Application• Gears subjected to high stresses, diverse parts subject to wear and fatigue in service.
• In the quenched and tempered condition: safety-critical parts.Characteristics• 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
| DIN |
EN |
| 1.6660 |
20NiCrMo13-4 |
Quality StandardEN 10084 2008 Case hardening steelsChemical 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.
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