Repair of a crack on the cement mill end wall

Abstract

This paper presents a comprehensive procedure for the rehabilitation of critical damage on the front wall of a cement mill. The repair addressed a crack measuring 700 mm in length and 160 mm in depth, located in the wall radius zone, which posed a significant risk to structural integrity and production continuity. The study provides a detailed analysis of the repair welding technology tailored to the base material, GS30Mn5V cast steel, with the application of specialized nickel-based electrodes (E Ni 6182). Particular emphasis is placed on the technological sequence of operations, including carefully controlled preheating within the temperature range of 180200°C, groove preparation using a graphite electrode, and subsequent multilayer welding. Mandatory interpass peening was applied to promote relaxation of residual stresses. In addition to the technological aspects, the paper examines the process of professional supervision, which encompassed non-destructive testing (NDT) at all stages of the repair. Despite challenging working conditions in a confined space and a crack depth exceeding initial estimates, the implemented methodology enabled a successful repair, with no occurrence of new cracks or permanent deformation.