Designation
DIN: | 40 CrMnNiMo 8-6-4 |
AFNOR: | 40 CMND 8 |
UNI: | - |
AISI: | ≈ P20 + Ni |
Chemical composition:
C | 0.40 |
Mn | 1.50 |
Cr | 1.90 |
Mo | 0.20 |
Ni | 1.10 |
Si
| 0.30 |
Strength:
280 - 325 HB
(≈ 950 - 1100 N/mm²)
Thermal conductivity at 100 °C:
33.5 W/m K
Character:
low-sulphur tool steel, supplied in pre-toughened condition; due to its nickel content, it features uniform strength even with maximum plate dimensions
Application:
large cavity plates with deep cavities for items such as bumpers or dashboards, moulding frames
Treatment by
highly suitable:
Polishing, EDM, nitriding, etching
suitable:
Hard chrome
Heat treatment:
already pre-toughened; usually no heat treatment required
Soft annealing:
710 to 740 °C for about 2 to 5 hours; slow controlled cooling of 10 to 20 °C per hour to about 600 °C further cooling in air, max. 220 HB
Hardening:
840 to 870 °C
15 to 30 minutes keeping curing temperature
quenching in oil/hot bath/air 180 bis 220 °C
obtainable hardness: 53 HRC
Tempering:
slow heating to tempering temperature immediately after hardening; minimum time in furnace: 1 hour per 20 mm part thickness; tempering twice is recommended
Annealing graph:
Vers l’aperçu de la construction de moules
Vers l’aperçu de la construction d'outils de découpe