Modeling fatigue crack and spalling for rolling die under hot milling

Abstract

In hot milling process, rolling die is subjected to nonsteady conditions which can rise the combinations of fatigue and spalling damage mechanism. An understanding about the failure mechanism of the rolling die is essential under hot rolling process. Fatigue crack growth and spalling process are governed by highly concentrated strain and stress in the crack tip region. Based on the theory of elastic‐plastic fracture mechanics, an analytical model are presented in this paper to determine the elliptical crack growth rate and spalling damage mechanism. The model includes new proposed constitutive equations for fatigue and spalling crack growth. To verify the models, finite element simulation and experimental data are considered. The results show good agreement with finite element simulation and experimental data.

Fatigue Failure Analysis for Bimetallic Work Roll in Hot Strip Mills

“…In this article, this internal fatigue failure caused by will be studied as the previous papers only focused on the surface spalling in backup rolls. [ 21–29 ] This surface failure starts from several mm inside from the surface caused by the shear stress under rolling fatigue is very different from the failures in Figure 6 caused by in Figure 5.…”

“…The previous roll failure studies mainly focused on surface failure, so‐called spalling, which is mainly caused by the shearing stress due to the rolling contact fatigue at several mm depth from the roll surface. [ 21–29 ] Compared with the spalling at the roll surface, few studies are available for the HSS/DCI boundary failure in the inner layer of work rolls. Some studies discussed the fatigue crack initiation at the internal layer without discussing the rolling normal stress causing this boundary failure.…”