Cr12MoV钢真空淬火过程研究

发布时间：2019-05-11 19:56

【摘要】：随着近年来国家工业发展的转型,由生产代加工逐步向自主研发制造转变,热处理作为提升零部件机械性能的关键技术也日益被国内各大机械零件加工使用厂商所重视。然而,在一些工业发达国家早就制定出了他们的热处理技术发展路线图,其中对降低能耗、缩短工艺时间、降低生产成本都有指标性的规划。在美国制定的热处理技术发展路线图中提到,到2020年要实现热处理零件零畸变和质量分散最低,这样的要求对热处理行业的发展是激励也同样是挑战。真空热处理技术作为当下先进的整体热处理技术,拥有无氧化、少畸变、无污染等优点,是实现热处理技术发展路线图目标的重要技术之一;冷处理技术同样具有低能耗、无污染、降低成本的优点,也是实现路线图目标的重要技术之一。本文将以冷作模具常用材料Cr12MoV为基础重点研究这两项技术,为生产实践提供数据支持。真空淬火在实际生产中常见的方式有真空油淬和高压气淬,真空水淬使用较少。本文研究了真空油淬及高压气淬两种淬火方式的淬火过程及材料淬火后的组织性能。运用实际测温、计算机数值模拟的方法比较淬火过程的差异;通过观察比较各组试验试样的金相照片、扫描电镜照片、X射线衍射结果、显微硬度,分析两种淬火方式下Cr12MoV钢组织性能的差异。依据分析结果得到的结论是:经两种淬火方式处理后,Cr12MoV钢的组织均为马氏体+碳化物+残余奥氏体;淬火后较淬火前硬度提高显著;经高压气淬方式处理的工件外观形貌更好更有利于降低人工操作成本。本文将真空油淬、回火、冷处理三种工艺进行组合,根据Cr12MoV钢的特性制定了多种工艺方案。通过观察比较各组试验试样的金相照片、扫描电镜照片、X射线衍射结果、显微硬度、磨损失量、磨损扫描电镜照片,分析各个工艺方案对材料组织性能的影响。其中含有冷处理的工艺方案,试样在处理后强度硬度和耐磨性都要优于其他工艺方案。比较两组含冷处理的工艺方案,可以发现淬火后直接冷处理+回火2次试样的强度硬度更好,而淬火后回火1次+冷处理+回火1次试样的耐磨性更好。依此结论,在实际生产中可根据待处理零件的性能要求进行工艺方案选择。本文还对高压气淬、回火、冷处理三种工艺进行组合,制定多种工艺方案。实验方法和结果分析与真空油淬实验一致。最终得到结论,经过冷处理的试样在强度硬度和耐磨性上都要优于没有冷处理的试样;淬火后直接冷处理和淬火后回火1次再冷处理对材料硬度强度的影响差异不大;淬火后回火1次再冷处理的试样耐磨性比淬火后直接冷处理的试样要好。本课题研究将理论与生产实践相结合,整个研究过程深入生产企业,对于生产工艺的选择有重要意义,具有一定的实际应用参考价值。
[Abstract]:With the transformation of national industrial development in recent years, heat treatment, as the key technology to improve the mechanical properties of parts and components, has been paid more and more attention by domestic manufacturers. However, in some industrial developed countries, their heat treatment technology development road map has long been drawn up, in which there are indicative plans for reducing energy consumption, shortening process time and reducing production costs. It is mentioned in the road map of heat treatment technology development in the United States that zero distortion and mass dispersion of heat treatment parts should be minimized by 2020, which is also a challenge to the development of heat treatment industry. Vacuum heat treatment technology, as an advanced integral heat treatment technology, has the advantages of no oxidation, less distortion, no pollution and so on. It is one of the important technologies to realize the development road map of heat treatment technology. Cold treatment technology also has the advantages of low energy consumption, no pollution and low cost. It is also one of the important technologies to achieve the road map goal. This paper will focus on the research of these two technologies based on the common material Cr12MoV of cold working die, and provide data support for production practice. The common ways of vacuum quenching in practical production are vacuum oil quenching and high pressure gas quenching, and the use of vacuum water quenching is less. In this paper, the quenching process of vacuum oil quenching and high pressure gas quenching and the microstructure and properties of the materials after quenching have been studied. The difference of quenching process is compared by using the method of actual temperature measurement and computer numerical simulation. The microstructure and properties of Cr12MoV steel were analyzed by observing and comparing the metallographic photographs, scanning electron microscopy (SEM) photos, X-ray diffraction (XRD) results and microhardness. According to the analysis results, it is concluded that the microstructure of Cr12MoV steel is martensitic carbide retained austenite after being treated by two quenching methods, and the hardness after quenching is significantly higher than that before quenching. The appearance of the workpiece treated by high pressure gas quenching is better and more beneficial to reduce the manual operation cost. In this paper, vacuum oil quenching, tempering and cold treatment are combined, and a variety of process schemes are worked out according to the characteristics of Cr12MoV steel. By observing and comparing the metallographic photographs, scanning electron microscope photographs, X-ray diffraction results, microhardness, wear loss and wear scanning electron microscope photos, the effects of each process scheme on the microstructure and properties of the materials were analyzed. There are cold treatment schemes, and the strength, hardness and wear resistance of the samples are better than those of other processing schemes. By comparing the two groups of cold treatment schemes, it can be found that the strength and hardness of the secondary samples after quenching are better, while the wear resistance of the samples after quenching and tempering for the first time is better. According to this conclusion, the process scheme can be selected according to the performance requirements of the parts to be processed in practical production. In this paper, three processes of high pressure gas quenching, tempering and cold treatment are combined, and a variety of process schemes are worked out. The experimental method and result analysis are consistent with the vacuum oil quenching experiment. Finally, it is concluded that the strength, hardness and wear resistance of the cold treated samples are better than those of the samples without cold treatment, and the effect of direct cooling treatment after quenching and tempering once after quenching on the hardness strength of the materials is not significant. The wear resistance of the sample tempered once after quenching is better than that of the sample treated directly after quenching. This research combines the theory with the production practice, and the whole research process goes deep into the production enterprise, which is of great significance for the selection of the production technology, and has certain practical application reference value.
【学位授予单位】：中原工学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG156.3;TG142.1

【相似文献】