【作者】 廖慧敏；

【导师】 龙思远；

【作者基本信息】 重庆大学 ， 材料加工工程， 2006， 硕士

【摘要】 镁合金具有质量轻、比强度和比刚度高、阻尼减震吸噪能力强、散热性好、铸造工艺性能良好、易于切削加工及回收等一系列优点,是21世纪新型绿色金属结构材料,以铸件的形式在汽摩、手持工具、3C、手持电器等领域获得越来越广泛的应用,已部分取代了钢铁、铝合金、工程塑料等传统结构材料,用于减轻产品的重量,提高产品的设计集成度、降低车辆的油耗和排放、抑制车辆震动和噪音、提高了成品的外观质量,取得了不菲的经济效益和社会效益。但我国的镁合金压铸生产相比于工业发达国家才刚刚起步、工艺技术不成熟、缺乏生产经验积累,还很落后。为了加快我国镁合金压铸技术的熟化、为压铸生产工艺设计和品质管理提供指导,本论文叙述压铸件质量标准及检验方法,并根据铸件分类标准将镁合金压铸件缺陷进行分类。根据镁合金压铸成形原理,分析了常见压铸缺陷的特征、形成机理及产生原因,并分析了压铸合金种类、压铸工艺对压铸件产品质量的影响,提出相应的解决措施。本文以重庆镁业股份有限公司压铸生产中出现的各种工艺缺陷分析为实例,借助外观特征、内部金相、扫描电镜等检测手段以及MAGMA数值模拟仿真软件等分析方法,通过试验观察、虚拟现实模拟、理论研究结合的方式,全面阐述了压铸工艺缺陷特征和形成机制,提出通过原材料品质控制、严格合金熔炼、改进浇注系统、镁合金压铸机性能调控、优化压铸工艺参数等切实可行的工艺对策,最后在实际生产中进行验证。研究结果表明,在压铸成形理论指导和现代计算机技术的指导下,可以实现产品生产工艺地合理开发,缩短产品生产调试周期,降低生产成本和风险,提高产品质量,最终达到提高镁合金压铸企业及其产品的市场竞争能力。更多还原

【Abstract】 Mg alloys are the lightest commercial structure allpys. They possess a property spectrum desirable for structure components, such as, high specific strength, outstanding damping capability, excellent heat transferring capability, excellent casting performance under pressure, easy to machining and recycling, and so on. They were claimed as the novel green metal of the 21th century, and has been massively used as castings on road vehicles, manual tools, 3C, handset wirings and so on, and began to replace the traditional materials, such as steel, Al alloys, engineering plastic and so on. they are used to lighten the components, to improve the integration of the products, to reduce oil consumption and exhaust gas emission, to diminish the vibration and noise of vehicles, to improve the exterior quality of the products, and substantial economic and social benefits have been achieved. However, as compared with the developed countries, Chinese Mg alloys die casting industry is just at its beginning stage. The processing techniques are not mature, no enough production experience accumulated.To boost the development of Mg die casting techniques of China, and to offer directions for Mg die casting process design and quality control, the present paper devoted to describe the quality standards and quality inspection, to classify processing imperfections in Mg die casting. After an in-depth description of characteristics and forming mechanism and conditions of various die casting defects, the measurements of quality control and defects elimination were suggested.To demonstrate the methodology and exemplifies the defect characteristics and identification, the processing defects appeared in die casting practice of Chongqing Mg Science and Technology Stock Company Limited were used. Aided by different investigation techniques such as morphology characterization, non-destructive analysis, chemistry and microstructure investigation, fracture analysis, and virtue processing by MAGMA, the characteristics, formation mechanism and control of different die casting defects commonly appeared in practice were described in details. With the proposed measurements, such as raw material quality control, stringent melting and pouring, improvement in processing and mould design, optimized processing conditions, the defects can be eliminated.The present work concluded that, with the guide of modern casting theory and computation technologies, more rational processing design can be achieved and更多还原