Category 03

Case-Hardening Steels

Case-hardening steels are low-carbon alloy steels (0.10–0.20% C) that, after thermochemical treatment (cementation), acquire a hard surface (HRC 58–62) and a tough core resistant to dynamic loads.

This combination makes them ideal for gearbox gears, power transmission components, pins and any part subject to surface wear and simultaneous dynamic loading.

We stock 18NiCrMo5 in round bars from Ø20 to Ø450 mm, with EN 10204 3.1 certificates. 17CrNiMo6 (1.6587) and 15CrNi6 (1.5919) are available on order.

18NiCrMo5 case-hardening bars
HRC 60
Surface
Hardness
Available Grades

Grades

GradeW.Nr.Standard%CDiametersAvailability
18NiCrMo51.6571EN 100840.15–0.21Ø20–Ø450In stock
17CrNiMo61.6587EN 100840.14–0.19Ø20–Ø450On order
15CrNi61.5919EN 100840.12–0.17Ø20–Ø300On order

18NiCrMo5 is maintained in permanent stock due to its broad range of applications, international equivalence (AISI 4317), and uniform performance across the full diameter range Ø20–Ø450 mm. Grades 17CrNiMo6 and 15CrNi6 are available on order for specialized applications.

Spotlight
18NiCrMo5

18NiCrMo5 / 1.6571

The most widely used case-hardening steel in the gear industry — for automotive, heavy vehicle and industrial gearboxes.

Chemical Composition (wt%)

C
0.15–0.21
Si
≤ 0.40
Mn
0.60–0.90
Cr
0.80–1.10
Ni
1.20–1.50
Mo
0.20–0.30
P
≤ 0.025
S
≤ 0.035

Mechanical Properties (after Cementation + Q+T)

PropertyValueNotes
Surface Hardness58–62 HRCAfter quenching
Core Hardness30–40 HRCTough core
Case Depth0.5–2.0 mmSelected during treatment
Core Yield Strength≥ 850 MPaTypical value
Fatigue ResistanceVery highDue to hard surface

Identification mark: Blue / Grey

Applications

Typical Applications

Gears & Pinions

Gearbox gears, differentials, industrial reducers, pump rotors.

Pins & Bolts

Power transmission pins, high fatigue-resistance bolts, connector components.

Camshafts

Internal combustion engine camshafts, distribution components.

Bearings

Bearing rings, roller bearing components, rotating component bases.

Need Case-Hardening Steels?

All main grades in stock or on order, with full certificates and traceability.

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