ROOT CAUSE ANALYSIS OF SURFACE DEFECTS IN COILS PRODUCED THROUGH THIN SLAB ROUTE

摘要

A metallurgical analysis of longitudinal cracks in a medium carbon grade of steel, produced through Thin Slab Casting and Rolling (TSCR) process is presented in this paper. Using characterization techniques, it was established that the defect originated from the funnel mold of thin slab caster. Temperature profiles of thermocouples in caster mold were employed to evaluate the heat transfer characteristics during primary solidification. The profiles helped to assess the performance of a standard mold flux used for casting this grade and hypothesize a possible mechanism of defect evolution. Slightly changed characteristics of the mold flux addressed the defect by promoting a stable and uniform heat transfer. This drastically lowered defect occurrence and rejections due to longitudinal cracks in this grade.