Estimation and Consequences of Shrinkage of Steel

Abstract

Industrial data set with 400 CC steel slabs were analysed by a statistical method for revealing the real connections between the technological parameters, heat transfer model results and the precisely determined centerline segregation index. Because of the poor correlations a new model was developed in which the shrinkage and deformations of the shells of the slabs can also be taken into account. It has been proved that the stopping of liquid movement below about 30 % liquid ratio plays an important role in the centerline segregation formation. The conclusions of the calculations are in good accordance with the results of the metallographical analysis.

Mushy szerkezet permeabilitásának számítása

“…A kérdéskör vizsgálatához a szál belsejében kialakuló térfogati viszonyok ismerete szükséges, ez a Liquid Motion Intensity (LMI) modell segítségével meghatározható [1,2]. Az LMI modell középvonali dúsulás becslésére való alkalmasságát a korábbi kutatások bizonyították [3,4].…”

Control of Centerline Segregation in Slab Casting

“…The amount of melt moving between the slices can be summarized along the whole strand or along the mushy area and from this the amount of melt flow and the rate of the flow can be defined. A detailed description of the model principles and of the simplifications applied can be found in earlier publications [1][2][3][4] . The following deformations of the strand can be taken into account in the model: …”

“…), and deformations of the strand (settings of the supporting rolls, bulging) must be taken into account. The volumetric flow rate can be calculated by the Liquid Motion Intensity (LMI) [1][2][3][4] model, taking into consideration also all the above mentioned and important deformation effects.…”

“…The Liquid Motion Intensity [1][2][3][4] (LMI) 2D model is used for the calculation of volume changes inside the strand under steady and non-steady casting conditions within the longitudinal cross section of the slab. The main task of the model is to define volumetric flow rate function (Q) inside the strand, taking into account the effect of chemical composition of the steel, the steel casting technology and the casting machine parameters as well.…”

“…The Liquid Motion Intensity (LMI) model provides these kind of data 1,2) . The suitability of the LMI model for the estimation of centerline segregation level has been demonstrated in previous research 3,4) .…”