This steel is intended for case hardening (carburizing the surface) followed by quenching, and—depending on the cross-section and processing parameters—it can be through-hardened to a depth of approximately up to 50 mm.
Compared to standard case-hardening steels, it offers higher strength and toughness in the core.
Tensile strength: approx. 900–1200 N/mm² (after proper heat treatment)
Typical applications
It is used for highly loaded machine components, especially:
gears, pinions
shafts, pins
crankshafts, connecting rods
camshafts and similar parts that must withstand high loads and fatigue
Heat treatment (overview)
Typical temperatures depending on the process route:
forging: 1100–800 °C
normalizing: 880–900 °C
soft annealing: 680–720 °C
intermediate annealing: 620–640 °C
quenching (oil): 830–860 °C
tempering: 150–200 °C
carburizing (case hardening): 860–880 °C
Chemical composition (typical)
The composition is designed to provide good hardenability, a hard surface, and a strong core:
C: 0.17%
Si: 0.40%
P: max. 0.025%
S: max. 0.035%
Cr: 1.50–1.80%
Ni: 1.40–1.70%
Mn: 0.50–0.80%
Mo: max. 0.10%
