螺纹冷滚压模拟及实验研究

【作者】 宋欢；

【导师】 李永堂；

【作者基本信息】 太原科技大学 ， 材料加工工程， 2010， 硕士

【摘要】 螺纹滚压是一种无切削加工方法,近年来螺纹冷滚压工艺及设备因其低耗、高效、高强度和高精度等优点,在生产中得到了广泛的应用。但是目前国内外在螺纹冷滚压精密成形的工艺方面的研究较少。因此对螺纹冷滚压进行研究,有助于促进这种无切削新技术的推广应用,具有重要的理论意义和实用价值。本文对螺纹冷滚压过程及原理进行了分析,将螺纹的滚压过程分为了四个阶段,并对四个阶段的成形过程进行了系统的分析。用DEFORM软件进行有限元数值模拟,得到了冷滚压加工过程中工件内部的应力场、应变场、速度场以及工件的形状变化等信息。在实验方面从金相组织、硬度分布及硬化层、等几个方面进行了对比分析。通过数值模拟得出了冷滚压螺纹在滚压过程中的受力情况,并验证了螺纹冷滚压理论分析的正确。通过金相组织实验可知冷滚压螺纹的表层组织被压碎,晶界变的模糊不清,而切削螺纹的金属被切断,金属组织未发生明显变化。冷滚压螺纹表面硬度高于切削螺纹面的硬度,冷滚压后的螺纹其硬度值可达330HV,而切削螺纹的硬度值基本没有发生变化,其硬度值为220HV。滚压螺纹的金属组织呈现连续分布的条形纤维组织,而切削螺纹的纤维组织被切断。调质处理的坯料在冷滚压加工后工件的组织性能及表面强化程度均优于未经调质处理的坯料滚压成形的工件。本课题为进一步研究螺纹冷滚压工艺提供了理论依据,并能够指导螺纹冷滚压的生产,具有理论价值和现实意义。更多还原

【Abstract】 In recent years, the technology cold rolling of thread technology was rapidly developed due to its high efficiency, low cost and perfect properties of its production. Few studies were carried out on the cold-rolling technological theory and the mechanical analysis of the precise forming both at home and abroad. Therefore, the research on the cold rolling of thread has important theoretical and practical value. It can promote the application of this non-cutting methord to be more popular.In this paper, the cold thread rolling process and theory were analyzed. The rolling process was divided into four stages according to the amount of feed of the thread rolling dies.The numerical simulations on the rolling process of solid parts were carried out with DEFORM software. The stress field, strain field, velocity field in the workpiece were got.In the experiments the microstructure, hardness and hardened layer, and several other areas were compared. The force of cold rolling thread was obtained by numerical simulation.And the theory of cold rolling thread was verified.Through the analysis and the comparation of the microstructure, hardness and hardened layer and residual stress, we conclude that: The microstructure of Cold rolled thread was crushed, grain boundaries become blurred, and the cutting threads were cut off, metal structure did not change significantly. the surface hardness of cold-rolling thread was better than cutting thread. Hardness of cold-rolling thread which was treated after heat treatment can reach 330HV, in contrast before heat treatment can only reach 220HV. The hardened layer of the cold-rolled thread have a certain depth in normal direction, otherwise, the hardness of the thread cutting have no diversification; cold rolled thread surface area have a continuous fibrous structure, and the microstructure was refined. The structure property and the suface hardness of thread which is rolled after heat treatment is better than cold rolled before heatment.The conclusion provides the theoretical basis for the further research of the cold rolling technology and practical operation. It has a theoretical significance and practical value.更多还原