【摘要】 为了解决ZF钢连铸过程中经常出现的表面裂纹问题,构建了几何物理模型,确立了借助于ADSTEFAN软件求解热应力和实测钢坯温度场相结合的方法。通过模拟不同过热度、不同拉速和结晶器不同锥度的浇注和凝固过程,分析它们的应力分布趋势。结果发现,随着拉速的提高,坯壳产生的热应力逐步减少。但拉速过快,坯壳厚度变薄,容易造成漏钢事故,有的可能产生重接,经过轧制产生表面裂纹。因此在提高拉速的同时应防止拉速过快产生漏钢、重接事故。随着过热度的提高,坯壳产生的热应力增加。因此在生产过程中应尽可能降低过热度来减少热应力。随着结晶器锥度的增加,坯壳产生的热应力增加,在实际生产时要选择合适的锥度,防止热应力的增加,因此在相同的条件下,坯壳角部的热应力比其他部位的热应力大得多。在结晶器的设计时应采用圆弧角,这样可有效减少热应力的产生。另外,拉速对热应力的影响要大于过热度的影响。更多还原

【Abstract】 In order to resolve surface crack resulting from the casting thermal stress during the continuous casting ZF steel slabs, a geometric-physical model was established, in which the combination of the Adstefan software with temperature field measured actually was considered. Filling and solidification of the ingots were simulated by the model at different over-heating degrees, different drawing velocities and different tapers of the mould to observe the stress distribution in the slabs. The results reveal that with increasing in drawing velocities, thermal stress in the billet shell is decreased. However, excessive high drawing velocity can lead to thin the thickness of the shell, easily resulting in the leakage of liquid steel, even more the occurrence of reunion, so the surface crack would occur in the slabs during rolling process. With increasing in drawing velocities, leakage of liquid steel and reunion should be controlled as possible. With increasing in over-heating degree, thermal stress in the shell is increased, so during production, over-heating degree should be decreased as possible to decrease thermal stress. Meanwhile, with increasing in taper of mould, thermal stress in the shell is increased, so during production, proper taper of mould should be considered to decrease the thermal stress. At the same conditions, the thermals tress in the corner of the shell is evidently higher than that in the other positions. Camber angle can be adopted in design of the mould to effectively decline the thermal stress in the shell. In addition, effects of drawing velocity on thermal stress are higher than over-heating degree.更多还原