The solidification of molten steel in continuous casting mold is a complicated non-equilibrium process with high cooling rate of 10-100 degrees C/s. At such a cooling rate, the segregation of the solute elements such as C, Si, Mn, P and S in brittle temperature range (Delta theta(B)) will vary with their initial contents and influence on the thermal strain significantly which could greatly increase the incidence of surface defects of strand. In this paper, a microsegregation model of solute elements in mushy zone with delta/gamma transformation during solidification was established based on the regular hexagon transverse cross section of dendrite shape proposed by Ueshima by finite difference method under the non-equilibrium solidification condition at 10 degrees C/s of cooling rate and the brittle temperature range Delta theta(B) was determined. The distribution characteristics of solute elements and the effect of their segregations on Delta theta(B) and thermal strain were investigated. The results show that both P and S are the most serious segregation elements in final stage of solidification and affect On Delta theta(B) significantly together with carbon content in molten steel. The mechanism that increasing contents of P and S may increase the probability of longitudinal surface crack for continuous casting strand was presented by calculating the change law of thermal strain with carbon content under different of P and S contents.
Cai Zhaozhen,Zhu Miaoyong. MICROSEGREGATION OF SOLUTE ELEMENTS IN SOLIDIFYING MUSHY ZONE OF STEEL AND ITS EFFECT ON LONGITUDINAL SURFACE CRACKS OF CONTINUOUS CASTING STRAND[J]. ACTA METALLURGICA SINICA,2009,45(8):949-955.
Cai Zhaozhen,&Zhu Miaoyong.(2009).MICROSEGREGATION OF SOLUTE ELEMENTS IN SOLIDIFYING MUSHY ZONE OF STEEL AND ITS EFFECT ON LONGITUDINAL SURFACE CRACKS OF CONTINUOUS CASTING STRAND.ACTA METALLURGICA SINICA,45(8),949-955.
Cai Zhaozhen,et al."MICROSEGREGATION OF SOLUTE ELEMENTS IN SOLIDIFYING MUSHY ZONE OF STEEL AND ITS EFFECT ON LONGITUDINAL SURFACE CRACKS OF CONTINUOUS CASTING STRAND".ACTA METALLURGICA SINICA 45.8(2009):949-955.