Premature failure of work-rolls in tandem mill: Some microstructural revelations
The microstructural features of prematurely spalled tandem mill work-rolls were examined in an attempt to correlate microstructure with spalling behavior and roll performance. Spalled samples were collected from work-rolls that had shown variations in roll life under similar conditions of mill usage. Optical microscopy revealed that a fine dispersion of spheroidal carbides in a matrix of tempered martensite was conducive to superior performance in terms of roll life (i.e., tonnage rolled), and that coarse angular and irregular shape carbides were detrimental to roll life.
Image analysis of roll microstructures indicated that small carbide size, large carbide volume fraction, and high carbide count were characteristic of higher-life rolls, and that large carbide size, low carbide volume fraction, and less carbide density were typical of lower-life rolls. The carbides in both types of microstructure were M7C3 type.
Keywordsroll breakage spalling tandem mill wear resistance work-roll
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- 1.W.L. Roberts: “Mill Rolls and Their Bearings,” Cold Rolling of Steel, G. Boothroyd and G.E. Dieter, ed., Marcel Dekker Inc., 1978, p. 109.Google Scholar
- 2.S. Kawashima, M. Yoshikawa, and S. Izumikawa: New Trend of Forged Hardened Steel Work Rolls and Back Up Rolls for Rolling Mills in Japan, 29th Mechanical Working and Steel Processing Conf. Proc., Iron and Steel Society, Warrendale, PA, 1988, vol. 25, pp. 49–57.Google Scholar
- 3.J.M. Chilton and M.J. Roberts: “Factors Influencing the Performance of Forged Hardened Steel Rolls,” Iron Steel Eng., Jan 1981, pp. 77–82.Google Scholar
- 4.C. Gaspard, P. Cosse, and A. Magnee: Contribution of E.S.R. and Progressive Induction Hardening to the Manufacture of Deep Hardened Work Rolls, 26th Mechanical Working and Steel Processing Conf. Proc., The Iron and Steel Society, Warrendale, PA, 1984, vol. 22, pp. 75–87.Google Scholar
- 5.J.Y. Cogne, B. Heritier, and J. Monnot: Proceedings of the Conference on Clean Steel 3, 23–26 June 1970 (Balatonfured, Hungary), The Iron and Steel Institute, London, 1972, p. 219.Google Scholar
- 6.P. Carless, H.T. Gisborne, and R. Price: Choice of Hardening Method for Forged Steel Work Rolls, 35th Mechanical Working and Steel Processing Conf. Proc., The Iron and Steel Society, Warrendale, PA, 1994, vol. 31, pp. 41–47.Google Scholar