Steel Grade Datasheet
C15/ 1.0401 / ≈ 1015 / 1018Unalloyed Low-Carbon Steel
What is C15 (1018) steel?
C15 (Werkstoff No. 1.0401, ≈AISI 1015/1018) is an unalloyed low-carbon steel with 0.12–0.18% carbon. Its low carbon gives excellent weldability, formability and cold heading. It has two main uses: as a case-hardening (carburizing) steel for lightly loaded parts, and as an economical general engineering steel. In the normalized condition it provides ~400–550 MPa tensile strength.
Chemical Composition
Cast analysis, % by weight (per the applicable EN standard)
| Element | Range (%) |
|---|---|
| C | 0.12–0.18 |
| Si | ≤ 0.40 |
| Mn | 0.30–0.60 |
| P | ≤ 0.045 |
| S | ≤ 0.045 |
Mechanical Properties (+N (normalize, tipik değerler) — sementasyon için +A halinde işlenir)
Values depend on ruling section / thickness (d).
| Section (mm) | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) |
|---|---|---|---|
| d ≤ 16 (+N) | ≈ 250 | 400–550 | 22 |
| 16 < d ≤ 40 (+N) | ≈ 240 | 380–530 | 24 |
Hardness: +A (annealed): ≤ ~143 HB (easily machined) · Carburized surface: ~58–62 HRC (shallow case; unalloyed core stays soft)
C15 / 1018 properties and use
International Equivalents
Values marked ≈ are nearest matches, not exact equivalents. Always confirm against the governing standard.
| System | Grade |
|---|---|
| EN | C15 / C15E |
| W.-Nr. (DIN) | 1.0401 (Ck15: 1.1141) |
| AISI/SAE | ≈ 1015 / 1018 |
| ASTM | A29 / A510 |
| JIS | S15C |
| GOST | ≈ Сталь 15 |
| BS (UK) | ≈ 040A15 (EN32) |
| GB (China) | 15 |
Applications
- Lightly loaded case-hardened parts (small gears, pins, bushings)
- Bolts, nuts and cold-headed fasteners
- Welded light structures and brackets
- General machine parts
- Cold-formed sheet and profiles
- Chain and linkage parts
Available Product Forms
Frequently Asked Questions
Are C15 and 1018 the same?+
Very close but not identical. Both are unalloyed low-carbon steels; C15 (1.0401) has 0.30–0.60% manganese, while AISI 1018 has 0.60–0.90% — 1018 gives slightly higher strength and hardenability. The nearest AISI to C15 is actually 1015. They are interchangeable for general use; for critical work follow the ordering standard.
Can C15 be case-hardened?+
Yes, but shallowly. Carburizing at 880–920 °C and quenching gives ~58–62 HRC at the surface, but because the steel is unalloyed the core stays soft and there is no deep hardening. It suits lightly loaded small parts; for higher core strength, alloyed 16MnCr5 is used.
Is C15 weldable?+
Yes, excellently. Its very low carbon (0.15%) allows welding by all common processes without preheat. It is among the most easily welded of the low-carbon steels.
What is the difference between C15 and C45?+
Carbon content: C15 0.15%, C45 0.45%. C15 is low strength but very tough and easy to weld/form — ideal for case hardening and cold heading. C45 hardens on quenching and is a medium-strength engineering steel for shafts/gears. Use C45 where strength is needed, C15 where forming/welding matters.
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References & Standards
Values on this page are reference data compiled from the applicable EN standard; certified material properties are defined by the mill test certificate (EN 10204 3.1).