In the study of clogging during steel continuous casting, less attention was paid to the clog fragmentation, although it always accompanies the clogging process. This paper introduces a sub-model for the clog fragmentation integrated into a comprehensive transient clogging model. In this sub-model, the intricate network of the clog is simplified as a bunch of fictitious cylinders. Each cylinder, called ‘clog finger’, contains a column of spherical non-metallic inclusions (NMIs), which are mechanically bound by sintering at contact points. The mechanical stress acting at the sintering neck between NMIs due to hydraulic forces of the melt flow is evaluated. Simulation of clogging/fragmentation in a real-scale SEN was conducted using the integrated clogging model. Comparing the simulation results with the as-clogged SEN observed in steel plants revealed a qualitative agreement. The effects of different parameters were discussed. The importance of the fragmentation and necessity to have such a sub-model were affirmed. Display omitted •A sub-model for the clog fragmentation was introduced and integrated into a comprehensive clogging model.•Simulation of clogging/fragmentation in a real-scale SEN was conducted using the integrated clogging model.•The simulation results were compared with the as-clogged SEN observed in steel plants.•The importance of the fragmentation and necessity to have such a sub-model were affirmed.