A study of pore closure and welding in hot rolling process
A study of pore closure and welding in hot rolling process
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DOI：
10.1016/0924-0136(96)02313-8
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发表时间：
1996-06
影响因子：
6.3
通讯作者：
A. Wang;P. Thomson;P. Hodgson
中科院分区：
文献类型：
--
作者：
A. Wang;P. Thomson;P. Hodgson
随着连续铸造原料的出现，在热轧过程中消除钢中气孔的工艺条件的设计变得更加关键。为了预测适当的工艺参数，进行了实验，其中在垂直于轧制方向的表面以下不同深度的钢板上钻孔。热轧后，通过光学显微镜检查变形孔的状态。用扫描电子显微镜观察了在闭孔平面上开有缺口的拉伸试样的断口，以研究闭孔表面之间的结合（焊接），因为这种结合是决定轧件横向机械性能的最重要因素。使用有限元软件ABAQUS将辊缝中的此类孔的变形建模为弹性/塑性平面应变问题，以调查孔周围的应变和应力，并分析促进孔闭合和闭合表面之间的焊接所需的条件。实验结果表明，轧制工艺参数和孔相对于轧制接触面的位置对孔的闭合率有较大影响。孔隙闭合的有限元模拟结果与实验结果吻合较好，表明一定水平的静水压力导致孔隙闭合，并且在压缩状态下压力的保持时间决定了孔隙表面的焊接程度;剪切有利于这种焊接。
The design of processing conditions to eliminate porosity in steel during hot rolling has become more critical with the advent of continuously cast feed stock. To predict appropriate process parameters, experiments were performed in which holes were drilled in steel slabs, at different depth below the surface perpendicular to the rolling direction. After hot rolling, the state of the deformed holes was examined by optical microscopy. The fracture surfaces of tensile specimens notched in the plane of the closed holes were examined under a scanning electron microscope to investigate the bonding ( welding ) between the surfaces of the closed holes because this bonding is the most important factor indetermining the transverse mechanical properties of the rolled product. The deformation of such holes in the roll gap was modelled as an clastic / plastic plane strain problem using the FE software ABAQUS to investigate the strain and stress around holes and to analyze the conditions required to promote pore closure and welding between the closed surfaces. Experiment results showed that the rate of pore closure was affected by the parameters of rolling process and the position of holes relative to the rolling contact surfaces. FE simulation of pore closure showed a good agreement with experimental results and showed that a certain level of hydrostatic pressure resulted in the closure of pore and that the holding period of the pressure in the compressive state determined the degree of welding of surface of pores; shear is favourable to this welding.