COLD ROLLING PROCESS
The process is applied on axles after the final machining and introduces high compressive stresses (-300 to -500 MPa) in the axle surface and sub surface area.
The advantage of compressive stresses are to :
- Increase the fatigue limit (> 20%)
- Limit almost completely crack propagation
- Retardate crack nucleation in corrosion-fatigue conditions
Lucchini RS developed an analytic model of the cold rolling process in order to define all relevant parameters that will ensure an optimal residual stress profile.