冷轧工作辊水淬油冷工艺参数控制

发布时间：2018-06-02 04:32

  本文选题：冷轧工作辊 + 水淬油冷　； 参考：《机械科学研究总院》2016年硕士论文

【摘要】：当今很多材料加工流程中都会涉及到轧制工艺,轧辊的性能很大程度上决定着产品质量。作为轧机上的关键部件,轧辊在运转时会受到来自外界的多种应力,同时这些力量的方向和力度都没有规律可循,所以轧辊的使用寿命是有限的。轧辊的寿命主要取决于轧辊的表面硬度、有效淬硬层深度和强韧性能,本文研究的小规格MC3冷轧工作辊主要应用于轧制不锈钢板带,其应具备多种优良的机械性能,包括硬度、韧度以及强度,表面硬度应达到HRC60,以防止轧辊在工作过程中失效。冷轧工作辊常用整体淬火热处理工艺,轧辊若要满足上述性能,淬火冷却过程宜采用水淬油冷工艺方式,然而其工艺参数受人为影响较大,MC3冷轧工作辊水淬油冷工艺参数的不稳定,造成轧辊的组织性能产生相应变化,加上生产时各方压力对其产生的损害,最后的结果就是轧辊很快不能正常工作,严重时会导致停产。针对该问题,本文对冷轧工作辊水淬油冷工艺参数进行深入研究。本文根据冷轧工作辊水淬油冷工艺特点,利用SEM扫描电子显微镜、金相显微镜、洛氏和维氏硬度计、冲击试验机等,利用设备检测组织性能,进而探讨影响轧辊使用寿命的各种外部和内部因素,并以此为依据提出了解决方案。同时也从工艺步骤上分析水淬时长如何影响材料的性能,继而对热处理流程做出改进。研究结果表明:(1)非正常失效的轧辊,硬度梯度在淬硬层周围较陡峭,金相组织变化明显;正常失效的轧辊硬度梯度较平缓,是热处理工艺设计欲达到的效果;(2)材料中弥散碳化物的比例和水淬时长有着一定的正比关系,淬火时形成片状马氏体的比例以及淬硬层深度也是如此。带来的结果是钢材硬度的加大。但是硬度梯度却不再那么大,曲线较缓和;(3)试块随着水淬时间的增加,冲击性能逐渐降低,并且随着表面距离的增加,相同位置冲击韧性下降趋势逐渐增大。锻后的MC3试块经870℃球化退火,调质处理,水淬210s后油冷,165℃回火处理后,表面硬度达到61HRC。与失效轧辊的组织性能对比后,试验试块在满足高硬度的同时,又具有平缓的硬度梯度分布和较好的心部基体韧性,说明水淬210s油冷是合适的热处理工艺参数。本文的研究结果满足了冷轧工作辊轧制不锈钢板带的使用性能要求,为实现MC3冷轧工作辊在恶劣复杂的工作条件下保持使用寿命的稳定乃至升高提供理论依据。
[Abstract]:Nowadays, rolling process is involved in many material processing processes, and the performance of roll largely determines the product quality. As the key component of the rolling mill, the roll will be subjected to a variety of external stresses in operation, and the direction and strength of these forces are not regular, so the service life of the roll is limited. The life of roll mainly depends on the surface hardness of roll, the depth of effective hardened layer and the strength and toughness of roll. In this paper, the small specification MC3 cold rolling work roll is mainly used in rolling stainless steel strip, which should have many excellent mechanical properties, including hardness. Toughness, strength and surface hardness should reach HRC 60 to prevent roll failure during work. The whole quenching and heat treatment technology is commonly used in cold rolling work roll. If the roll wants to satisfy the above properties, the quenching and cooling process should be done by water quenching oil cooling process. However, the unstability of water quenched oil cooling process parameters of MC3 cold rolling work roll is greatly influenced by human being, resulting in the corresponding change of the structure and properties of the roll, and the damage caused by the pressure on the roll during the production. The end result is that rollers quickly fail to work properly, leading to shutdown in severe cases. In order to solve this problem, the water quenching process parameters of cold rolling work roll are studied in this paper. According to the characteristics of water-quenched oil cooling process of cold rolling work roll, SEM scanning electron microscope, metallographic microscope, Rockwell and Vickers hardness tester, impact tester and so on are used to test the microstructure and properties. Furthermore, various external and internal factors affecting roll service life are discussed, and the solutions are put forward. At the same time, it also analyzes how the water quenching time affects the properties of the material, and then improves the heat treatment process. The results show that the hardness gradient is steeper around the hardened layer and the metallographic structure changes obviously in the abnormal failure roll, and the hardness gradient of the normal failure roll is more gentle. The proportion of dispersed carbides in the material is proportional to the time of water quenching, as is the proportion of martensite formed during quenching and the depth of hardened layer. The result is an increase in steel hardness. However, the hardness gradient is not so large, and the curve is more moderate. With the increase of water quenching time, the impact property decreases gradually, and with the increase of surface distance, the impact toughness decreases gradually at the same position. After spheroidizing annealing at 870 鈩，

本文编号：1967407