摘要
本研究以一种支承辊用钢为试验材料,采用膨胀法并结合金相-硬度法,在L78 RITA型淬火相变仪上测定了试验钢种的临界转变点Ac_1,Ac_3;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CCT(Continuous Cooling Transformation)曲线;然后用金相组织观察方法,研究了连续冷却过程中奥氏体转变过程及其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。试验结果表明,随着冷却速度的增加,材料的硬度越来越大。本研究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处理工艺的流程优化提供了理论依据。
A kind of backup roll steel was selected for experiment. The critical transition temperature Ac_1,Ac_3 of this steel was determined by Quenching phase change apparatus, combining with dilatometric measurement, microscopic test and hardness measurement, the CCT diagram was obtained by measuring the expanding cures of the material at different cooling rates. The transformation process and the product morphology of the austenite were analyzed by micro structure observation. The hardness at different cooling rate was measured. The experiment results indicate that the hardness of the material increases with the increase of the 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.
引文
1康大韬,叶国斌.大型锻件材料及热处理[M].北京:龙门书局,1998.
2 杨胜蓉.YB/T5129-93钢的连续冷却转变曲线图的测定方法(膨胀法)[M].北京:中国标准出版社,1997.