提出了一种可降低铸锭宏观偏析的铸造工艺：层状铸造(layer casting,LC)。将铸锭分为数个甚至数十个浇包逐次间隔浇注,使每包次浇入的金属液依次、逐层凝固,从而达到降低铸锭中宏观偏析的目的。采用实验与数值模拟相结合的手段验证该工艺的可行性和适用性。分别采用传统铸造工艺和层状铸造工艺制备Al-4.0%Cu (质量分数)小铸锭,采用直读光谱仪测量铸锭中心截面处Cu含量并绘制出对应的宏观偏析图。实验结果表明：采用传统铸造工艺制备的铸锭出现明显的宏观偏析,包括铸锭底部严重的负偏析和顶部正偏析;而采用层状铸造工艺制备的铸锭没有出现大范围严重的宏观偏析,铸锭中心线上最小负偏析和最大正偏析分别降低了24.6%和77.2%,说明层状铸造工艺可一定程度改善铸锭宏观偏析。同时,采用柱状晶-等轴晶混合三相凝固模型对100和13 t钢锭的传统铸造工艺以及层状铸造工艺的宏观偏析的形成进行数值模拟预测。模拟结果表明：采用层状铸造工艺可有效改善大型钢锭中的宏观偏析,并且随着钢锭尺寸的增大,该工艺对宏观偏析的改善效果愈加明显。并对层状铸造工艺抑制宏观偏析的作用机理进行了分析。

Macrosegregation, or compositional heterogeneity, is a very common and serious defect in large steel ingots, which is hard to remove in the following processing procedures. It not only decides the final properties of the product, but also restricts downstream hot working processing severely. This compositional heterogeneity occurs due to the relative motion between the liquid and solid phases during solidification. Therefore, it is necessary to develop an effective method to manufacture large ingots with less macrosegregation. In this work, a novel casting method was proposed to alleviate macrosegregation of large ingots, i.e., layer casting (LC). With this method, alloy melt will be poured into the mould step by step, so that the melt could be solidified layer by layer and the macrosegregation will be alleviated. Both experimental and numerical studies were carried out to verify the feasibility and effectiveness of LC method. Two small Al-4.0%Cu (mass fraction) ingots were cast using two casting methods, conventional casting method, in which melt was cast into mould in one stage, and LC method, in which melt was cast into mould in several stages. Each ingot was sectioned into two parts along the center line, and then the specimens were measured by optical emission spectrometry to obtain the compositional distribution of Cu. Both severe bottom negative segregation and top positive segregation zones were observed in the ingot fabricated by conventional casting method. More homogeneity of compositional distribution was observed in the ingot fabricated by LC method, and the max negative and positive macrosegregation along the center line decreased by 24.6% and 77.2%, respectively. At the same time, a mixed three-phase (equiaxed, columnar and liquid) solidification model was employed to study the solidification processing in large ingots. The macrosegregation formation processes of 100 t and 13 t steel ingots fabricated by both conventional casting and LC methods were numerically simulated. The simulation results indicated that LC method had the capability of alleviating macrosegregation of large steel ingots significantly, compared with conventional casting method. With the increment of ingot size and amount of ladles, LC method had more significant effect on the alleviation of macrosegregation in large ingots. The mechanism of macrosegregation alleviation of LC method was analyzed.