Reasonable Temperature Schedules for Cold or Hot Charging of Continuously Cast Slabs

摘要

There are occasionally transversely fracture problems for some continuously cast slabs during transportation or handling away from their storage state. There are also steel slabs being very sensitive to the formation of surface cracks during hot charging or following rolling process. It is revealed that steels with higher contents of pearlite delayed transformation elements have higher crack-sensitivity with room cooling condition, which should be slowly cooled down after cut to length from hot strand or charged to reheating furnace directly. Steels with higher contents of carbonitride forming elements, however, are even crack sensitive to hot charging temperatures due to the precipitation induced ductility tough. Based on thermodynamic theory for carbonitride precipitation in austenite and a solid-state phase transformation model, the CCT diagrams and the hot charging brittleness temperature range of related steels have been presented for the reasonable determination of their cold or hot charging temperature schedules.