异形坯连铸坯壳应力与鼓肚变形分析

Analysis of Shell Stress and Dilatancy Distortion in the Process of Beam Blank Continuous Casting

坯壳应力引起的鼓肚变形是影响铸坯质量的重要因素,为防止过大的鼓肚变形,依据湍动能理论、热流传递理论和粘弹性理论,建立了异形坯三维热力耦合模型,开发了鼓肚分析软件,从而避免了漏钢事故的发生。该模型将温度场和应力场的计算相互耦合,交替进行。结果表明异形坯截面最危险点位于腹板中部,其次为翼板中点,在两者相结合的圆角部,由于凝固坯壳比较薄,其应力值也比较大;当坯壳厚度小于20mm时,两点的鼓肚变形量将分别超过其极限变形量,铸坯出结晶器时必然发生漏钢事故。该模型通过预测坯壳应力和鼓肚变形量为现场安全生产提供了理论依据。

Dilatancy distortion caused by shell stress is an important factor that can affect the quality of casting blank. According to turbulent theory and thermal flow transfer theory and viscoelasticity theory, three-dimension heat-stress coupled model of beam blank is built and dilatancy analysis software is developed to avoid the excessive dilatancy distortion and occurrence of breakout. The computation of temperature filed is coupled with that of stress field in this model. The results indicate that the most dangerous point of beam blank section is located at the middle of web plate, the next is located at middle of flange girth. The solidification shell at the conjunctional arc of web plate and flange girth is so thin that the stress value is greater. The dilatancy distortion values of the dangerous point will exceed the limited distortion values and the breakout accident will be happened necessarily when the shell thickness is less than 20 mm. The model can provide the theory for the field safety production by the prediction of shell stress and dilatancy distortion value.