Analysis of surface and internal cracks in continuously cast beam blank
Analysis of surface and internal cracks in continuously cast beam blank
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DOI：
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发表时间：
1997
影响因子：
2.1
通讯作者：
K. Kim;H. Han;T. Yeo;Y. Lee;K. Oh;D. Lee
中科院分区：
文献类型：
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作者：
K. Kim;H. Han;T. Yeo;Y. Lee;K. Oh;D. Lee
已经开发了二维瞬态耦合热弹塑性有限元模型。该模型使用糊状区以及 δ 和 γ 两相区的热机械特性模型，结合了溶质元素的微观偏析对热泪的影响。该模型成功分析了梁毛坯凝固壳在模具中凝固过程中的热机械行为。在凝固的初始阶段，在凸缘尖端拐角处形成气隙，这减少了热流并在凸缘尖端拐角处产生热点。在梁坯铸造初期，腹板和圆角的表层会产生较大的拉应力，从而导致表面裂纹。在铸造过程中，凸缘尖端区域处于脆性温度范围内，因为气隙减少了从梁毛坯到模具的热传递。从铸造中期开始，法兰尖端的内部区域会产生很大的拉应力，这反过来会导致法兰尖端区域的内部裂纹。这些分析结果与报告的观察结果非常一致。
A two-dimensional transient coupled thermoelastoplastic finite element model has been developed. The model incorporates the effect of microsegregation of solute elements on hot tears using a thermomechanical property model of the mushy zone and the two phase zone of δ and γ. The model successfully analyses the thermomechanical behaviour of the solidifying shell of a beam blank during solidification in the mould. Air gaps form at the flange tip corners in the initial stage of solidification which reduce the heat flow and give rise to hot spots at the flange tip corners. Large tensile stresses develop in the surface layers of the web and the fillet which can cause surface cracks in the initial stage of beam blank casting. The flange tip region is in a brittle temperature range during casting because the air gap reduces the heat transfer from the beam blank to the mould. A large tensile stress develops in the internal region of the flange tip from the intermediate stage of casting, which in turn can cause internal cracking in the flange tip region. These analysis results are in good agreement with reported observations.