Metallurgical and Materials Transactions B

, Volume 31, Issue 6, pp 1483–1490

Analysis of secondary oxide-scale failure at entry into the roll gap

  • M. Krzyzanowski
  • J. H. Beynon
  • C. M. Sellars
Article

DOI: 10.1007/s11663-000-0033-z

Cite this article as:
Krzyzanowski, M., Beynon, J.H. & Sellars, C.M. Metall and Materi Trans B (2000) 31: 1483. doi:10.1007/s11663-000-0033-z

Abstract

Both numerical analysis based on finite-element (FE) modeling and experimental evidence concerning the secondary oxide-scale failure at entry into the roll gap are presented and reviewed for a better understanding of events at the roll-workpiece interface, in turn, leading to better definition of the boundary conditions for process models. Attention is paid to the two limit modes leading to oxide-scale failure, which were observed earlier during tensile testing under rolling conditions. These are considered in relation to the temperature, the oxide-scale thickness, and other hot-rolling parameters. The mathematical model used for the analysis is composed of macro and micro parts, which allow for simulation of metal/scale flow, heat transfer, cracking of the oxide scale, as well as sliding along the oxide/metal interface and spallation of the scale from the metal surface. The different modes of oxide-scale failure were predicted, taking into account stress-directed diffusion, fracture and adhesion of the oxide scale, strain, strain rate, and temperature. Stalled hot-rolling tests under controlled conditions have been used to verify the types of oxide-scale failure and have shown good predictive capabilities of the model. The stock temperature and the oxide-scale thickness are important parameters, which, depending on other rolling conditions, may cause either through-thickness cracking of the scale at the entry or lead to entry of a nonfractured scale when the scale/metal interface is not strong enough to transmit the metal deformation.

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2000

Authors and Affiliations

  • M. Krzyzanowski
    • 1
  • J. H. Beynon
    • 1
  • C. M. Sellars
    • 1
  1. 1.the Institute for Microstructural and Mechanical Process Engineering: IMMPETUSThe University of SheffieldSheffieldUnited Kingdom