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基于ALE算法和三维热弹黏塑性本构方程并考虑湍流的影响,模拟了连铸起步段低碳钢带液芯压下薄板坯的凝固行为、应力应变分布及变形情况。研究表明,薄板坯连铸液芯压下过程中对板坯的压缩作用主要由板坯中未凝固的部分(液芯部分)来承担,板坯凝固坯壳部分在板坯厚度方向的尺寸变化不大。连铸液芯压下过程中板坯不同位置处的应力不同,板坯在经过液芯压下辊前后,应力发生了较大的变化。在板坯近角部区域应力最大,窄面区域所承受的应力比宽面区域大。连铸液芯压下过程中板坯的等效应变与液芯压下量有关,液芯压下量越大,等效应变值越大,而且应变最大值出现在窄面,且随着时间而发生变化,在起步段的某一时刻(13.5s)应变达到最大值,此时更易接近板坯的临界等效应变,从而诱发裂纹等缺陷。研究证实了对带液芯压下薄板坯连铸起步段开展瞬态数值分析的必要性。
Based on the ALE algorithm and the three-dimensional visco-elastic constitutive equation, and considering the influence of turbulence, the solidification behavior, stress-strain distribution and deformation of the thin slab under liquid core compression during the initial stage of continuous casting are simulated. The results show that the compressive effect on the slab during the slab casting process is mainly caused by the non-solidified part (liquid core part) of the slab, and the change of the slab solidified shell part in the thickness direction of the slab Not big. The stress of slab at different positions during the process of the continuous casting liquid core pressing is different, and the stress changes greatly before and after the slab is pressed by the liquid core. In the near corner of the slab, the stress is the largest, and the stress in the narrow area is greater than that in the wide area. The equivalent strain of slab in continuous casting liquid core reduction is related to the reduction of liquid core pressure. The larger the liquid core pressure, the larger the equivalent strain value, and the maximum strain appears on the narrow surface, However, the strain reaches a maximum at a certain time (13.5s) at the initial stage, and the critical equivalent strain of the slab is more easily approached at this time, thereby causing defects such as cracks. The research confirms the necessity of carrying out transient numerical analysis on the initial stage of slab casting with liquid core.