Abstract Over the last years, deep rolling has been adopted to improve the fatigue strength of railway axles. In particular, recent researches between PoliMi and LucchiniRS have shown the possibility to greatly enhance the residual lifetime of axles in presence of defects from running in service by inhibiting the propagation of cracks under normal loading conditions and retarding the appearance of corrosion-fatigue phenomena. Therefore, the new automatic machining line for axles setup by LucchiniRS includes a modern cold-rolling machine as a finishing process for premium quality axles. This paper is devoted to discuss the optimization of the cold-rolling process considering all the relevant parameters (load, roller radius, pitch) through a novel model able to simulate the build-up of residual stresses. The model was validated by comparing the residual stress path with the experimental outcomes, showing a good agreement for the various combination of the adopted parameters. The exploitation of the model will enable the designer to optimize the cold-rolling process taking advantage of the increase of fatigue properties in the definition of a safe life maintenance plan.
[1]
D. Hills,et al.
Some useful results in the classical Hertz contact problem
,
1983
.
[2]
Gabriel Abba,et al.
Approximate Analytical Model for Hertzian Elliptical Contact Problems
,
2006
.
[3]
Uwe Zerbst,et al.
Safe life and damage tolerance aspects of railway axles – A review
,
2013
.
[4]
Stefano Beretta,et al.
An investigation about the influence of deep rolling on fatigue crack growth in railway axles made of a medium strength steel
,
2014
.
[5]
J. Chaboche,et al.
Modelization of the Strain Memory Effect on the Cyclic Hardening of 316 Stainless Steel
,
1979
.
[6]
E. Tanaka,et al.
A nonproportionality parameter and a cyclic viscoplastic constitutive model taking into account amplitude dependences and memory effects of isotropic hardening.
,
1994
.