【作者】 胡茂良；

【导师】 吉泽升；

【作者基本信息】 哈尔滨理工大学 ， 材料学， 2005， 硕士

【摘要】 本文采用液态模锻工艺,研究了汽车空调器摇盘模具和工艺方面的问题,根据摇盘的结构和尺寸要求,工作环境特点,对摇盘模具,包括预热温度和定量勺等试验工装进行了合理的设计,采用控制其它工艺参数不变而只让其中一个参数在一定范围内变化的方法制定了试验方案,并且对试验中工艺参数进行合理的优化选取,对试验中的操作规律和要求进行了研究。摇盘模具最佳参数为:凸模和凹模取单边间隙0.1mm,凸模脱模斜度控制在1~2°,凹模、凸模和五个顶杆,均采用3Cr2W8V 合金模具钢制造,热处理后硬度为HRC48~52,其余部分选用45 钢。摇盘模具预热系统采用Cr20Ni80 镍铬合金材料电阻丝加热,直径d 为1.5mm,节经D 选用36mm,螺距h 选用4mm,螺旋柱长度L’为0.91m,采用220V 单相接法。定量勺选用圆柱体,底面直径41mm,高51mm。液态模锻是一种优质、高效的工艺方法,在正常情况下,是能保证做出内部组织致密、表面光洁、力学性能优良的制件。但是,在实际操作中,往往仍会出现很多缺陷。缩松、缩孔和裂纹是摇盘主要缺陷,易在摇盘键槽和5 个圆台底角附近出现,浇注温度和模具预热温度高一些,加压速度快一些和保压时间长一些,可减少缩松和缩孔的产生。摇盘制件内形成的缩孔、缩松过程中大都伴随有铝合金液中气体的析出,缩孔、缩松和气孔是伴生的。摇盘凸模接触到铝合金液时,控制加压速度平稳一些,可减少气孔的产生。通过对摇盘常温力学性能测试和微观组织及断口的分析,可以看出选用4A11 铝合金在液态模锻工艺下成形,摇盘的微观组织良好,大部分制件的微观组织均匀,Si 颗粒分布均匀,无严重粗化现象。最佳工艺参数为浇注温度740℃,模具预热温度250℃,施加的压力1850kN,即比压为139.45MPa 时,摇盘的力学性能最好。在最佳工艺参数条件下,摇盘的强度σ_b≥310Mpa,维氏硬度HV0.1≥100,断后延伸率能达到5%。更多还原

【Abstract】 Based on the technology of liquid die forging, the technology of air-conditioner swaying tray of automobile and the die set is investigated. According to the structure, the size and the operation of air-conditioner swaying tray, experimental equipment including preheated temperature and quantitative scoop is designed and experimental programme is made by controlling other parameters invariant and admitting a parameter variant. At the same time, important technological parameters of experiment are optimized, and operating instructions and requires are studied. The optimized parameters of the die set of swaying tray show that single clearance between female die and male die is 0.1mm, pattern draft of male die is controlled of 1~2°, punch-die and five pins are made of 3Cr2W8V alloy steel which can reach HRC 48~52 by controlling the heat-treating and the others are made of 45 steel. Preheating system of the die set of swaying tray is heated by adopting Cr20Ni80 resistance wire, as diameter d is 1.5mm, node-pitch D is 36mm, screw-pitch h is 4mm, spiral column L’ is 0.91m, 220V single-phase contacting is adopted. Column is used in the quantitative scoop, as diameter of basal plane is 41mm and height is 51mm. Liquid state forging creates a way in advanced quality and high production. In common place, workpiece is showed that internal structure is tight, surface is luster and mechanical property is good. In practice production, a lot of defection is produced. Shrinkage property, shrinkage cavity and crack are the primary defection of swaying tray, which can appear in the keyway and near the bottom angle of the five round desk. It can decrease the shrinkage porosity and shrinkage cavity by heightening the pouring temperature and the preheated temperature, accelerating the velocity, extending the holding pressure time. Forming the shrinkage property and shrinkage cavity accompanies with precipitating the gas from the liquid of aluminium. It can decrease the production of air hole by controlling the stableness of the velocity when female die contacted the liquid of aluminium. By means of measuring room temperature mechanical properties and analyzing microstructure and fracture, it is shown that microstructure is very condense, Si grains are very fine and have no phenomena of coarsening. Mechanical properties are best by taking the optimal technical parameters of 740℃pouring temperature, 250℃preheated temperature of die set and 1850kN pressure (139.45Mpa). Taking the optimal technical parameters, the hardness of swaying tray can attain HV0.1≥100, the strength can attain σb≥310Mpa and the plasticity can reach 5%.更多还原