Abstract: Eutectic carbide is a key factor affecting the service performance and service life of Cr8 cold- working die steel.In this paper， aiming at the problem that the carbide non-uniformity in the rolling process of Cr8 steel continuous casting billet exceeds the national standard GB/T 1299—2014（Level 3）. The rolling model of Cr8 flat steel is established by using Deform finite element simulation software， and the equivalent strain， strain rate and temperature changes in the rolling process are simulated. The morphology characteristics of Cr8 flat steel carbide at different temperature （time） are studied and compared with its continuous casting billet. The results show that the temperature between the center and 1/4 thickness of Cr8 flat steel reaches 1 230 ℃ during rolling， and the carbide is dissolved and precipitated in the triangle grain boundary zone of Cr8 flat steel， resulting in the carbide inhomogeneity level exceeding 3. By reducing the heating temperature and controlling the rolling temperature below 1 200 ℃， the carbide non-uniformity of 24 mm Cr8 flat steel is reduced from grade 4 to grade 2， and the product quality is significantly improved.

Key words: Cr8 Flat Steel, Eutectic Carbides, Simulation, Temperature Rise

摘要： 共晶碳化物是影响 Cr8冷作模具钢服役性能及使用寿命的关键因素。针对Cr8钢连铸坯轧制成扁钢后出现的碳化物不均匀度超过国家标准GB/T1299—2014（3级）的问题进行分析。采用Deform有限元模拟软件建立Cr8扁钢的轧制模型，对轧制过程中的等效应变、应变速率、温度变化情况进行模拟，并研究了不同温度下保温（时间）Cr8扁钢碳化物的形貌特征，与其连铸坯进行对比。模拟与实验结果表明，轧制过程中，Cr8扁钢中心至1/4厚度区域温度达到1230 ℃，使Cr8扁钢的三角晶界区碳化物重新溶解析出，导致碳化物不均匀度的级别超过3级。因此，通过降低加热温度，控制轧制温度低于1200 ℃，将厚度24 mm的Cr8扁钢碳化物不均匀度由4级降低至2级，使产品质量显著提高，同时降低了能耗、节约了成本。

关键词: Cr8扁钢, 共晶碳化物, 模拟, 温升