Strand Billet Caster And Improvement Of Quality Control

The internal quality of slab produced in billet in No1steelmaking plant of SISG wasstudied in this paper. The internal quality of billet was analyzed to study the cause of internaldefect. A series of measures on manual operation, equipment improvement, processoptimization and so on were taken, and The internal defect rate is reduced to9.4x10-4.Remarkable economic benefits were achieved at the same time. The main conclusions are asfollows:1. There was an obvious correlation between superheat of liquid steel and internal qualityof slab. The internal quality of slab can be improved significantly by reducing the tappingtemperature of molten steel, strengthening the detection of tundish temperature and keepingthe superheat temperature below25℃.2. There was an obvious correlation between casting speed instability and internalquality of slab. Frequent fluctuations of soft reduction parameters and secondary coolingwater amount caused by casting speed instability resulted in internal quality defects. Thecasting speed instability caused by equipment and procedure convergence can be preventedeffectively by implementing a typical casting speed system during casting process.3. There was an obvious correlation between secondary cooling water process andinternal quality of slab. The internal quality of slab can be improved significantly byoptimizing water distribution model.4. The C content in molten steel and billet internal quality have significant correlation,the melting process in molten steel by optimizing the content of C, can improve the slabinternal crack.