【作者】 李强；

【导师】 罗守靖；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2006， 硕士

【摘要】 锻造由于存在塑性变形,使制件性能控制易实现,但制件形状则受到很大限制;而液态压铸,由于流变性充填,容易实现制件形状的精确控制,而对于性能控制,则难以实现。如果两者融合,扬长避短,实现双控,就可以提出一种新的成形方法,即液态铸锻双控成形。其实质就是在压铸基础上,待型腔中的液态金属还没有完全凝固时,立即施加一个变形力,打碎已经凝固的枝晶组织。铸锻双控成形工艺主要适合生产形状复杂和强度要求高的汽车零部件和其它结构件。本文介绍了液态铸锻双控成形技术的实现方法和所生产零件的性能。通过立式合模和立式压射系统与卧式合模和卧式压射系统的对比,确定采用立式机的形式,并与香港捷讯压铸机制造厂共同合作来设计和制造能够进行批量零件生产的专用成形机。双控成形模具的设计和制造。设计时将参照压铸模的设计方法,提出多种方案,并使用FLOW 3D仿真设计软件来模拟金属液的填充过程,预测可能产生缺陷的位置,从而决定浇注系统的形状和分布,冷却水道的流向和位置,分流锥的大小和位置。然后以AZ91D镁合金摩托车发动机外壳为例,进行五因素(压射速度、浇注温度、锻造时间、压射比压、锻造压力)四水平L16(45)正交实验,在普通压铸过程中关闭锻造功能。对实验结果进行分析得出:宏观上,与压铸相比,双控成形制件的冷纹、缩水、气孔和缩松等缺陷明显减少;双控成形工艺参数中锻造压力对制件的力学性能影响最大,其次为模锻延时,影响最小的为压射比压;在相同工艺参数条件下,与普通压铸相比,双控成形制件的平均抗拉强度和伸长率分别提高84.394%和101.761%;双控成形制件可进行热处理强化,具有显著的固溶时效强化特征。更多还原

【Abstract】 Because of the existence of plastic deformation, die forging can easily control performances of parts but the shape of parts would be limited greatly; however, because of rheological filling, die casting can not easily control performances but the shape of parts. If we adopt the advantages of two forming methods simultaneously, we can present a new forming method that is liquid combination process of die casting and forging. In fact in the die casting process, when the liquid metal have not solidified completely, in order to break arborescent structures which have already solidified and then proceed fine-crystal intensification, we apply a deforming force ,so the mechanical properties of parts produced by liquid combination process of die casting and forging will be improved significantly. And the parts can be heat treated in order to improve mechanical properties such as strength of extension etc. The liquid combination process is mainly applicable for car parts and other structural parts with complex shape and required high strength.The paper mainly introduces the implementation technique of liquid combination process of die casting and forging and the performances of parts which produced.Compared vertical injection system with horizontal injection system, we decide to select the former formation. We cooperate with Jiexun Machine Manufactory of Hong Kong to design and manufacture the special purpose machine which can batch production.Reference to the designation of die casting mould, we put forward some kinds of projects respect to the design and manufacture of dies of the special purpose machine. And we simulate die casting filling process、surface defect distribution and temperature field etc. of AZ91D magnesium alloy shell part with FLOW3D software. According to simulation results we decide the location of parting face and cooling system、the shape and location of runner and gating system etc.After that we take the AZ91D magnesium alloy shell of motorcycle engine as an example to proceed fine factors(plunger injection speed、pouring更多还原