石墨电极中针状焦晶粒取向的研究

A STUDY ON THE ORIENTATION OF NEEDLE COKE GRAINS IN A GRAPHITE ELECTRODE

针状焦晶粒的取向是影响石墨电极多种性能指标的一个重要因素。本文采用图像分析的方法,系统地研究了一种优等石墨电极中针状焦晶粒的取向与其在电极中的径向位置的依赖关系。在这种石墨电极中,越接近电极的表面,晶粒的取向越趋于和电极的对称轴平行,并且晶粒择扰取向的程变越高。针状焦晶粒取向的这种变化关系被认为是由于挤压成型时挤压速度梯度沿径向的变化所致,研究结果还表明,本文描述的用图像仪测定的晶粒取向角,可以作为晶粒取向的一种量度,这种方法在某些情况下,比通常采用的X射线法更加方便。

The orientation of needle-coke grains in graphite electrodes is one of the important factors affecting many of the electrode properties. This paper reports a systematic study on the needle-coke grain orientation as a function of radial position of a premium grade graphite electrode using image analysis. Moving towards the center of the graphite rod, the grain orientation becomes progressively offset from the axis of the electrode and the orientation distribution becomes increesingly broader. The variation in needle-coke grain orientation is considered as the effects of the radial change of extrusion velocity gradients during the extrusion stage of manufacture. The results of the study also indicate that the orientation angle determined by image analysis can be a measure of grain orientation. In some cases, the image analysis method is more convenient than the commonly used X-ray diffraction method.