Investigation of the relationship between surface quality and mould powder used in continuous casting of blooms for quality and special steels
Different types of mould powders (fly ash, synthetic, granulated and prefused) were tested during continuous casting for their effect on strand surface quality. Their viscosity at 1500 C was considered an important characteristic. The investigation showed that varying meniscus levels cause mould powder inclusions in the rim area of the strand resulting in cracks in the finished material. Highly fluid mould powders are better in this respect than powders with higher viscosity. Mould oscillation also has an influence on the surface quality. Reducing the stroke and simultaneously increasing the oscillation frequency during the casting of blooms resulted in better surface quality of the rolled billets. To diminish local carbon enrichment of the strand surface in bloom sizes, the C content of mould powders was limited. A relationship seemed to exist between surface roughness of the mould and viscosity of the mould powder. Higher viscosity powders gave better surface quality in the coated plate moulds and for lead-bearing free machining steels in uncoated moulds. However better results were achieved with lower viscosity powders in uncoated moulds on (Al + Ca) deoxidised steels and unleaded free machining steels.
Bibliographic Reference: EUR 12119 DE (1989) MF, 154 pp., ECU 8, blow-up copy ECU 20
Record Number: 198910722 / Last updated on: 1994-12-01
Original language: de
Available languages: de