高镍铬离心复合球墨铸铁轧辊热处理工艺及其性能的研究.docVIP

((高镍铬离心复合球墨铸铁轧辊热处理工艺及其性能的研究 摘要: 采用热膨胀法测定了离心球磨铸铁轧辊的相变点，根据其临界转变温度，进行和回火实验，研究了热处理工艺对轧辊的影响。结果表明：860 ℃和890 ℃时，轧辊硬度值较高；温度为920 ℃时，正火冷却后残余奥氏体（Ar）量增多，导致硬度明显下降；正火温度为830℃时，由于加热不足而出现硬度较低的珠光体组织。860℃正火冷却后，在400℃回火时应力消除比较完全，碳化物尚未长大，细小且均匀弥散的分布在针状马氏体基体上，轧辊硬度值较高，有利于阻止裂纹的扩展。 ，热处理，硬度 Ding Meiliang1,Yu Baojun1, Sun Lin1,Yu Xiaojun2 (1 Institute of Research of Iron and Steel, Jinfeng Town, Zhangjiagang City, Jiangsu Province, 215625; 2 Jiangsu Shagang Group, Shasteel, Jinfeng Town, Zhangjiagang City, Jiangsu Province, 215625 ) Abstract: Dilatometry was carried out to determine the phase transformation temperature of a high Ni-Cr centrifugal composite ductile iron rolls. Based on the critical transformation temperature, the ductile cast iron rolls were quenched and tempered in order, and the effect of normalizing temperature and tempering temperature on them was forced. The results show that the hardness for ductile cast iron roll is the highest, when the normalizing temperature is between 860 ℃ and 890 ℃. The amount of residual austenite increases when the normalizing temperature is above 890 ℃, leading to the obvious decrement of hardness. When the normalizing temperature is 830 ℃, pearlite with lower hardness generates due to the insufficiency of heat. Cooled after 860 ℃ normalizing and tempered at 860 ℃, the stress of the ductile cast iron roll relieves completely, and the fine carbide uniformly and dispersedly distributes in martensite, restraining the crack extension, therefore, the hardness value is relatively high. Key words: high Ni-Cr, roll, heat treatment, hardness 1 前言 热连轧精轧工作辊与灼热的钢坯接触，使轧辊表面温度升高，与板坯离以后，轧辊随即又在连续喷水下急速冷却，从而使轧辊表面承受交变的热应力作用。因此，所用的轧辊需要兼有高的强度与韧性，并且要有良好的耐磨性与抗热疲劳性能[1-]。目前，离心复合球墨铸铁轧辊的热处理主要有两种形式，一种是低于临界转变温度的亚临界热处理[4]，另一种是高于临界点的高温热处理[5]。国内对离心复合球墨铸铁轧辊的亚临界热处理研究较多[6]，而对高于临界点的高温热处理研究较少。本文Gleeble 3800热/力物理模拟试验机以热膨胀法测得了离心球墨铸铁轧辊的相变点，并制定了热处理工艺[]，采用光学显微镜（OM）、扫描电子显微镜（SEM)、DST-型硬度计等实验设备，研究了热处理前后分析了正火温度回火温度获离心复合球墨铸铁轧辊热处理工艺。 离心复合球墨铸铁轧辊化学成分Table 1 Chemical composition of ductile cast i