基于分形維數的模具鋼電渣重熔鑄坯碳偏析形貌特征研究基于分形維數的模具鋼電渣重熔鑄坯碳偏析形貌特征研究MORPHOLOGY CHARACTERISTICS OF CARBON SEGREGATION IN DIE STEEL BILLET BY ESR BASED ON FRACTAL DIEMENSION C元素偏析問題制約著電渣重熔工藝生產高端H13模具鋼，因此很有必要對偏析點形貌特征展開精細化研究。本文引入分形維數，從面積數目與輪廓形貌兩個方面對鑄坯內不同位置的偏析特征展開定量化分析。結果表明，鑄坯的整體偏析程度主要受大偏析點影響，且大偏析點越大或越多，偏析率越大；鑄坯內偏析點形貌具有分形特征，且分形維數可以作為衡量區域內偏析點彌散程度的一個重要指標，即分形維數越大，偏析點分布越為彌散，大偏析點逐漸向小偏析點轉變；在柱狀晶等軸晶轉變區與凝固終點等軸晶區，偏析點的分形維數相對較小。 Carbon segregation plays a very important role for the production of high-quality H13 Die Steel by Electro Slag Remelting Technique, so it is very necessary to do the delicacy study for segregation point morphology. In this research, fractal dimension is introduced, and segregation characteristics of different locations in the billet are quantitatively investigated in terms of area, number and outline morphology. Firstly, it is shown that the whole segregation extent in the billet is mostly influenced by the large segregation point. The segregation ratio will be increased when increasing the number or area of the large segregation point. Secondly, it is found that fractal is a very important characteristics of the segregation point morphology in the billet. Moreover, fractal dimension can be used as a criterion for measuring the dispersion degree of the segregation. The dispersion degree will be increased when increasing the corresponding fractal dimension, and the large segregation point will be disintegrated by the small segregation point. Finally, the fractal dimensions in the columnar-equiaxed transition area and the solidifying end equiaxed area are less than the value of other locations. 全文下載：http://pan.baidu.com/s/1nvuj3vF
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