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通过空冷和水冷实验研究了高硅钢的铸态组织,发现高硅钢铸态组织主要由粗大的柱状晶构成,水冷铸锭中柱状晶比例高达90%以上.依据铸锭的化学成分和晶粒统计结果,确定了3D-CAFE法模拟所需的枝晶生长动力学系数及高斯分布等参数.采用CAFE法对不同冷却条件下高硅钢的凝固过程进行模拟研究,发现空冷铸锭较水冷铸锭的温度场更均匀,糊状区更宽阔;空冷铸锭呈“过渡式”凝固,水冷铸锭呈“分层式”凝固;空冷流场较水冷流场更稳定,凝固末期冒口处出现明显的抽吸现象,而水冷模拟结果中未观察到该现象.组织模拟结果发现,模拟得到的高硅钢凝固组织无论是形貌还是晶粒尺寸都与实验结果相一致;最后通过改变浇注温度模拟研究了过热度对高硅钢凝固组织的影响,结果表明,随着过热度的降低,铸锭中心等轴晶率提高,晶粒数量增加,晶粒尺寸变得细小.
The as-cast microstructure of high-silicon steel was studied by air-cooling and water-cooling experiments. It was found that the as-cast microstructure of high-silicon steel mainly consisted of coarse columnar grains with the proportion of columnar grains as high as 90% .According to the chemical composition and grain statistics As a result, parameters such as dendritic growth kinetics coefficient and Gaussian distribution required for the 3D-CAFE method simulation were determined.Using CAFE method to simulate the solidification process of high-silicon steel under different cooling conditions, it was found that the air- The temperature field is more uniform and the mushy zone is wider; the air-cooled ingot shows “transitional” solidification, and the water-cooled ingot presents “layered” solidification; the air-cooled flow field is more stable than the water-cooled flow field, The phenomenon of aspiration was not observed in the water cooling simulation results.The results of the tissue simulation showed that the solidified microstructure of the high silicon steel was in good agreement with the experimental results both in morphology and in grain size. The influence of superheat degree on the solidified microstructure of high silicon steel was studied by temperature simulation. The results show that as the degree of superheat decreases, the equiaxed grain rate in the center of the ingot increases, the number of grains increases and the grain size becomes smaller.