Applications
- Replaces any carbon steel where higher mechanical strength or hardness is required.
- It is an alternative to replace steels such as AISI 4140 and 4340.
- Mechanical parts of machinery in general, such as elements for clamping or transmission of movement (shafts, axles, low-speed gears, worms, sprockets, high-strength bolts, machine bodies, torsion bars, etc.).
Characteristics:
- In the prehardened condition (treated or quenched), it has a very good combination of toughness and strength that allows its direct use in machinery parts applications.
- Machinability 59%.
- Greater uniformity of hardness from surface to core.
- Greater resistance to mechanical fatigue than 4140 steel.
- Machinery grade or low-alloy steel with improved hardenability; in the annealed condition, it can be subjected to hardening by quenching and tempering to hardness values around 50 HRC (see general heat treatment recommendations).
Chemical Composition
| Variant | %C | %Mn | %Si | %Ni | %Cr | %Mo |
|---|---|---|---|---|---|---|
| 9840 RT | 0.38 - 0.43 | 0.70 - 0.90 | 0.20 - 0.53 | 0.85 - 1.15 | 0.70 - 0.90 | 0.20 - 0.30 |