Material degradation analysis and evaluation of repair feasibility for a rotary kiln shell using metallographic replication

Abstract

This paper presents a detailed technical analysis of the degradation of a rotary kiln steel shell based on metallographic replica examinations, with the objective of assessing the feasibility of repair or determining the need for shell section replacement. The key findings revealed pronounced intergranular degradation (cracking along grain boundaries), numerous microvoids, and the initiation of microcracks, indicating the occurrence of creep damage and material fatigue. Based on the observed degradation mechanisms, the replacement of the damaged shell section is recommended, as local repair welding is considered inadequate due to the extensive material deterioration and the high risk of continued crack propagation and the formation of new defects. In addition, further inspection activities and a comprehensive assessment of the remaining service life of the kiln are recommended.