The effectiveness of development and application of quality control integration technology for concasting 260 mm x300 mm bloom of alloy steels produced with 50 t EAF-LF(VD)-CC flow sheet at Laiwu Steel is briefly presented. The quality of concasting bloom is improved by development of process control technologies including suitable bloom cleanliness and protection casting

secondary cooling equipment design for dynamic control of secondary cooling

precision parameters integration optimization

and on-line prediction and qualification system for bloom quality with hot charging process. The examination qualified rate of pickled macrostructure of rolled steel products increases from 97. 50% in 2007 to 99. 01% in 2009

the qualified rate of bloom is more than 99.92%

the yield of products increases from original 96. 50% to 96. 80%

and the hot charging rate raises from 45% to 75%.