EN 10084 — Case hardening steels. Technical delivery conditions
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Scope
Case-hardening steels supplied as bar, rod, wire, forgings and hot-rolled flat products: C10E to C16E, 17Cr3, 16MnCr5, 20MnCr5, 18CrMo4, 20NiCrMo2-2, 18CrNiMo7-6, 20MoCr4 and others, with their +H hardenability bands and R (controlled S) variants. Specifies chemistry, Jominy bands, delivery hardness (+A, +FP, +S, +TH) and informative core properties.
Grades covered by EN 10084
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Nearest equivalents |
|---|---|---|---|---|---|---|
| 16MnCr5 | 1.7131 | Alloy case-hardening steel | 0.14 – 0.19 | ≥ 590 | 780–1080 | 5115, SCr415 / SCr420, 16CrMn / 20CrMn |
| C10 | 1.0301 | Unalloyed low-carbon case-hardening steel | 0.07 – 0.13 | ≥ 295 | 490–690 | 1010, 1008, S10C / S09CK |
| C15 | 1.0401 | Unalloyed case-hardening steel | 0.12 – 0.18 | ≥ 355 | 590–780 | 1015, 1018, S15C / S15CK |
Revision history and superseded standards
| Year | Change |
|---|---|
| 1998 | EN 10084:1998 — first European edition |
| 2008 | EN 10084:2008 — current; hardenability bands revised, 18CrNiMo7-6 added |
Supersedes: DIN 17210:1986 (Ck15, 16MnCr5, 20MnCr5); EN 10084:1998.
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Related standards
Case hardening is a surface treatment with a core specification
Case hardening steels are low-carbon — typically 0.10 to 0.20 % — precisely so that carbon can be added to the surface afterwards. Carburising at 880–950 °C diffuses carbon into the outer layer; quenching then produces a hard martensitic case over a tough, comparatively soft core.
What EN 10084 specifies is the core: the chemistry, the hardenability band and the mechanical properties of the base material. Case depth and surface hardness belong to the heat treatment specification rather than to the steel grade, and they appear on the drawing, not on the mill certificate.
The H suffix and the Jominy band
A grade written 16MnCr5 carries its normal chemical limits. The same grade written with an H is supplied to a guaranteed hardenability band, verified by the Jominy end-quench test, with HH and HL variants for the upper and lower halves of that band.
For a gear that must hold a case depth and a distortion tolerance across a production run, the H variant is the specification that matters. Ordering the plain grade and hoping successive heats behave alike is how case depth drifts between batches.