摘要
结晶器内钢液凝固前沿温度梯度的降低可以阻碍柱状晶的生长、促进柱状晶向等轴晶的转变和提高等轴晶率,从而有利于铸坯组织的均质化。基于上述原理,研究了可用于降低钢液凝固前沿温度梯度的带隔热镀层的新型结晶器的传热特性,并在方坯连铸机上进行了工业试验,分析了其对方坯凝固组织的影响。结果表明,低温度梯度结晶器可满足连铸生产要求;与传统结晶器相比,低温度梯度结晶器出口铸坯表面温度提高了108℃,相近拉速下该结晶器的平均热流密度相对更低,表明其减缓了钢液在凝固初期的传热,从而降低了凝固前沿的温度梯度;通过与低过热度、电磁搅拌技术相结合,低温度梯度结晶器生产的铸坯等轴晶率提高了8%～13%,中心偏析和缩孔严重程度明显降低。
The growth of columnar grain can be restrained and the transformation from columnar grain to equiaxed grain will be promoted by decreasing temperature gradient on solidified front in the mould to increase equiaxed grain ratio, which is beneficial for homogenization of billet structure. Based on above-mentioned theory, the heat transfer character of a new mould with heat insulated coating for decreasing temperature gradient was researched. Industrial trials were carried out on a billet caster using the mould. The effect of this technology on solidification structure of billet was analyzed. The results show that the low temperature gradient could meet the need of continuous casting. The surface temperature of billet is increased by 108 ℃ and average heat flux is lower compared to traditional mould as the casting speed is similar, which indicates that heat transfer at the initial stages of solidification of molten steel had been restrained and therefore the temperature gradient on solidified front is decreased. The equiaxed grain ratio of billet produced by the low temperature gradient mould integrated with low superheat and EMBR technology is increased by 8%-13% and the severity of center segregation and cavitation have been reduced obviously.
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2010年第10期20-24,共5页
Journal of Iron and Steel Research
基金
国家973计划资助项目(2004CB619107)
关键词
温度梯度
等轴晶
传热
结晶器
temperature gradient
equiaxed grain
heat transfer
mould
