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20NiCrMo13-4 1.6660 Case Hardening Steels

20NiCrMo13-4 1.6660 Case Hardening Steels Case Hardening Steels 20NiCrMo13-4 1.6660 Case Hardening Steels 20NiCrMo13 4 1

20NiCrMo13-4 1.6660 Case Hardening Steels


• Gears subjected to high stresses, diverse parts subject to wear and fatigue in service.
• In the quenched and tempered condition: safety-critical parts.


• High mechanical properties.
• Good fatigue strength.
• After carburising, quenching and tempering, the surface hardness is around 730 HV.
• Good toughness of the carburised layer.
• For some carburising applications, oil quenching can be replaced with gas pressure quenching in order to minimise distortion due to the heat treatment.

All Grades Comparison

1.6660 20NiCrMo13-4

Quality Standard

EN 10084 2008 Case hardening steels

Chemical Composition(%)

C Mn Si P S Cr Ni Mo
0.17-0.22 0.30-0.60 0.40 max 0.025 max 0.035 max 0.80-1.20 3.00-3.50 0.30-0.50

Hardness requirements for products delivered in the conditions

Process Hardness
treated to improve shearability 277HB max
soft annealed 255HB max
treated to hardness range 207HB-255HB
treated to ferrite-pearlite structure and hardness range 197HB-241HB

Conditions for heat treating test bars and treatment of the steels:

Process Temperatures (oC)
End quench test 850
Carburizing 880-980
Core-hardening 825-880
Case-hardening 800-850
Tempering 150-250

Mill′s test certificate:

EN 10204/3.1 with all relevant data reg. chem. composition, mech. properties and results of testing.