Effect of Porosity on Deformation, Damage, and Fracture of Cast Steel
Effect of Porosity on Deformation, Damage, and Fracture of Cast Steel
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DOI：
10.1007/s11661-013-1669-z
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
R. Hardin;C. Beckermann
中科院分区：
文献类型：
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作者：
R. Hardin;C. Beckermann
采用实验和计算相结合的方法研究了铸钢拉伸过程中中心缩松对变形、损伤和断裂的影响。将含有收缩孔隙的钢板浇铸在砂型中，机加工成试样，并进行拉伸试验直至断裂。孔隙率为0.10 ~ 0.27%的试样，其厚度段的平均体积孔隙率在0.10 ~ 0.27%之间。具有孔隙的试验铸件的延展性显著降低，伸长率数据范围为12.8 - 19.6%，而完好材料的伸长率为22%。射线成像用于测量和重建试样中的孔隙度场。重建的孔隙率场，然后在有限元应力分析模拟拉伸试验。根据存在的孔隙率，局部弹性性能降低。多孔金属塑性理论用于模拟由于孔隙和断裂引起的损伤。实测应力-应变曲线和断裂行为与预测值吻合较好。通过比较测量和模拟的伸长率，可以很好地预测延性的降低。在这项研究中使用的计算建模方法允许详细评估孔隙度的影响，包括其大小，形状和位置，对钢铸件的断裂行为。
A combined experimental and computational study is performed to investigate the effect of centerline shrinkage porosity on deformation, damage, and fracture of cast steel under tensile testing. Steel plates containing shrinkage porosity are cast in sand molds, machined into test coupons, and tensile tested to fracture. The average volumetric porosity in the gage section of the specimens with porosity ranges from 0.10 to 0.27 pct. Ductility in the test castings with porosity is markedly reduced with the percent elongation data ranging from 12.8 to 19.6 pct;vs22 pct elongation for the sound material. Radiographic imaging is used to measure and reconstruct the porosity field in the test specimens. The reconstructed porosity field is then used in a finite-element stress analysis simulating the tensile testing. Local elastic properties are reduced according to the porosity fraction present. Porous metal plasticity theory is used to model the damage due to porosity and the fracture. Good agreement is obtained between the measured and predicted stress–strain curves and fracture behaviors. The reduction in ductility is predicted well by comparing the measured and the simulated elongations. The computational modeling approach used in this study allows for a detailed evaluation of the effect of porosity, including its size, shape, and location, on the fracture behavior of steel castings.