Designation
DIN: | 90 MnCrV 8 |
AFNOR: | 90 MV 8
|
UNI: | 90 MnVCr 8 KU |
AISI: | ≈ O2 |
Chemical composition:
C | 0.90 |
Si | 0.20 |
Mn | 2.00 |
Cr | 0.40 |
V | 0.10 |
Strength:
max. 230 HB
(≈ max. 780 N/mm²)
Thermal conductivity at 100 °C:
33 W/m K
Character:
steel for through-hardening with good machinability and high wear resistance; low warping and high dimensional stability; with high toughness and through hardenability (uniform hardness for cross sections 40 mm)
Application:
cavity plates and inserts exposed to abrasive stress; cutting punches; wear plates, cutting dies and guiding plates; guiding rails
Treatment by
unusual:
Polishing, etching, nitriding » 1.2379
is possible:
EDM, hard chroming
Heat treatment:
Soft annealing:
680 to 720 °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:
790 to 820 °C
Quenching in oil/hot bath
Obtainable hardness: 63-65 HRC
Tempering:
slow heating (to avoid forming of cracks) to tempering temperature immediately after hardening; tempering twice with intermediate cooling down to 20 °C increases the steel's toughness
max. obtainable hardness after tempering: 58−60 HRC
Annealing graph:
Technical tip:
- Steel grade 1.2510 is an adequate alternative with regards to its properties, machinability and dimensional stability after heat treatment
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