The Researsh On Side Dam Materials For Twin-Roll Continuous Strip Casting

Twin-roll continuous strip casting process has received many attentions from the steel producers all of the world for its low energy consumption,short procedure,high speed and low production cost which conformed to the developing trend.The experts of steel industry have all recognized that the commercial application of the twin-roll continuous strip casting process will lead to a revolution to steelmaking and become a landmark event for this field. However, the poor quality of casting strip and process stability happened in the research hindered its industrial application. The side dam materials become one of the main defect. Accordingly, this paper dealed with the experimental and theoretical investigations on composition design and production process of new side dam materials with the support of SJTU and BAOSTEEL.The mechanical properties of the side dam material is tested by 2031.3000.010 stress test system and FV-700Vicker's hardness tester;the thermal properties are tested by LFA427 Laser conductometer,STA449C/6/GJupiter thermal analyzer and Dil402e/7/FSO RPY;The thermal stability and inoxidizability are tested in chamber electric oven and thermal shock oven.; the phases and microstructures are tested by XRD and SEM.In ZBS materials , increasing the content of BN will decrease the density ,worsen the mechanical properties and improve the thermal stability that the optimum combination properties are abtained when the BN content is 40% .The ZBS Materials exhibit a trend that with the increase of BNwt% ,the mechanical property and inoxidizability increase first then decrease ,which showing the best combination property on the point of 3wt%BN. The analyses indicate that adding a proper amount of Si to the raw materials can get SiC in sintering process, which can strengthen the matrix and form compact oxide film on the surface after oxidation reaction. The film hinders the oxidation of the ZBS material effectively. However, the Si will decease the density of ZBS and increase the apparent porosity,which result a poor mechanical property and inoxidizability. The Ill effects are most significant when the Siwt% is between 7% and 11%.T(iC,N)is attained in sintering process of ZBT. The microstructure displays a shape of porous petals. With the increasing of Ti in raw material,the density and mechanical property decrease sharply. The inoxidizability of ZBT is so poor that the material lose its shape after oxidation for 1h at 15000C.Compared with ZBC and ZBT ,the ZBS materials have the best combination properties.The thermal expansion coefficient and thermal conductivity of ZBS3 reach 3.7×10-6 0C-1and 5.3W/(m*K)respectively which is superior to those of other side dam materials produced by hot press process in other countries.