Study on the Crack Formation Mechanism of Micro-alloyed Steel Slab during Hot Delivery Process

Based on experimental investigation of precipitates behavior, formation mechanism on hot delivery crack of microalloy steel was analyzed by binding microstructure evolution and thermal stress changing. The results show that different conveied way and different hot charging temperature are effect significantly on precipitates behavior in charging slab. The hot delivery crack of microalloy steel was formed by resultant force of precipitates behavior, microstructure evolution and thermal stress changing. The microstructure evolution that it is the formation of pro-eutectoid ferrite omentum on austenitic grain boundaries in Arl similar to Ar3 is the leading role on formation of hot delivery crack. It is supply conditions for precipitated particles distributed along the austenitic grain boundaries and formation of hot delivery crack of microalloy steel.