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运用凝固传热模型,计算出了连铸坯在不同凝固阶段的冷却速率,对经典的BF微观偏析模型进行了修正,并以此为基础建立了由化学成分的不均匀性导致的Mn-Cr系齿轮钢淬透性带宽预测模型,分析了不同二次冷却强度对淬透性带宽的影响。由淬透性带宽预测模型得知,20Cr Mn Ti连铸坯试样淬透性带宽呈抛物线状分布,淬透性带宽曲线在端淬距离0~15 mm范围内呈上升趋势,距离端淬距离超过15 mm时呈下降趋势,距离端淬约15mm处试样的淬透性带宽取得最大值;适当提高二冷区冷却强度可以缩小连铸坯试样的最大淬透性带宽。
The solidification heat transfer model was used to calculate the cooling rate of continuous casting billet at different solidification stages. The classical BF micro-segregation model was modified and based on this, the Mn-Cr Department of hardenability of gear steel bandwidth prediction model, analysis of the different secondary cooling strength on the hardenability of the bandwidth. From the hardenability bandwidth prediction model, the hardenability bandwidth of 20Cr Mn Ti slab samples showed a parabolic distribution. The hardenability bandwidth curve showed an upward trend in the range of 0-15 mm of the end quenching distance, When it exceeds 15 mm, it shows a downward trend, and the maximum hardenability bandwidth of the sample at the distance of 15 mm from the end quench is maximized. Appropriately increasing the cooling intensity of the second cooling zone can reduce the maximum hardenability bandwidth of the slab sample.