大型支承辊Cr4材料连续冷却转变曲线的测定
Determination of Continuous Cooling Transformation Curve of Heavy Backup Roll Material Cr4
张 琪1, 陈学文1, 刘永辉2, 张菁丽1
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作者单位：(1. 河南科技大学 材料科学与工程学院, 河南 洛阳 471003; 2. 青海海尔模具有限公司, 山东 青岛 266103)
中文关键字：膨胀法； 金相-硬度法； CCT曲线； 微观组织
英文关键字：dilatometric method; microscopic test and hardness measurement; CCT diagram; microstructure
中文摘要：采用膨胀法并结合金相-硬度法，在Gleeble-1500D热模拟机上测定了Cr4钢的临界转变点Ac1，Ac3 以及Ms点；测定了不同冷却速度下连续冷却时的膨胀曲线，得到了该材料的连续冷却转变曲线(CCT曲线)；结合金相组织观察方法，研究了连续冷却过程中奥氏体转变过程及转变产物的组织形貌；测定了不同冷却速度下相转变后的硬度值。结果表明，随着冷却速度的增加，材料的硬度也越来越大。为大型支承辊热加工工艺过程微观组织模拟提供了重要的基础参数，同时也为大型支承辊的锻造及热加工工艺路线的制定提供了理论依据。
英文摘要：The critical transition temperature Ac1, Ac3 and Ms of Cr4 steel was determined by Gleeble-1500D thermal simulation testing machine, combining with dilatometric measurement, microscopic test and hardness measurement, the CCT diagram was obtained by measuring the expanding curves of the material at different cooling rates. The transformation process and the product morphology of the austenite were analyzed by microstructure observation. The hardness at different cooling rate was measured. The experiment results indicate that the hardness of the material increases with the increase of cooling rate. These results provide important basic parameters for simulating the thermal processing process of the heavy backup roll and theoretical basis for designing the forging and heat treatment technology of the product.