Material number 1.0401: C15
1.0401 is the European material number (Werkstoffnummer, EN 10027-2) for C15, unalloyed case-hardening steel specified in EN 10084.
Reading 1.0401 digit by digit
An EN 10027-2 number has the form 1.XXYY. The leading 1 marks it as steel. The pair 04 is the steel group, and for this number that group is steels 0.12–0.25 % C or Rm 400–500 MPa. The final pair 01 is a sequential count inside that group and carries no meaning of its own — 1.0401 is simply the 1th entry registered there.
The group digits are the useful part. Reading 04 tells you what kind of steel you are looking at before you know anything else about it, and the 2 other numbers from group 04 held here are listed below.
1.0401 identity card
| Item | Value |
|---|---|
| Material number (EN 10027-2) | 1.0401 |
| Symbolic grade name | C15 |
| Steel group | 04 — steels 0.12–0.25 % C or Rm 400–500 MPa |
| Sequential number in group | 01 |
| Specified in | EN 10084 |
| Steel family | Case-hardening steel |
| Yield, first condition in the table | ≥ 355 MPa (Core after carburize, harden & temper, 11 mm ref. bar (C15E)) |
| Tensile, same condition | 590–780 MPa |
| Cross-references held | 9 grades in 6 systems |
C15 (1.0401) / C15E (1.1141, ex Ck15) is the plain 0.15 % carbon case-hardening steel of EN 10084: carburized surface 55–62 HRC, core 440–590 MPa. Composition, heat treatment, 1015/S15C/15# equivalents.
Full data sheet for C15 → · Equivalent grades → · EN 10084 →
Group 04 — the neighbouring numbers
Same group digits, so the same broad class of steel. The sequential digits do not rank them.