高速列车制动盘盘毂锻造工艺模拟与试制

IMR OpenIR

	高速列车制动盘盘毂锻造工艺模拟与试制
	张龙
学位类型	硕士
导师	李殿中 ; 孙明月
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料工程
关键词	高速列车制动盘盘毂模锻工艺模具设计有限元模拟 High Speed Train Brake Disc Hub Die Forging Process Die Design Fem
摘要	" 高速铁路作为一种高效、环境友好的运输方式，是解决我国当前铁路运输瓶颈问题的必然选择，是经济社会发展的必然趋势。安全是高铁发展的首要前提，高速列车制动盘盘毂是刹车系统的核心零部件，其质量稳定性对于实现列车安全、有效地制动起到至关重要的作用。由于其特殊的工作环境，对盘毂锻件的组织和性能提出极高要求，制造难度大。目前我国该类锻件全部依赖进口，严重制约了我国高铁行业的发展。盘毂零件外形为法兰式的环筒形，并在法兰端设置9个齿形结构，用于连接刹车盘。由于盘毂形状复杂，一般采用自由锻造方法制造，但自由锻方法生产的锻件不但加工余量大、材料利用率低，而且厚大的截面尺寸严重影响锻件的淬透性，造成组织性能不稳定，威胁产品使用安全。本研究采用模拟与实验相结合的方式，设计出一套全新的盘毂模锻锻造模具及工艺方法，并对工艺过程进行了有限元模拟和优化。在此基础上，完成了模具制造、试验件的锻造和解剖分析，最终形成了完善的成套模具设计和工艺方案图纸。本文的研究成果对于打破国外技术垄断，推进高速铁路自主化和安全化建设具有重要意义。论文的主要研究内容和结论包括： 1)完成了盘毂锻件自由锻工艺设计、试制和解剖分析。设计并实施了盘毂锻件的自由锻工艺，锻件经自由锻、热处理、精加工后，在零件上取样进行金相和力学性能检测。检测结果表明：由于自由锻方法制造的盘毂锻件壁厚较大，采用水淬油冷的工艺无法完全淬透，锻件由表及里的组织分别为全马氏体、下贝氏体、上贝氏体、珠光体和铁素体。自由锻之后的精加工工序将锻件表面性能较好的马氏体和下贝氏体组织加工掉，零件上只保留了上贝氏体、珠光体和铁素体组织，因此导致零件强度和冲击韧性偏低。 2)完成了盘毂锻件模锻工艺和加工模具设计。针对盘毂锻件的外形结构特点，制定了模锻工艺流程，在综合考虑成形工序和坯料有效充型的基础上，设计了预锻模和终锻模的模腔形状和尺寸，并绘制了模具CAD图纸。确定模锻工艺流程依次为镦粗、预锻和终锻，终锻时将预制坯翻转180°成形。在此基础上，结合试验锻锤设备的特点，在锻造模具上分别设置了导向系统和定位装置，以保证变形过程坯料与模具之间准确的相对位置，确保锻件精确成形。 3)完成了盘毂模锻过程的模拟仿真与工艺优化，并完成了样件试制与解剖分析。基于实测的40CrA材料热物性参数和高温应力应变曲线，对盘毂镦粗、预锻、终锻全流程进行了热力耦合模拟仿真，获得了应力、应变和温度随时间的变化规律；研究了盘毂成形过程的金属流动机制，预测了产生充不满和折叠缺陷的位置；预测了盘毂完全成形所需的锻锤吨位和打击次数；对终锻模具的最大主应力进行了分析，预测了模具在实际生产中可能产生的塌陷、开裂缺陷及其位置。在此基础上，根据模拟结果对工艺和模具进行了优化设计，并进行了锻造试验，完成了锻件的试制和解剖分析，获得了组织性能合格的样件，验证了模锻工艺的可行性和模拟的准确性.
其他摘要	" As an efficient, environmentally friendly transport mode, high-speed railway has an inevitable choice to solve China railway transport bottlenecks, and the inevitable trend of economic and social development. However, security is the most important prerequisite for the development of high-speed railway. Brake disc hub is the core component of the braking system, and its quality plays a crucial role for train safety and effective braking. Due to its special working environment, the disc hub forgings must have good microstructure and properties, which make it difficult to manufacture. Now such forgings all depend on imports, which have seriously restricted the development of high-speed rail industry in China. The shape of disc hub is a flanged ring, and sets on 9 tooth structure at the flange side to connect the brakes. Free forging method is generally used because of complex shape of the disc hub, but the free forgings have not only a large allowance, but also low material utilization rate. Hardenability is low because of heavy sectional dimension, resulting in the instability of the microstructure and properties and the threat of product safety. In this study new forging molds and process methods are designed, and the processes are simulated and optimized using FEM and experimental method. On this basis, the mold manufacturing, forging and anatomical analysis of the forging was completed, and ultimately a perfect set of mold design and drawings of the process plan were formed. The results of this paper are meaningful for breaking the monopoly of foreign technology, and promoting the autonomy and security of high-speed railway construction. The main research contents and results in this study include: 1)The forging process design, trial production and anatomical analysis of the disc hub forging were completed. The free forging process was design and implemented. After free forging, heat treatment and finish machining, metallographic and mechanical performance of the product sample was tested. Test results showe that: because of the large wall thickness, the free forging can not be completely quenched by the water quenching and oil cooling process. From outside to inside of the forging, the organizations were martensite, lower bainite, upper bainite, pearlite and ferrite. Good organizations like martensite and lower bainite were removed by finishing operations after free forging, while upper bainite, pearlite and ferrite were remained, causing lower strength and impact toughness. 2)The die forging process and die design were completed. The die forging process was developed based on the shape and structure characteristics of the disc hub. Considering the forming process and effective filling, the shape and size of pre-forging and final-forging dies were designed, and CAD drawings of the dies were drew. The forging process includes upsetting, pre-forging and final-forging. During the final-forging process, the billet was turned 180¡ã. On this basis, considering the hammer device characteristics, the guidance system and positioning device were set on the forging dies to ensure the accurate relative position of billet and mould during the deformation process so the precise forming of the forging can be ensured. 3)The Numerical simulation and optimization of the die forging processes were completed, and the prototype and anatomical analysis were conducted. Based on the measured thermal properties and high temperature stress strain curve of 40CrA material, the thermo-mechanical coupling simulation for die forging processes was conducted. The variation of stress, strain and temperature with time were got. The unfilled and folding defect locations were predicted by metal flow mechanism analysis. The desired hammer tonnage and hit number for completely forming were predicted. The maximum principal stress of the final forging die was analyzed to predict the possible collapse, crack defects and their position in the actual production. On this basis, according to the simulation results of the process, mold optimization design was carried out. The forging test, finish forging production and anatomical analysis were conducted, and a forging with qualified microstructure and properties were acquired, which verified the feasible of forging process and the accuracy of simulation. "
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64556
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	张龙. 高速列车制动盘盘毂锻造工艺模拟与试制[D]. 北京. 中国科学院金属研究所,2012.