Life of rolls in a cold rolling mill in a steel plantÐ operation versus manufacture A.K. Ray a, *, K.K. Mishra c , G. Das b , P.N. Chaudhary c a MTE Division, National Metallurgical Laboratory, Jamshedpur 831007, India b MTC Division, National Metallurgical Laboratory, Jamshedpur 831007, India c IRM Division, National Metallurgical Laboratory, Jamshedpur 831007, India Received 11 December 1998; accepted 19 January 1999 Abstract Failures of rolls occur due to improper manufacturing and operational parameters. Prematurely failed (spalled) roll samples collected from a reputed steel plant were examined for their chemistry, inclusion content, microstructures, carbide characteristics, hardness and retained austenite content. The residual stresses were also measured on the inner and outer surfaces of the spalled roll pieces. The higher content of retained austenite was primarily responsible for the spalling of indigenous rolls for which subzero treatment has been recommended. Several suggestions have also been made for smooth operation of the mill and consequently for the life extension of work rolls. # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Fatigue; Life extension; Retained austenite; Rolling mill; Spalling 1. Introduction The work rolls used in cold rolling mills are expected to perform under very arduous operating conditions. With the advent of faster mills and the increase in load, the quality of rolls needs continuous improvement. Cold mill rolls should withstand mechanical and thermal shock, must have excellent wear resistance and very little plastic deformation. The premature failure of a cold mill roll increases not only the cost of the rolls but also the down time of the mill, aecting productivity. The reasons for premature failure of forged and induction hardened alloy steel work rolls can be attributed to the combined eects of mechanical and Engineering Failure Analysis 7 (2000) 55±67 1350-6307/00/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S1350-6307(99)00004-7 www.elsevier.com/locate/engfailanal * Corresponding author. Tel.: +91-657-426091; fax: +91-657-426527. E-mail address: asokroy@csnml.ren.nic.in (A.K. Ray).