116结晶器振动条件下弯月面处初始凝固区域温度波动研究9-27.docVIP

结晶器振动条件下弯月面处初始凝固区域温度波动研究 金小礼，雷作胜，马宁博，邓康，任忠鸣 （上海大学，上海市现代冶金与材料制备重点实验室，上海，200072） 摘 要： 关键词： Initial solidification area temperature fluctuation in meniscus in continuous casting with mold oscillation JIN Xiaoli, LEI Zuosheng, MA Ningbo, DENG Kang , REN Zhongming Shanghai Key Laboratory of Modern Metallurgy Material Processing, Shanghai 200072, China Corresponding author’s e-mail: lei_zsh@staff.shu.edu.cn Abstract: The effect of mold oscillation on heat transfer during initial solidification stage was studied, and two-dimensional heat transfer mathematical model under mold oscillation was established. The heat transfer process was calculated with this mathematical model, it was found that the temperature of initial solidification area fluctuated with mold oscillation. Experiments of Tin continuous casting were carried out, temperature fluctuation phenomena was verified by the measurement results. The calculation and experiment results suggested that mold oscillation might lead to temperature fluctuation, it maybe a key factor to the formation of oscillation marks. Some techniques which used to improve billets quality can be explained by the temperature fluctuation. Any technique used to reduce temperature fluctuation is helpful to decrease oscillation marks depth and improve billets surface quality. Key words: continuous casting, meniscus mechanism of oscillation mark formation, mathematical modeling 1 前言 在连铸中引入结晶器振动，被认为是连铸得以工业化应用的关键技术革命[1]。结晶器振动可以有效改善铸坯的润滑，避免坯壳与结晶器壁粘结和拉漏，使连铸过程得以稳定顺利进行。同时，结晶器振动又会使铸坯表面产生周期性的横向皱折，即振痕。鉴于振痕存在的普遍性，一般，非异常的振痕并不视为铸坯的表面缺陷。 随着技术的日益成熟，连铸朝着近终形、高速度、高质量方向发展[2]，对铸坯质量的要求不断提高，振痕受到越来越多的关注。由于振痕处几何形状、显微组织以及合金成分的不连连续[3]，使之成为铸坯表面裂纹形成的密集区，也是轧制过程的裂纹诱发区。而对于一些难连铸钢种，比如包晶钢、不锈钢等，振痕对铸坯表面质量的影响尤其突出[4、5]，在高拉速条件下，振痕对铸坯表面质量的决定作用也日益凸现[6]，弄清铸坯表面振痕形成的机理，  国家自然科学基金50874133）、上海市教委（2006AZ003）和长江学者和创新团队发展计划资助（IRT0739） 作者介绍：金小礼（1981-），男，博士研究生 从而提出有针对性的减轻甚至消除振痕的技术，对于无缺陷铸坯的生产和实现高速连铸连轧，具有非常重大的意义。 结晶器振动过程中，初始凝固区域和水冷结晶器接触部分会随结晶器振动发生周期性改变，这可能使初始凝固区域的温度产生周期性变化