.30–0.60. |
| 10 | GB/T (China) | Identical | GB/T 699 grade 10 (10#): C 0.07–0.13, Mn 0.35–0.65. |
| 10 / 10kp | GOST (Russia/CIS) | Identical | GOST 1050 Steel 10: C 0.07–0.14, Mn 0.35–0.65. |
| S10C / S09CK | JIS (Japan) | Identical | JIS G4051 S10C: C 0.08–0.13, Mn 0.30–0.60; S09CK is the case-hardening quality. |
| 1008 | AISI / SAE | Near | C ≤ 0.10, Mn 0.30–0.50: covers the lower half of C10; the usual US cold-heading/sheet grade. |
| C8C / C10C | EN (European) | Near | EN 10263-2 cold-heading wire grades (C 0.06–0.10 / 0.08–0.13) — what 'C8' usually refers to. |
| C15 | EN (European) | Near | Next carbon step (0.12–0.18 %) with slightly stronger core. |
Identical = same composition and mechanical limits within rounding. Near = one limit differs (e.g. carbon max or impact temperature). Functional = interchangeable for most uses after an engineering check. Full cross-reference for C10 →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| Ck10 | DIN 17210 (withdrawn) | = C10E (1.1121). |
| C10 (1.0301) | DIN 17210 | Base quality. |
| 045M10 / 040A10 | BS 970 | |
| XC10 | NF A 35-551 |
Product forms and tolerance standards
Product forms: bar (hot-rolled, bright), wire rod and cold-heading wire (dominant form), strip and sheet (as DC01-type or C10S), seamless tube (EN 10305-1 E155 / C10).
Dimensional tolerances: bright bar: EN 10278; wire rod: EN 10108 / EN 10263 (cold-heading).
Key property values
C10 hardness
Delivery (+A) ≤ 131 HB; normalized ≈ 110–140 HB; cold-drawn 160–200 HB; carburized surface 55–60 HRC (shallow case 0.2–0.6 mm); core 10–20 HRC.
C10 yield and tensile strength
Normalized: yield ≈ 240–300 MPa, tensile ≈ 400–480 MPa, elongation ≈ 30 %. Cold-drawn: yield ≥ 390 MPa, tensile 500–650 MPa. Carburized core (11 mm ref.): 490–690 MPa.
Heat treatment
Carburize 880–980 °C; quench in water from 880–920 °C (small parts) or oil; temper 150–200 °C. Normalize 900–940 °C. Spheroidize (+AC) 680–710 °C for cold heading. Ac1 ≈ 725 °C, Ac3 ≈ 875 °C.
Physical properties
Density 7.85 g/cm³, E = 210 GPa, conductivity ≈ 52 W/m·K, expansion 12.2 × 10⁻⁶/K.
Weldability
Excellent weldability (CEV ≈ 0.15 %): all processes, no preheat, ideal for resistance welding of headed parts and tube. Do not weld carburized surfaces.
Machining, forming and heat treatment
Machinability is poor-to-fair when annealed (gummy, built-up edge) — index ≈ 55–60 %; cold-drawn bar machines better. C10R with controlled sulphur is used for automatic lathes. Cold heading, extrusion, drawing and bending are excellent — the reason it exists. Hot forging 1200–900 °C.
Typical applications
- Cold-headed screws, rivets, nails and small fasteners (property classes 4.6–5.8)
- Clevis pins, spring pins, small bushes and rollers (carburized)
- Deep-drawn cups, caps and housings
- Bright-drawn shafting for low-stress parts
- Welded tube and fittings, bicycle and furniture tube (E155/E195 lineage)
- Chain side plates and links
Frequently asked questions
What is C8 steel or C12 steel?
There is no C8 or C12 in EN 10084. 'C8' usually means C8C (EN 10263-2 cold-heading wire, C 0.06–0.10) or an 0.08 % carbon commercial steel; 'C12' is C12C or an 0.10–0.15 % C steel. For bar and case-hardening parts, C10E covers the C8 range and C15E the C12 range.
Is C10 the same as 1010?
Yes. AISI/SAE 1010 has C 0.08–0.13 and Mn 0.30–0.60 — the same window as C10. Case-hardening quality C10E corresponds to 1010 with tighter P/S.
What is C10 used for?
Mainly cold-headed fasteners and small pressed or drawn parts, and small carburized parts such as pins, rollers and bushes. It is also a general low-carbon bar and tube steel.
What is the difference between C10 and C15?
Carbon: 0.07–0.13 vs 0.12–0.18 %. C15 gives a slightly stronger core after carburizing and is used for somewhat larger or more loaded parts; C10 forms more easily.
Related grades
Verified against EN 10084:2008; EN 10084:2008 Tables 3, 6 and Annex F; EN 10263-2:2017 (C8C/C10C/C12C). Last checked: September 2026.