Influence of Strain Ratio on Surface Roughening in Biaxial Stretching of IF Steel Sheets
Influence of Strain Ratio on Surface Roughening in Biaxial Stretching of IF Steel Sheets
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DOI：
10.2355/isijinternational.isijint-2017-612
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发表时间：
2018-01-01
影响因子：
1.8
通讯作者：
Takuda, Hirohiko
中科院分区：
文献类型：
--
作者：
Kubo, Masahiro;Hama, Takayuki;Takuda, Hirohiko
随着对流线型汽车覆盖件的需求不断增加，冲压成形过程中的表面粗糙化是一个亟待解决的重要问题。然而，尽管板料在冲压成形过程中会经历各种变形模式，但变形模式对表面粗糙化的影响还不清楚。此外，表面粗糙化行为的无间隙原子（IF）钢，这是现在常用的外板，还没有研究。在这项研究中，变形方式对IF钢表面粗糙化行为的影响进行了研究，重点是详细的织构发展的影响。等双轴和平面应变拉伸下，表面粗糙度的发展和微观结构的变化的差异进行了研究，使用宏观Marciniak测试和微观原位观察。此外，晶体取向的分布对表面粗糙度的发展的影响进行了数值研究，使用晶体塑性有限元分析。结果表明，表面粗糙度是更大的平面应变拉伸比等双轴拉伸，无论IF钢测试，由于晶粒之间的变形阻力取决于晶体取向的较大差异。因此，可以通过减小晶粒间变形阻力的差异来改善冲压成形后的表面质量。
Due to an increasing demand for automobile outer panels with sharper streamlines, surface roughening during press forming is recognized as an important problem to be solved. However, although sheets are subjected to various deformation modes during press forming, the influence of deformation mode on surface roughening is not yet understood. Moreover, surface roughening behavior in Interstitial Free (IF) steels, which are now commonly utilized for outer panels, has not been studied. In this study the effect of deformation mode on surface roughening behavior in IF steels was examined, focusing in detail on the effect of texture development. Differences in surface roughness development and changes of microstructure were examined under equi-biaxial and plane-strain tension, using a macroscopic Marciniak test and microscopic in-situ observations. In addition, the influence of the distribution of crystal orientations on surface roughness development was numerically examined using a crystal plasticity finite-element analysis. The results showed that surface roughening was larger for plane-strain tension than for equi-biaxial tension regardless of the IF steels tested, due to the larger difference in deformation resistance among crystal grains depending on crystal orientation. It is therefore suggested that surface quality after press forming could be improved by reducing the difference in deformation resistance among the grains.