【作者】 缪宏；

【导师】 左敦稳；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2011， 博士

【摘要】 随着内螺纹加工向高性能、低成本、低能耗方向的发展,采用冷挤压成形工艺净成形内螺纹成为抗疲劳加工技术的重要组成部分,在航空、航天和高速列车等领域具有巨大的应用前景。本文针对高强度钢内螺纹冷挤压加工中出现的问题,以理论分析与试验相结合的方法,系统地研究了高强度钢内螺纹冷挤压加工的关键技术,着重研究了冷挤压内螺纹的表面性能、挤压过程的在线监测及其有限元分析,为冷挤压内螺纹技术的推广应用开展积极探索。本文完成的主要工作和取得的成果如下:1.建立了冷挤压内螺纹接触应力与挤压力的力学模型建立了冷挤压内螺纹接触应力与挤压力的力学模型。通过合理假设选取挤压过程中的各工艺参数,计算了加工过程中挤压变形区工件沿挤压丝锥棱齿法向的接触应力及挤压力,为进一步研究内螺纹冷挤压过程中的工艺参数优化、加工稳定性、控制冷挤压加工质量和预测挤压丝锥失效机理等问题提供理论依据。2.开展了高强度钢内螺纹的冷挤压加工与工艺特性分析利用自制的挤压丝锥及其专用扭矩夹持装置对Q460高强度钢内螺纹的冷挤压工艺特性进行实验研究,探索了各工艺参数对挤压内螺纹质量的影响,采用优选工艺参数获得了理想的内螺纹,并探讨了大直径内螺纹的冷挤压工艺,为冷挤压内螺纹技术的推广应用奠定了基础。3.分析了冷挤压成形内螺纹的表面性能在微观条件下,从零件状态因素(表层残余应力、表面粗糙度、表层显微组织以及表面显微硬度与硬化层)与工作条件因素(腐蚀环境),研究了Q460高强度钢冷挤压内螺纹的性能。4.设计制作了内螺纹冷挤压过程的在线监测系统采用多传感器数据融合技术,利用自行设计的监测系统,开展了加工过程中扭矩信号、温度信号、振动信号及声发射信号进行信号分析、特征提取与选择以及模式识别等方面的研究,预测了Q460高强度钢内螺纹冷挤压加工过程中出现的一系列现象,提高了内螺纹冷挤压加工技术的可靠性。5.对内螺纹冷挤压过程进行了有限元仿真,并对仿真结果进行了实验验证利用DEFORM软件模拟了Q460高强度钢内螺纹挤压成形的过程,得出了温度场、应力场与应变场分布云图,分析了工艺参数如工件底孔直径、挤压速度、摩擦因子与挤压次数等对内螺纹挤压过程中挤压温度与挤压扭矩的影响规律,并通过实验,验证其模型的有效性,为内螺纹冷挤压工艺支持决策系统实际应用提供数据支持。6.开发了内螺纹冷挤压工艺支持决策系统建立了内螺纹冷挤压工艺模型库、知识库、应用实例库和试验库,开发了决策支持系统,实现了内螺纹冷挤压工艺相关信息集中统一管理,保持数据的实时一致性,提高信息的共享程度。更多还原

【Abstract】 As external thread processing develops to high Performance, low cost and lower energy consumption, the cold-extruding shaping technology of internal thread is an important part of anti-fatigue machining technology. It has great potential for aeronautics, astronautics and rapid trains. Aiming at the problems in cold-extruding high-strength steel internal thread, the key technique of cold-extruding high-strength steel internal thread was systematically investigated through combining theoretical analysis and testing technique. And surface properties of cold-extruding internal thread, online monitoring of the extrusion process and finite element analysis were studied deeply. The work can provide a basis for the application and dissemination of this cold-extruding internal thread. The main work is as follows:1. Establishing mechanical model of contact stress and extrusion force in the process of cold-extruding internal thread. The mechanical model of contact stress and extrusion force in the process of cold-extruding internal thread was established. The technological parameters in the extrusion processes of internal thread were determined through reasonable propositions. And the contact stress along the normal direction of the tap-teeth and the extrusion force were calculated. It is provide the theory basis for the optimization of technological parameters, machining stability, controlling quality, predicting the failure mechanism of extrusion tap, and so on.2. Analysis on cold-extruding technology characteristics of high-strength steel internal thread. The cold-extruding technology characteristics of Q460 high-strength steel internal thread were studied experimentally by using self-made extrusion tap and corresponding special torque holding device. And the effect of the technology parameters on the quality of internal thread was analyzed. The ideal internal thread was obtained through selecting processing parameters, and the cold-extruding technology of the large diameter internal thread was investigated. It provides a basis for the application and dissemination of this cold-extruding internal thread.3. Analysis on the surface properties of cold-extruding internal thread. In microscopic condition, the surface properties of cold-extruding internal thread of Q460 high-strength steel was studied from the part state such as surface residual stress, roughness, microstructure, micro-hardness and hardened-layer and from running conditions such as corrosion environment.4. Designed by online monitoring system of the extrusion process of internal thread. Based on multi-sensor data fusion technique, the torque signal, temperature signal, vibration signal and acoustic emission signal were studied on signal analysis, feature parameters extraction and selection and pattern recognition by using self-designed monitoring system. And it predicted the emergence of a range of issues in processed Q460 high-strength steel internal thread. It increased the reliability of cold-extruding internal thread.5. Simulation on the cold-extruding process of internal thread. The deformation cloud of temperature field, stress field and strain field was obtained by using DEFORM to simulate the cold-extruding process of Q460 high-strength steel internal thread. The effects of the hole-diameter of the work, extrusion speed, friction factor and extrusion times on the extrusion temperature and the extrusion torque were analyzed. And the validity of the model was verified by experiment. It provides the data support for practical application of decision-making support system of cold-extruding internal thread technology.6. Development on the decision-making support system of cold-extruding internal thread technology. The model libraries, knowledge base, application example libraries and experiment libraries were established and the decision-making support system was developed. The relevant information of the extrusion technology was centralized and unified management. It maintained real-time consistency of the data and increased information share.更多还原