Centreline defects in strips produced through thin slab casting and rolling

Abstract

Segregation in conventional slabs has been the topic of multiple researches; the centreline segregation in thin slabs has not been explicitly reported in published literature. However, a centreline band (defect) is invariably observed on macroetching high-manganese (>1 wt-%) strips from thin slab casting and rolling route of TATA Steel, Jamshedpur. A study was conducted to establish the exact nature of centreline defects and correlate with observation in the corresponding slab. Presence of second phases at the centreline due to heavy manganese enrichment was observed to be the source of defect band. In summary, this paper establishes a direct correlation between defects in hot-rolled strips and macrosegregation in thin slabs and highlights countermeasures taken to address the defect.

Controlling Variability in Mechanical Properties of Plates by Reducing Centerline Segregation to Meet Strain-Based Design of Pipeline Steel

“…The content of Mn in the centerline of plates had the same trend as the carbon content, i.e., for sample B-4#, sample A-4#, and sample A-2#, the maximum Mn content was 1.813 wt.%, 2.382 wt.%, and 2.385 wt.%, respectively. A previous study [24] reported that the content of Mn was at 1.82 wt.% or 1.76 wt.%, the corresponding microstructure was ferrite, while the content of Mn was up to 2.9 wt.%, its microstructure was bainite/martensite. Literature [25] also suggested that segregation is caused by an enrichment of Mn in the centerline region of plates.…”