Journal of Failure Analysis and Prevention

, Volume 5, Issue 6, pp 30–38 | Cite as

Genesis of spalling in tandem mill work-rolls: Some observations in microstructural degeneration

  • M. S. Prasad
  • S. K. Dhua
  • C. D. Singh
  • Amitava Ray
Case Histories

Abstract

Macroscopic investigations of spalled 3% Cr-variety forged steel work-rolls used in the tandem mill of an integrated steel plant showed steel strip welding on roll surfaces. Microstructural observations of roll samples at regions away from strip-welded zones showed the desired uniform dispersion of fine globular carbides in tempered martensite. Quantitative image analysis of all investigated rolls also showed desirable carbide characteristics, with >4 vol.% carbides and >200,000 individual carbides/mm2. The carbide sizes ranged from 0.69 to 0.83 µm. In contrast, optical and scanning electron microscopy (SEM) observations of the strip-welded regions showed microstructural degeneration thought to have occurred from surface and/or subsurface damage caused by localized thermal shock and intense pressure. This possibly resulted in the formation of a rehardened and heavily retempered zone at the strip-welded region. Cracks originated in the heavily retempered zone due to residual tensile stresses and propagated under the applied rolling stresses to produce spalling.

Keywords

microstructural degeneration spalling tandem mill work-rolls 

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Copyright information

© ASM International 2005

Authors and Affiliations

  • M. S. Prasad
    • 1
  • S. K. Dhua
    • 1
  • C. D. Singh
    • 1
  • Amitava Ray
    • 1
  1. 1.R&D Center for Iron & SteelSteel Authority of India LimitedDorandaIndia

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