Determination of Mould Powder Crystallinity Using X-Ray Diffractometry

In the continuous casting of steel the surface quality of the cast product is highly dependent upon the horizontal heat transfer between the steel shell and the mould. The horizontal heat transfer is a function of both the thickness and the degree of crystallinity of the solid slag film formed between the steel shell and the watercooled copper mould. This study is focused on the measurement of the crystalline fraction present in different slag films using two different X-ray diffraction techniques. The results obtained are compared with those obtained from metallographic examination of the slag film. The advantages and disadvantages of different techniques for the measurement of the crystalline fraction of a slag film are discussed. cracking or process control problems such as sticker breakouts, are to be avoided 121. The horizontal heat transfer is a complex process involving both lattice (k|) and radiation (k R ) conduction. The latter is a process involving absorption and re-emission and it can be a major mode of heat transport in glasses at high temperatures. The horizontal heat transfer arising from lattice conduction can be represented as an overall thermal resistance, R,^ made up of resistances in series /. This is shown in Eq. 1 where d is the thickness of the slag layer, k is the thermal conductivity, the subscripts, gl, crys, I and Cu/sl are the glass, crystalline and liquid phases and the Cu/'slag interface, respectively. R,o,al -Rcu/sl + ( d/k) g | + (d/k) CIys + (d/k). (I)